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stdlib: qsort and bsearch changes.
- Always use internal qsort and bsearch implementation. - add "_r" reentrant versions. The reasons for always using the internal versions is that the C runtime versions' callbacks are not mark STDCALL, so we would have add bridge functions for them anyhow, The C runtime qsort_r/qsort_s have different orders of arguments on different platforms, and most importantly: qsort() isn't a stable sort, and isn't guaranteed to give the same ordering for two objects marked as equal by the callback...as such, Visual Studio and glibc can give different sort results for the same data set...in this sense, having one piece of code shared on all platforms makes sense here, for reliabillity. bsearch does not have a standard _r version at all, and suffers from the same SDLCALL concern. Since the code is simple and we would have to work around the C runtime, it's easier to just go with the built-in function and remove all the CMake C runtime tests. Fixes #9159.
This commit is contained in:
Ryan C. Gordon
parent
af58ed978e
commit
1e8b006d43
17 changed files with 97 additions and 83 deletions
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@ -20,17 +20,10 @@
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*/
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#include "SDL_internal.h"
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#ifdef HAVE_QSORT
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void SDL_qsort(void *base, size_t nmemb, size_t size, int (*compare) (const void *, const void *))
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{
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if (!base) {
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return;
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}
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qsort(base, nmemb, size, compare);
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}
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#else
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// SDL3 always uses its own internal qsort implementation, below, so
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// it can guarantee stable sorts across platforms and not have to
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// tapdance to support the various qsort_r interfaces, or bridge from
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// the C runtime's non-SDLCALL compare functions.
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#ifdef assert
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#undef assert
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@ -52,10 +45,6 @@ void SDL_qsort(void *base, size_t nmemb, size_t size, int (*compare) (const void
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#undef memmove
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#endif
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#define memmove SDL_memmove
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#ifdef qsortG
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#undef qsortG
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#endif
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#define qsortG SDL_qsort
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/*
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This code came from Gareth McCaughan, under the zlib license.
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@ -67,6 +56,8 @@ Everything below this comment until the HAVE_QSORT #endif was from Gareth
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Thank you to Gareth for relicensing this code under the zlib license for our
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benefit!
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Update for SDL3: we have modified this from a qsort function to qsort_r.
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--ryan.
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*/
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@ -152,7 +143,7 @@ benefit!
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#undef DEBUG_QSORT
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static char _ID[]="<qsort.c gjm 1.15 2016-03-10>";
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static char _ID[]="<qsort.c gjm WITH CHANGES FOR SDL3 1.15 2016-03-10>";
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#endif
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/* END SDL CHANGE ... commented this out with an #if 0 block. --ryan. */
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@ -274,19 +265,19 @@ typedef struct { char * first; char * last; } stack_entry;
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/* and so is the pivoting logic (note: last is inclusive): */
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#define Pivot(swapper,sz) \
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if ((size_t)(last-first)>PIVOT_THRESHOLD*sz) mid=pivot_big(first,mid,last,sz,compare);\
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if ((size_t)(last-first)>PIVOT_THRESHOLD*sz) mid=pivot_big(first,mid,last,sz,compare,userdata);\
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else { \
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if (compare(first,mid)<0) { \
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if (compare(mid,last)>0) { \
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if (compare(userdata,first,mid)<0) { \
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if (compare(userdata,mid,last)>0) { \
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swapper(mid,last); \
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if (compare(first,mid)>0) swapper(first,mid);\
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if (compare(userdata,first,mid)>0) swapper(first,mid);\
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} \
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} \
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else { \
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if (compare(mid,last)>0) swapper(first,last)\
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if (compare(userdata,mid,last)>0) swapper(first,last)\
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else { \
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swapper(first,mid); \
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if (compare(mid,last)>0) swapper(mid,last);\
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if (compare(userdata,mid,last)>0) swapper(mid,last);\
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} \
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} \
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first+=sz; last-=sz; \
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@ -299,8 +290,8 @@ typedef struct { char * first; char * last; } stack_entry;
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/* and so is the partitioning logic: */
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#define Partition(swapper,sz) { \
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do { \
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while (compare(first,pivot)<0) first+=sz; \
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while (compare(pivot,last)<0) last-=sz; \
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while (compare(userdata,first,pivot)<0) first+=sz; \
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while (compare(userdata,pivot,last)<0) last-=sz; \
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if (first<last) { \
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swapper(first,last); \
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first+=sz; last-=sz; } \
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@ -323,7 +314,7 @@ typedef struct { char * first; char * last; } stack_entry;
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first=base; \
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last=first + ((nmemb>limit ? limit : nmemb)-1)*sz;\
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while (last!=base) { \
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if (compare(first,last)>0) first=last; \
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if (compare(userdata,first,last)>0) first=last; \
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last-=sz; } \
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if (first!=base) swapper(first,(char*)base);
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@ -334,7 +325,7 @@ typedef struct { char * first; char * last; } stack_entry;
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char *test; \
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/* Find the right place for |first|. \
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* My apologies for var reuse. */ \
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for (test=first-size;compare(test,first)>0;test-=size) ; \
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for (test=first-size;compare(userdata,test,first)>0;test-=size) ; \
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test+=size; \
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if (test!=first) { \
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/* Shift everything in [test,first) \
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@ -362,7 +353,7 @@ typedef struct { char * first; char * last; } stack_entry;
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/* ---------------------------------------------------------------------- */
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static char * pivot_big(char *first, char *mid, char *last, size_t size,
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int compare(const void *, const void *)) {
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int (SDLCALL * compare)(void *, const void *, const void *), void *userdata) {
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size_t d=(((last-first)/size)>>3)*size;
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#ifdef DEBUG_QSORT
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fprintf(stderr, "pivot_big: first=%p last=%p size=%lu n=%lu\n", first, (unsigned long)last, size, (unsigned long)((last-first+1)/size));
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@ -372,38 +363,38 @@ fprintf(stderr, "pivot_big: first=%p last=%p size=%lu n=%lu\n", first, (unsigned
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#ifdef DEBUG_QSORT
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fprintf(stderr,"< %d %d %d @ %p %p %p\n",*(int*)a,*(int*)b,*(int*)c, a,b,c);
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#endif
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m1 = compare(a,b)<0 ?
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(compare(b,c)<0 ? b : (compare(a,c)<0 ? c : a))
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: (compare(a,c)<0 ? a : (compare(b,c)<0 ? c : b));
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m1 = compare(userdata,a,b)<0 ?
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(compare(userdata,b,c)<0 ? b : (compare(userdata,a,c)<0 ? c : a))
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: (compare(userdata,a,c)<0 ? a : (compare(userdata,b,c)<0 ? c : b));
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}
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{ char *a=mid-d, *b=mid, *c=mid+d;
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#ifdef DEBUG_QSORT
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fprintf(stderr,". %d %d %d @ %p %p %p\n",*(int*)a,*(int*)b,*(int*)c, a,b,c);
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#endif
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m2 = compare(a,b)<0 ?
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(compare(b,c)<0 ? b : (compare(a,c)<0 ? c : a))
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: (compare(a,c)<0 ? a : (compare(b,c)<0 ? c : b));
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m2 = compare(userdata,a,b)<0 ?
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(compare(userdata,b,c)<0 ? b : (compare(userdata,a,c)<0 ? c : a))
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: (compare(userdata,a,c)<0 ? a : (compare(userdata,b,c)<0 ? c : b));
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}
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{ char *a=last-2*d, *b=last-d, *c=last;
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#ifdef DEBUG_QSORT
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fprintf(stderr,"> %d %d %d @ %p %p %p\n",*(int*)a,*(int*)b,*(int*)c, a,b,c);
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#endif
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m3 = compare(a,b)<0 ?
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(compare(b,c)<0 ? b : (compare(a,c)<0 ? c : a))
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: (compare(a,c)<0 ? a : (compare(b,c)<0 ? c : b));
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m3 = compare(userdata,a,b)<0 ?
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(compare(userdata,b,c)<0 ? b : (compare(userdata,a,c)<0 ? c : a))
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: (compare(userdata,a,c)<0 ? a : (compare(userdata,b,c)<0 ? c : b));
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}
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#ifdef DEBUG_QSORT
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fprintf(stderr,"-> %d %d %d @ %p %p %p\n",*(int*)m1,*(int*)m2,*(int*)m3, m1,m2,m3);
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#endif
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return compare(m1,m2)<0 ?
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(compare(m2,m3)<0 ? m2 : (compare(m1,m3)<0 ? m3 : m1))
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: (compare(m1,m3)<0 ? m1 : (compare(m2,m3)<0 ? m3 : m2));
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return compare(userdata,m1,m2)<0 ?
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(compare(userdata,m2,m3)<0 ? m2 : (compare(userdata,m1,m3)<0 ? m3 : m1))
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: (compare(userdata,m1,m3)<0 ? m1 : (compare(userdata,m2,m3)<0 ? m3 : m2));
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}
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/* ---------------------------------------------------------------------- */
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static void qsort_nonaligned(void *base, size_t nmemb, size_t size,
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int (*compare)(const void *, const void *)) {
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static void qsort_r_nonaligned(void *base, size_t nmemb, size_t size,
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int (SDLCALL * compare)(void *, const void *, const void *), void *userdata) {
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stack_entry stack[STACK_SIZE];
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int stacktop=0;
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@ -433,8 +424,8 @@ static void qsort_nonaligned(void *base, size_t nmemb, size_t size,
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free(pivot);
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}
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static void qsort_aligned(void *base, size_t nmemb, size_t size,
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int (*compare)(const void *, const void *)) {
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static void qsort_r_aligned(void *base, size_t nmemb, size_t size,
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int (SDLCALL * compare)(void *,const void *, const void *), void *userdata) {
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stack_entry stack[STACK_SIZE];
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int stacktop=0;
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@ -464,8 +455,8 @@ static void qsort_aligned(void *base, size_t nmemb, size_t size,
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free(pivot);
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}
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static void qsort_words(void *base, size_t nmemb,
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int (*compare)(const void *, const void *)) {
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static void qsort_r_words(void *base, size_t nmemb,
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int (SDLCALL * compare)(void *,const void *, const void *), void *userdata) {
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stack_entry stack[STACK_SIZE];
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int stacktop=0;
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@ -507,7 +498,7 @@ fprintf(stderr, "after partitioning first=#%lu last=#%lu\n", (first-(char*)base)
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/* Find the right place for |first|. My apologies for var reuse */
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int *pl=(int*)(first-WORD_BYTES),*pr=(int*)first;
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*(int*)pivot=*(int*)first;
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for (;compare(pl,pivot)>0;pr=pl,--pl) {
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for (;compare(userdata,pl,pivot)>0;pr=pl,--pl) {
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*pr=*pl; }
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if (pr!=(int*)first) *pr=*(int*)pivot;
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}
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@ -516,28 +507,34 @@ fprintf(stderr, "after partitioning first=#%lu last=#%lu\n", (first-(char*)base)
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/* ---------------------------------------------------------------------- */
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extern void qsortG(void *base, size_t nmemb, size_t size,
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int (*compare)(const void *, const void *)) {
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extern void SDL_qsort_r(void *base, size_t nmemb, size_t size,
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int (SDLCALL * compare)(void *, const void *, const void *), void *userdata) {
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if (nmemb<=1) return;
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if (((size_t)base|size)&(WORD_BYTES-1))
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qsort_nonaligned(base,nmemb,size,compare);
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qsort_r_nonaligned(base,nmemb,size,compare,userdata);
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else if (size!=WORD_BYTES)
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qsort_aligned(base,nmemb,size,compare);
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qsort_r_aligned(base,nmemb,size,compare,userdata);
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else
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qsort_words(base,nmemb,compare);
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qsort_r_words(base,nmemb,compare,userdata);
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}
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#endif /* HAVE_QSORT */
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void *SDL_bsearch(const void *key, const void *base, size_t nmemb, size_t size, int (*compare)(const void *, const void *))
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static int SDLCALL qsort_non_r_bridge(void *userdata, const void *a, const void *b)
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{
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int (SDLCALL *compare)(const void *, const void *) = (int (SDLCALL *)(const void *, const void *)) userdata;
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return compare(a, b);
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}
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void SDL_qsort(void *base, size_t nmemb, size_t size, int (SDLCALL *compare) (const void *, const void *))
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{
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SDL_qsort_r(base, nmemb, size, qsort_non_r_bridge, compare);
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}
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// Don't use the C runtime for such a simple function, since we want to allow SDLCALL callbacks and userdata.
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// SDL's replacement: Taken from the Public Domain C Library (PDCLib):
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// Permission is granted to use, modify, and / or redistribute at will.
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void *SDL_bsearch_r(const void *key, const void *base, size_t nmemb, size_t size, int (SDLCALL *compare)(void *, const void *, const void *), void *userdata)
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{
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#ifdef HAVE_BSEARCH
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return bsearch(key, base, nmemb, size, compare);
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#else
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/* SDL's replacement: Taken from the Public Domain C Library (PDCLib):
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Permission is granted to use, modify, and / or redistribute at will.
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*/
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const void *pivot;
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size_t corr;
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int rc;
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@ -547,7 +544,7 @@ void *SDL_bsearch(const void *key, const void *base, size_t nmemb, size_t size,
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corr = nmemb % 2;
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nmemb /= 2;
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pivot = (const char *)base + (nmemb * size);
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rc = compare(key, pivot);
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rc = compare(userdata, key, pivot);
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if (rc > 0) {
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base = (const char *)pivot + size;
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@ -559,5 +556,11 @@ void *SDL_bsearch(const void *key, const void *base, size_t nmemb, size_t size,
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}
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return NULL;
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#endif /* HAVE_BSEARCH */
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}
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void *SDL_bsearch(const void *key, const void *base, size_t nmemb, size_t size, int (SDLCALL *compare)(const void *, const void *))
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{
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// qsort_non_r_bridge just happens to match calling conventions, so reuse it.
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return SDL_bsearch_r(key, base, nmemb, size, qsort_non_r_bridge, compare);
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}
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