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/*
* Copyright (c) 2015, Ford Motor Company
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following
* disclaimer in the documentation and/or other materials provided with the
* distribution.
*
* Neither the name of the Ford Motor Company nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#include "utils/gen_hash.h"
#include <cstdlib>
#include <locale>
#include <string>
#include "utils/custom_string.h"
namespace utils {
const std::string gen_hash(size_t size) {
static const char symbols[] =
"0123456789"
"abcdefghijklmnopqrstuvwxyz"
"ABCDEFGHIJKLMNOPQRSTUVWXYZ";
static const size_t capacity = sizeof(symbols) - 1;
std::string hash(size, '\0');
for (std::string::iterator i = hash.begin(); i != hash.end(); ++i) {
int index = std::rand() % capacity;
*i = symbols[index];
}
return hash;
}
int32_t Djb2HashFromString(const std::string& str_to_hash) {
uint32_t hash = 5381U;
std::string::const_iterator it = str_to_hash.begin();
std::string::const_iterator it_end = str_to_hash.end();
for (; it != it_end; ++it) {
hash = ((hash << 5) + hash) + (*it);
}
// Reset sign bit in case it has been set.
// This is needed to avoid overflow for signed int.
const int32_t result = hash & 0x7FFFFFFF;
return result;
}
uint32_t CaseInsensitiveFaq6HashFromString(const char* cstr) {
uint32_t hash = 0;
std::locale loc;
for (; *cstr; ++cstr) {
char lower_char = std::tolower(*cstr, loc);
hash += static_cast<uint32_t>(lower_char);
hash += (hash << 10);
hash ^= (hash >> 6);
}
hash += (hash << 3);
hash ^= (hash >> 11);
hash += (hash << 15);
return hash;
}
uint32_t CaseInsensitiveFaq6HashFromString(
const custom_string::CustomString& str_to_hash) {
uint32_t hash = 0;
if (str_to_hash.is_ascii_string()) {
hash = CaseInsensitiveFaq6HashFromString(str_to_hash.c_str());
} else {
const std::wstring& wstr = str_to_hash.ToWStringLowerCase();
size_t size = wstr.size();
for (size_t i = 0; i < size; ++i) {
hash += static_cast<uint32_t>(wstr[i]);
hash += (hash << 10);
hash ^= (hash >> 6);
}
hash += (hash << 3);
hash ^= (hash >> 11);
hash += (hash << 15);
}
return hash;
}
} // namespace utils
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