47 lines
1.6 KiB
C++
47 lines
1.6 KiB
C++
/*
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* Copyright 2021 Google LLC
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*
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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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#include "varint.h"
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#include <cstdint>
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char* Varint::Encode32(char* sptr, uint32_t v) {
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return Encode32Inline(sptr, v);
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}
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char* Varint::Encode64(char* sptr, uint64_t v) {
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if (v < (1u << 28)) {
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return Varint::Encode32(sptr, v);
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} else {
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// Operate on characters as unsigneds
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unsigned char* ptr = reinterpret_cast<unsigned char*>(sptr);
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// Rather than computing four subresults and or'ing each with 0x80,
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// we can do two ors now. (Doing one now wouldn't work.)
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const uint32_t x32 = v | (1 << 7) | (1 << 21);
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const uint32_t y32 = v | (1 << 14) | (1 << 28);
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*(ptr++) = x32;
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*(ptr++) = y32 >> 7;
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*(ptr++) = x32 >> 14;
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*(ptr++) = y32 >> 21;
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if (v < (1ull << 35)) {
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*(ptr++) = v >> 28;
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return reinterpret_cast<char*>(ptr);
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} else {
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*(ptr++) = (v >> 28) | (1 << 7);
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return Varint::Encode32(reinterpret_cast<char*>(ptr), v >> 35);
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}
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}
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}
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