offset as either a byte (if <256), or a 0 byte with a STRLEN before.
"better" in that the reading can be inlined, and even then the object
code is smaller (function calls have space overhead). So goodbye
Perl_sv_read_offset() and hello SvOOK_offset().
p4raw-id: //depot/perl@32838
}
if (type <= SVt_PVLV && !isGV_with_GP(sv)) {
if (SvPVX_const(sv)) {
- UV delta = SvOOK(sv) ? sv_read_offset(sv) : 0;
+ STRLEN delta;
if (SvOOK(sv)) {
+ SvOOK_offset(sv, delta);
Perl_dump_indent(aTHX_ level, file," OFFSET = %"UVuf"\n",
delta);
+ } else {
+ delta = 0;
}
Perl_dump_indent(aTHX_ level, file," PV = 0x%"UVxf" ", PTR2UV(SvPVX_const(sv)));
if (SvOOK(sv)) {
Amdb |char* |sv_pvn_force |NN SV* sv|NULLOK STRLEN* lp
Apd |char* |sv_pvutf8n_force|NN SV* sv|NULLOK STRLEN* lp
Apd |char* |sv_pvbyten_force|NN SV* sv|NULLOK STRLEN* lp
-Ap |UV |sv_read_offset |NN const SV *const sv
Apd |char* |sv_recode_to_utf8 |NN SV* sv|NN SV *encoding
Apd |bool |sv_cat_decode |NN SV* dsv|NN SV *encoding|NN SV *ssv|NN int *offset \
|NN char* tstr|int tlen
#define sv_pos_b2u Perl_sv_pos_b2u
#define sv_pvutf8n_force Perl_sv_pvutf8n_force
#define sv_pvbyten_force Perl_sv_pvbyten_force
-#define sv_read_offset Perl_sv_read_offset
#define sv_recode_to_utf8 Perl_sv_recode_to_utf8
#define sv_cat_decode Perl_sv_cat_decode
#define sv_reftype Perl_sv_reftype
#define sv_pos_b2u(a,b) Perl_sv_pos_b2u(aTHX_ a,b)
#define sv_pvutf8n_force(a,b) Perl_sv_pvutf8n_force(aTHX_ a,b)
#define sv_pvbyten_force(a,b) Perl_sv_pvbyten_force(aTHX_ a,b)
-#define sv_read_offset(a) Perl_sv_read_offset(aTHX_ a)
#define sv_recode_to_utf8(a,b) Perl_sv_recode_to_utf8(aTHX_ a,b)
#define sv_cat_decode(a,b,c,d,e,f) Perl_sv_cat_decode(aTHX_ a,b,c,d,e,f)
#define sv_reftype(a,b) Perl_sv_reftype(aTHX_ a,b)
Perl_sv_pvn_force
Perl_sv_pvutf8n_force
Perl_sv_pvbyten_force
-Perl_sv_read_offset
Perl_sv_recode_to_utf8
Perl_sv_cat_decode
Perl_sv_reftype
=item SvOOK
X<SvOOK>
-Returns a U32 indicating whether the SvIVX is a valid offset value for
-the SvPVX. This hack is used internally to speed up removal of characters
-from the beginning of a SvPV. When SvOOK is true, then the start of the
-allocated string buffer is really (SvPVX - SvIVX).
+Returns a U32 indicating whether the pointer to the string buffer is offset.
+This hack is used internally to speed up removal of characters from the
+beginning of a SvPV. When SvOOK is true, then the start of the
+allocated string buffer is actually C<SvOOK_offset()> bytes before SvPVX.
+This offset used to be stored in SvIVX, but is now stored within the spare
+part of the buffer.
U32 SvOOK(SV* sv)
=for hackers
Found in file sv.h
+=item SvOOK_offset
+X<SvOOK_offset>
+
+Reads into I<len> the offset from SvPVX back to the true start of the
+allocated buffer, which will be non-zero if C<sv_chop> has been used to
+efficiently remove characters from start of the buffer. Implemented as a
+macro, which takes the address of I<len>, which must be of type C<STRLEN>.
+Evaluates I<sv> more than once. Sets I<len> to 0 if C<SvOOK(sv)> is false.
+
+ void SvOOK_offset(NN SV*sv, STRLEN len)
+
+=for hackers
+Found in file sv.h
+
=item SvPOK
X<SvPOK>
PERL_CALLCONV char* Perl_sv_pvbyten_force(pTHX_ SV* sv, STRLEN* lp)
__attribute__nonnull__(pTHX_1);
-PERL_CALLCONV UV Perl_sv_read_offset(pTHX_ const SV *const sv)
- __attribute__nonnull__(pTHX_1);
-
PERL_CALLCONV char* Perl_sv_recode_to_utf8(pTHX_ SV* sv, SV *encoding)
__attribute__nonnull__(pTHX_1)
__attribute__nonnull__(pTHX_2);
int
Perl_sv_backoff(pTHX_ register SV *sv)
{
- UV delta = sv_read_offset(sv);
+ STRLEN delta;
const char * const s = SvPVX_const(sv);
PERL_UNUSED_CONTEXT;
assert(SvOOK(sv));
assert(SvTYPE(sv) != SVt_PVHV);
assert(SvTYPE(sv) != SVt_PVAV);
+ SvOOK_offset(sv, delta);
+
SvLEN_set(sv, SvLEN(sv) + delta);
SvPV_set(sv, SvPVX(sv) - delta);
Move(s, SvPVX(sv), SvCUR(sv)+1, char);
sv_unglob(sv);
}
-UV
-Perl_sv_read_offset(pTHX_ const SV *const sv) {
- U8 *p;
- UV delta = 0;
- U8 c;
-
- if (!SvOOK(sv))
- return 0;
- p = (U8*)SvPVX_const(sv);
- if (!p)
- return 0;
-
- c = *--p;
- delta = c & 0x7F;
- while ((c & 0x80)) {
- UV const last_delta = delta;
- delta <<= 7;
- if (delta < last_delta)
- Perl_croak(aTHX_ "panic: overflow in sv_read_offset from %"UVuf
- " to %"UVuf, last_delta, delta);
- c = *--p;
- delta |= c & 0x7F;
- }
-#ifdef DEBUGGING
- {
- /* Validate the preceding buffer's sentinels to verify that no-one is
- using it. */
- const U8 *const real_start = (U8 *) SvPVX_const(sv) - delta;
- while (p > real_start) {
- --p;
- assert (*p == (U8)PTR2UV(p));
- }
- }
-#endif
- return delta;
-}
-
/*
=for apidoc sv_chop
void
Perl_sv_chop(pTHX_ register SV *sv, register const char *ptr)
{
- register STRLEN delta;
- UV old_delta;
+ STRLEN delta;
+ STRLEN old_delta;
U8 *p;
#ifdef DEBUGGING
const U8 *real_start;
SvFLAGS(sv) |= SVf_OOK;
old_delta = 0;
} else {
- old_delta = sv_read_offset(sv);
+ SvOOK_offset(sv, old_delta);
}
SvLEN_set(sv, SvLEN(sv) - delta);
SvCUR_set(sv, SvCUR(sv) - delta);
real_start = p - delta;
#endif
- if (delta < 0x80) {
+ assert(delta);
+ if (delta < 0x100) {
*--p = (U8) delta;
} else {
- /* Code lovingly ripped from pp_pack.c: */
- U8 buf[(sizeof(UV)*CHAR_BIT)/7+1];
- U8 *in = buf;
- STRLEN len;
- do {
- *in++ = (U8)((delta & 0x7f) | 0x80);
- delta >>= 7;
- } while (delta);
- buf[0] &= 0x7f; /* clear continue bit */
-
- len = in - buf;
- p -= len;
- Copy(buf, p, len, U8);
+ *--p = 0;
+ p -= sizeof(STRLEN);
+ Copy((U8*)&delta, p, sizeof(STRLEN), U8);
}
#ifdef DEBUGGING
freescalar:
/* Don't bother with SvOOK_off(sv); as we're only going to free it. */
if (SvOOK(sv)) {
- SvPV_set(sv, SvPVX_mutable(sv) - sv_read_offset(sv));
+ STRLEN offset;
+ SvOOK_offset(sv, offset);
+ SvPV_set(sv, SvPVX_mutable(sv) - offset);
/* Don't even bother with turning off the OOK flag. */
}
if (SvROK(sv)) {
Returns a boolean indicating whether the SV contains a v-string.
=for apidoc Am|U32|SvOOK|SV* sv
-Returns a U32 indicating whether the SvIVX is a valid offset value for
-the SvPVX. This hack is used internally to speed up removal of characters
-from the beginning of a SvPV. When SvOOK is true, then the start of the
-allocated string buffer is really (SvPVX - SvIVX).
+Returns a U32 indicating whether the pointer to the string buffer is offset.
+This hack is used internally to speed up removal of characters from the
+beginning of a SvPV. When SvOOK is true, then the start of the
+allocated string buffer is actually C<SvOOK_offset()> bytes before SvPVX.
+This offset used to be stored in SvIVX, but is now stored within the spare
+part of the buffer.
=for apidoc Am|U32|SvROK|SV* sv
Tests if the SV is an RV.
if (SvLEN(sv)) { \
assert(!SvROK(sv)); \
if(SvOOK(sv)) { \
- SvPV_set(sv, SvPVX_mutable(sv) \
- - sv_read_offset(sv)); \
+ STRLEN zok; \
+ SvOOK_offset(sv, zok); \
+ SvPV_set(sv, SvPVX_mutable(sv) - zok); \
SvFLAGS(sv) &= ~SVf_OOK; \
} \
Safefree(SvPVX(sv)); \
#define newSVpvn_utf8(s, len, u) newSVpvn_flags((s), (len), (u) ? SVf_UTF8 : 0)
/*
+=for apidoc Am|void|SvOOK_offset|NN SV*sv|STRLEN len
+
+Reads into I<len> the offset from SvPVX back to the true start of the
+allocated buffer, which will be non-zero if C<sv_chop> has been used to
+efficiently remove characters from start of the buffer. Implemented as a
+macro, which takes the address of I<len>, which must be of type C<STRLEN>.
+Evaluates I<sv> more than once. Sets I<len> to 0 if C<SvOOK(sv)> is false.
+
+=cut
+*/
+
+#ifdef DEBUGGING
+/* Does the bot know something I don't?
+10:28 <@Nicholas> metabatman
+10:28 <+meta> Nicholas: crash
+*/
+# define SvOOK_offset(sv, offset) STMT_START { \
+ assert(sizeof(offset) == sizeof(STRLEN)); \
+ if (SvOOK(sv)) { \
+ const U8 *crash = (U8*)SvPVX_const(sv); \
+ offset = *--crash; \
+ if (!offset) { \
+ crash -= sizeof(STRLEN); \
+ Copy(crash, (U8 *)&offset, sizeof(STRLEN), U8); \
+ } \
+ { \
+ /* Validate the preceding buffer's sentinels to \
+ verify that no-one is using it. */ \
+ const U8 *const bonk = (U8 *) SvPVX_const(sv) - offset; \
+ while (crash > bonk) { \
+ --crash; \
+ assert (*crash == (U8)PTR2UV(crash)); \
+ } \
+ } \
+ } else { \
+ offset = 0; \
+ } \
+ } STMT_END
+#else
+ /* This is the same code, but avoids using any temporary variables: */
+# define SvOOK_offset(sv, offset) STMT_START { \
+ assert(sizeof(offset) == sizeof(STRLEN)); \
+ if (SvOOK(sv)) { \
+ offset = ((U8*)SvPVX_const(sv))[-1]; \
+ if (!offset) { \
+ Copy(SvPVX_const(sv) - 1 - sizeof(STRLEN), \
+ (U8 *)&offset, sizeof(STRLEN), U8); \
+ } \
+ } else { \
+ offset = 0; \
+ } \
+ } STMT_END
+#endif
+/*
* Local variables:
* c-indentation-style: bsd
* c-basic-offset: 4
projects / p5sagit/p5-mst-13.2.git / commitdiff