ts_hash_map.cpp

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/* +------------------------------------------------------------------------+
   |                     Mobile Robot Programming Toolkit (MRPT)            |
   |                          http://www.mrpt.org/                          |
   |                                                                        |
   | Copyright (c) 2005-2017, Individual contributors, see AUTHORS file     |
   | See: http://www.mrpt.org/Authors - All rights reserved.                |
   | Released under BSD License. See details in http://www.mrpt.org/License |
   +------------------------------------------------------------------------+ */

#include "base-precomp.h"  // Precompiled headers

#include <mrpt/utils/ts_hash_map.h>
#include <mrpt/utils/bits.h>
#include <cstring>
#include <cstdlib>

void mrpt::utils::reduced_hash(const std::string& value, uint64_t& out_hash)
{
        // dbj2 method:
        uint64_t hash = 5381;
        const char* str = value.c_str();
        int c;
        while ((c = *str++) != 0)
                hash = ((hash << 5) + hash) + c; /* hash * 33 + c */
        out_hash = hash;
}
void mrpt::utils::reduced_hash(const std::string& value, uint8_t& out_hash)
{
        uint64_t hash;
        reduced_hash(value, hash);
        out_hash =
                ((SELBYTE0(hash) ^ SELBYTE1(hash)) ^ SELBYTE2(hash)) ^ SELBYTE3(hash);
}
void mrpt::utils::reduced_hash(const std::string& value, uint16_t& out_hash)
{
        uint64_t hash;
        reduced_hash(value, hash);
        out_hash = MAKEWORD16B(
                SELBYTE0(hash) ^ SELBYTE1(hash), SELBYTE2(hash) ^ SELBYTE3(hash));
}

void mrpt::utils::reduced_hash(const std::string& value, uint32_t& out_hash)
{
        uint64_t hash;
        reduced_hash(value, hash);
        out_hash = (hash & 0xffffffff) ^ ((hash >> 32) & 0xffffffff);
}