mirror/perl
1
0
Fork 0
mirror of https://github.com/Perl/perl5.git synced 2026-01-26 16:39:36 +00:00
Code Issues Packages Projects Releases Wiki Activity

Perl_av_extend_guts: use Zero() rather than a while loop to set NULLs

Browse Source
This commit is contained in:
Richard Leach 2020-08-18 19:28:04 +01:00 committed by Karl Williamson
parent 440c1856da
commit 399fef93c9
1 changed files with 42 additions and 35 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

77
av.c
View File

@ -95,6 +95,7 @@ Perl_av_extend(pTHX_ AV *av, SSize_t key)
}
/* The guts of av_extend. *Not* for general use! */
/* Also called directly from pp_assign, padlist_store, padnamelist_store */
void
Perl_av_extend_guts(pTHX_ AV *av, SSize_t key, SSize_t *maxp, SV ***allocp,
SV ***arrayp)
@ -106,25 +107,21 @@ Perl_av_extend_guts(pTHX_ AV *av, SSize_t key, SSize_t *maxp, SV ***allocp,
"panic: av_extend_guts() negative count (%" IVdf ")", (IV)key);
if (key > *maxp) {
SV** ary;
SSize_t tmp;
SSize_t newmax;
SSize_t ary_offset = *maxp + 1;
SSize_t to_null = 0;
SSize_t newmax = 0;
if (av && *allocp != *arrayp) { /* a shifted SV* array exists */
to_null = *arrayp - *allocp;
*maxp += to_null;
if (av && *allocp != *arrayp) {
ary = *allocp + AvFILLp(av) + 1;
tmp = *arrayp - *allocp;
Move(*arrayp, *allocp, AvFILLp(av)+1, SV*);
*maxp += tmp;
*arrayp = *allocp;
if (AvREAL(av)) {
while (tmp)
ary[--tmp] = NULL;
}
if (key > *maxp - 10) {
newmax = key + *maxp;
goto resize;
}
} else if (*allocp) {
} else if (*allocp) { /* a full SV* array exists */
#ifdef Perl_safesysmalloc_size
/* Whilst it would be quite possible to move this logic around
@ -151,15 +148,15 @@ Perl_av_extend_guts(pTHX_ AV *av, SSize_t key, SSize_t *maxp, SV ***allocp,
newmax = (key > SSize_t_MAX - newmax)
? SSize_t_MAX : key + newmax;
resize:
{
/* it should really be newmax+1 here, but if newmax
* happens to equal SSize_t_MAX, then newmax+1 is
* undefined. This means technically we croak one
* index lower than we should in theory; in practice
* its unlikely the system has SSize_t_MAX/sizeof(SV*)
* bytes to spare! */
MEM_WRAP_CHECK_s(newmax, SV*, "Out of memory during array extend");
}
{
/* it should really be newmax+1 here, but if newmax
* happens to equal SSize_t_MAX, then newmax+1 is
* undefined. This means technically we croak one
* index lower than we should in theory; in practice
* its unlikely the system has SSize_t_MAX/sizeof(SV*)
* bytes to spare! */
MEM_WRAP_CHECK_s(newmax, SV*, "Out of memory during array extend");
}
#ifdef STRESS_REALLOC
{
SV ** const old_alloc = *allocp;
@ -173,31 +170,41 @@ Perl_av_extend_guts(pTHX_ AV *av, SSize_t key, SSize_t *maxp, SV ***allocp,
#ifdef Perl_safesysmalloc_size
resized:
#endif
ary = *allocp + *maxp + 1;
tmp = newmax - *maxp;
if (av == PL_curstack) { /* Oops, grew stack (via av_store()?) */
to_null += newmax - *maxp;
*maxp = newmax;
/* See GH#18014 for discussion of when this might be needed: */
if (av == PL_curstack) { /* Oops, grew stack (via av_store()?) */
PL_stack_sp = *allocp + (PL_stack_sp - PL_stack_base);
PL_stack_base = *allocp;
PL_stack_max = PL_stack_base + newmax;
}
} else {
newmax = key < 3 ? 3 : key;
} else { /* there is no SV* array yet */
*maxp = key < 3 ? 3 : key;
{
/* see comment above about newmax+1*/
MEM_WRAP_CHECK_s(newmax, SV*, "Out of memory during array extend");
MEM_WRAP_CHECK_s(*maxp, SV*,
"Out of memory during array extend");
}
Newx(*allocp, newmax+1, SV*);
ary = *allocp + 1;
tmp = newmax;
*allocp[0] = NULL; /* For the stacks */
/* Newxz isn't used below because testing showed it to be slower
* than Newx+Zero (also slower than Newx + the previous while
* loop) for small arrays, which are very common in perl. */
Newx(*allocp, *maxp+1, SV*);
/* Stacks require only the first element to be &PL_sv_undef
* (set elsewhere). However, since non-stack AVs are likely
* to dominate in modern production applications, stacks
* don't get any special treatment here. */
ary_offset = 0;
to_null = *maxp+1;
goto zero;
}
if (av && AvREAL(av)) {
while (tmp)
ary[--tmp] = NULL;
zero:
Zero(*allocp + ary_offset,to_null,SV*);
}
*arrayp = *allocp;
*maxp = newmax;
}
}