Nils O. Selåsdal
54 lines
1.2 KiB
C
54 lines
1.2 KiB
C
#include <string.h>
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#include "ucore/heapsort.h"
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static void
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uc_sift(unsigned char *base, size_t start, size_t count, size_t width,
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uc_hs_cmp cmp, uc_hs_swp swap, void *cookie)
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{
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size_t root = start, child;
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while ((root * 2 + 1) < count) {
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child = root * 2 + 1;
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if (child < (count - 1)) {
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int rc = cmp(&base[child * width], &base[(child + 1) * width], cookie);
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if (rc < 0) {
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child++;
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}
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}
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if (cmp(&base[root * width], &base[child * width], cookie) < 0) {
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swap(base + root * width, base + child * width);
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root = child;
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} else {
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return;
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}
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}
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}
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void
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uc_heapsort(void *base_, size_t count, size_t width,
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uc_hs_cmp cmp, uc_hs_swp swap, void *cookie)
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{
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long start;
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long end;
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unsigned char *base = base_;
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if (count == 0 || width == 0) {
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return;
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}
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start = count / 2 - 1,
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end = count - 1;
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while (start >= 0) {
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uc_sift(base, start, count, width, cmp, swap, cookie);
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start--;
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}
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while (end > 0) {
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swap(base + end * width, base);
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uc_sift(base, 0, end, width, cmp, swap, cookie);
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end--;
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}
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}
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