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28 lines
584 B
C++
28 lines
584 B
C++
/*
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Copyright (C) 1990, 2000, 2002 Free Software Foundation
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written by Doug Lea <dl@rocky.oswego.edu>
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*/
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#include <hash.h>
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/*
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Some useful hash function.
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It's not a particularly good hash function (<< 5 would be better than << 4),
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but people believe in it because it comes from Dragon book.
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*/
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unsigned int
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hashpjw (const unsigned char *x, unsigned int len) // From Dragon book, p436
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{
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unsigned int h = 0;
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unsigned int g;
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for (; len > 0; len--)
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{
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h = (h << 4) + *x++;
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if ((g = h & 0xf0000000) != 0)
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h = (h ^ (g >> 24)) ^ g;
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}
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return h;
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}
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