mirror of https://github.com/TheAlgorithms/C
82 lines
1.4 KiB
C
82 lines
1.4 KiB
C
/*
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author: Christian Bender
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This is the implementation unit of the hash-functions.
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Overview about hash-functions:
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- sdbm
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- djb2
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- xor8 (8 bits)
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- adler_32 (32 bits)
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*/
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long long sdbm(char s[])
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{
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long long hash = 0;
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int i = 0;
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while (s[i] != '\0')
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{
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hash = s[i] + (hash << 6) + (hash << 16) - hash;
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i++;
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}
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return hash;
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}
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long long djb2(char s[])
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{
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long long hash = 5381; /* init value */
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int i = 0;
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while (s[i] != '\0')
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{
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hash = ((hash << 5) + hash) + s[i];
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i++;
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}
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return hash;
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}
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char xor8(char s[])
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{
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int hash = 0;
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int i = 0;
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while (s[i] != '\0')
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{
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hash = (hash + s[i]) & 0xff;
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i++;
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}
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return (((hash ^ 0xff) + 1) & 0xff);
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}
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int adler_32(char s[])
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{
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int a = 1;
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int b = 0;
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const int MODADLER = 65521;
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int i = 0;
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while (s[i] != '\0')
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{
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a = (a + s[i]) % MODADLER;
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b = (b + a) % MODADLER;
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i++;
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}
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return (b << 16) | a;
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}
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/* crc32 Hash-Algorithm*/
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#include <inttypes.h>
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uint32_t crc32(char *data)
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{
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int i = 0;
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uint32_t crc = 0xffffffff;
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while (data[i] != '\0')
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{
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uint8_t byte = data[i];
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crc = crc ^ byte;
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for (int j = 8; j > 0; --j)
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crc = (crc >> 1) ^ (0xEDB88320 & (-(crc & 1)));
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i++;
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}
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return crc ^ 0xffffffff;
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} |