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stdlib: add qsort_r

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This commit is contained in:
Emil Renner Berthing 2013-09-11 18:58:25 +02:00
commit 194f9cf93d
2 changed files with 26 additions and 14 deletions
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3
include/stdlib.h
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@ -54,6 +54,9 @@ int system (const char *);
void *bsearch (const void *, const void *, size_t, size_t, int (*)(const void *, const void *));
void qsort (void *, size_t, size_t, int (*)(const void *, const void *));
#ifdef _GNU_SOURCE
void qsort_r (void *, size_t, size_t, int (*)(const void *, const void *, void *), void *);
#endif
int abs (int);
long labs (long);

37
src/stdlib/qsort.c
View file

@ -29,6 +29,7 @@
#define ntz(x) a_ctz_l((x))
typedef int (*cmpfun)(const void *, const void *);
typedef int (*cmpfun_r)(const void *, const void *, void *);
static inline int pntz(size_t p[2]) {
int r = ntz(p[0] - 1);
@ -85,7 +86,7 @@ static inline void shr(size_t p[2], int n)
p[1] >>= n;
}
static void sift(unsigned char *head, size_t width, cmpfun cmp, int pshift, size_t lp[])
static void sift(unsigned char *head, size_t width, cmpfun_r cmp, void *arg, int pshift, size_t lp[])
{
unsigned char *rt, *lf;
unsigned char *ar[14 * sizeof(size_t) + 1];
@ -96,10 +97,10 @@ static void sift(unsigned char *head, size_t width, cmpfun cmp, int pshift, size
rt = head - width;
lf = head - width - lp[pshift - 2];
if((*cmp)(ar[0], lf) >= 0 && (*cmp)(ar[0], rt) >= 0) {
if((*cmp)(ar[0], lf, arg) >= 0 && (*cmp)(ar[0], rt, arg) >= 0) {
break;
}
if((*cmp)(lf, rt) >= 0) {
if((*cmp)(lf, rt, arg) >= 0) {
ar[i++] = lf;
head = lf;
pshift -= 1;
@ -112,7 +113,7 @@ static void sift(unsigned char *head, size_t width, cmpfun cmp, int pshift, size
cycle(width, ar, i);
}
static void trinkle(unsigned char *head, size_t width, cmpfun cmp, size_t pp[2], int pshift, int trusty, size_t lp[])
static void trinkle(unsigned char *head, size_t width, cmpfun_r cmp, void *arg, size_t pp[2], int pshift, int trusty, size_t lp[])
{
unsigned char *stepson,
*rt, *lf;
@ -127,13 +128,13 @@ static void trinkle(unsigned char *head, size_t width, cmpfun cmp, size_t pp[2],
ar[0] = head;
while(p[0] != 1 || p[1] != 0) {
stepson = head - lp[pshift];
if((*cmp)(stepson, ar[0]) <= 0) {
if((*cmp)(stepson, ar[0], arg) <= 0) {
break;
}
if(!trusty && pshift > 1) {
rt = head - width;
lf = head - width - lp[pshift - 2];
if((*cmp)(rt, stepson) >= 0 || (*cmp)(lf, stepson) >= 0) {
if((*cmp)(rt, stepson, arg) >= 0 || (*cmp)(lf, stepson, arg) >= 0) {
break;
}
}
@ -147,11 +148,11 @@ static void trinkle(unsigned char *head, size_t width, cmpfun cmp, size_t pp[2],
}
if(!trusty) {
cycle(width, ar, i);
sift(head, width, cmp, pshift, lp);
sift(head, width, cmp, arg, pshift, lp);
}
}
void qsort(void *base, size_t nel, size_t width, cmpfun cmp)
void qsort_r(void *base, size_t nel, size_t width, cmpfun_r cmp, void *arg)
{
size_t lp[12*sizeof(size_t)];
size_t i, size = width * nel;
@ -170,14 +171,14 @@ void qsort(void *base, size_t nel, size_t width, cmpfun cmp)
while(head < high) {
if((p[0] & 3) == 3) {
sift(head, width, cmp, pshift, lp);
sift(head, width, cmp, arg, pshift, lp);
shr(p, 2);
pshift += 2;
} else {
if(lp[pshift - 1] >= high - head) {
trinkle(head, width, cmp, p, pshift, 0, lp);
trinkle(head, width, cmp, arg, p, pshift, 0, lp);
} else {
sift(head, width, cmp, pshift, lp);
sift(head, width, cmp, arg, pshift, lp);
}
if(pshift == 1) {
@ -193,7 +194,7 @@ void qsort(void *base, size_t nel, size_t width, cmpfun cmp)
head += width;
}
trinkle(head, width, cmp, p, pshift, 0, lp);
trinkle(head, width, cmp, arg, p, pshift, 0, lp);
while(pshift != 1 || p[0] != 1 || p[1] != 0) {
if(pshift <= 1) {
@ -205,11 +206,19 @@ void qsort(void *base, size_t nel, size_t width, cmpfun cmp)
pshift -= 2;
p[0] ^= 7;
shr(p, 1);
trinkle(head - lp[pshift] - width, width, cmp, p, pshift + 1, 1, lp);
trinkle(head - lp[pshift] - width, width, cmp, arg, p, pshift + 1, 1, lp);
shl(p, 1);
p[0] |= 1;
trinkle(head - width, width, cmp, p, pshift, 1, lp);
trinkle(head - width, width, cmp, arg, p, pshift, 1, lp);
}
head -= width;
}
}
static int helper(const void *a, const void *b, void *arg) {
return (*(cmpfun)arg)(a, b);
}
void qsort(void *base, size_t nel, size_t width, cmpfun cmp) {
qsort_r(base, nel, width, helper, (void *)cmp);
}