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63 lines
1.9 KiB
63 lines
1.9 KiB
/*
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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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#pragma once
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#include <cstdint>
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#include <string>
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#include <vector>
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#include "varint.h"
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namespace dist_proc {
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namespace aggregation {
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namespace encoding {
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class Encoder {
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public:
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// Initialize encoder to encode into "buf"
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Encoder(void* buf, size_t maxn);
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static void AppendToString(const int64_t src, std::string* dst);
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static void SerializeToPackedStringAll(std::vector<int64_t>::const_iterator begin,
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std::vector<int64_t>::const_iterator end,
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std::string* dst);
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private:
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// Max number of bytes needed to encode 64 bits as a varint (= ceil(64 / 7)).
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static const int8_t kMaxLength = 10;
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// buf_ points into the orig_ buffer, just past the last encoded byte.
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unsigned char* buf_ = nullptr;
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// limits_ points just past the last allocated byte in the orig_ buffer.
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unsigned char* limit_ = nullptr;
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// orig_ points to the start of the encoding buffer, whether or not the
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// Encoder owns it.
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unsigned char* orig_ = nullptr;
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void put_varint64(uint64_t v);
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// Return number of bytes encoded so far.
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size_t length() const;
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// Return ptr to start of encoded data.
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const char* base() const {
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return reinterpret_cast<const char*>(orig_);
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}
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};
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} // namespace encoding
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} // namespace aggregation
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} // namespace dist_proc
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