Nils O. Selåsdal
42 lines
985 B
C
42 lines
985 B
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)
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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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&& cmp(&base[child * width], &base[(child + 1) * width]) < 0)
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child++;
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if (cmp(&base[root * width], &base[child * width]) < 0) {
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memcpy(base + root * width, base + child * width, 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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void
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uc_heapsort(void *base_, size_t count, size_t width,
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uc_hs_cmp cmp)
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{
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int start = count / 2 - 1, end = count - 1;
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unsigned char *base = base_;
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while (start >= 0) {
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uc_sift(base, start, count, width, cmp);
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start--;
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}
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while (end > 0) {
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memcpy(base + end * width, base, width);
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uc_sift(base, 0, end, width, cmp);
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end--;
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}
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}
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