Re: encoding neutral unpack
[p5sagit/p5-mst-13.2.git] / pp_pack.c
index d3fd37a..edbeb5b 100644 (file)
--- a/pp_pack.c
+++ b/pp_pack.c
@@ -1,6 +1,7 @@
 /*    pp_pack.c
  *
- *    Copyright (c) 1991-2002, Larry Wall
+ *    Copyright (C) 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
+ *    2000, 2001, 2002, 2003, 2004, 2005, by Larry Wall and others
  *
  *    You may distribute under the terms of either the GNU General Public
  *    License or the Artistic License, as specified in the README file.
  * some salt.
  */
 
+/* This file contains pp ("push/pop") functions that
+ * execute the opcodes that make up a perl program. A typical pp function
+ * expects to find its arguments on the stack, and usually pushes its
+ * results onto the stack, hence the 'pp' terminology. Each OP structure
+ * contains a pointer to the relevant pp_foo() function.
+ *
+ * This particular file just contains pp_pack() and pp_unpack(). See the
+ * other pp*.c files for the rest of the pp_ functions.
+ */
+
+
 #include "EXTERN.h"
 #define PERL_IN_PP_PACK_C
 #include "perl.h"
 
-/*
- * The compiler on Concurrent CX/UX systems has a subtle bug which only
- * seems to show up when compiling pp.c - it generates the wrong double
- * precision constant value for (double)UV_MAX when used inline in the body
- * of the code below, so this makes a static variable up front (which the
- * compiler seems to get correct) and uses it in place of UV_MAX below.
- */
-#ifdef CXUX_BROKEN_CONSTANT_CONVERT
-static double UV_MAX_cxux = ((double)UV_MAX);
+#if PERL_VERSION >= 9
+#define PERL_PACK_CAN_BYTEORDER
+#define PERL_PACK_CAN_SHRIEKSIGN
 #endif
 
 /*
@@ -54,34 +60,52 @@ static double UV_MAX_cxux = ((double)UV_MAX);
 /* CROSSCOMPILE and MULTIARCH are going to affect pp_pack() and pp_unpack().
    --jhi Feb 1999 */
 
-#if SHORTSIZE != SIZE16 || LONGSIZE != SIZE32
-#   define PERL_NATINT_PACK
-#endif
-
-#if LONGSIZE > 4 && defined(_CRAY)
-#  if BYTEORDER == 0x12345678
-#    define OFF16(p)   (char*)(p)
-#    define OFF32(p)   (char*)(p)
+#if U16SIZE > SIZE16 || U32SIZE > SIZE32
+#  if BYTEORDER == 0x1234 || BYTEORDER == 0x12345678    /* little-endian */
+#    define OFF16(p)   ((char*)(p))
+#    define OFF32(p)   ((char*)(p))
 #  else
-#    if BYTEORDER == 0x87654321
+#    if BYTEORDER == 0x4321 || BYTEORDER == 0x87654321  /* big-endian */
 #      define OFF16(p) ((char*)(p) + (sizeof(U16) - SIZE16))
 #      define OFF32(p) ((char*)(p) + (sizeof(U32) - SIZE32))
 #    else
-       }}}} bad cray byte order
+       ++++ bad cray byte order
 #    endif
 #  endif
-#  define COPY16(s,p)  (*(p) = 0, Copy(s, OFF16(p), SIZE16, char))
-#  define COPY32(s,p)  (*(p) = 0, Copy(s, OFF32(p), SIZE32, char))
-#  define COPYNN(s,p,n) (*(p) = 0, Copy(s, (char *)(p), n, char))
-#  define CAT16(sv,p)  sv_catpvn(sv, OFF16(p), SIZE16)
-#  define CAT32(sv,p)  sv_catpvn(sv, OFF32(p), SIZE32)
 #else
-#  define COPY16(s,p)  Copy(s, p, SIZE16, char)
-#  define COPY32(s,p)  Copy(s, p, SIZE32, char)
-#  define COPYNN(s,p,n) Copy(s, (char *)(p), n, char)
-#  define CAT16(sv,p)  sv_catpvn(sv, (char*)(p), SIZE16)
-#  define CAT32(sv,p)  sv_catpvn(sv, (char*)(p), SIZE32)
-#endif
+#  define OFF16(p)     ((char *) (p))
+#  define OFF32(p)     ((char *) (p))
+#endif
+
+#define COPY16(s,p)  Copy(s, OFF16(p), SIZE16, char)
+#define COPY32(s,p)  Copy(s, OFF32(p), SIZE32, char)
+#define CAT16(sv,p)  sv_catpvn(sv, OFF16(p), SIZE16)
+#define CAT32(sv,p)  sv_catpvn(sv, OFF32(p), SIZE32)
+
+/* Only to be used inside a loop (see the break) */
+#define COPYVAR(s,strend,utf8,var,format)              \
+STMT_START {                                           \
+    if (utf8) {                                                \
+        if (!next_uni_bytes(aTHX_ &s, strend,          \
+            (char *) &var, sizeof(var))) break;                \
+    } else {                                           \
+        Copy(s, (char *) &var, sizeof(var), char);     \
+        s += sizeof(var);                              \
+    }                                                  \
+    DO_BO_UNPACK(var, format);                         \
+} STMT_END
+
+/* Avoid stack overflow due to pathological templates. 100 should be plenty. */
+#define MAX_SUB_TEMPLATE_LEVEL 100
+
+/* flags (note that type modifiers can also be used as flags!) */
+#define FLAG_UNPACK_WAS_UTF8    0x40   /* original had FLAG_UNPACK_DO_UTF8 */
+#define FLAG_UNPACK_PARSE_UTF8  0x20   /* Parse as utf8 */
+#define FLAG_UNPACK_ONLY_ONE  0x10
+#define FLAG_UNPACK_DO_UTF8     0x08   /* The underlying string is utf8 */
+#define FLAG_SLASH            0x04
+#define FLAG_COMMA            0x02
+#define FLAG_PACK             0x01
 
 STATIC SV *
 S_mul128(pTHX_ SV *sv, U8 m)
@@ -123,388 +147,959 @@ S_mul128(pTHX_ SV *sv, U8 m)
 #define ISUUCHAR(ch)    (memchr(PL_uuemap, (ch), sizeof(PL_uuemap)-1) || (ch) == ' ')
 #endif
 
-#define UNPACK_ONLY_ONE        0x1
-#define UNPACK_DO_UTF8 0x2
+/* type modifiers */
+#define TYPE_IS_SHRIEKING      0x100
+#define TYPE_IS_BIG_ENDIAN     0x200
+#define TYPE_IS_LITTLE_ENDIAN  0x400
+#define TYPE_ENDIANNESS_MASK   (TYPE_IS_BIG_ENDIAN|TYPE_IS_LITTLE_ENDIAN)
+#define TYPE_MODIFIERS(t)      ((t) & ~0xFF)
+#define TYPE_NO_MODIFIERS(t)   ((t) & 0xFF)
+
+#ifdef PERL_PACK_CAN_SHRIEKSIGN
+#define SHRIEKING_ALLOWED_TYPES "sSiIlLxXnNvV"
+#else
+#define SHRIEKING_ALLOWED_TYPES "sSiIlLxX"
+#endif
 
-STATIC char *
-S_group_end(pTHX_ register char *pat, register char *patend, char ender)
-{
-    while (pat < patend) {
-       char c = *pat++;
+#ifndef PERL_PACK_CAN_BYTEORDER
+/* Put "can't" first because it is shorter  */
+# define TYPE_ENDIANNESS(t)    0
+# define TYPE_NO_ENDIANNESS(t) (t)
 
-       if (isSPACE(c))
-           continue;
-       else if (c == ender)
-           return --pat;
-       else if (c == '#') {
-           while (pat < patend && *pat != '\n')
-               pat++;
-           continue;
-       } else if (c == '(')
-           pat = group_end(pat, patend, ')') + 1;
-       else if (c == '[')
-           pat = group_end(pat, patend, ']') + 1;
-    }
-    Perl_croak(aTHX_ "No group ending character `%c' found", ender);
-    return 0;
-}
+# define ENDIANNESS_ALLOWED_TYPES   ""
 
-#define TYPE_IS_SHRIEKING      0x100
+# define DO_BO_UNPACK(var, type)
+# define DO_BO_PACK(var, type)
+# define DO_BO_UNPACK_PTR(var, type, pre_cast)
+# define DO_BO_PACK_PTR(var, type, pre_cast)
+# define DO_BO_UNPACK_N(var, type)
+# define DO_BO_PACK_N(var, type)
+# define DO_BO_UNPACK_P(var)
+# define DO_BO_PACK_P(var)
 
-/* Returns the sizeof() struct described by pat */
-STATIC I32
-S_measure_struct(pTHX_ char *pat, register char *patend)
-{
-    I32 datumtype;
-    register I32 len;
-    register I32 total = 0;
-    int commas = 0;
-    int star;          /* 1 if count is *, -1 if no count given, -2 for / */
-#ifdef PERL_NATINT_PACK
-    int natint;                /* native integer */
-    int unatint;       /* unsigned native integer */
-#endif
-    char buf[2];
-    register int size;
+#else
 
-    while ((pat = next_symbol(pat, patend)) < patend) {
-       datumtype = *pat++ & 0xFF;
-#ifdef PERL_NATINT_PACK
-       natint = 0;
+# define TYPE_ENDIANNESS(t)    ((t) & TYPE_ENDIANNESS_MASK)
+# define TYPE_NO_ENDIANNESS(t) ((t) & ~TYPE_ENDIANNESS_MASK)
+
+# define ENDIANNESS_ALLOWED_TYPES   "sSiIlLqQjJfFdDpP("
+
+# define DO_BO_UNPACK(var, type)                                              \
+        STMT_START {                                                          \
+          switch (TYPE_ENDIANNESS(datumtype)) {                               \
+            case TYPE_IS_BIG_ENDIAN:    var = my_betoh ## type (var); break;  \
+            case TYPE_IS_LITTLE_ENDIAN: var = my_letoh ## type (var); break;  \
+            default: break;                                                   \
+          }                                                                   \
+        } STMT_END
+
+# define DO_BO_PACK(var, type)                                                \
+        STMT_START {                                                          \
+          switch (TYPE_ENDIANNESS(datumtype)) {                               \
+            case TYPE_IS_BIG_ENDIAN:    var = my_htobe ## type (var); break;  \
+            case TYPE_IS_LITTLE_ENDIAN: var = my_htole ## type (var); break;  \
+            default: break;                                                   \
+          }                                                                   \
+        } STMT_END
+
+# define DO_BO_UNPACK_PTR(var, type, pre_cast)                                \
+        STMT_START {                                                          \
+          switch (TYPE_ENDIANNESS(datumtype)) {                               \
+            case TYPE_IS_BIG_ENDIAN:                                          \
+              var = (void *) my_betoh ## type ((pre_cast) var);               \
+              break;                                                          \
+            case TYPE_IS_LITTLE_ENDIAN:                                       \
+              var = (void *) my_letoh ## type ((pre_cast) var);               \
+              break;                                                          \
+            default:                                                          \
+              break;                                                          \
+          }                                                                   \
+        } STMT_END
+
+# define DO_BO_PACK_PTR(var, type, pre_cast)                                  \
+        STMT_START {                                                          \
+          switch (TYPE_ENDIANNESS(datumtype)) {                               \
+            case TYPE_IS_BIG_ENDIAN:                                          \
+              var = (void *) my_htobe ## type ((pre_cast) var);               \
+              break;                                                          \
+            case TYPE_IS_LITTLE_ENDIAN:                                       \
+              var = (void *) my_htole ## type ((pre_cast) var);               \
+              break;                                                          \
+            default:                                                          \
+              break;                                                          \
+          }                                                                   \
+        } STMT_END
+
+# define BO_CANT_DOIT(action, type)                                           \
+        STMT_START {                                                          \
+          switch (TYPE_ENDIANNESS(datumtype)) {                               \
+             case TYPE_IS_BIG_ENDIAN:                                         \
+               Perl_croak(aTHX_ "Can't %s big-endian %ss on this "            \
+                                "platform", #action, #type);                  \
+               break;                                                         \
+             case TYPE_IS_LITTLE_ENDIAN:                                      \
+               Perl_croak(aTHX_ "Can't %s little-endian %ss on this "         \
+                                "platform", #action, #type);                  \
+               break;                                                         \
+             default:                                                         \
+               break;                                                         \
+           }                                                                  \
+         } STMT_END
+
+# if PTRSIZE == INTSIZE
+#  define DO_BO_UNPACK_P(var)  DO_BO_UNPACK_PTR(var, i, int)
+#  define DO_BO_PACK_P(var)    DO_BO_PACK_PTR(var, i, int)
+# elif PTRSIZE == LONGSIZE
+#  define DO_BO_UNPACK_P(var)  DO_BO_UNPACK_PTR(var, l, long)
+#  define DO_BO_PACK_P(var)    DO_BO_PACK_PTR(var, l, long)
+# else
+#  define DO_BO_UNPACK_P(var)  BO_CANT_DOIT(unpack, pointer)
+#  define DO_BO_PACK_P(var)    BO_CANT_DOIT(pack, pointer)
+# endif
+
+# if defined(my_htolen) && defined(my_letohn) && \
+    defined(my_htoben) && defined(my_betohn)
+#  define DO_BO_UNPACK_N(var, type)                                           \
+         STMT_START {                                                         \
+           switch (TYPE_ENDIANNESS(datumtype)) {                              \
+             case TYPE_IS_BIG_ENDIAN:    my_betohn(&var, sizeof(type)); break;\
+             case TYPE_IS_LITTLE_ENDIAN: my_letohn(&var, sizeof(type)); break;\
+             default: break;                                                  \
+           }                                                                  \
+         } STMT_END
+
+#  define DO_BO_PACK_N(var, type)                                             \
+         STMT_START {                                                         \
+           switch (TYPE_ENDIANNESS(datumtype)) {                              \
+             case TYPE_IS_BIG_ENDIAN:    my_htoben(&var, sizeof(type)); break;\
+             case TYPE_IS_LITTLE_ENDIAN: my_htolen(&var, sizeof(type)); break;\
+             default: break;                                                  \
+           }                                                                  \
+         } STMT_END
+# else
+#  define DO_BO_UNPACK_N(var, type)    BO_CANT_DOIT(unpack, type)
+#  define DO_BO_PACK_N(var, type)      BO_CANT_DOIT(pack, type)
+# endif
+
+#endif
+
+#define PACK_SIZE_CANNOT_CSUM          0x80
+#define PACK_SIZE_SPARE                        0x40
+#define PACK_SIZE_MASK                 0x3F
+
+
+struct packsize_t {
+    const unsigned char *array;
+    int first;
+    int size;
+};
+
+#define PACK_SIZE_NORMAL 0
+#define PACK_SIZE_SHRIEKING 1
+
+/* These tables are regenerated by genpacksizetables.pl (and then hand pasted
+   in).  You're unlikely ever to need to regenerate them.  */
+#if 'J'-'I' == 1
+/* ASCII */
+unsigned char size_normal[53] = {
+  /* C */ sizeof(unsigned char),
+#if defined(HAS_LONG_DOUBLE) && defined(USE_LONG_DOUBLE)
+  /* D */ LONG_DOUBLESIZE,
+#else
+  0,
+#endif
+  0,
+  /* F */ NVSIZE,
+  0, 0,
+  /* I */ sizeof(unsigned int),
+  /* J */ UVSIZE,
+  0,
+  /* L */ SIZE32,
+  0,
+  /* N */ SIZE32,
+  0, 0,
+#if defined(HAS_QUAD)
+  /* Q */ sizeof(Uquad_t),
+#else
+  0,
+#endif
+  0,
+  /* S */ SIZE16,
+  0,
+  /* U */ sizeof(char),
+  /* V */ SIZE32,
+  /* W */ sizeof(unsigned char),
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+  /* c */ sizeof(char),
+  /* d */ sizeof(double),
+  0,
+  /* f */ sizeof(float),
+  0, 0,
+  /* i */ sizeof(int),
+  /* j */ IVSIZE,
+  0,
+  /* l */ SIZE32,
+  0,
+  /* n */ SIZE16,
+  0,
+  /* p */ sizeof(char *) | PACK_SIZE_CANNOT_CSUM,
+#if defined(HAS_QUAD)
+  /* q */ sizeof(Quad_t),
+#else
+  0,
+#endif
+  0,
+  /* s */ SIZE16,
+  0, 0,
+  /* v */ SIZE16,
+  /* w */ sizeof(char) | PACK_SIZE_CANNOT_CSUM,
+};
+unsigned char size_shrieking[46] = {
+  /* I */ sizeof(unsigned int),
+  0, 0,
+  /* L */ sizeof(unsigned long),
+  0,
+#if defined(PERL_PACK_CAN_SHRIEKSIGN)
+  /* N */ SIZE32,
+#else
+  0,
 #endif
-       if (*pat == '!') {
-           static const char *natstr = "sSiIlLxX";
-
-           if (strchr(natstr, datumtype)) {
-               if (datumtype == 'x' || datumtype == 'X') {
-                   datumtype |= TYPE_IS_SHRIEKING;
-               } else {                /* XXXX Should be redone similarly! */
-#ifdef PERL_NATINT_PACK
-                   natint = 1;
+  0, 0, 0, 0,
+  /* S */ sizeof(unsigned short),
+  0, 0,
+#if defined(PERL_PACK_CAN_SHRIEKSIGN)
+  /* V */ SIZE32,
+#else
+  0,
+#endif
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+  /* i */ sizeof(int),
+  0, 0,
+  /* l */ sizeof(long),
+  0,
+#if defined(PERL_PACK_CAN_SHRIEKSIGN)
+  /* n */ SIZE16,
+#else
+  0,
 #endif
-               }
-               pat++;
-           }
-           else
-               Perl_croak(aTHX_ "'!' allowed only after types %s", natstr);
-       }
-       len = find_count(&pat, patend, &star);
-       if (star > 0)                   /*  */
-               Perl_croak(aTHX_ "%s not allowed in length fields", "count *");
-       else if (star < 0)              /* No explicit len */
-               len = datumtype != '@';
-
-       switch(datumtype) {
-       default:
-           Perl_croak(aTHX_ "Invalid type in unpack: '%c'", (int)datumtype);
-       case '@':
-       case '/':
-       case 'U':                       /* XXXX Is it correct? */
-       case 'w':
-       case 'u':
-           buf[0] = (char)datumtype;
-           buf[1] = 0;
-           Perl_croak(aTHX_ "%s not allowed in length fields", buf);
-       case ',': /* grandfather in commas but with a warning */
-           if (commas++ == 0 && ckWARN(WARN_UNPACK))
-               Perl_warner(aTHX_ packWARN(WARN_UNPACK),
-                           "Invalid type in unpack: '%c'", (int)datumtype);
-           /* FALL THROUGH */
-       case '%':
-           size = 0;
-           break;
-       case '(':
-       {
-           char *beg = pat, *end;
-
-           if (star >= 0)
-               Perl_croak(aTHX_ "()-group starts with a count");
-           end = group_end(beg, patend, ')');
-           pat = end + 1;
-           len = find_count(&pat, patend, &star);
-           if (star < 0)               /* No count */
-               len = 1;
-           else if (star > 0)  /* Star */
-               Perl_croak(aTHX_ "%s not allowed in length fields", "count *");
-           /* XXXX Theoretically, we need to measure many times at different
-              positions, since the subexpression may contain
-              alignment commands, but be not of aligned length.
-              Need to detect this and croak().  */
-           size = measure_struct(beg, end);
-           break;
-       }
-       case 'X' | TYPE_IS_SHRIEKING:
-           /* XXXX Is this useful?  Then need to treat MEASURE_BACKWARDS. */
-           if (!len)                   /* Avoid division by 0 */
-               len = 1;
-           len = total % len;          /* Assumed: the start is aligned. */
-           /* FALL THROUGH */
-       case 'X':
-           size = -1;
-           if (total < len)
-               Perl_croak(aTHX_ "X outside of string");
-           break;
-       case 'x' | TYPE_IS_SHRIEKING:
-           if (!len)                   /* Avoid division by 0 */
-               len = 1;
-           star = total % len;         /* Assumed: the start is aligned. */
-           if (star)                   /* Other portable ways? */
-               len = len - star;
-           else
-               len = 0;
-           /* FALL THROUGH */
-       case 'x':
-       case 'A':
-       case 'Z':
-       case 'a':
-       case 'c':
-       case 'C':
-           size = 1;
-           break;
-       case 'B':
-       case 'b':
-           len = (len + 7)/8;
-           size = 1;
-           break;
-       case 'H':
-       case 'h':
-           len = (len + 1)/2;
-           size = 1;
-           break;
-       case 's':
-#if SHORTSIZE == SIZE16
-           size = SIZE16;
+  0, 0, 0, 0,
+  /* s */ sizeof(short),
+  0, 0,
+#if defined(PERL_PACK_CAN_SHRIEKSIGN)
+  /* v */ SIZE16
 #else
-           size = (natint ? sizeof(short) : SIZE16);
+  0
 #endif
-           break;
-       case 'v':
-       case 'n':
-       case 'S':
-#if SHORTSIZE == SIZE16
-           size = SIZE16;
+};
+struct packsize_t packsize[2] = {
+  {size_normal, 67, 53},
+  {size_shrieking, 73, 46}
+};
+#else
+/* EBCDIC (or bust) */
+unsigned char size_normal[100] = {
+  /* c */ sizeof(char),
+  /* d */ sizeof(double),
+  0,
+  /* f */ sizeof(float),
+  0, 0,
+  /* i */ sizeof(int),
+  0, 0, 0, 0, 0, 0, 0,
+  /* j */ IVSIZE,
+  0,
+  /* l */ SIZE32,
+  0,
+  /* n */ SIZE16,
+  0,
+  /* p */ sizeof(char *) | PACK_SIZE_CANNOT_CSUM,
+#if defined(HAS_QUAD)
+  /* q */ sizeof(Quad_t),
+#else
+  0,
+#endif
+  0, 0, 0, 0, 0, 0, 0, 0, 0,
+  /* s */ SIZE16,
+  0, 0,
+  /* v */ SIZE16,
+  /* w */ sizeof(char) | PACK_SIZE_CANNOT_CSUM,
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0,
+  /* C */ sizeof(unsigned char),
+#if defined(HAS_LONG_DOUBLE) && defined(USE_LONG_DOUBLE)
+  /* D */ LONG_DOUBLESIZE,
+#else
+  0,
+#endif
+  0,
+  /* F */ NVSIZE,
+  0, 0,
+  /* I */ sizeof(unsigned int),
+  0, 0, 0, 0, 0, 0, 0,
+  /* J */ UVSIZE,
+  0,
+  /* L */ SIZE32,
+  0,
+  /* N */ SIZE32,
+  0, 0,
+#if defined(HAS_QUAD)
+  /* Q */ sizeof(Uquad_t),
 #else
-           unatint = natint && datumtype == 'S';
-           size = (unatint ? sizeof(unsigned short) : SIZE16);
+  0,
+#endif
+  0, 0, 0, 0, 0, 0, 0, 0, 0,
+  /* S */ SIZE16,
+  0,
+  /* U */ sizeof(char),
+  /* V */ SIZE32,
+  /* W */ sizeof(unsigned char),
+};
+unsigned char size_shrieking[93] = {
+  /* i */ sizeof(int),
+  0, 0, 0, 0, 0, 0, 0, 0, 0,
+  /* l */ sizeof(long),
+  0,
+#if defined(PERL_PACK_CAN_SHRIEKSIGN)
+  /* n */ SIZE16,
+#else
+  0,
 #endif
-           break;
-       case 'i':
-           size = sizeof(int);
-           break;
-       case 'I':
-           size = sizeof(unsigned int);
-           break;
-       case 'j':
-           size = IVSIZE;
-           break;
-       case 'J':
-           size = UVSIZE;
-           break;
-       case 'l':
-#if LONGSIZE == SIZE32
-           size = SIZE32;
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+  /* s */ sizeof(short),
+  0, 0,
+#if defined(PERL_PACK_CAN_SHRIEKSIGN)
+  /* v */ SIZE16,
+#else
+  0,
+#endif
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+  0, 0, 0, 0, 0, 0, 0, 0, 0,
+  /* I */ sizeof(unsigned int),
+  0, 0, 0, 0, 0, 0, 0, 0, 0,
+  /* L */ sizeof(unsigned long),
+  0,
+#if defined(PERL_PACK_CAN_SHRIEKSIGN)
+  /* N */ SIZE32,
 #else
-           size = (natint ? sizeof(long) : SIZE32);
+  0,
 #endif
-           break;
-       case 'V':
-       case 'N':
-       case 'L':
-#if LONGSIZE == SIZE32
-           size = SIZE32;
+  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+  /* S */ sizeof(unsigned short),
+  0, 0,
+#if defined(PERL_PACK_CAN_SHRIEKSIGN)
+  /* V */ SIZE32
 #else
-           unatint = natint && datumtype == 'L';
-           size = (unatint ? sizeof(unsigned long) : SIZE32);
+  0
 #endif
-           break;
-       case 'P':
-           len = 1;
-           /* FALL THROUGH */
-       case 'p':
-           size = sizeof(char*);
-           break;
-#ifdef HAS_QUAD
-       case 'q':
-           size = sizeof(Quad_t);
-           break;
-       case 'Q':
-           size = sizeof(Uquad_t);
-           break;
+};
+struct packsize_t packsize[2] = {
+  {size_normal, 131, 100},
+  {size_shrieking, 137, 93}
+};
 #endif
-       case 'f':
-           size = sizeof(float);
-           break;
-       case 'd':
-           size = sizeof(double);
-           break;
-       case 'F':
-           size = NVSIZE;
-           break;
-#if defined(HAS_LONG_DOUBLE) && defined(USE_LONG_DOUBLE)
-       case 'D':
-           size = LONG_DOUBLESIZE;
+
+STATIC U8
+next_uni_byte(pTHX_ char **s, const char *end, I32 datumtype)
+{
+    UV val;
+    STRLEN retlen;
+    val =
+       UNI_TO_NATIVE(utf8n_to_uvuni(*s, end-*s, &retlen,
+                                    ckWARN(WARN_UTF8) ? 0 : UTF8_ALLOW_ANY));
+    /* We try to process malformed UTF-8 as much as possible (preferrably with
+       warnings), but these two mean we make no progress in the string and
+       might enter an infinite loop */
+    if (retlen == (STRLEN) -1 || retlen == 0)
+       Perl_croak(aTHX_ "Malformed UTF-8 string in unpack");
+    if (val >= 0x100) {
+       Perl_warner(aTHX_ packWARN(WARN_UNPACK),
+                   "Character in '%c' format wrapped in unpack",
+                   (int) datumtype);
+       val &= 0xff;
+    }
+    *s += retlen;
+    return val;
+}
+
+#define NEXT_BYTE(utf8, s, strend, datumtype) ((utf8) ? \
+       next_uni_byte(aTHX_ &(s), (strend), (datumtype)) : \
+       *(U8 *)(s)++)
+
+STATIC bool
+next_uni_bytes(pTHX_ char **s, char *end, char *buf, int buf_len)
+{
+    UV val;
+    STRLEN retlen;
+    char *from = *s;
+    int bad = 0;
+    U32 flags = ckWARN(WARN_UTF8) ?
+       UTF8_CHECK_ONLY : (UTF8_CHECK_ONLY | UTF8_ALLOW_ANY);
+    for (;buf_len > 0; buf_len--) {
+       if (from >= end) return FALSE;
+       val = UNI_TO_NATIVE(utf8n_to_uvuni(from, end-from, &retlen, flags));
+       if (retlen == (STRLEN) -1 || retlen == 0) {
+           from += UTF8SKIP(from);
+           bad |= 1;
+       } else from += retlen;
+       if (val >= 0x100) {
+           bad |= 2;
+           val &= 0xff;
+       }
+       *(U8 *)buf++ = val;
+    }
+    /* We have enough characters for the buffer. Did we have problems ? */
+    if (bad) {
+       if (bad & 1) {
+           /* Rewalk the string fragment while warning */
+           char *ptr;
+           flags = ckWARN(WARN_UTF8) ? 0 : UTF8_ALLOW_ANY;
+           for (ptr = *s; ptr < from; ptr += UTF8SKIP(ptr)) {
+               if (ptr >= end) break;
+               utf8n_to_uvuni(ptr, end-ptr, &retlen, flags);
+           }
+           if (from > end) from = end;
+       }
+       if ((bad & 2) && ckWARN(WARN_UNPACK))
+           Perl_warner(aTHX_ packWARN(WARN_UNPACK),
+                       "Character(s) wrapped in unpack");
+    }
+    *s = from;
+    return TRUE;
+}
+
+STATIC bool
+next_uni_uu(pTHX_ char **s, const char *end, I32 *out)
+{
+    UV val;
+    STRLEN retlen;
+    char *from = *s;
+    val = UNI_TO_NATIVE(utf8n_to_uvuni(*s, end-*s, &retlen, UTF8_CHECK_ONLY));
+    if (val >= 0x100 || !ISUUCHAR(val) ||
+       retlen == (STRLEN) -1 || retlen == 0) {
+       *out = 0;
+       return FALSE;
+    }
+    *out = PL_uudmap[val] & 077;
+    *s = from;
+    return TRUE;
+}
+
+/* Returns the sizeof() struct described by pat */
+STATIC I32
+S_measure_struct(pTHX_ register tempsym_t* symptr)
+{
+    register I32 len = 0;
+    register I32 total = 0;
+    int star;
+
+    register int size;
+
+    while (next_symbol(symptr)) {
+       int which = (symptr->code & TYPE_IS_SHRIEKING)
+           ? PACK_SIZE_SHRIEKING : PACK_SIZE_NORMAL;
+       int offset
+           = TYPE_NO_MODIFIERS(symptr->code) - packsize[which].first;
+
+        switch( symptr->howlen ){
+        case e_no_len:
+       case e_number:
+           len = symptr->length;
            break;
-#endif
+        case e_star:
+           Perl_croak(aTHX_ "Within []-length '*' not allowed in %s",
+                       symptr->flags & FLAG_PACK ? "pack" : "unpack" );
+            break;
+        }
+
+       if ((offset >= 0) && (offset < packsize[which].size))
+           size = packsize[which].array[offset] & PACK_SIZE_MASK;
+       else
+           size = 0;
+
+       if (!size) {
+           /* endianness doesn't influence the size of a type */
+           switch(TYPE_NO_ENDIANNESS(symptr->code)) {
+           default:
+               Perl_croak(aTHX_ "Invalid type '%c' in %s",
+                          (int)TYPE_NO_MODIFIERS(symptr->code),
+                          symptr->flags & FLAG_PACK ? "pack" : "unpack" );
+           case '@':
+           case '/':
+           case 'U':                   /* XXXX Is it correct? */
+           case 'w':
+           case 'u':
+               Perl_croak(aTHX_ "Within []-length '%c' not allowed in %s",
+                          (int)symptr->code,
+                          symptr->flags & FLAG_PACK ? "pack" : "unpack" );
+           case '%':
+               size = 0;
+               break;
+           case '(':
+               {
+                   tempsym_t savsym = *symptr;
+                   symptr->patptr = savsym.grpbeg;
+                   symptr->patend = savsym.grpend;
+                   /* XXXX Theoretically, we need to measure many times at
+                      different positions, since the subexpression may contain
+                      alignment commands, but be not of aligned length.
+                      Need to detect this and croak().  */
+                   size = measure_struct(symptr);
+                   *symptr = savsym;
+                   break;
+               }
+           case 'X' | TYPE_IS_SHRIEKING:
+               /* XXXX Is this useful?  Then need to treat MEASURE_BACKWARDS.
+                */
+               if (!len)               /* Avoid division by 0 */
+                   len = 1;
+               len = total % len;      /* Assumed: the start is aligned. */
+               /* FALL THROUGH */
+           case 'X':
+               size = -1;
+               if (total < len)
+                   Perl_croak(aTHX_ "'X' outside of string in %s",
+                              symptr->flags & FLAG_PACK ? "pack" : "unpack" );
+               break;
+           case 'x' | TYPE_IS_SHRIEKING:
+               if (!len)               /* Avoid division by 0 */
+                   len = 1;
+               star = total % len;     /* Assumed: the start is aligned. */
+               if (star)               /* Other portable ways? */
+                   len = len - star;
+               else
+                   len = 0;
+               /* FALL THROUGH */
+           case 'x':
+           case 'A':
+           case 'Z':
+           case 'a':
+               size = 1;
+               break;
+           case 'B':
+           case 'b':
+               len = (len + 7)/8;
+               size = 1;
+               break;
+           case 'H':
+           case 'h':
+               len = (len + 1)/2;
+               size = 1;
+               break;
+
+           case 'P':
+               len = 1;
+               size = sizeof(char*);
+               break;
+           }
        }
        total += len * size;
     }
     return total;
 }
 
-/* Returns -1 on no count or on star */
-STATIC I32
-S_find_count(pTHX_ char **ppat, register char *patend, int *star)
+
+/* locate matching closing parenthesis or bracket
+ * returns char pointer to char after match, or NULL
+ */
+STATIC char *
+S_group_end(pTHX_ register char *patptr, register char *patend, char ender)
 {
-    char *pat = *ppat;
-    I32 len;
+    while (patptr < patend) {
+       char c = *patptr++;
 
-    *star = 0;
-    if (pat >= patend)
-       len = 1;
-    else if (*pat == '*') {
-       pat++;
-       *star = 1;
-       len = -1;
+       if (isSPACE(c))
+           continue;
+       else if (c == ender)
+           return patptr-1;
+       else if (c == '#') {
+           while (patptr < patend && *patptr != '\n')
+               patptr++;
+           continue;
+       } else if (c == '(')
+           patptr = group_end(patptr, patend, ')') + 1;
+       else if (c == '[')
+           patptr = group_end(patptr, patend, ']') + 1;
     }
-    else if (isDIGIT(*pat)) {
-       len = *pat++ - '0';
-       while (isDIGIT(*pat)) {
-           len = (len * 10) + (*pat++ - '0');
-           if (len < 0)                /* 50% chance of catching... */
-               Perl_croak(aTHX_ "Repeat count in pack/unpack overflows");
+    Perl_croak(aTHX_ "No group ending character '%c' found in template",
+               ender);
+    return 0;
+}
+
+
+/* Convert unsigned decimal number to binary.
+ * Expects a pointer to the first digit and address of length variable
+ * Advances char pointer to 1st non-digit char and returns number
+ */ 
+STATIC char *
+S_get_num(pTHX_ register char *patptr, I32 *lenptr )
+{
+  I32 len = *patptr++ - '0';
+  while (isDIGIT(*patptr)) {
+    if (len >= 0x7FFFFFFF/10)
+      Perl_croak(aTHX_ "pack/unpack repeat count overflow");
+    len = (len * 10) + (*patptr++ - '0');
+  }
+  *lenptr = len;
+  return patptr;
+}
+
+/* The marvellous template parsing routine: Using state stored in *symptr,
+ * locates next template code and count
+ */
+STATIC bool
+S_next_symbol(pTHX_ register tempsym_t* symptr )
+{
+  register char* patptr = symptr->patptr; 
+  register char* patend = symptr->patend; 
+
+  symptr->flags &= ~FLAG_SLASH;
+
+  while (patptr < patend) {
+    if (isSPACE(*patptr))
+      patptr++;
+    else if (*patptr == '#') {
+      patptr++;
+      while (patptr < patend && *patptr != '\n')
+       patptr++;
+      if (patptr < patend)
+       patptr++;
+    } else {
+      /* We should have found a template code */ 
+      I32 code = *patptr++ & 0xFF;
+      U32 inherited_modifiers = 0;
+
+      if (code == ','){ /* grandfather in commas but with a warning */
+       if (((symptr->flags & FLAG_COMMA) == 0) && ckWARN(WARN_UNPACK)){
+          symptr->flags |= FLAG_COMMA;
+         Perl_warner(aTHX_ packWARN(WARN_UNPACK),
+                     "Invalid type ',' in %s",
+                      symptr->flags & FLAG_PACK ? "pack" : "unpack" );
+        }
+       continue;
+      }
+      
+      /* for '(', skip to ')' */
+      if (code == '(') {  
+        if( isDIGIT(*patptr) || *patptr == '*' || *patptr == '[' )
+          Perl_croak(aTHX_ "()-group starts with a count in %s",
+                     symptr->flags & FLAG_PACK ? "pack" : "unpack" );
+        symptr->grpbeg = patptr;
+        patptr = 1 + ( symptr->grpend = group_end(patptr, patend, ')') );
+        if( symptr->level >= MAX_SUB_TEMPLATE_LEVEL )
+         Perl_croak(aTHX_ "Too deeply nested ()-groups in %s",
+                     symptr->flags & FLAG_PACK ? "pack" : "unpack" );
+      }
+
+      /* look for group modifiers to inherit */
+      if (TYPE_ENDIANNESS(symptr->flags)) {
+        if (strchr(ENDIANNESS_ALLOWED_TYPES, TYPE_NO_MODIFIERS(code)))
+          inherited_modifiers |= TYPE_ENDIANNESS(symptr->flags);
+      }
+
+      /* look for modifiers */
+      while (patptr < patend) {
+        const char *allowed;
+        I32 modifier = 0;
+        switch (*patptr) {
+          case '!':
+            modifier = TYPE_IS_SHRIEKING;
+            allowed = SHRIEKING_ALLOWED_TYPES;
+            break;
+#ifdef PERL_PACK_CAN_BYTEORDER
+          case '>':
+            modifier = TYPE_IS_BIG_ENDIAN;
+            allowed = ENDIANNESS_ALLOWED_TYPES;
+            break;
+          case '<':
+            modifier = TYPE_IS_LITTLE_ENDIAN;
+            allowed = ENDIANNESS_ALLOWED_TYPES;
+            break;
+#endif
+          default:
+            break;
+        }
+
+        if (modifier == 0)
+          break;
+
+        if (!strchr(allowed, TYPE_NO_MODIFIERS(code)))
+          Perl_croak(aTHX_ "'%c' allowed only after types %s in %s", *patptr,
+                     allowed, symptr->flags & FLAG_PACK ? "pack" : "unpack" );
+
+        if (TYPE_ENDIANNESS(code | modifier) == TYPE_ENDIANNESS_MASK)
+          Perl_croak(aTHX_ "Can't use both '<' and '>' after type '%c' in %s",
+                     (int) TYPE_NO_MODIFIERS(code),
+                     symptr->flags & FLAG_PACK ? "pack" : "unpack" );
+        else if (TYPE_ENDIANNESS(code | modifier | inherited_modifiers) ==
+                 TYPE_ENDIANNESS_MASK)
+          Perl_croak(aTHX_ "Can't use '%c' in a group with different byte-order in %s",
+                     *patptr, symptr->flags & FLAG_PACK ? "pack" : "unpack" );
+
+        if (ckWARN(WARN_UNPACK)) {
+          if (code & modifier)
+           Perl_warner(aTHX_ packWARN(WARN_UNPACK),
+                        "Duplicate modifier '%c' after '%c' in %s",
+                        *patptr, (int) TYPE_NO_MODIFIERS(code),
+                        symptr->flags & FLAG_PACK ? "pack" : "unpack" );
+        }
+
+        code |= modifier;
+        patptr++;
+      }
+
+      /* inherit modifiers */
+      code |= inherited_modifiers;
+
+      /* look for count and/or / */ 
+      if (patptr < patend) {
+       if (isDIGIT(*patptr)) {
+         patptr = get_num( patptr, &symptr->length );
+          symptr->howlen = e_number;
+
+        } else if (*patptr == '*') {
+          patptr++;
+          symptr->howlen = e_star;
+
+        } else if (*patptr == '[') {
+          char* lenptr = ++patptr;            
+          symptr->howlen = e_number;
+          patptr = group_end( patptr, patend, ']' ) + 1;
+          /* what kind of [] is it? */
+          if (isDIGIT(*lenptr)) {
+            lenptr = get_num( lenptr, &symptr->length );
+            if( *lenptr != ']' )
+              Perl_croak(aTHX_ "Malformed integer in [] in %s",
+                         symptr->flags & FLAG_PACK ? "pack" : "unpack");
+          } else {
+            tempsym_t savsym = *symptr;
+            symptr->patend = patptr-1;
+            symptr->patptr = lenptr;
+            savsym.length = measure_struct(symptr);
+            *symptr = savsym;
+          }
+        } else {
+          symptr->howlen = e_no_len;
+          symptr->length = 1;
+        }
+
+        /* try to find / */
+        while (patptr < patend) {
+          if (isSPACE(*patptr))
+            patptr++;
+          else if (*patptr == '#') {
+            patptr++;
+            while (patptr < patend && *patptr != '\n')
+             patptr++;
+            if (patptr < patend)
+             patptr++;
+          } else {
+            if (*patptr == '/') {
+              symptr->flags |= FLAG_SLASH;
+              patptr++;
+              if (patptr < patend &&
+                  (isDIGIT(*patptr) || *patptr == '*' || *patptr == '['))
+                Perl_croak(aTHX_ "'/' does not take a repeat count in %s",
+                           symptr->flags & FLAG_PACK ? "pack" : "unpack" );
+            }
+            break;
+         }
        }
+      } else {
+        /* at end - no count, no / */
+        symptr->howlen = e_no_len;
+        symptr->length = 1;
+      }
+
+      symptr->code = code;
+      symptr->patptr = patptr; 
+      return TRUE;
     }
-    else if (*pat == '[') {
-       char *end = group_end(++pat, patend, ']');
-
-       len = 0;
-       *ppat = end + 1;
-       if (isDIGIT(*pat))
-           return find_count(&pat, end, star);
-       return measure_struct(pat, end);
-    }
-    else
-       len = *star = -1;
-    *ppat = pat;
-    return len;
+  }
+  symptr->patptr = patptr; 
+  return FALSE;
 }
 
-STATIC char *
-S_next_symbol(pTHX_ register char *pat, register char *patend)
+/*
+   There is no way to cleanly handle the case where we should process the 
+   string per byte in its upgraded form while it's really in downgraded form
+   (e.g. estimates like strend-s as an upper bound for the number of 
+   characters left wouldn't work). So if we foresee the need of this 
+   (pattern starts with U or contains U0), we want to work on the encoded 
+   version of the string. Users are advised to upgrade their pack string 
+   themselves if they need to do a lot of unpacks like this on it
+*/
+STATIC bool 
+need_utf8(const char *pat, const char *patend)
 {
+    bool first = TRUE;
     while (pat < patend) {
-       if (isSPACE(*pat))
+       if (pat[0] == '#') {
            pat++;
-       else if (*pat == '#') {
-           pat++;
-           while (pat < patend && *pat != '\n')
-               pat++;
-           if (pat < patend)
-               pat++;
-       }
-       else
-           return pat;
+           pat = memchr(pat, '\n', patend-pat);
+           if (!pat) return FALSE;
+       } else if (pat[0] == 'U') {
+           if (first || pat[1] == '0') return TRUE;
+       } else first = FALSE;
+       pat++;
+    }
+    return FALSE;
+}
+
+STATIC char
+first_symbol(const char *pat, const char *patend) {
+    while (pat < patend) {
+       if (pat[0] != '#') return pat[0];
+       pat++;
+       pat = memchr(pat, '\n', patend-pat);
+       if (!pat) return 0;
+       pat++;
     }
-    return pat;
+    return 0;
 }
 
 /*
 =for apidoc unpack_str
 
-The engine implementing unpack() Perl function.
+The engine implementing unpack() Perl function. Note: parameters strbeg, new_s
+and ocnt are not used. This call should not be used, use unpackstring instead.
 
 =cut */
 
 I32
 Perl_unpack_str(pTHX_ char *pat, register char *patend, register char *s, char *strbeg, char *strend, char **new_s, I32 ocnt, U32 flags)
 {
+    tempsym_t sym = { 0 };
+
+    if (flags & FLAG_UNPACK_DO_UTF8) flags |= FLAG_UNPACK_WAS_UTF8;
+    else if (need_utf8(pat, patend)) {
+       /* We probably should try to avoid this in case a scalar context call
+          wouldn't get to the "U0" */
+       STRLEN len = strend - s;
+       s = bytes_to_utf8(s, &len);
+       SAVEFREEPV(s);
+       strend = s + len;
+       flags |= FLAG_UNPACK_DO_UTF8;
+    }
+
+    if (first_symbol(pat, patend) != 'U' && (flags & FLAG_UNPACK_DO_UTF8))
+       flags |= FLAG_UNPACK_PARSE_UTF8;
+
+    sym.patptr = pat;
+    sym.patend = patend;
+    sym.flags  = flags;
+
+    return unpack_rec(&sym, s, s, strend, NULL );
+}
+
+/*
+=for apidoc unpackstring
+
+The engine implementing unpack() Perl function. C<unpackstring> puts the
+extracted list items on the stack and returns the number of elements.
+Issue C<PUTBACK> before and C<SPAGAIN> after the call to this function.
+
+=cut */
+
+I32
+Perl_unpackstring(pTHX_ char *pat, register char *patend, register char *s, char *strend, U32 flags)
+{
+    tempsym_t sym = { 0 };
+
+    if (flags & FLAG_UNPACK_DO_UTF8) flags |= FLAG_UNPACK_WAS_UTF8;
+    else if (need_utf8(pat, patend)) {
+       /* We probably should try to avoid this in case a scalar context call
+          wouldn't get to the "U0" */
+       STRLEN len = strend - s;
+       s = bytes_to_utf8(s, &len);
+       SAVEFREEPV(s);
+       strend = s + len;
+       flags |= FLAG_UNPACK_DO_UTF8;
+    }
+
+    if (first_symbol(pat, patend) != 'U' && (flags & FLAG_UNPACK_DO_UTF8))
+       flags |= FLAG_UNPACK_PARSE_UTF8;
+
+    sym.patptr = pat;
+    sym.patend = patend;
+    sym.flags  = flags;
+
+    return unpack_rec(&sym, s, s, strend, NULL );
+}
+
+STATIC
+I32
+S_unpack_rec(pTHX_ tempsym_t* symptr, char *s, char *strbeg, char *strend, char **new_s )
+{
     dSP;
-    I32 datumtype;
-    register I32 len;
-    register I32 bits = 0;
-    register char *str;
+    I32 datumtype, ai32;
+    I32 len = 0;
     SV *sv;
-    I32 start_sp_offset = SP - PL_stack_base;
-
-    /* These must not be in registers: */
-    short ashort;
-    int aint;
-    long along;
-#ifdef HAS_QUAD
-    Quad_t aquad;
-#endif
-    U16 aushort;
-    unsigned int auint;
-    U32 aulong;
-#ifdef HAS_QUAD
-    Uquad_t auquad;
-#endif
-    char *aptr;
-    float afloat;
-    double adouble;
-    I32 checksum = 0;
-    UV cuv = 0;
-    NV cdouble = 0.0;
-    const int bits_in_uv = 8 * sizeof(cuv);
-    int commas = 0;
-    int star;          /* 1 if count is *, -1 if no count given, -2 for / */
-#ifdef PERL_NATINT_PACK
-    int natint;                /* native integer */
-    int unatint;       /* unsigned native integer */
-#endif
-    IV aiv;
-    UV auv;
-    NV anv;
-#if defined(HAS_LONG_DOUBLE) && defined(USE_LONG_DOUBLE)
-    long double aldouble;
-#endif
-    bool do_utf8 = (flags & UNPACK_DO_UTF8) != 0;
+    I32 start_sp_offset = SP - PL_stack_base;
+    howlen_t howlen;
 
-    while ((pat = next_symbol(pat, patend)) < patend) {
-       datumtype = *pat++ & 0xFF;
-#ifdef PERL_NATINT_PACK
-       natint = 0;
-#endif
+    I32 checksum = 0;
+    UV cuv = 0;
+    NV cdouble = 0.0;
+    const int bits_in_uv = 8 * sizeof(cuv);
+    char* strrelbeg = s;
+    bool beyond = FALSE;
+    bool explicit_length;
+    bool unpack_only_one = (symptr->flags & FLAG_UNPACK_ONLY_ONE) != 0;
+    bool utf8 = (symptr->flags & FLAG_UNPACK_PARSE_UTF8) ? 1 : 0;
+
+    while (next_symbol(symptr)) {
+        datumtype = symptr->code;
        /* do first one only unless in list context
-          / is implemented by unpacking the count, then poping it from the
+          / is implemented by unpacking the count, then popping it from the
           stack, so must check that we're not in the middle of a /  */
-        if ( (flags & UNPACK_ONLY_ONE)
+        if ( unpack_only_one
             && (SP - PL_stack_base == start_sp_offset + 1)
-            && (datumtype != '/') )
+            && (datumtype != '/') )   /* XXX can this be omitted */
             break;
-       if (*pat == '!') {
-           static const char natstr[] = "sSiIlLxX";
-
-           if (strchr(natstr, datumtype)) {
-               if (datumtype == 'x' || datumtype == 'X') {
-                   datumtype |= TYPE_IS_SHRIEKING;
-               } else {                /* XXXX Should be redone similarly! */
-#ifdef PERL_NATINT_PACK
-                   natint = 1;
-#endif
+
+        switch( howlen = symptr->howlen ){
+        case e_no_len:
+       case e_number:
+           len = symptr->length;
+           break;
+        case e_star:
+           len = strend - strbeg;      /* long enough */          
+           break;
+        }
+
+        explicit_length = TRUE;
+      redo_switch:
+        beyond = s >= strend;
+       {
+           int which = (symptr->code & TYPE_IS_SHRIEKING)
+               ? PACK_SIZE_SHRIEKING : PACK_SIZE_NORMAL;
+           const int rawtype = TYPE_NO_MODIFIERS(datumtype);
+           int offset = rawtype - packsize[which].first;
+
+           if (offset >= 0 && offset < packsize[which].size) {
+               /* Data about this template letter  */
+               unsigned char data = packsize[which].array[offset];
+
+               if (data) {
+                   /* data nonzero means we can process this letter.  */
+                   long size = data & PACK_SIZE_MASK;
+                   long howmany = (strend - s) / size;
+                   if (len > howmany)
+                       len = howmany;
+
+                   if (!checksum || (data & PACK_SIZE_CANNOT_CSUM)) {
+                       if (len && unpack_only_one) len = 1;
+                       EXTEND(SP, len);
+                       EXTEND_MORTAL(len);
+                   }
                }
-               pat++;
            }
-           else
-               Perl_croak(aTHX_ "'!' allowed only after types %s", natstr);
        }
-       len = find_count(&pat, patend, &star);
-       if (star > 0)
-               len = strend - strbeg;  /* long enough */
-       else if (star < 0)              /* No explicit len */
-               len = datumtype != '@';
-
-      redo_switch:
-       switch(datumtype) {
+       switch(TYPE_NO_ENDIANNESS(datumtype)) {
        default:
-           Perl_croak(aTHX_ "Invalid type in unpack: '%c'", (int)datumtype);
-       case ',': /* grandfather in commas but with a warning */
-           if (commas++ == 0 && ckWARN(WARN_UNPACK))
-               Perl_warner(aTHX_ packWARN(WARN_UNPACK),
-                           "Invalid type in unpack: '%c'", (int)datumtype);
-           break;
+           Perl_croak(aTHX_ "Invalid type '%c' in unpack", (int)TYPE_NO_MODIFIERS(datumtype) );
+
        case '%':
-           if (len == 1 && pat[-1] != '1' && pat[-1] != ']')
+           if (howlen == e_no_len)
                len = 16;               /* len is not specified */
            checksum = len;
            cuv = 0;
@@ -513,107 +1108,163 @@ Perl_unpack_str(pTHX_ char *pat, register char *patend, register char *s, char *
            break;
        case '(':
        {
-           char *beg = pat;
-           char *ss = s;               /* Move from register */
-
-           if (star >= 0)
-               Perl_croak(aTHX_ "()-group starts with a count");
-           aptr = group_end(beg, patend, ')');
-           pat = aptr + 1;
-           if (star != -2) {
-               len = find_count(&pat, patend, &star);
-               if (star < 0)           /* No count */
-                   len = 1;
-               else if (star > 0)      /* Star */
-                   len = strend - strbeg; /* long enough? */
-           }
+            tempsym_t savsym = *symptr;
+           U32 group_modifiers = TYPE_MODIFIERS(datumtype & ~symptr->flags);
+           symptr->flags |= group_modifiers;
+            symptr->patend = savsym.grpend;
+            symptr->level++;
            PUTBACK;
            while (len--) {
-               unpack_str(beg, aptr, ss, strbeg, strend, &ss,
-                          ocnt + SP - PL_stack_base - start_sp_offset, flags);
-               if (star > 0 && ss == strend)
-                   break;              /* No way to continue */
+               symptr->patptr = savsym.grpbeg;
+               if (utf8) symptr->flags |=  FLAG_UNPACK_PARSE_UTF8;
+               else      symptr->flags &= ~FLAG_UNPACK_PARSE_UTF8;
+               unpack_rec(symptr, s, strbeg, strend, &s);
+                if (s == strend && savsym.howlen == e_star)
+                   break; /* No way to continue */
            }
            SPAGAIN;
-           s = ss;
+           symptr->flags &= ~group_modifiers;
+            savsym.flags = symptr->flags;
+            *symptr = savsym;
            break;
        }
        case '@':
-           if (len > strend - strbeg)
-               Perl_croak(aTHX_ "@ outside of string");
-           s = strbeg + len;
+           if (utf8) {
+               s = strrelbeg;
+               while (len > 0) {
+                   if (s >= strend)
+                       Perl_croak(aTHX_ "'@' outside of string in unpack");
+                   s += UTF8SKIP(s);
+                   len--;
+               }
+               if (s > strend)
+                   Perl_croak(aTHX_ "'@' outside of string with malformed UTF-8 in unpack");
+           } else {
+           if (len > strend - strrelbeg)
+               Perl_croak(aTHX_ "'@' outside of string in unpack");
+           s = strrelbeg + len;
+           }
            break;
        case 'X' | TYPE_IS_SHRIEKING:
            if (!len)                   /* Avoid division by 0 */
                len = 1;
-           len = (s - strbeg) % len;
+           if (utf8) {
+               char *hop, *last;
+               I32 l;
+               for (l=len, hop = strbeg; hop < s; l++, hop += UTF8SKIP(hop))
+                   if (l == len) {
+                       last = hop;
+                       l = 0;
+                   }
+               s = last;
+               break;
+           } else len = (s - strbeg) % len;
            /* FALL THROUGH */
        case 'X':
+           if (utf8) {
+               while (len > 0) {
+                   if (s <= strbeg)
+                       Perl_croak(aTHX_ "'X' outside of string in unpack");
+                   while (UTF8_IS_CONTINUATION(*--s)) {
+                       if (s <= strbeg)
+                           Perl_croak(aTHX_ "'X' outside of string in unpack");
+                   }
+                   len--;
+               }
+           } else {
            if (len > s - strbeg)
-               Perl_croak(aTHX_ "X outside of string");
+               Perl_croak(aTHX_ "'X' outside of string in unpack" );
            s -= len;
+           }
            break;
        case 'x' | TYPE_IS_SHRIEKING:
            if (!len)                   /* Avoid division by 0 */
                len = 1;
-           aint = (s - strbeg) % len;
-           if (aint)                   /* Other portable ways? */
-               len = len - aint;
-           else
-               len = 0;
+           if (utf8) {
+               char *hop = strbeg;
+               I32 l = 0;
+               for (hop = strbeg; hop < s; hop += UTF8SKIP(hop)) l++;
+               if (s != hop)
+                   Perl_croak(aTHX_ "Malformed UTF-8 string in unpack");
+               ai32 = l % len;
+           } else ai32 = (s - strbeg) % len;
+           if (ai32 == 0) break;
+           len -= ai32;
            /* FALL THROUGH */
        case 'x':
+           if (utf8) {
+               while (len>0) {
+                   if (s >= strend)
+                       Perl_croak(aTHX_ "'x' outside of string in unpack");
+                   s += UTF8SKIP(s);
+                   len--;
+               }
+           } else {
            if (len > strend - s)
-               Perl_croak(aTHX_ "x outside of string");
+               Perl_croak(aTHX_ "'x' outside of string in unpack");
            s += len;
+           };
            break;
        case '/':
-           if (ocnt + SP - PL_stack_base - start_sp_offset <= 0)
-               Perl_croak(aTHX_ "/ must follow a numeric type");
-           datumtype = *pat++;
-           if (*pat == '*')
-               pat++;          /* ignore '*' for compatibility with pack */
-           if (isDIGIT(*pat))
-               Perl_croak(aTHX_ "/ cannot take a count" );
-           len = POPi;
-           star = -2;
-           goto redo_switch;
+           Perl_croak(aTHX_ "'/' must follow a numeric type in unpack");
+            break;
        case 'A':
        case 'Z':
        case 'a':
-           if (len > strend - s)
+           if (checksum) {
+               /* Preliminary length estimate is assumed done in 'W' */
+               if (len > strend - s) len = strend - s;
+               goto W_checksum;
+           }
+           if (utf8) {
+               I32 l;
+               char *hop;
+               for (l=len, hop=s; l>0; l--, hop += UTF8SKIP(hop)) {
+                   if (hop >= strend) {
+                       if (hop > strend)
+                           Perl_croak(aTHX_ "Malformed UTF-8 string in unpack");
+                       break;
+               }
+               }
+               if (hop > strend)
+                   Perl_croak(aTHX_ "Malformed UTF-8 string in unpack");
+               len = hop - s;
+           } else if (len > strend - s)
                len = strend - s;
-           if (checksum)
-               goto uchar_checksum;
-           sv = NEWSV(35, len);
-           sv_setpvn(sv, s, len);
-           if (datumtype == 'A' || datumtype == 'Z') {
-               aptr = s;       /* borrow register */
-               if (datumtype == 'Z') { /* 'Z' strips stuff after first null */
-                   s = SvPVX(sv);
-                   while (*s)
-                       s++;
-                   if (star > 0) /* exact for 'Z*' */
-                       len = s - SvPVX(sv) + 1;
-               }
-               else {          /* 'A' strips both nulls and spaces */
-                   s = SvPVX(sv) + len - 1;
-                   while (s >= SvPVX(sv) && (!*s || isSPACE(*s)))
-                       s--;
-                   *++s = '\0';
-               }
-               SvCUR_set(sv, s - SvPVX(sv));
-               s = aptr;       /* unborrow register */
+
+           if (datumtype == 'Z') {
+               /* 'Z' strips stuff after first null */
+               char *ptr;
+               for (ptr = s; ptr < strend; ptr++) if (*ptr == 0) break;
+               sv = newSVpvn(s, ptr-s);
+               if (howlen == e_star) /* exact for 'Z*' */
+                   len = ptr-s + (ptr != strend ? 1 : 0);
+           } else if (datumtype == 'A') {
+               /* 'A' strips both nulls and spaces */
+               char *ptr;
+               for (ptr = s+len-1; ptr >= s; ptr--)
+                   if (*ptr != 0 && !isSPACE(*ptr)) break;
+               ptr++;
+               sv = newSVpvn(s, ptr-s);
+           } else sv = newSVpvn(s, len);
+
+           if (utf8) {
+               SvUTF8_on(sv);
+               /* Undo any upgrade done due to need_utf8() */
+               if (!(symptr->flags & FLAG_UNPACK_WAS_UTF8))
+                   sv_utf8_downgrade(sv, 0);
            }
-           s += len;
            XPUSHs(sv_2mortal(sv));
+           s += len;
            break;
        case 'B':
-       case 'b':
-           if (star > 0 || len > (strend - s) * 8)
+       case 'b': {
+           char *str;
+           if (howlen == e_star || len > (strend - s) * 8)
                len = (strend - s) * 8;
            if (checksum) {
                if (!PL_bitcount) {
+                   int bits;
                    Newz(601, PL_bitcount, 256, char);
                    for (bits = 1; bits < 256; bits++) {
                        if (bits & 1)   PL_bitcount[bits]++;
@@ -626,681 +1277,553 @@ Perl_unpack_str(pTHX_ char *pat, register char *patend, register char *s, char *
                        if (bits & 128) PL_bitcount[bits]++;
                    }
                }
+               if (utf8) {
+                   while (len >= 8 && s < strend) {
+                       cuv += PL_bitcount[next_uni_byte(aTHX_ &s, strend, datumtype)];
+                       len -= 8;
+                   }
+               } else {
                while (len >= 8) {
-                   cuv += PL_bitcount[*(unsigned char*)s++];
+                       cuv += PL_bitcount[*(U8 *)s++];
                    len -= 8;
                }
-               if (len) {
-                   bits = *s;
+               }
+               if (len && s < strend) {
+                   U8 bits;
+                   bits = NEXT_BYTE(utf8, s, strend, datumtype);
                    if (datumtype == 'b') {
                        while (len-- > 0) {
                            if (bits & 1) cuv++;
                            bits >>= 1;
                        }
-                   }
-                   else {
+                   } else {
                        while (len-- > 0) {
-                           if (bits & 128) cuv++;
+                           if (bits & 0x80) cuv++;
                            bits <<= 1;
                        }
                    }
                }
                break;
            }
-           sv = NEWSV(35, len + 1);
-           SvCUR_set(sv, len);
+
+           sv = sv_2mortal(NEWSV(35, len ? len : 1));
            SvPOK_on(sv);
            str = SvPVX(sv);
            if (datumtype == 'b') {
-               aint = len;
-               for (len = 0; len < aint; len++) {
-                   if (len & 7)                /*SUPPRESS 595*/
-                       bits >>= 1;
-                   else
-                       bits = *s++;
-                   *str++ = '0' + (bits & 1);
-               }
-           }
-           else {
-               aint = len;
-               for (len = 0; len < aint; len++) {
-                   if (len & 7)
-                       bits <<= 1;
-                   else
-                       bits = *s++;
-                   *str++ = '0' + ((bits & 128) != 0);
+               U8 bits;
+               ai32 = len;
+               for (len = 0; len < ai32; len++) {
+                   if (len & 7) bits >>= 1;
+                   else if (utf8) {
+                       if (s >= strend) break;
+                       bits = next_uni_byte(aTHX_ &s, strend, datumtype);
+                   } else bits = *(U8 *) s++;
+                   *str++ = bits & 1 ? '1' : '0';
+               }
+           } else {
+               U8 bits;
+               ai32 = len;
+               for (len = 0; len < ai32; len++) {
+                   if (len & 7) bits <<= 1;
+                   else if (utf8) {
+                       if (s >= strend) break;
+                       bits = next_uni_byte(aTHX_ &s, strend, datumtype);
+                   } else bits = *(U8 *) s++;
+                   *str++ = bits & 0x80 ? '1' : '0';
                }
            }
            *str = '\0';
-           XPUSHs(sv_2mortal(sv));
+           SvCUR_set(sv, str - SvPVX(sv));
+           XPUSHs(sv);
            break;
+       }
        case 'H':
-       case 'h':
-           if (star > 0 || len > (strend - s) * 2)
+       case 'h': {
+           char *str;
+             /* Preliminary length estimate, acceptable for utf8 too */
+           if (howlen == e_star || len > (strend - s) * 2)
                len = (strend - s) * 2;
-           sv = NEWSV(35, len + 1);
-           SvCUR_set(sv, len);
+             sv = sv_2mortal(NEWSV(35, len ? len : 1));
            SvPOK_on(sv);
            str = SvPVX(sv);
            if (datumtype == 'h') {
-               aint = len;
-               for (len = 0; len < aint; len++) {
-                   if (len & 1)
-                       bits >>= 4;
-                   else
-                       bits = *s++;
+                 U8 bits;
+                 ai32 = len;
+                 for (len = 0; len < ai32; len++) {
+                     if (len & 1) bits >>= 4;
+                     else if (utf8) {
+                         if (s >= strend) break;
+                         bits = next_uni_byte(aTHX_ &s, strend, datumtype);
+                     } else bits = * (U8 *) s++;
                    *str++ = PL_hexdigit[bits & 15];
                }
-           }
-           else {
-               aint = len;
-               for (len = 0; len < aint; len++) {
-                   if (len & 1)
-                       bits <<= 4;
-                   else
-                       bits = *s++;
+           } else {
+               U8 bits;
+               ai32 = len;
+               for (len = 0; len < ai32; len++) {
+                   if (len & 1) bits <<= 4;
+                   else if (utf8) {
+                       if (s >= strend) break;
+                       bits = next_uni_byte(aTHX_ &s, strend, datumtype);
+                   } else bits = *(U8 *) s++;
                    *str++ = PL_hexdigit[(bits >> 4) & 15];
                }
            }
            *str = '\0';
-           XPUSHs(sv_2mortal(sv));
+           SvCUR_set(sv, str - SvPVX(sv));
+           XPUSHs(sv);
            break;
+       }
        case 'c':
-           if (len > strend - s)
-               len = strend - s;
-           if (checksum) {
-               while (len-- > 0) {
-                   aint = *s++;
-                   if (aint >= 128)    /* fake up signed chars */
-                       aint -= 256;
-                   if (checksum > bits_in_uv)
-                       cdouble += (NV)aint;
-                   else
-                       cuv += aint;
-               }
-           }
-           else {
-                if (len && (flags & UNPACK_ONLY_ONE))
-                    len = 1;
-               EXTEND(SP, len);
-               EXTEND_MORTAL(len);
-               while (len-- > 0) {
-                   aint = *s++;
-                   if (aint >= 128)    /* fake up signed chars */
-                       aint -= 256;
-                   sv = NEWSV(36, 0);
-                   sv_setiv(sv, (IV)aint);
-                   PUSHs(sv_2mortal(sv));
-               }
+           while (len-- > 0) {
+               int aint = NEXT_BYTE(utf8, s, strend, datumtype);
+               if (aint >= 128)        /* fake up signed chars */
+                   aint -= 256;
+               if (!checksum)
+                   PUSHs(sv_2mortal(newSViv((IV)aint)));
+               else if (checksum > bits_in_uv)
+                   cdouble += (NV)aint;
+               else
+                   cuv += aint;
            }
            break;
        case 'C':
-       unpack_C: /* unpack U will jump here if not UTF-8 */
+       case 'W':
+         W_checksum:
             if (len == 0) {
-               do_utf8 = FALSE;
+                if (explicit_length && datumtype == 'C') 
+                   /* Switch to "character" mode */
+                   utf8 = (symptr->flags & FLAG_UNPACK_DO_UTF8) ? 1 : 0;
                break;
            }
-           if (len > strend - s)
-               len = strend - s;
-           if (checksum) {
-             uchar_checksum:
-               while (len-- > 0) {
-                   auint = *s++ & 255;
-                   cuv += auint;
-               }
+           if (datumtype == 'C' ? 
+                (symptr->flags & FLAG_UNPACK_DO_UTF8) && 
+               !(symptr->flags & FLAG_UNPACK_WAS_UTF8) : utf8) {
+               while (len-- > 0 && s < strend) {
+                   UV val;
+                   STRLEN retlen;
+                   val =
+                       UNI_TO_NATIVE(utf8n_to_uvuni(s, strend-s, &retlen,
+                                                    ckWARN(WARN_UTF8) ? 0 : UTF8_ALLOW_ANY));
+                   if (retlen == (STRLEN) -1 || retlen == 0)
+                       Perl_croak(aTHX_ "Malformed UTF-8 string in unpack");
+                   s += retlen;
+                   if (!checksum)
+                       PUSHs(sv_2mortal(newSVuv((UV) val)));
+                   else if (checksum > bits_in_uv)
+                       cdouble += (NV) val;
+                   else
+                       cuv += val;
            }
-           else {
-                if (len && (flags & UNPACK_ONLY_ONE))
-                    len = 1;
-               EXTEND(SP, len);
-               EXTEND_MORTAL(len);
+           } else if (!checksum)
                while (len-- > 0) {
-                   auint = *s++ & 255;
-                   sv = NEWSV(37, 0);
-                   sv_setiv(sv, (IV)auint);
-                   PUSHs(sv_2mortal(sv));
-               }
+                   U8 ch = *(U8 *) s++;
+                   PUSHs(sv_2mortal(newSVuv((UV) ch)));
            }
+           else if (checksum > bits_in_uv)
+               while (len-- > 0) cdouble += (NV) *(U8 *) s++;
+           else
+               while (len-- > 0) cuv += *(U8 *) s++;
            break;
        case 'U':
            if (len == 0) {
-               do_utf8 = TRUE;
-               break;
-           }
-           if (!do_utf8)
-                goto unpack_C;
-           if (len > strend - s)
-               len = strend - s;
-           if (checksum) {
-               while (len-- > 0 && s < strend) {
-                   STRLEN alen;
-                   auint = NATIVE_TO_UNI(utf8n_to_uvchr((U8*)s, strend - s, &alen, ckWARN(WARN_UTF8) ? 0 : UTF8_ALLOW_ANYUV));
-                   along = alen;
-                   s += along;
-                   if (checksum > bits_in_uv)
-                       cdouble += (NV)auint;
+                if (explicit_length) {
+                   /* Switch to "bytes in UTF-8" mode */
+                   if (symptr->flags & FLAG_UNPACK_DO_UTF8) utf8 = 0;
                    else
-                       cuv += auint;
+                       /* Should be impossible due to the need_utf8() test */
+                       Perl_croak(aTHX_ "U0 mode on a byte string");
                }
+               break;
            }
-           else {
-                if (len && (flags & UNPACK_ONLY_ONE))
-                    len = 1;
+           if (len > strend - s) len = strend - s;
+               if (!checksum) {
+               if (len && unpack_only_one) len = 1;
                EXTEND(SP, len);
                EXTEND_MORTAL(len);
-               while (len-- > 0 && s < strend) {
-                   STRLEN alen;
-                   auint = NATIVE_TO_UNI(utf8n_to_uvchr((U8*)s, strend - s, &alen, ckWARN(WARN_UTF8) ? 0 : UTF8_ALLOW_ANYUV));
-                   along = alen;
-                   s += along;
-                   sv = NEWSV(37, 0);
-                   sv_setuv(sv, (UV)auint);
-                   PUSHs(sv_2mortal(sv));
                }
+           while (len-- > 0 && s < strend) {
+               STRLEN retlen;
+               UV auv;
+               if (utf8) {
+                   U8 result[UTF8_MAXLEN];
+                   char *ptr;
+                   STRLEN len;
+                   ptr = s;
+                   /* Bug: warns about bad utf8 even if we are short on bytes
+                      and will break out of the loop */
+                   if (!next_uni_bytes(aTHX_ &ptr, strend, result, 1))
+                       break;
+                   len = UTF8SKIP(result);
+                   if (!next_uni_bytes(aTHX_ &ptr, strend, &result[1], len-1))
+                       break;
+                   auv = utf8n_to_uvuni(result, len, &retlen, ckWARN(WARN_UTF8) ? 0 : UTF8_ALLOW_ANYUV);
+                   s = ptr;
+               } else {
+                   auv = utf8n_to_uvuni((U8*)s, strend - s, &retlen, ckWARN(WARN_UTF8) ? 0 : UTF8_ALLOW_ANYUV);
+                   if (retlen == (STRLEN) -1 || retlen == 0)
+                       Perl_croak(aTHX_ "Malformed UTF-8 string in unpack");
+                   s += retlen;
+               }
+               if (!checksum)
+                   PUSHs(sv_2mortal(newSVuv((UV) auv)));
+               else if (checksum > bits_in_uv)
+                   cdouble += (NV) auv;
+               else
+                   cuv += auv;
            }
            break;
-       case 's':
-#if SHORTSIZE == SIZE16
-           along = (strend - s) / SIZE16;
-#else
-           along = (strend - s) / (natint ? sizeof(short) : SIZE16);
-#endif
-           if (len > along)
-               len = along;
-           if (checksum) {
+       case 's' | TYPE_IS_SHRIEKING:
 #if SHORTSIZE != SIZE16
-               if (natint) {
-                   short ashort;
-                   while (len-- > 0) {
-                       COPYNN(s, &ashort, sizeof(short));
-                       s += sizeof(short);
-                       if (checksum > bits_in_uv)
-                           cdouble += (NV)ashort;
-                       else
-                           cuv += ashort;
-
-                   }
-               }
+           while (len-- > 0) {
+               short ashort;
+               COPYVAR(s, strend, utf8, ashort, s);
+               if (!checksum)
+                   PUSHs(sv_2mortal(newSViv((IV)ashort)));
+               else if (checksum > bits_in_uv)
+                   cdouble += (NV)ashort;
                else
+                   cuv += ashort;
+           }
+           break;
+#else
+           /* Fallthrough! */
 #endif
-                {
-                   while (len-- > 0) {
-                       COPY16(s, &ashort);
-#if SHORTSIZE > SIZE16
-                       if (ashort > 32767)
-                         ashort -= 65536;
-#endif
-                       s += SIZE16;
-                       if (checksum > bits_in_uv)
-                           cdouble += (NV)ashort;
-                       else
-                           cuv += ashort;
-                   }
-               }
+       case 's':
+           while (len-- > 0) {
+               I16 ai16;
+
+#if U16SIZE > SIZE16
+               ai16 = 0;
+#endif
+               if (utf8) {
+                   if (!next_uni_bytes(aTHX_ &s, strend, 
+                                       OFF16(&ai16), SIZE16)) break;
+               } else {
+               COPY16(s, &ai16);
+                   s += SIZE16;
+               }
+               DO_BO_UNPACK(ai16, 16);
+#if U16SIZE > SIZE16
+               if (ai16 > 32767)
+                   ai16 -= 65536;
+#endif
+               if (!checksum)
+                   PUSHs(sv_2mortal(newSViv((IV)ai16)));
+               else if (checksum > bits_in_uv)
+                   cdouble += (NV)ai16;
+               else
+                   cuv += ai16;
            }
-           else {
-                if (len && (flags & UNPACK_ONLY_ONE))
-                    len = 1;
-               EXTEND(SP, len);
-               EXTEND_MORTAL(len);
+           break;
+       case 'S' | TYPE_IS_SHRIEKING:
 #if SHORTSIZE != SIZE16
-               if (natint) {
-                   short ashort;
-                   while (len-- > 0) {
-                       COPYNN(s, &ashort, sizeof(short));
-                       s += sizeof(short);
-                       sv = NEWSV(38, 0);
-                       sv_setiv(sv, (IV)ashort);
-                       PUSHs(sv_2mortal(sv));
-                   }
-               }
+           while (len-- > 0) {
+               unsigned short aushort;
+               COPYVAR(s, strend, utf8, aushort, s);
+               if (!checksum)
+                   PUSHs(sv_2mortal(newSVuv((UV) aushort)));
+               else if (checksum > bits_in_uv)
+                   cdouble += (NV)aushort;
                else
-#endif
-                {
-                   while (len-- > 0) {
-                       COPY16(s, &ashort);
-#if SHORTSIZE > SIZE16
-                       if (ashort > 32767)
-                         ashort -= 65536;
-#endif
-                       s += SIZE16;
-                       sv = NEWSV(38, 0);
-                       sv_setiv(sv, (IV)ashort);
-                       PUSHs(sv_2mortal(sv));
-                   }
-               }
+                   cuv += aushort;
            }
            break;
+#else
+            /* Fallhrough! */
+#endif
        case 'v':
        case 'n':
        case 'S':
-#if SHORTSIZE == SIZE16
-           along = (strend - s) / SIZE16;
-#else
-           unatint = natint && datumtype == 'S';
-           along = (strend - s) / (unatint ? sizeof(unsigned short) : SIZE16);
-#endif
-           if (len > along)
-               len = along;
-           if (checksum) {
-#if SHORTSIZE != SIZE16
-               if (unatint) {
-                   unsigned short aushort;
-                   while (len-- > 0) {
-                       COPYNN(s, &aushort, sizeof(unsigned short));
-                       s += sizeof(unsigned short);
-                       if (checksum > bits_in_uv)
-                           cdouble += (NV)aushort;
-                       else
-                           cuv += aushort;
-                   }
-               }
-               else
-#endif
-                {
-                   while (len-- > 0) {
-                       COPY16(s, &aushort);
-                       s += SIZE16;
+           while (len-- > 0) {
+               U16 au16;
+#if U16SIZE > SIZE16
+               au16 = 0;
+#endif
+               if (utf8) {
+                   if (!next_uni_bytes(aTHX_ &s, strend, 
+                                       OFF16(&au16), SIZE16)) break;
+               } else {
+               COPY16(s, &au16);
+               s += SIZE16;
+               }
+               DO_BO_UNPACK(au16, 16);
 #ifdef HAS_NTOHS
-                       if (datumtype == 'n')
-                           aushort = PerlSock_ntohs(aushort);
+               if (datumtype == 'n')
+                   au16 = PerlSock_ntohs(au16);
 #endif
 #ifdef HAS_VTOHS
-                       if (datumtype == 'v')
-                           aushort = vtohs(aushort);
+               if (datumtype == 'v')
+                   au16 = vtohs(au16);
 #endif
-                       if (checksum > bits_in_uv)
-                           cdouble += (NV)aushort;
-                       else
-                           cuv += aushort;
-                   }
-               }
+               if (!checksum)
+                   PUSHs(sv_2mortal(newSVuv((UV)au16)));
+               else if (checksum > bits_in_uv)
+                   cdouble += (NV)au16;
+               else
+                   cuv += au16;
            }
-           else {
-                if (len && (flags & UNPACK_ONLY_ONE))
-                    len = 1;
-               EXTEND(SP, len);
-               EXTEND_MORTAL(len);
-#if SHORTSIZE != SIZE16
-               if (unatint) {
-                   unsigned short aushort;
-                   while (len-- > 0) {
-                       COPYNN(s, &aushort, sizeof(unsigned short));
-                       s += sizeof(unsigned short);
-                       sv = NEWSV(39, 0);
-                       sv_setiv(sv, (UV)aushort);
-                       PUSHs(sv_2mortal(sv));
-                   }
-               }
+           break;
+#ifdef PERL_PACK_CAN_SHRIEKSIGN
+       case 'v' | TYPE_IS_SHRIEKING:
+       case 'n' | TYPE_IS_SHRIEKING:
+           while (len-- > 0) {
+               I16 ai16;
+# if U16SIZE > SIZE16
+               ai16 = 0;
+# endif
+               if (utf8) {
+                   if (!next_uni_bytes(aTHX_ &s, strend,
+                                       (char *) &ai16, sizeof(ai16))) break;
+               } else {
+               COPY16(s, &ai16);
+               s += SIZE16;
+               }
+# ifdef HAS_NTOHS
+               if (datumtype == ('n' | TYPE_IS_SHRIEKING))
+                   ai16 = (I16) PerlSock_ntohs((U16) ai16);
+# endif /* HAS_NTOHS */
+# ifdef HAS_VTOHS
+               if (datumtype == ('v' | TYPE_IS_SHRIEKING))
+                   ai16 = (I16) vtohs((U16) ai16);
+# endif /* HAS_VTOHS */
+               if (!checksum)
+                   PUSHs(sv_2mortal(newSViv((IV)ai16)));
+               else if (checksum > bits_in_uv)
+                   cdouble += (NV) ai16;
                else
-#endif
-                {
-                   while (len-- > 0) {
-                       COPY16(s, &aushort);
-                       s += SIZE16;
-                       sv = NEWSV(39, 0);
-#ifdef HAS_NTOHS
-                       if (datumtype == 'n')
-                           aushort = PerlSock_ntohs(aushort);
-#endif
-#ifdef HAS_VTOHS
-                       if (datumtype == 'v')
-                           aushort = vtohs(aushort);
-#endif
-                       sv_setiv(sv, (UV)aushort);
-                       PUSHs(sv_2mortal(sv));
-                   }
-               }
+                   cuv += ai16;
            }
            break;
+#endif /* PERL_PACK_CAN_SHRIEKSIGN */
        case 'i':
-           along = (strend - s) / sizeof(int);
-           if (len > along)
-               len = along;
-           if (checksum) {
-               while (len-- > 0) {
-                   Copy(s, &aint, 1, int);
-                   s += sizeof(int);
-                   if (checksum > bits_in_uv)
-                       cdouble += (NV)aint;
-                   else
-                       cuv += aint;
-               }
-           }
-           else {
-                if (len && (flags & UNPACK_ONLY_ONE))
-                    len = 1;
-               EXTEND(SP, len);
-               EXTEND_MORTAL(len);
-               while (len-- > 0) {
-                   Copy(s, &aint, 1, int);
-                   s += sizeof(int);
-                   sv = NEWSV(40, 0);
-#ifdef __osf__
-                    /* Without the dummy below unpack("i", pack("i",-1))
-                     * return 0xFFffFFff instead of -1 for Digital Unix V4.0
-                     * cc with optimization turned on.
-                    *
-                    * The bug was detected in
-                    * DEC C V5.8-009 on Digital UNIX V4.0 (Rev. 1091) (V4.0E)
-                    * with optimization (-O4) turned on.
-                    * DEC C V5.2-040 on Digital UNIX V4.0 (Rev. 564) (V4.0B)
-                    * does not have this problem even with -O4.
-                    *
-                    * This bug was reported as DECC_BUGS 1431
-                    * and tracked internally as GEM_BUGS 7775.
-                    *
-                    * The bug is fixed in
-                    * Tru64 UNIX V5.0:      Compaq C V6.1-006 or later
-                    * UNIX V4.0F support:   DEC C V5.9-006 or later
-                    * UNIX V4.0E support:   DEC C V5.8-011 or later
-                    * and also in DTK.
-                    *
-                    * See also few lines later for the same bug.
-                    */
-                    (aint) ?
-                       sv_setiv(sv, (IV)aint) :
-#endif
-                   sv_setiv(sv, (IV)aint);
-                   PUSHs(sv_2mortal(sv));
-               }
+       case 'i' | TYPE_IS_SHRIEKING:
+           while (len-- > 0) {
+               int aint;
+               COPYVAR(s, strend, utf8, aint, i);
+               if (!checksum)
+                   PUSHs(sv_2mortal(newSViv((IV)aint)));
+               else if (checksum > bits_in_uv)
+                   cdouble += (NV)aint;
+               else
+                   cuv += aint;
            }
            break;
        case 'I':
-           along = (strend - s) / sizeof(unsigned int);
-           if (len > along)
-               len = along;
-           if (checksum) {
-               while (len-- > 0) {
-                   Copy(s, &auint, 1, unsigned int);
-                   s += sizeof(unsigned int);
-                   if (checksum > bits_in_uv)
-                       cdouble += (NV)auint;
-                   else
-                       cuv += auint;
-               }
-           }
-           else {
-                if (len && (flags & UNPACK_ONLY_ONE))
-                    len = 1;
-               EXTEND(SP, len);
-               EXTEND_MORTAL(len);
-               while (len-- > 0) {
-                   Copy(s, &auint, 1, unsigned int);
-                   s += sizeof(unsigned int);
-                   sv = NEWSV(41, 0);
-#ifdef __osf__
-                    /* Without the dummy below unpack("I", pack("I",0xFFFFFFFF))
-                     * returns 1.84467440737096e+19 instead of 0xFFFFFFFF.
-                    * See details few lines earlier. */
-                    (auint) ?
-                       sv_setuv(sv, (UV)auint) :
-#endif
-                   sv_setuv(sv, (UV)auint);
-                   PUSHs(sv_2mortal(sv));
-               }
+       case 'I' | TYPE_IS_SHRIEKING:
+           while (len-- > 0) {
+               unsigned int auint;
+               COPYVAR(s, strend, utf8, auint, i);
+               if (!checksum)
+                   PUSHs(sv_2mortal(newSVuv((UV)auint)));
+               else if (checksum > bits_in_uv)
+                   cdouble += (NV)auint;
+               else
+                   cuv += auint;
            }
            break;
        case 'j':
-           along = (strend - s) / IVSIZE;
-           if (len > along)
-               len = along;
-           if (checksum) {
-               while (len-- > 0) {
-                   Copy(s, &aiv, 1, IV);
-                   s += IVSIZE;
-                   if (checksum > bits_in_uv)
-                       cdouble += (NV)aiv;
-                   else
-                       cuv += aiv;
-               }
-           }
-           else {
-                if (len && (flags & UNPACK_ONLY_ONE))
-                    len = 1;
-               EXTEND(SP, len);
-               EXTEND_MORTAL(len);
-               while (len-- > 0) {
-                   Copy(s, &aiv, 1, IV);
-                   s += IVSIZE;
-                   sv = NEWSV(40, 0);
-                   sv_setiv(sv, aiv);
-                   PUSHs(sv_2mortal(sv));
-               }
+           while (len-- > 0) {
+               IV aiv;
+#if IVSIZE == INTSIZE
+               COPYVAR(s, strend, utf8, aiv, i);
+#elif IVSIZE == LONGSIZE
+               COPYVAR(s, strend, utf8, aiv, l);
+#elif defined(HAS_QUAD) && IVSIZE == U64SIZE
+               COPYVAR(s, strend, utf8, aiv, 64);
+#else
+               Perl_croak(aTHX_ "'j' not supported on this platform");
+#endif
+               if (!checksum)
+                   PUSHs(sv_2mortal(newSViv(aiv)));
+               else if (checksum > bits_in_uv)
+                   cdouble += (NV)aiv;
+               else
+                   cuv += aiv;
            }
            break;
        case 'J':
-           along = (strend - s) / UVSIZE;
-           if (len > along)
-               len = along;
-           if (checksum) {
-               while (len-- > 0) {
-                   Copy(s, &auv, 1, UV);
-                   s += UVSIZE;
-                   if (checksum > bits_in_uv)
-                       cdouble += (NV)auv;
-                   else
-                       cuv += auv;
-               }
+           while (len-- > 0) {
+               UV auv;
+#if IVSIZE == INTSIZE
+               COPYVAR(s, strend, utf8, auv, i);
+#elif IVSIZE == LONGSIZE
+               COPYVAR(s, strend, utf8, auv, l);
+#elif defined(HAS_QUAD) && IVSIZE == U64SIZE
+               COPYVAR(s, strend, utf8, auv, 64);
+#else
+               Perl_croak(aTHX_ "'J' not supported on this platform");
+#endif
+               if (!checksum)
+                   PUSHs(sv_2mortal(newSVuv(auv)));
+               else if (checksum > bits_in_uv)
+                   cdouble += (NV)auv;
+               else
+                   cuv += auv;
            }
-           else {
-                if (len && (flags & UNPACK_ONLY_ONE))
-                    len = 1;
-               EXTEND(SP, len);
-               EXTEND_MORTAL(len);
-               while (len-- > 0) {
-                   Copy(s, &auv, 1, UV);
-                   s += UVSIZE;
-                   sv = NEWSV(41, 0);
-                   sv_setuv(sv, auv);
-                   PUSHs(sv_2mortal(sv));
-               }
+           break;
+       case 'l' | TYPE_IS_SHRIEKING:
+#if LONGSIZE != SIZE32
+           while (len-- > 0) {
+               long along;
+               COPYVAR(s, strend, utf8, along, l);
+               if (!checksum)
+                   PUSHs(sv_2mortal(newSViv((IV)along)));
+               else if (checksum > bits_in_uv)
+                   cdouble += (NV)along;
+               else
+                   cuv += along;
            }
            break;
-       case 'l':
-#if LONGSIZE == SIZE32
-           along = (strend - s) / SIZE32;
 #else
-           along = (strend - s) / (natint ? sizeof(long) : SIZE32);
+           /* Fallthrough! */
 #endif
-           if (len > along)
-               len = along;
-           if (checksum) {
-#if LONGSIZE != SIZE32
-               if (natint) {
-                   while (len-- > 0) {
-                       COPYNN(s, &along, sizeof(long));
-                       s += sizeof(long);
-                       if (checksum > bits_in_uv)
-                           cdouble += (NV)along;
-                       else
-                           cuv += along;
-                   }
-               }
+       case 'l':
+           while (len-- > 0) {
+               I32 ai32;
+#if U32SIZE > SIZE32
+               ai32 = 0;
+#endif
+               if (utf8) {
+                   if (!next_uni_bytes(aTHX_ &s, strend,
+                                       OFF32(&ai32), SIZE32)) break;
+               } else {
+               COPY32(s, &ai32);
+                   s += SIZE32;
+               }
+               DO_BO_UNPACK(ai32, 32);
+#if U32SIZE > SIZE32
+               if (ai32 > 2147483647) ai32 -= 4294967296;
+#endif
+               if (!checksum)
+                   PUSHs(sv_2mortal(newSViv((IV)ai32)));
+               else if (checksum > bits_in_uv)
+                   cdouble += (NV)ai32;
                else
-#endif
-                {
-                   while (len-- > 0) {
-#if LONGSIZE > SIZE32 && INTSIZE == SIZE32
-                       I32 along;
-#endif
-                       COPY32(s, &along);
-#if LONGSIZE > SIZE32
-                       if (along > 2147483647)
-                         along -= 4294967296;
-#endif
-                       s += SIZE32;
-                       if (checksum > bits_in_uv)
-                           cdouble += (NV)along;
-                       else
-                           cuv += along;
-                   }
-               }
+                   cuv += ai32;
            }
-           else {
-                if (len && (flags & UNPACK_ONLY_ONE))
-                    len = 1;
-               EXTEND(SP, len);
-               EXTEND_MORTAL(len);
+           break;
+       case 'L' | TYPE_IS_SHRIEKING:
 #if LONGSIZE != SIZE32
-               if (natint) {
-                   while (len-- > 0) {
-                       COPYNN(s, &along, sizeof(long));
-                       s += sizeof(long);
-                       sv = NEWSV(42, 0);
-                       sv_setiv(sv, (IV)along);
-                       PUSHs(sv_2mortal(sv));
-                   }
-               }
-               else
-#endif
-                {
-                   while (len-- > 0) {
-#if LONGSIZE > SIZE32 && INTSIZE == SIZE32
-                       I32 along;
-#endif
-                       COPY32(s, &along);
-#if LONGSIZE > SIZE32
-                       if (along > 2147483647)
-                         along -= 4294967296;
-#endif
-                       s += SIZE32;
-                       sv = NEWSV(42, 0);
-                       sv_setiv(sv, (IV)along);
-                       PUSHs(sv_2mortal(sv));
-                   }
-               }
+           while (len-- > 0) {
+               unsigned long aulong;
+               COPYVAR(s, strend, utf8, aulong, l);
+               if (!checksum)
+                   PUSHs(sv_2mortal(newSVuv((UV)aulong)));
+               else if (checksum > bits_in_uv)
+                   cdouble += (NV)aulong;
+               else
+                   cuv += aulong;
            }
            break;
+#else
+            /* Fall through! */
+#endif
        case 'V':
        case 'N':
        case 'L':
-#if LONGSIZE == SIZE32
-           along = (strend - s) / SIZE32;
-#else
-           unatint = natint && datumtype == 'L';
-           along = (strend - s) / (unatint ? sizeof(unsigned long) : SIZE32);
-#endif
-           if (len > along)
-               len = along;
-           if (checksum) {
-#if LONGSIZE != SIZE32
-               if (unatint) {
-                   unsigned long aulong;
-                   while (len-- > 0) {
-                       COPYNN(s, &aulong, sizeof(unsigned long));
-                       s += sizeof(unsigned long);
-                       if (checksum > bits_in_uv)
-                           cdouble += (NV)aulong;
-                       else
-                           cuv += aulong;
-                   }
-               }
-               else
-#endif
-                {
-                   while (len-- > 0) {
-                       COPY32(s, &aulong);
-                       s += SIZE32;
+           while (len-- > 0) {
+               U32 au32;
+#if U32SIZE > SIZE32
+               au32 = 0;
+#endif
+               if (utf8) {
+                   if (!next_uni_bytes(aTHX_ &s, strend,
+                                       OFF32(&au32), SIZE32)) break;
+               } else {
+               COPY32(s, &au32);
+               s += SIZE32;
+               }
+               DO_BO_UNPACK(au32, 32);
 #ifdef HAS_NTOHL
-                       if (datumtype == 'N')
-                           aulong = PerlSock_ntohl(aulong);
+               if (datumtype == 'N')
+                   au32 = PerlSock_ntohl(au32);
 #endif
 #ifdef HAS_VTOHL
-                       if (datumtype == 'V')
-                           aulong = vtohl(aulong);
+               if (datumtype == 'V')
+                   au32 = vtohl(au32);
 #endif
-                       if (checksum > bits_in_uv)
-                           cdouble += (NV)aulong;
-                       else
-                           cuv += aulong;
-                   }
-               }
+               if (!checksum)
+                    PUSHs(sv_2mortal(newSVuv((UV)au32)));
+                else if (checksum > bits_in_uv)
+                    cdouble += (NV)au32;
+                else
+                    cuv += au32;
            }
-           else {
-                if (len && (flags & UNPACK_ONLY_ONE))
-                    len = 1;
-               EXTEND(SP, len);
-               EXTEND_MORTAL(len);
-#if LONGSIZE != SIZE32
-               if (unatint) {
-                   unsigned long aulong;
-                   while (len-- > 0) {
-                       COPYNN(s, &aulong, sizeof(unsigned long));
-                       s += sizeof(unsigned long);
-                       sv = NEWSV(43, 0);
-                       sv_setuv(sv, (UV)aulong);
-                       PUSHs(sv_2mortal(sv));
-                   }
-               }
+           break;
+#ifdef PERL_PACK_CAN_SHRIEKSIGN
+       case 'V' | TYPE_IS_SHRIEKING:
+       case 'N' | TYPE_IS_SHRIEKING:
+           while (len-- > 0) {
+               I32 ai32;
+# if U32SIZE > SIZE32
+               ai32 = 0;
+# endif
+               if (utf8) {
+                   if (!next_uni_bytes(aTHX_ &s, strend,
+                                       OFF32(&ai32), SIZE32)) break;
+               } else {
+               COPY32(s, &ai32);
+               s += SIZE32;
+               }
+# ifdef HAS_NTOHL
+               if (datumtype == ('N' | TYPE_IS_SHRIEKING))
+                   ai32 = (I32)PerlSock_ntohl((U32)ai32);
+# endif
+# ifdef HAS_VTOHL
+               if (datumtype == ('V' | TYPE_IS_SHRIEKING))
+                   ai32 = (I32)vtohl((U32)ai32);
+# endif
+               if (!checksum)
+                   PUSHs(sv_2mortal(newSViv((IV)ai32)));
+               else if (checksum > bits_in_uv)
+                   cdouble += (NV)ai32;
                else
-#endif
-                {
-                   while (len-- > 0) {
-                       COPY32(s, &aulong);
-                       s += SIZE32;
-#ifdef HAS_NTOHL
-                       if (datumtype == 'N')
-                           aulong = PerlSock_ntohl(aulong);
-#endif
-#ifdef HAS_VTOHL
-                       if (datumtype == 'V')
-                           aulong = vtohl(aulong);
-#endif
-                       sv = NEWSV(43, 0);
-                       sv_setuv(sv, (UV)aulong);
-                       PUSHs(sv_2mortal(sv));
-                   }
-               }
+                   cuv += ai32;
            }
            break;
+#endif /* PERL_PACK_CAN_SHRIEKSIGN */
        case 'p':
-           along = (strend - s) / sizeof(char*);
-           if (len > along)
-               len = along;
-           EXTEND(SP, len);
-           EXTEND_MORTAL(len);
            while (len-- > 0) {
-               if (sizeof(char*) > strend - s)
-                   break;
-               else {
-                   Copy(s, &aptr, 1, char*);
-                   s += sizeof(char*);
+               char *aptr;
+               if (utf8) {
+                   if (!next_uni_bytes(aTHX_ &s, strend,
+                                       (char *) &aptr, sizeof(aptr))) break;
+               } else {
+               Copy(s, &aptr, 1, char*);
+                   s += sizeof(aptr);
                }
-               sv = NEWSV(44, 0);
-               if (aptr)
-                   sv_setpv(sv, aptr);
-               PUSHs(sv_2mortal(sv));
+               DO_BO_UNPACK_P(aptr);
+               /* newSVpv generates undef if aptr is NULL */
+               PUSHs(sv_2mortal(newSVpv(aptr, 0)));
            }
            break;
        case 'w':
-            if (len && (flags & UNPACK_ONLY_ONE))
-                len = 1;
-           EXTEND(SP, len);
-           EXTEND_MORTAL(len);
            {
                UV auv = 0;
                U32 bytes = 0;
                
-               while ((len > 0) && (s < strend)) {
-                   auv = (auv << 7) | (*s & 0x7f);
+               while (len > 0 && s < strend) {
+                   U8 ch;
+                   ch = NEXT_BYTE(utf8, s, strend, 'w');
+                   auv = (auv << 7) | (ch & 0x7f);
                    /* UTF8_IS_XXXXX not right here - using constant 0x80 */
-                   if ((U8)(*s++) < 0x80) {
+                   if (ch < 0x80) {
                        bytes = 0;
-                       sv = NEWSV(40, 0);
-                       sv_setuv(sv, auv);
-                       PUSHs(sv_2mortal(sv));
+                       PUSHs(sv_2mortal(newSVuv(auv)));
                        len--;
                        auv = 0;
+                       continue;
                    }
-                   else if (++bytes >= sizeof(UV)) {   /* promote to string */
+                   if (++bytes >= sizeof(UV)) {        /* promote to string */
                        char *t;
                        STRLEN n_a;
 
                        sv = Perl_newSVpvf(aTHX_ "%.*"UVf, (int)TYPE_DIGITS(UV), auv);
                        while (s < strend) {
-                           sv = mul128(sv, (U8)(*s & 0x7f));
-                           if (!(*s++ & 0x80)) {
+                           ch = NEXT_BYTE(utf8, s, strend, 'w');
+                           sv = mul128(sv, (U8)(ch & 0x7f));
+                           if (!(ch & 0x80)) {
                                bytes = 0;
                                break;
                            }
@@ -1315,196 +1838,123 @@ Perl_unpack_str(pTHX_ char *pat, register char *patend, register char *s, char *
                    }
                }
                if ((s >= strend) && bytes)
-                   Perl_croak(aTHX_ "Unterminated compressed integer");
+                   Perl_croak(aTHX_ "Unterminated compressed integer in unpack");
            }
            break;
        case 'P':
-           if (star > 0)
-               Perl_croak(aTHX_ "P must have an explicit size");
+           if (symptr->howlen == e_star)
+               Perl_croak(aTHX_ "'P' must have an explicit size in unpack");
            EXTEND(SP, 1);
-           if (sizeof(char*) > strend - s)
-               break;
-           else {
+           if (sizeof(char*) <= strend - s) {
+               char *aptr;
+               if (utf8) {
+                   if (!next_uni_bytes(aTHX_ &s, strend, (char *) &aptr,
+                                       sizeof(aptr))) break;
+               } else {
                Copy(s, &aptr, 1, char*);
-               s += sizeof(char*);
+                   s += sizeof(aptr);
+           }
+               DO_BO_UNPACK_P(aptr);
+           /* newSVpvn generates undef if aptr is NULL */
+           PUSHs(sv_2mortal(newSVpvn(aptr, len)));
            }
-           sv = NEWSV(44, 0);
-           if (aptr)
-               sv_setpvn(sv, aptr, len);
-           PUSHs(sv_2mortal(sv));
            break;
 #ifdef HAS_QUAD
        case 'q':
-           along = (strend - s) / sizeof(Quad_t);
-           if (len > along)
-               len = along;
-           if (checksum) {
-               while (len-- > 0) {
-                   Copy(s, &aquad, 1, Quad_t);
-                   s += sizeof(Quad_t);
-                   if (checksum > bits_in_uv)
-                       cdouble += (NV)aquad;
-                   else
-                       cuv += aquad;
-               }
+           while (len-- > 0) {
+               Quad_t aquad;
+               COPYVAR(s, strend, utf8, aquad, 64);
+               if (!checksum)
+                    PUSHs(sv_2mortal(aquad >= IV_MIN && aquad <= IV_MAX ?
+                                    newSViv((IV)aquad) : newSVnv((NV)aquad)));
+               else if (checksum > bits_in_uv)
+                   cdouble += (NV)aquad;
+               else
+                   cuv += aquad;
            }
-            else {
-                if (len && (flags & UNPACK_ONLY_ONE))
-                    len = 1;
-                EXTEND(SP, len);
-                EXTEND_MORTAL(len);
-                while (len-- > 0) {
-                    if (s + sizeof(Quad_t) > strend)
-                        aquad = 0;
-                    else {
-                       Copy(s, &aquad, 1, Quad_t);
-                       s += sizeof(Quad_t);
-                    }
-                    sv = NEWSV(42, 0);
-                    if (aquad >= IV_MIN && aquad <= IV_MAX)
-                       sv_setiv(sv, (IV)aquad);
-                    else
-                        sv_setnv(sv, (NV)aquad);
-                    PUSHs(sv_2mortal(sv));
-                }
-            }
            break;
        case 'Q':
-           along = (strend - s) / sizeof(Uquad_t);
-           if (len > along)
-               len = along;
-           if (checksum) {
-               while (len-- > 0) {
-                   Copy(s, &auquad, 1, Uquad_t);
-                   s += sizeof(Uquad_t);
-                   if (checksum > bits_in_uv)
-                       cdouble += (NV)auquad;
-                   else
-                       cuv += auquad;
-               }
+           while (len-- > 0) {
+               Uquad_t auquad;
+               COPYVAR(s, strend, utf8, auquad, 64);
+               if (!checksum)
+                   PUSHs(sv_2mortal(auquad <= UV_MAX ?
+                                    newSVuv((UV)auquad):newSVnv((NV)auquad)));
+               else if (checksum > bits_in_uv)
+                   cdouble += (NV)auquad;
+               else
+                   cuv += auquad;
            }
-            else {
-                if (len && (flags & UNPACK_ONLY_ONE))
-                    len = 1;
-                EXTEND(SP, len);
-                EXTEND_MORTAL(len);
-                while (len-- > 0) {
-                    if (s + sizeof(Uquad_t) > strend)
-                        auquad = 0;
-                    else {
-                        Copy(s, &auquad, 1, Uquad_t);
-                        s += sizeof(Uquad_t);
-                    }
-                    sv = NEWSV(43, 0);
-                    if (auquad <= UV_MAX)
-                        sv_setuv(sv, (UV)auquad);
-                    else
-                   sv_setnv(sv, (NV)auquad);
-                    PUSHs(sv_2mortal(sv));
-                }
-            }
            break;
-#endif
+#endif /* HAS_QUAD */
        /* float and double added gnb@melba.bby.oz.au 22/11/89 */
        case 'f':
-           along = (strend - s) / sizeof(float);
-           if (len > along)
-               len = along;
-           if (checksum) {
-               while (len-- > 0) {
-                   Copy(s, &afloat, 1, float);
-                   s += sizeof(float);
+           while (len-- > 0) {
+               float afloat;
+               if (utf8) {
+                   if (!next_uni_bytes(aTHX_ &s, strend, (char *) &afloat,
+                                       sizeof(afloat))) break;
+               } else {
+               Copy(s, &afloat, 1, float);
+               s += sizeof(float);
+               }
+               DO_BO_UNPACK_N(afloat, float);
+               if (!checksum)
+                   PUSHs(sv_2mortal(newSVnv((NV)afloat)));
+               else
                    cdouble += afloat;
                }
-           }
-           else {
-                if (len && (flags & UNPACK_ONLY_ONE))
-                    len = 1;
-               EXTEND(SP, len);
-               EXTEND_MORTAL(len);
-               while (len-- > 0) {
-                   Copy(s, &afloat, 1, float);
-                   s += sizeof(float);
-                   sv = NEWSV(47, 0);
-                   sv_setnv(sv, (NV)afloat);
-                   PUSHs(sv_2mortal(sv));
-               }
-           }
            break;
        case 'd':
-           along = (strend - s) / sizeof(double);
-           if (len > along)
-               len = along;
-           if (checksum) {
-               while (len-- > 0) {
-                   Copy(s, &adouble, 1, double);
-                   s += sizeof(double);
+           while (len-- > 0) {
+               double adouble;
+               if (utf8) {
+                   if (!next_uni_bytes(aTHX_ &s, strend, (char *) &adouble,
+                                       sizeof(adouble))) break;
+               } else {
+               Copy(s, &adouble, 1, double);
+               s += sizeof(double);
+               }
+               DO_BO_UNPACK_N(adouble, double);
+               if (!checksum)
+                   PUSHs(sv_2mortal(newSVnv((NV)adouble)));
+               else
                    cdouble += adouble;
                }
-           }
-           else {
-                if (len && (flags & UNPACK_ONLY_ONE))
-                    len = 1;
-               EXTEND(SP, len);
-               EXTEND_MORTAL(len);
-               while (len-- > 0) {
-                   Copy(s, &adouble, 1, double);
-                   s += sizeof(double);
-                   sv = NEWSV(48, 0);
-                   sv_setnv(sv, (NV)adouble);
-                   PUSHs(sv_2mortal(sv));
-               }
-           }
            break;
        case 'F':
-           along = (strend - s) / NVSIZE;
-           if (len > along)
-               len = along;
-           if (checksum) {
-               while (len-- > 0) {
-                   Copy(s, &anv, 1, NV);
-                   s += NVSIZE;
+           while (len-- > 0) {
+               NV anv;
+               if (utf8) {
+                   if (!next_uni_bytes(aTHX_ &s, strend,
+                                       (char *) &anv, sizeof(anv))) break;
+               } else {
+               Copy(s, &anv, 1, NV);
+               s += NVSIZE;
+               }
+               DO_BO_UNPACK_N(anv, NV);
+               if (!checksum)
+                   PUSHs(sv_2mortal(newSVnv(anv)));
+               else
                    cdouble += anv;
                }
-           }
-           else {
-                if (len && (flags & UNPACK_ONLY_ONE))
-                    len = 1;
-               EXTEND(SP, len);
-               EXTEND_MORTAL(len);
-               while (len-- > 0) {
-                   Copy(s, &anv, 1, NV);
-                   s += NVSIZE;
-                   sv = NEWSV(48, 0);
-                   sv_setnv(sv, anv);
-                   PUSHs(sv_2mortal(sv));
-               }
-           }
            break;
 #if defined(HAS_LONG_DOUBLE) && defined(USE_LONG_DOUBLE)
        case 'D':
-           along = (strend - s) / LONG_DOUBLESIZE;
-           if (len > along)
-               len = along;
-           if (checksum) {
-               while (len-- > 0) {
-                   Copy(s, &aldouble, 1, long double);
-                   s += LONG_DOUBLESIZE;
+           while (len-- > 0) {
+               long double aldouble;
+               if (utf8) {
+                   if (!next_uni_bytes(aTHX_ &s, strend, (char *) &aldouble,
+                                       sizeof(aldouble))) break;
+               } else {
+               Copy(s, &aldouble, 1, long double);
+               s += LONG_DOUBLESIZE;
+               }
+               DO_BO_UNPACK_N(aldouble, long double);
+               if (!checksum)
+                   PUSHs(sv_2mortal(newSVnv((NV)aldouble)));
+               else
                    cdouble += aldouble;
-               }
-           }
-           else {
-                if (len && (flags & UNPACK_ONLY_ONE))
-                    len = 1;
-               EXTEND(SP, len);
-               EXTEND_MORTAL(len);
-               while (len-- > 0) {
-                   Copy(s, &aldouble, 1, long double);
-                   s += LONG_DOUBLESIZE;
-                   sv = NEWSV(48, 0);
-                   sv_setnv(sv, (NV)aldouble);
-                   PUSHs(sv_2mortal(sv));
-               }
            }
            break;
 #endif
@@ -1525,11 +1975,38 @@ Perl_unpack_str(pTHX_ char *pat, register char *patend, register char *s, char *
                  */
                 PL_uudmap[' '] = 0;
             }
-
-           along = (strend - s) * 3 / 4;
-           sv = NEWSV(42, along);
-           if (along)
-               SvPOK_on(sv);
+           {
+               STRLEN l = (STRLEN) (strend - s) * 3 / 4;
+               sv = sv_2mortal(NEWSV(42, l));
+               if (l) SvPOK_on(sv);
+           }
+           if (utf8) {
+               while (next_uni_uu(aTHX_ &s, strend, &len)) {
+                   I32 a, b, c, d;
+                   char hunk[4];
+
+                   hunk[3] = '\0';
+                   while (len > 0) {
+                       next_uni_uu(aTHX_ &s, strend, &a);
+                       next_uni_uu(aTHX_ &s, strend, &b);
+                       next_uni_uu(aTHX_ &s, strend, &c);
+                       next_uni_uu(aTHX_ &s, strend, &d);
+                       hunk[0] = (char)((a << 2) | (b >> 4));
+                       hunk[1] = (char)((b << 4) | (c >> 2));
+                       hunk[2] = (char)((c << 6) | d);
+                       sv_catpvn(sv, hunk, (len > 3) ? 3 : len);
+                       len -= 3;
+                   }
+                   if (s < strend) {
+                       if (*s == '\n') s++;
+                       else {
+                           /* possible checksum byte */
+                           char *skip = s+UTF8SKIP(s);
+                           if (skip < strend && *skip == '\n') s = skip+1;
+                       }
+                   }
+               }
+           } else {
            while (s < strend && *s > ' ' && ISUUCHAR(*s)) {
                I32 a, b, c, d;
                char hunk[4];
@@ -1565,38 +2042,62 @@ Perl_unpack_str(pTHX_ char *pat, register char *patend, register char *s, char *
                    if (s + 1 < strend && s[1] == '\n')
                        s += 2;
            }
-           XPUSHs(sv_2mortal(sv));
+           }
+           XPUSHs(sv);
            break;
        }
+
        if (checksum) {
-           sv = NEWSV(42, 0);
-           if (strchr("fFdD", datumtype) ||
+           if (strchr("fFdD", TYPE_NO_MODIFIERS(datumtype)) ||
              (checksum > bits_in_uv &&
-              strchr("csSiIlLnNUvVqQjJ", datumtype)) ) {
-               NV trouble;
+              strchr("cCsSiIlLnNUWvVqQjJ", TYPE_NO_MODIFIERS(datumtype))) ) {
+               NV trouble, anv;
 
-                adouble = (NV) (1 << (checksum & 15));
+                anv = (NV) (1 << (checksum & 15));
                while (checksum >= 16) {
                    checksum -= 16;
-                   adouble *= 65536.0;
+                   anv *= 65536.0;
                }
                while (cdouble < 0.0)
-                   cdouble += adouble;
-               cdouble = Perl_modf(cdouble / adouble, &trouble) * adouble;
-               sv_setnv(sv, cdouble);
+                   cdouble += anv;
+               cdouble = Perl_modf(cdouble / anv, &trouble) * anv;
+               sv = newSVnv(cdouble);
            }
            else {
                if (checksum < bits_in_uv) {
                    UV mask = ((UV)1 << checksum) - 1;
-
                    cuv &= mask;
                }
-               sv_setuv(sv, cuv);
+               sv = newSVuv(cuv);
            }
            XPUSHs(sv_2mortal(sv));
            checksum = 0;
        }
+    
+        if (symptr->flags & FLAG_SLASH){
+            if (SP - PL_stack_base - start_sp_offset <= 0)
+                Perl_croak(aTHX_ "'/' must follow a numeric type in unpack");
+            if( next_symbol(symptr) ){
+              if( symptr->howlen == e_number )
+               Perl_croak(aTHX_ "Count after length/code in unpack" );
+              if( beyond ){
+               /* ...end of char buffer then no decent length available */
+               Perl_croak(aTHX_ "length/code after end of string in unpack" );
+              } else {
+               /* take top of stack (hope it's numeric) */
+                len = POPi;
+                if( len < 0 )
+                    Perl_croak(aTHX_ "Negative '/' count in unpack" );
+              }
+            } else {
+               Perl_croak(aTHX_ "Code missing after '/' in unpack" );
+            }
+            datumtype = symptr->code;
+            explicit_length = FALSE;
+           goto redo_switch;
+        }
     }
+
     if (new_s)
        *new_s = s;
     PUTBACK;
@@ -1610,23 +2111,17 @@ PP(pp_unpack)
     I32 gimme = GIMME_V;
     STRLEN llen;
     STRLEN rlen;
-    register char *pat = SvPV(left, llen);
-#ifdef PACKED_IS_OCTETS
-    /* Packed side is assumed to be octets - so force downgrade if it
-       has been UTF-8 encoded by accident
-     */
-    register char *s = SvPVbyte(right, rlen);
-#else
-    register char *s = SvPV(right, rlen);
-#endif
+    char *pat = SvPV(left,  llen);
+    char *s   = SvPV(right, rlen);
     char *strend = s + rlen;
-    register char *patend = pat + llen;
-    register I32 cnt;
+    char *patend = pat + llen;
+    I32 cnt;
 
     PUTBACK;
-    cnt = unpack_str(pat, patend, s, s, strend, NULL, 0,
-                    ((gimme == G_SCALAR) ? UNPACK_ONLY_ONE : 0)
-                    | (DO_UTF8(right) ? UNPACK_DO_UTF8 : 0));
+    cnt = unpackstring(pat, patend, s, strend,
+                    ((gimme == G_SCALAR) ? FLAG_UNPACK_ONLY_ONE : 0)
+                    | (DO_UTF8(right) ? FLAG_UNPACK_DO_UTF8 : 0));
+
     SPAGAIN;
     if ( !cnt && gimme == G_SCALAR )
        PUSHs(&PL_sv_undef);
@@ -1737,107 +2232,144 @@ S_div128(pTHX_ SV *pnum, bool *done)
   return (m);
 }
 
-#define PACK_CHILD     0x1
+
 
 /*
 =for apidoc pack_cat
 
-The engine implementing pack() Perl function.
+The engine implementing pack() Perl function. Note: parameters next_in_list and
+flags are not used. This call should not be used; use packlist instead.
 
 =cut */
 
+
 void
 Perl_pack_cat(pTHX_ SV *cat, char *pat, register char *patend, register SV **beglist, SV **endlist, SV ***next_in_list, U32 flags)
 {
+    tempsym_t sym = { 0 };
+    sym.patptr = pat;
+    sym.patend = patend;
+    sym.flags  = FLAG_PACK;
+
+    (void)pack_rec( cat, &sym, beglist, endlist );
+}
+
+
+/*
+=for apidoc packlist
+
+The engine implementing pack() Perl function.
+
+=cut */
+
+
+void
+Perl_packlist(pTHX_ SV *cat, char *pat, register char *patend, register SV **beglist, SV **endlist )
+{
+    tempsym_t sym = { 0 };
+    sym.patptr = pat;
+    sym.patend = patend;
+    sym.flags  = FLAG_PACK;
+
+    (void)pack_rec( cat, &sym, beglist, endlist );
+}
+
+
+STATIC
+SV **
+S_pack_rec(pTHX_ SV *cat, register tempsym_t* symptr, register SV **beglist, SV **endlist )
+{
     register I32 items;
     STRLEN fromlen;
-    register I32 len;
-    I32 datumtype;
+    register I32 len = 0;
     SV *fromstr;
     /*SUPPRESS 442*/
     static char null10[] = {0,0,0,0,0,0,0,0,0,0};
     static char *space10 = "          ";
-    int star;
+    bool found;
 
     /* These must not be in registers: */
     char achar;
-    I16 ashort;
-    int aint;
-    unsigned int auint;
-    I32 along;
-    U32 aulong;
-    IV aiv;
-    UV auv;
-    NV anv;
-#if defined(HAS_LONG_DOUBLE) && defined(USE_LONG_DOUBLE)
-    long double aldouble;
-#endif
+    I16 ai16;
+    U16 au16;
+    I32 ai32;
+    U32 au32;
 #ifdef HAS_QUAD
     Quad_t aquad;
     Uquad_t auquad;
 #endif
+#if SHORTSIZE != SIZE16
+    short ashort;
+    unsigned short aushort;
+#endif
+    int aint;
+    unsigned int auint;
+#if LONGSIZE != SIZE32
+    long along;
+    unsigned long aulong;
+#endif
     char *aptr;
     float afloat;
     double adouble;
-    int commas = 0;
-#ifdef PERL_NATINT_PACK
-    int natint;                /* native integer */
+#if defined(HAS_LONG_DOUBLE) && defined(USE_LONG_DOUBLE)
+    long double aldouble;
 #endif
+    IV aiv;
+    UV auv;
+    NV anv;
+
+    int strrelbeg = SvCUR(cat);
+    tempsym_t lookahead;
 
     items = endlist - beglist;
+    found = next_symbol( symptr );
+
 #ifndef PACKED_IS_OCTETS
-    pat = next_symbol(pat, patend);
-    if (pat < patend && *pat == 'U' && !flags)
+    if (symptr->level == 0 && found && symptr->code == 'U' ){
        SvUTF8_on(cat);
+    }
 #endif
-    while ((pat = next_symbol(pat, patend)) < patend) {
+
+    while (found) {
        SV *lengthcode = Nullsv;
 #define NEXTFROM ( lengthcode ? lengthcode : items-- > 0 ? *beglist++ : &PL_sv_no)
-       datumtype = *pat++ & 0xFF;
-#ifdef PERL_NATINT_PACK
-       natint = 0;
-#endif
-        if (*pat == '!') {
-           static const char natstr[] = "sSiIlLxX";
-
-           if (strchr(natstr, datumtype)) {
-               if (datumtype == 'x' || datumtype == 'X') {
-                   datumtype |= TYPE_IS_SHRIEKING;
-               } else {                /* XXXX Should be redone similarly! */
-#ifdef PERL_NATINT_PACK
-                   natint = 1;
-#endif
-               }
-               pat++;
-           }
-           else
-               Perl_croak(aTHX_ "'!' allowed only after types %s", natstr);
-       }
-       len = find_count(&pat, patend, &star);
-       if (star > 0)                   /* Count is '*' */
-           len = strchr("@Xxu", datumtype) ? 0 : items;
-       else if (star < 0)              /* Default len */
-           len = 1;
-       if (*pat == '/') {              /* doing lookahead how... */
-           ++pat;
-           if ((*pat != 'a' && *pat != 'A' && *pat != 'Z') || pat[1] != '*')
-               Perl_croak(aTHX_ "/ must be followed by a*, A* or Z*");
-           lengthcode = sv_2mortal(newSViv(sv_len(items > 0
+
+        I32 datumtype = symptr->code;
+        howlen_t howlen;
+
+        switch( howlen = symptr->howlen ){
+        case e_no_len:
+       case e_number:
+           len = symptr->length;
+           break;
+        case e_star:
+           len = strchr("@Xxu", TYPE_NO_MODIFIERS(datumtype)) ? 0 : items; 
+           break;
+        }
+
+        /* Look ahead for next symbol. Do we have code/code? */
+        lookahead = *symptr;
+        found = next_symbol(&lookahead);
+       if ( symptr->flags & FLAG_SLASH ) {
+           if (found){
+               if ( 0 == strchr( "aAZ", lookahead.code ) ||
+                     e_star != lookahead.howlen )
+                   Perl_croak(aTHX_ "'/' must be followed by 'a*', 'A*' or 'Z*' in pack");
+               lengthcode = sv_2mortal(newSViv(sv_len(items > 0
                                                   ? *beglist : &PL_sv_no)
-                                            + (*pat == 'Z' ? 1 : 0)));
+                                           + (lookahead.code == 'Z' ? 1 : 0)));
+           } else {
+               Perl_croak(aTHX_ "Code missing after '/' in pack");
+            }
        }
-       switch(datumtype) {
+
+       switch(TYPE_NO_ENDIANNESS(datumtype)) {
        default:
-           Perl_croak(aTHX_ "Invalid type in pack: '%c'", (int)datumtype);
-       case ',': /* grandfather in commas but with a warning */
-           if (commas++ == 0 && ckWARN(WARN_PACK))
-               Perl_warner(aTHX_ packWARN(WARN_PACK),
-                           "Invalid type in pack: '%c'", (int)datumtype);
-           break;
+           Perl_croak(aTHX_ "Invalid type '%c' in pack", (int)TYPE_NO_MODIFIERS(datumtype));
        case '%':
-           Perl_croak(aTHX_ "%% may only be used in unpack");
+           Perl_croak(aTHX_ "'%%' may not be used in pack");
        case '@':
-           len -= SvCUR(cat);
+           len += strrelbeg - SvCUR(cat);
            if (len > 0)
                goto grow;
            len = -len;
@@ -1846,27 +2378,20 @@ Perl_pack_cat(pTHX_ SV *cat, char *pat, register char *patend, register SV **beg
            break;
        case '(':
        {
-           char *beg = pat;
-           SV **savebeglist = beglist; /* beglist de-register-ed */
-
-           if (star >= 0)
-               Perl_croak(aTHX_ "()-group starts with a count");
-           aptr = group_end(beg, patend, ')');
-           pat = aptr + 1;
-           if (star != -2) {
-               len = find_count(&pat, patend, &star);
-               if (star < 0)           /* No count */
-                   len = 1;
-               else if (star > 0)      /* Star */
-                   len = items;        /* long enough? */
-           }
+            tempsym_t savsym = *symptr;
+           U32 group_modifiers = TYPE_MODIFIERS(datumtype & ~symptr->flags);
+           symptr->flags |= group_modifiers;
+            symptr->patend = savsym.grpend;
+            symptr->level++;
            while (len--) {
-               pack_cat(cat, beg, aptr, savebeglist, endlist,
-                        &savebeglist, PACK_CHILD);
-               if (star > 0 && savebeglist == endlist)
+               symptr->patptr = savsym.grpbeg;
+               beglist = pack_rec(cat, symptr, beglist, endlist );
+               if (savsym.howlen == e_star && beglist == endlist)
                    break;              /* No way to continue */
            }
-           beglist = savebeglist;
+           symptr->flags &= ~group_modifiers;
+            lookahead.flags = symptr->flags;
+            *symptr = savsym;
            break;
        }
        case 'X' | TYPE_IS_SHRIEKING:
@@ -1877,7 +2402,7 @@ Perl_pack_cat(pTHX_ SV *cat, char *pat, register char *patend, register SV **beg
        case 'X':
          shrink:
            if ((I32)SvCUR(cat) < len)
-               Perl_croak(aTHX_ "X outside of string");
+               Perl_croak(aTHX_ "'X' outside of string in pack");
            SvCUR(cat) -= len;
            *SvEND(cat) = '\0';
            break;
@@ -1890,6 +2415,7 @@ Perl_pack_cat(pTHX_ SV *cat, char *pat, register char *patend, register SV **beg
            else
                len = 0;
            /* FALL THROUGH */
+
        case 'x':
          grow:
            while (len >= 10) {
@@ -1903,14 +2429,14 @@ Perl_pack_cat(pTHX_ SV *cat, char *pat, register char *patend, register SV **beg
        case 'a':
            fromstr = NEXTFROM;
            aptr = SvPV(fromstr, fromlen);
-           if (star > 0) { /* -2 after '/' */  
+           if (howlen == e_star) {   
                len = fromlen;
                if (datumtype == 'Z')
                    ++len;
            }
            if ((I32)fromlen >= len) {
                sv_catpvn(cat, aptr, len);
-               if (datumtype == 'Z')
+               if (datumtype == 'Z' && len > 0)
                    *(SvEND(cat)-1) = '\0';
            }
            else {
@@ -1941,7 +2467,7 @@ Perl_pack_cat(pTHX_ SV *cat, char *pat, register char *patend, register SV **beg
                fromstr = NEXTFROM;
                saveitems = items;
                str = SvPV(fromstr, fromlen);
-               if (star > 0)
+               if (howlen == e_star)
                    len = fromlen;
                aint = SvCUR(cat);
                SvCUR(cat) += (len+7)/8;
@@ -1997,7 +2523,7 @@ Perl_pack_cat(pTHX_ SV *cat, char *pat, register char *patend, register SV **beg
                fromstr = NEXTFROM;
                saveitems = items;
                str = SvPV(fromstr, fromlen);
-               if (star > 0)
+               if (howlen == e_star)
                    len = fromlen;
                aint = SvCUR(cat);
                SvCUR(cat) += (len+1)/2;
@@ -2048,13 +2574,13 @@ Perl_pack_cat(pTHX_ SV *cat, char *pat, register char *patend, register SV **beg
        case 'c':
            while (len-- > 0) {
                fromstr = NEXTFROM;
-               switch (datumtype) {
+               switch (TYPE_NO_MODIFIERS(datumtype)) {
                case 'C':
                    aint = SvIV(fromstr);
                    if ((aint < 0 || aint > 255) &&
                        ckWARN(WARN_PACK))
                        Perl_warner(aTHX_ packWARN(WARN_PACK),
-                                   "Character in \"C\" format wrapped");
+                                   "Character in 'C' format wrapped in pack");
                    achar = aint & 255;
                    sv_catpvn(cat, &achar, sizeof(char));
                    break;
@@ -2063,7 +2589,7 @@ Perl_pack_cat(pTHX_ SV *cat, char *pat, register char *patend, register SV **beg
                    if ((aint < -128 || aint > 127) &&
                        ckWARN(WARN_PACK))
                        Perl_warner(aTHX_ packWARN(WARN_PACK),
-                                   "Character in \"c\" format wrapped");
+                                   "Character in 'c' format wrapped in pack" );
                    achar = aint & 255;
                    sv_catpvn(cat, &achar, sizeof(char));
                    break;
@@ -2074,7 +2600,7 @@ Perl_pack_cat(pTHX_ SV *cat, char *pat, register char *patend, register SV **beg
            while (len-- > 0) {
                fromstr = NEXTFROM;
                auint = UNI_TO_NATIVE(SvUV(fromstr));
-               SvGROW(cat, SvCUR(cat) + UTF8_MAXLEN + 1);
+               SvGROW(cat, SvCUR(cat) + UTF8_MAXBYTES + 1);
                SvCUR_set(cat,
                          (char*)uvchr_to_utf8_flags((U8*)SvEND(cat),
                                                     auint,
@@ -2101,8 +2627,20 @@ Perl_pack_cat(pTHX_ SV *cat, char *pat, register char *patend, register SV **beg
                     afloat = _float_constants[0];   /* single prec. inf. */
                else afloat = (float)SvNV(fromstr);
 #else
+# if defined(VMS) && !defined(__IEEE_FP)
+/* IEEE fp overflow shenanigans are unavailable on VAX and optional
+ * on Alpha; fake it if we don't have them.
+ */
+               if (SvNV(fromstr) > FLT_MAX)
+                    afloat = FLT_MAX;
+               else if (SvNV(fromstr) < -FLT_MAX)
+                    afloat = -FLT_MAX;
+               else afloat = (float)SvNV(fromstr);
+# else
                afloat = (float)SvNV(fromstr);
+# endif
 #endif
+               DO_BO_PACK_N(afloat, float);
                sv_catpvn(cat, (char *)&afloat, sizeof (float));
            }
            break;
@@ -2122,96 +2660,123 @@ Perl_pack_cat(pTHX_ SV *cat, char *pat, register char *patend, register SV **beg
                     adouble = _double_constants[0];   /* double prec. inf. */
                else adouble = (double)SvNV(fromstr);
 #else
+# if defined(VMS) && !defined(__IEEE_FP)
+/* IEEE fp overflow shenanigans are unavailable on VAX and optional
+ * on Alpha; fake it if we don't have them.
+ */
+               if (SvNV(fromstr) > DBL_MAX)
+                    adouble = DBL_MAX;
+               else if (SvNV(fromstr) < -DBL_MAX)
+                    adouble = -DBL_MAX;
+               else adouble = (double)SvNV(fromstr);
+# else
                adouble = (double)SvNV(fromstr);
+# endif
 #endif
+               DO_BO_PACK_N(adouble, double);
                sv_catpvn(cat, (char *)&adouble, sizeof (double));
            }
            break;
        case 'F':
+           Zero(&anv, 1, NV); /* can be long double with unused bits */
            while (len-- > 0) {
                fromstr = NEXTFROM;
                anv = SvNV(fromstr);
+               DO_BO_PACK_N(anv, NV);
                sv_catpvn(cat, (char *)&anv, NVSIZE);
            }
            break;
 #if defined(HAS_LONG_DOUBLE) && defined(USE_LONG_DOUBLE)
        case 'D':
+           /* long doubles can have unused bits, which may be nonzero */
+           Zero(&aldouble, 1, long double);
            while (len-- > 0) {
                fromstr = NEXTFROM;
                aldouble = (long double)SvNV(fromstr);
+               DO_BO_PACK_N(aldouble, long double);
                sv_catpvn(cat, (char *)&aldouble, LONG_DOUBLESIZE);
            }
            break;
 #endif
+#ifdef PERL_PACK_CAN_SHRIEKSIGN
+       case 'n' | TYPE_IS_SHRIEKING:
+#endif
        case 'n':
            while (len-- > 0) {
                fromstr = NEXTFROM;
-               ashort = (I16)SvIV(fromstr);
+               ai16 = (I16)SvIV(fromstr);
 #ifdef HAS_HTONS
-               ashort = PerlSock_htons(ashort);
+               ai16 = PerlSock_htons(ai16);
 #endif
-               CAT16(cat, &ashort);
+               CAT16(cat, &ai16);
            }
            break;
+#ifdef PERL_PACK_CAN_SHRIEKSIGN
+       case 'v' | TYPE_IS_SHRIEKING:
+#endif
        case 'v':
            while (len-- > 0) {
                fromstr = NEXTFROM;
-               ashort = (I16)SvIV(fromstr);
+               ai16 = (I16)SvIV(fromstr);
 #ifdef HAS_HTOVS
-               ashort = htovs(ashort);
+               ai16 = htovs(ai16);
 #endif
-               CAT16(cat, &ashort);
+               CAT16(cat, &ai16);
            }
            break;
-       case 'S':
+        case 'S' | TYPE_IS_SHRIEKING:
 #if SHORTSIZE != SIZE16
-           if (natint) {
-               unsigned short aushort;
-
+           {
                while (len-- > 0) {
                    fromstr = NEXTFROM;
                    aushort = SvUV(fromstr);
+                   DO_BO_PACK(aushort, s);
                    sv_catpvn(cat, (char *)&aushort, sizeof(unsigned short));
                }
-           }
-           else
+            }
+            break;
+#else
+            /* Fall through! */
 #endif
+       case 'S':
             {
-               U16 aushort;
-
                while (len-- > 0) {
                    fromstr = NEXTFROM;
-                   aushort = (U16)SvUV(fromstr);
-                   CAT16(cat, &aushort);
+                   au16 = (U16)SvUV(fromstr);
+                   DO_BO_PACK(au16, 16);
+                   CAT16(cat, &au16);
                }
 
            }
            break;
-       case 's':
+       case 's' | TYPE_IS_SHRIEKING:
 #if SHORTSIZE != SIZE16
-           if (natint) {
-               short ashort;
-
+           {
                while (len-- > 0) {
                    fromstr = NEXTFROM;
                    ashort = SvIV(fromstr);
+                   DO_BO_PACK(ashort, s);
                    sv_catpvn(cat, (char *)&ashort, sizeof(short));
                }
            }
-           else
+            break;
+#else
+            /* Fall through! */
 #endif
-            {
-               while (len-- > 0) {
-                   fromstr = NEXTFROM;
-                   ashort = (I16)SvIV(fromstr);
-                   CAT16(cat, &ashort);
-               }
+       case 's':
+           while (len-- > 0) {
+               fromstr = NEXTFROM;
+               ai16 = (I16)SvIV(fromstr);
+               DO_BO_PACK(ai16, 16);
+               CAT16(cat, &ai16);
            }
            break;
        case 'I':
+       case 'I' | TYPE_IS_SHRIEKING:
            while (len-- > 0) {
                fromstr = NEXTFROM;
                auint = SvUV(fromstr);
+               DO_BO_PACK(auint, i);
                sv_catpvn(cat, (char*)&auint, sizeof(unsigned int));
            }
            break;
@@ -2219,6 +2784,13 @@ Perl_pack_cat(pTHX_ SV *cat, char *pat, register char *patend, register SV **beg
            while (len-- > 0) {
                fromstr = NEXTFROM;
                aiv = SvIV(fromstr);
+#if IVSIZE == INTSIZE
+               DO_BO_PACK(aiv, i);
+#elif IVSIZE == LONGSIZE
+               DO_BO_PACK(aiv, l);
+#elif defined(HAS_QUAD) && IVSIZE == U64SIZE
+               DO_BO_PACK(aiv, 64);
+#endif
                sv_catpvn(cat, (char*)&aiv, IVSIZE);
            }
            break;
@@ -2226,6 +2798,13 @@ Perl_pack_cat(pTHX_ SV *cat, char *pat, register char *patend, register SV **beg
            while (len-- > 0) {
                fromstr = NEXTFROM;
                auv = SvUV(fromstr);
+#if UVSIZE == INTSIZE
+               DO_BO_PACK(auv, i);
+#elif UVSIZE == LONGSIZE
+               DO_BO_PACK(auv, l);
+#elif defined(HAS_QUAD) && UVSIZE == U64SIZE
+               DO_BO_PACK(auv, 64);
+#endif
                sv_catpvn(cat, (char*)&auv, UVSIZE);
            }
            break;
@@ -2235,7 +2814,7 @@ Perl_pack_cat(pTHX_ SV *cat, char *pat, register char *patend, register SV **beg
                anv = SvNV(fromstr);
 
                if (anv < 0)
-                   Perl_croak(aTHX_ "Cannot compress negative numbers");
+                   Perl_croak(aTHX_ "Cannot compress negative numbers in pack");
 
                 /* 0xFFFFFFFFFFFFFFFF may cast to 18446744073709551616.0,
                    which is == UV_MAX_P1. IOK is fine (instead of UV_only), as
@@ -2264,7 +2843,7 @@ Perl_pack_cat(pTHX_ SV *cat, char *pat, register char *patend, register SV **beg
                    /* Copy string and check for compliance */
                    from = SvPV(fromstr, len);
                    if ((norm = is_an_int(from, len)) == NULL)
-                       Perl_croak(aTHX_ "can compress only unsigned integer");
+                       Perl_croak(aTHX_ "Can only compress unsigned integers in pack");
 
                    New('w', result, len, char);
                    in = result + len;
@@ -2277,15 +2856,31 @@ Perl_pack_cat(pTHX_ SV *cat, char *pat, register char *patend, register SV **beg
                    SvREFCNT_dec(norm); /* free norm */
                 }
                else if (SvNOKp(fromstr)) {
-                   char   buf[sizeof(NV) * 2]; /* 8/7 <= 2 */
+                   /* 10**NV_MAX_10_EXP is the largest power of 10
+                      so 10**(NV_MAX_10_EXP+1) is definately unrepresentable
+                      given 10**(NV_MAX_10_EXP+1) == 128 ** x solve for x:
+                      x = (NV_MAX_10_EXP+1) * log (10) / log (128)
+                      And with that many bytes only Inf can overflow.
+                      Some C compilers are strict about integral constant
+                      expressions so we conservatively divide by a slightly
+                      smaller integer instead of multiplying by the exact
+                      floating-point value.
+                   */
+#ifdef NV_MAX_10_EXP
+/*                 char   buf[1 + (int)((NV_MAX_10_EXP + 1) * 0.47456)]; -- invalid C */
+                   char   buf[1 + (int)((NV_MAX_10_EXP + 1) / 2)]; /* valid C */
+#else
+/*                 char   buf[1 + (int)((308 + 1) * 0.47456)]; -- invalid C */
+                   char   buf[1 + (int)((308 + 1) / 2)]; /* valid C */
+#endif
                    char  *in = buf + sizeof(buf);
 
                     anv = Perl_floor(anv);
                    do {
                        NV next = Perl_floor(anv / 128);
-                       *--in = (unsigned char)(anv - (next * 128)) | 0x80;
                        if (in <= buf)  /* this cannot happen ;-) */
-                           Perl_croak(aTHX_ "Cannot compress integer");
+                           Perl_croak(aTHX_ "Cannot compress integer in pack");
+                       *--in = (unsigned char)(anv - (next * 128)) | 0x80;
                        anv = next;
                    } while (anv > 0);
                    buf[sizeof(buf) - 1] &= 0x7f; /* clear continue bit */
@@ -2300,7 +2895,7 @@ Perl_pack_cat(pTHX_ SV *cat, char *pat, register char *patend, register SV **beg
                    /* Copy string and check for compliance */
                    from = SvPV(fromstr, len);
                    if ((norm = is_an_int(from, len)) == NULL)
-                       Perl_croak(aTHX_ "can compress only unsigned integer");
+                       Perl_croak(aTHX_ "Can only compress unsigned integers in pack");
 
                    New('w', result, len, char);
                    in = result + len;
@@ -2315,72 +2910,84 @@ Perl_pack_cat(pTHX_ SV *cat, char *pat, register char *patend, register SV **beg
            }
             break;
        case 'i':
+       case 'i' | TYPE_IS_SHRIEKING:
            while (len-- > 0) {
                fromstr = NEXTFROM;
                aint = SvIV(fromstr);
+               DO_BO_PACK(aint, i);
                sv_catpvn(cat, (char*)&aint, sizeof(int));
            }
            break;
+#ifdef PERL_PACK_CAN_SHRIEKSIGN
+       case 'N' | TYPE_IS_SHRIEKING:
+#endif
        case 'N':
            while (len-- > 0) {
                fromstr = NEXTFROM;
-               aulong = SvUV(fromstr);
+               au32 = SvUV(fromstr);
 #ifdef HAS_HTONL
-               aulong = PerlSock_htonl(aulong);
+               au32 = PerlSock_htonl(au32);
 #endif
-               CAT32(cat, &aulong);
+               CAT32(cat, &au32);
            }
            break;
+#ifdef PERL_PACK_CAN_SHRIEKSIGN
+       case 'V' | TYPE_IS_SHRIEKING:
+#endif
        case 'V':
            while (len-- > 0) {
                fromstr = NEXTFROM;
-               aulong = SvUV(fromstr);
+               au32 = SvUV(fromstr);
 #ifdef HAS_HTOVL
-               aulong = htovl(aulong);
+               au32 = htovl(au32);
 #endif
-               CAT32(cat, &aulong);
+               CAT32(cat, &au32);
            }
            break;
-       case 'L':
+       case 'L' | TYPE_IS_SHRIEKING:
 #if LONGSIZE != SIZE32
-           if (natint) {
-               unsigned long aulong;
-
+           {
                while (len-- > 0) {
                    fromstr = NEXTFROM;
                    aulong = SvUV(fromstr);
+                   DO_BO_PACK(aulong, l);
                    sv_catpvn(cat, (char *)&aulong, sizeof(unsigned long));
                }
            }
-           else
+           break;
+#else
+            /* Fall though! */
 #endif
+       case 'L':
             {
                while (len-- > 0) {
                    fromstr = NEXTFROM;
-                   aulong = SvUV(fromstr);
-                   CAT32(cat, &aulong);
+                   au32 = SvUV(fromstr);
+                   DO_BO_PACK(au32, 32);
+                   CAT32(cat, &au32);
                }
            }
            break;
-       case 'l':
+       case 'l' | TYPE_IS_SHRIEKING:
 #if LONGSIZE != SIZE32
-           if (natint) {
-               long along;
-
+           {
                while (len-- > 0) {
                    fromstr = NEXTFROM;
                    along = SvIV(fromstr);
+                   DO_BO_PACK(along, l);
                    sv_catpvn(cat, (char *)&along, sizeof(long));
                }
            }
-           else
+           break;
+#else
+            /* Fall though! */
 #endif
-            {
-               while (len-- > 0) {
-                   fromstr = NEXTFROM;
-                   along = SvIV(fromstr);
-                   CAT32(cat, &along);
-               }
+       case 'l':
+            while (len-- > 0) {
+               fromstr = NEXTFROM;
+               ai32 = SvIV(fromstr);
+               DO_BO_PACK(ai32, 32);
+               CAT32(cat, &ai32);
            }
            break;
 #ifdef HAS_QUAD
@@ -2388,6 +2995,7 @@ Perl_pack_cat(pTHX_ SV *cat, char *pat, register char *patend, register SV **beg
            while (len-- > 0) {
                fromstr = NEXTFROM;
                auquad = (Uquad_t)SvUV(fromstr);
+               DO_BO_PACK(auquad, 64);
                sv_catpvn(cat, (char*)&auquad, sizeof(Uquad_t));
            }
            break;
@@ -2395,18 +3003,19 @@ Perl_pack_cat(pTHX_ SV *cat, char *pat, register char *patend, register SV **beg
            while (len-- > 0) {
                fromstr = NEXTFROM;
                aquad = (Quad_t)SvIV(fromstr);
+               DO_BO_PACK(aquad, 64);
                sv_catpvn(cat, (char*)&aquad, sizeof(Quad_t));
            }
            break;
 #endif
        case 'P':
            len = 1;            /* assume SV is correct length */
-           /* FALL THROUGH */
+           /* Fall through! */
        case 'p':
            while (len-- > 0) {
                fromstr = NEXTFROM;
-               if (fromstr == &PL_sv_undef)
-                   aptr = NULL;
+               SvGETMAGIC(fromstr);
+               if (!SvOK(fromstr)) aptr = NULL;
                else {
                    STRLEN n_a;
                    /* XXX better yet, could spirit away the string to
@@ -2422,10 +3031,11 @@ Perl_pack_cat(pTHX_ SV *cat, char *pat, register char *patend, register SV **beg
                                "Attempt to pack pointer to temporary value");
                    }
                    if (SvPOK(fromstr) || SvNIOK(fromstr))
-                       aptr = SvPV(fromstr,n_a);
+                       aptr = SvPV_flags(fromstr, n_a, 0);
                    else
-                       aptr = SvPV_force(fromstr,n_a);
+                       aptr = SvPV_force_flags(fromstr, n_a, 0);
                }
+               DO_BO_PACK_P(aptr);
                sv_catpvn(cat, (char*)&aptr, sizeof(char*));
            }
            break;
@@ -2450,9 +3060,9 @@ Perl_pack_cat(pTHX_ SV *cat, char *pat, register char *patend, register SV **beg
            }
            break;
        }
+       *symptr = lookahead;
     }
-    if (next_in_list)
-       *next_in_list = beglist;
+    return beglist;
 }
 #undef NEXTFROM
 
@@ -2468,7 +3078,7 @@ PP(pp_pack)
     MARK++;
     sv_setpvn(cat, "", 0);
 
-    pack_cat(cat, pat, patend, MARK, SP + 1, NULL, 0);
+    packlist(cat, pat, patend, MARK, SP + 1);
 
     SvSETMAGIC(cat);
     SP = ORIGMARK;
@@ -2476,3 +3086,12 @@ PP(pp_pack)
     RETURN;
 }
 
+/*
+ * Local variables:
+ * c-indentation-style: bsd
+ * c-basic-offset: 4
+ * indent-tabs-mode: t
+ * End:
+ *
+ * vim: shiftwidth=4:
+*/