142 lines
4.4 KiB
C++
142 lines
4.4 KiB
C++
/*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*
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* Copyright 2015 Danny Robson <danny@nerdcruft.net>
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*/
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#include "common.hpp"
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#include "../../debug.hpp"
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///////////////////////////////////////////////////////////////////////////////
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namespace util::hash::murmur {
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template <>
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uint32_t
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tail<uint32_t> (const uint8_t *restrict bytes, size_t len)
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{
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uint32_t h = 0;
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switch (len % sizeof (uint32_t)) {
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case 3: h += bytes[2] << 16;
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case 2: h += bytes[1] << 8;
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case 1: h += bytes[0];
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break;
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default:
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unreachable ();
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}
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return h;
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}
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}
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//-----------------------------------------------------------------------------
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namespace util::hash::murmur {
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template <>
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uint64_t
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tail<uint64_t> (const uint8_t *restrict bytes, size_t len)
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{
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uint64_t h = 0;
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switch (len % sizeof (uint64_t)) {
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case 7: h += uint64_t(bytes[6]) << 48;
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case 6: h += uint64_t(bytes[5]) << 40;
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case 5: h += uint64_t(bytes[4]) << 32;
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case 4: h += uint64_t(bytes[3]) << 24;
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case 3: h += uint64_t(bytes[2]) << 16;
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case 2: h += uint64_t(bytes[1]) << 8;
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case 1: h += uint64_t(bytes[0]);
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break;
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default:
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unreachable ();
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}
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return h;
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}
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}
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//-----------------------------------------------------------------------------
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namespace util::hash::murmur {
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template <>
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std::array<uint32_t,4>
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tail_array<uint32_t> (const uint8_t *restrict bytes, size_t len)
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{
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std::array<uint32_t,4> result {0,0,0,0};
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switch (len % 16) {
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case 15: result[3] |= bytes[14] << 16;
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case 14: result[3] |= bytes[13] << 8;
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case 13: result[3] |= bytes[12] << 0;
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case 12: result[2] |= bytes[11] << 24;
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case 11: result[2] |= bytes[10] << 16;
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case 10: result[2] |= bytes[ 9] << 8;
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case 9: result[2] |= bytes[ 8] << 0;
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case 8: result[1] |= bytes[ 7] << 24;
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case 7: result[1] |= bytes[ 6] << 16;
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case 6: result[1] |= bytes[ 5] << 8;
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case 5: result[1] |= bytes[ 4] << 0;
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case 4: result[0] |= bytes[ 3] << 24;
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case 3: result[0] |= bytes[ 2] << 16;
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case 2: result[0] |= bytes[ 1] << 8;
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case 1: result[0] |= bytes[ 0] << 0;
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break;
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default:
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unreachable ();
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}
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return result;
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}
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}
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//-----------------------------------------------------------------------------
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namespace util::hash::murmur {
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template <>
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std::array<uint64_t,2>
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tail_array<uint64_t> (const uint8_t *restrict bytes, size_t len)
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{
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std::array<uint64_t,2> result {0, 0};
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switch(len & 15)
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{
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case 15: result[1] |= ((uint64_t)bytes[14]) << 48;
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case 14: result[1] |= ((uint64_t)bytes[13]) << 40;
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case 13: result[1] |= ((uint64_t)bytes[12]) << 32;
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case 12: result[1] |= ((uint64_t)bytes[11]) << 24;
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case 11: result[1] |= ((uint64_t)bytes[10]) << 16;
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case 10: result[1] |= ((uint64_t)bytes[ 9]) << 8;
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case 9: result[1] |= ((uint64_t)bytes[ 8]) << 0;
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case 8: result[0] |= ((uint64_t)bytes[ 7]) << 56;
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case 7: result[0] |= ((uint64_t)bytes[ 6]) << 48;
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case 6: result[0] |= ((uint64_t)bytes[ 5]) << 40;
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case 5: result[0] |= ((uint64_t)bytes[ 4]) << 32;
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case 4: result[0] |= ((uint64_t)bytes[ 3]) << 24;
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case 3: result[0] |= ((uint64_t)bytes[ 2]) << 16;
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case 2: result[0] |= ((uint64_t)bytes[ 1]) << 8;
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case 1: result[0] |= ((uint64_t)bytes[ 0]) << 0;
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break;
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default:
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unreachable ();
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};
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return result;
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}
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}
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