/* hv.h
*
- * Copyright (c) 1991-2000, Larry Wall
+ * Copyright (c) 1991-2001, Larry Wall
*
* You may distribute under the terms of either the GNU General Public
* License or the Artistic License, as specified in the README file.
*
*/
+/* typedefs to eliminate some typing */
typedef struct he HE;
typedef struct hek HEK;
+/* entry in hash value chain */
struct he {
- HE *hent_next;
- HEK *hent_hek;
- SV *hent_val;
+ HE *hent_next; /* next entry in chain */
+ HEK *hent_hek; /* hash key */
+ SV *hent_val; /* scalar value that was hashed */
};
+/* hash key -- defined separately for use as shared pointer */
struct hek {
- U32 hek_hash;
- I32 hek_len;
- char hek_key[1];
+ U32 hek_hash; /* hash of key */
+ I32 hek_len; /* length of hash key */
+ char hek_key[1]; /* variable-length hash key */
};
+/* hash structure: */
/* This structure must match the beginning of struct xpvmg in sv.h. */
struct xpvhv {
char * xhv_array; /* pointer to malloced string */
STRLEN xhv_max; /* subscript of last element of xhv_array */
IV xhv_keys; /* how many elements in the array */
NV xnv_nv; /* numeric value, if any */
+#define xhv_placeholders xnv_nv
MAGIC* xmg_magic; /* magic for scalar array */
HV* xmg_stash; /* class package */
char *xhv_name; /* name, if a symbol table */
};
+/* hash a key */
+/* FYI: This is the "One-at-a-Time" algorithm by Bob Jenkins */
+/* from requirements by Colin Plumb. */
+/* (http://burtleburtle.net/bob/hash/doobs.html) */
#define PERL_HASH(hash,str,len) \
STMT_START { \
register const char *s_PeRlHaSh = str; \
register I32 i_PeRlHaSh = len; \
register U32 hash_PeRlHaSh = 0; \
- while (i_PeRlHaSh--) \
- hash_PeRlHaSh = hash_PeRlHaSh * 33 + *s_PeRlHaSh++; \
- (hash) = hash_PeRlHaSh + (hash_PeRlHaSh>>5); \
+ while (i_PeRlHaSh--) { \
+ hash_PeRlHaSh += *s_PeRlHaSh++; \
+ hash_PeRlHaSh += (hash_PeRlHaSh << 10); \
+ hash_PeRlHaSh ^= (hash_PeRlHaSh >> 6); \
+ } \
+ hash_PeRlHaSh += (hash_PeRlHaSh << 3); \
+ hash_PeRlHaSh ^= (hash_PeRlHaSh >> 11); \
+ (hash) = (hash_PeRlHaSh + (hash_PeRlHaSh << 15)); \
} STMT_END
/*
+=head1 Hash Manipulation Functions
+
=for apidoc AmU||HEf_SVKEY
This flag, used in the length slot of hash entries and magic structures,
-specifies the structure contains a C<SV*> pointer where a C<char*> pointer
+specifies the structure contains an C<SV*> pointer where a C<char*> pointer
is to be expected. (For information only--not to be used).
+=head1 Handy Values
+
=for apidoc AmU||Nullhv
Null HV pointer.
+=head1 Hash Manipulation Functions
+
=for apidoc Am|char*|HvNAME|HV* stash
Returns the package name of a stash. See C<SvSTASH>, C<CvSTASH>.
*/
/* these hash entry flags ride on hent_klen (for use only in magic/tied HVs) */
-#define HEf_SVKEY -2 /* hent_key is a SV* */
+#define HEf_SVKEY -2 /* hent_key is an SV* */
#define Nullhv Null(HV*)
-#define HvARRAY(hv) ((HE**)((XPVHV*) SvANY(hv))->xhv_array)
+#define HvARRAY(hv) (*(HE***)&((XPVHV*) SvANY(hv))->xhv_array)
#define HvFILL(hv) ((XPVHV*) SvANY(hv))->xhv_fill
#define HvMAX(hv) ((XPVHV*) SvANY(hv))->xhv_max
-#define HvKEYS(hv) ((XPVHV*) SvANY(hv))->xhv_keys
#define HvRITER(hv) ((XPVHV*) SvANY(hv))->xhv_riter
#define HvEITER(hv) ((XPVHV*) SvANY(hv))->xhv_eiter
#define HvPMROOT(hv) ((XPVHV*) SvANY(hv))->xhv_pmroot
#define HvNAME(hv) ((XPVHV*) SvANY(hv))->xhv_name
+/* the number of keys (including any placeholers) */
+#define XHvTOTALKEYS(xhv) ((xhv)->xhv_keys)
+
+/* The number of placeholders in the enumerated-keys hash */
+#define XHvPLACEHOLDERS(xhv) ((xhv)->xhv_placeholders)
+
+/* the number of keys that exist() (i.e. excluding placeholers) */
+#define XHvUSEDKEYS(xhv) (XHvTOTALKEYS(xhv) - XHvPLACEHOLDERS(xhv))
+
+/*
+ * HvKEYS gets the number of keys that actually exist(), and is provided
+ * for backwards compatibility with old XS code. The core uses HvUSEDKEYS
+ * (keys, excluding placeholdes) and HvTOTALKEYS (including placeholders)
+ */
+#define HvKEYS(hv) XHvUSEDKEYS((XPVHV*) SvANY(hv))
+#define HvUSEDKEYS(hv) XHvUSEDKEYS((XPVHV*) SvANY(hv))
+#define HvTOTALKEYS(hv) XHvTOTALKEYS((XPVHV*) SvANY(hv))
+#define HvPLACEHOLDERS(hv) XHvPLACEHOLDERS((XPVHV*) SvANY(hv))
+
+
#define HvSHAREKEYS(hv) (SvFLAGS(hv) & SVphv_SHAREKEYS)
#define HvSHAREKEYS_on(hv) (SvFLAGS(hv) |= SVphv_SHAREKEYS)
#define HvSHAREKEYS_off(hv) (SvFLAGS(hv) &= ~SVphv_SHAREKEYS)
#define HeKEY(he) HEK_KEY(HeKEY_hek(he))
#define HeKEY_sv(he) (*(SV**)HeKEY(he))
#define HeKLEN(he) HEK_LEN(HeKEY_hek(he))
+#define HeKUTF8(he) HEK_UTF8(HeKEY_hek(he))
+#define HeKLEN_UTF8(he) (HeKUTF8(he) ? -HeKLEN(he) : HeKLEN(he))
#define HeVAL(he) (he)->hent_val
#define HeHASH(he) HEK_HASH(HeKEY_hek(he))
#define HePV(he,lp) ((HeKLEN(he) == HEf_SVKEY) ? \
#define HEK_HASH(hek) (hek)->hek_hash
#define HEK_LEN(hek) (hek)->hek_len
#define HEK_KEY(hek) (hek)->hek_key
+#define HEK_UTF8(hek) (*(HEK_KEY(hek)+HEK_LEN(hek)))
+/* calculate HV array allocation */
#if defined(STRANGE_MALLOC) || defined(MYMALLOC)
# define PERL_HV_ARRAY_ALLOC_BYTES(size) ((size) * sizeof(HE*))
#else
? (size) * sizeof(HE*) \
: (size) * sizeof(HE*) * 2 - MALLOC_OVERHEAD)
#endif
+
+/* available as a function in hv.c */
+#define Perl_sharepvn(sv, len, hash) HEK_KEY(share_hek(sv, len, hash))
+#define sharepvn(sv, len, hash) Perl_sharepvn(sv, len, hash)