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50 lines
967 B
C
50 lines
967 B
C
/*
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* bsearch.c
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*
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* Ullrich von Bassewitz, 17.06.1998
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*/
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#include <stdlib.h>
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void* bsearch (const void* key, const void* base, size_t n, size_t size,
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int (*cmp) (const void*, const void*))
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{
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int current;
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int result;
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int found = 0;
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int first = 0;
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int last = n - 1;
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/* Binary search */
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while (first <= last) {
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/* Set current to mid of range */
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current = (last + first) / 2;
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/* Do a compare */
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result = cmp ((void*) (((int) base) + current*size), key);
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if (result < 0) {
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first = current + 1;
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} else {
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last = current - 1;
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if (result == 0) {
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/* Found one entry that matches the search key. However there may be
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* more than one entry with the same key value and ANSI guarantees
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* that we return the first of a row of items with the same key.
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*/
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found = 1;
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}
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}
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}
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/* Did we find the entry? */
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return (void*) (found? ((int) base) + first*size : 0);
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}
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