67 lines
1.3 KiB
C
67 lines
1.3 KiB
C
#ifndef _WDL_MERGESORT_H_
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#define _WDL_MERGESORT_H_
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#include "wdltypes.h"
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static void WDL_STATICFUNC_UNUSED WDL_mergesort(void *base, size_t nmemb, size_t size, int (*compar)(const void *, const void *), char *tmpspace)
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{
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char *b1,*b2;
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size_t n1, n2;
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if (nmemb < 2) return;
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n1 = nmemb / 2;
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b1 = (char *) base;
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n2 = nmemb - n1;
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b2 = b1 + (n1 * size);
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if (nmemb>2)
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{
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WDL_mergesort(b1, n1, size, compar, tmpspace);
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WDL_mergesort(b2, n2, size, compar, tmpspace);
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}
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do
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{
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if (compar(b1, b2) > 0) // out of order, go to full merge
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{
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size_t sofar = b1-(char*)base;
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memcpy(tmpspace,base,sofar);
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memcpy(tmpspace+sofar, b2, size);
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b2 += size;
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n2--;
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char *writeptr=tmpspace+sofar+size;
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while (n1 > 0 && n2 > 0)
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{
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if (compar(b1, b2) > 0)
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{
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memcpy(writeptr, b2, size);
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b2 += size;
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n2--;
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}
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else
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{
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memcpy(writeptr, b1, size);
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b1 += size;
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n1--;
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}
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writeptr += size;
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}
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if (n1 > 0) memcpy(writeptr, b1, n1 * size);
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memcpy(base, tmpspace, (nmemb - n2) * size);
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break;
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}
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// in order, just advance
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b1 += size;
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n1--;
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}
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while (n1 > 0 && n2 > 0);
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}
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#endif//_WDL_MERGESORT_H_
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