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176 lines
3.4 KiB
C++
176 lines
3.4 KiB
C++
#include "GeneralHashFunctions.h"
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unsigned int RSHash(const std::string& str)
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{
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unsigned int b = 378551;
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unsigned int a = 63689;
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unsigned int hash = 0;
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for(std::size_t i = 0; i < str.length(); i++)
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{
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hash = hash * a + str[i];
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a = a * b;
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}
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return hash;
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}
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/* End Of RS Hash Function */
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unsigned int JSHash(const std::string& str)
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{
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unsigned int hash = 1315423911;
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for(std::size_t i = 0; i < str.length(); i++)
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{
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hash ^= ((hash << 5) + str[i] + (hash >> 2));
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}
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return hash;
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}
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/* End Of JS Hash Function */
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unsigned int PJWHash(const std::string& str)
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{
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unsigned int BitsInUnsignedInt = (unsigned int)(sizeof(unsigned int) * 8);
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unsigned int ThreeQuarters = (unsigned int)((BitsInUnsignedInt * 3) / 4);
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unsigned int OneEighth = (unsigned int)(BitsInUnsignedInt / 8);
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unsigned int HighBits = (unsigned int)(0xFFFFFFFF) << (BitsInUnsignedInt - OneEighth);
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unsigned int hash = 0;
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unsigned int test = 0;
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for(std::size_t i = 0; i < str.length(); i++)
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{
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hash = (hash << OneEighth) + str[i];
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if((test = hash & HighBits) != 0)
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{
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hash = (( hash ^ (test >> ThreeQuarters)) & (~HighBits));
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}
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}
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return hash;
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}
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/* End Of P. J. Weinberger Hash Function */
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unsigned int ELFHash(const std::string& str)
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{
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unsigned int hash = 0;
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unsigned int x = 0;
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for(std::size_t i = 0; i < str.length(); i++)
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{
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hash = (hash << 4) + str[i];
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if((x = hash & 0xF0000000L) != 0)
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{
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hash ^= (x >> 24);
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}
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hash &= ~x;
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}
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return hash;
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}
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/* End Of ELF Hash Function */
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unsigned int BKDRHash(const std::string& str)
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{
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unsigned int seed = 131; // 31 131 1313 13131 131313 etc..
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unsigned int hash = 0;
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for(std::size_t i = 0; i < str.length(); i++)
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{
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hash = (hash * seed) + str[i];
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}
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return hash;
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}
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/* End Of BKDR Hash Function */
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unsigned int SDBMHash(const std::string& str)
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{
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unsigned int hash = 0;
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for(std::size_t i = 0; i < str.length(); i++)
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{
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hash = str[i] + (hash << 6) + (hash << 16) - hash;
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}
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return hash;
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}
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/* End Of SDBM Hash Function */
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unsigned int DJBHash(const std::string& str)
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{
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unsigned int hash = 5381;
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for(std::size_t i = 0; i < str.length(); i++)
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{
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hash = ((hash << 5) + hash) + str[i];
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}
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return hash;
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}
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/* End Of DJB Hash Function */
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unsigned int DEKHash(const std::string& str)
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{
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unsigned int hash = static_cast<unsigned int>(str.length());
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for(std::size_t i = 0; i < str.length(); i++)
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{
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hash = ((hash << 5) ^ (hash >> 27)) ^ str[i];
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}
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return hash;
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}
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/* End Of DEK Hash Function */
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unsigned int BPHash(const std::string& str)
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{
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unsigned int hash = 0;
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for(std::size_t i = 0; i < str.length(); i++)
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{
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hash = hash << 7 ^ str[i];
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}
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return hash;
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}
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/* End Of BP Hash Function */
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unsigned int FNVHash(const std::string& str)
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{
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const unsigned int fnv_prime = 0x811C9DC5;
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unsigned int hash = 0;
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for(std::size_t i = 0; i < str.length(); i++)
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{
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hash *= fnv_prime;
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hash ^= str[i];
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}
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return hash;
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}
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/* End Of FNV Hash Function */
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unsigned int APHash(const std::string& str)
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{
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unsigned int hash = 0;
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for(std::size_t i = 0; i < str.length(); i++)
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{
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hash ^= ((i & 1) == 0) ? ( (hash << 7) ^ str[i] ^ (hash >> 3)) :
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(~((hash << 11) ^ str[i] ^ (hash >> 5)));
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}
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return hash;
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}
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/* End Of AP Hash Function */
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