github.com/cockroachdb/cockroach@v20.2.0-alpha.1+incompatible/c-deps/libroach/chunked_buffer.h (about)

     1  // Copyright 2018 The Cockroach Authors.
     2  //
     3  // Use of this software is governed by the Business Source License
     4  // included in the file licenses/BSL.txt.
     5  //
     6  // As of the Change Date specified in that file, in accordance with
     7  // the Business Source License, use of this software will be governed
     8  // by the Apache License, Version 2.0, included in the file
     9  // licenses/APL.txt.
    10  
    11  #pragma once
    12  
    13  #include <rocksdb/db.h>
    14  #include "libroach.h"
    15  
    16  namespace cockroach {
    17  
    18  class chunkedBuffer {
    19   public:
    20    chunkedBuffer() { Clear(); }
    21    ~chunkedBuffer() { Clear(); }
    22  
    23    // Write a key/value pair to this chunkedBuffer.
    24    void Put(const rocksdb::Slice& key, const rocksdb::Slice& value);
    25  
    26    // Clear this chunkedBuffer.
    27    void Clear();
    28  
    29    void GetChunks(DBSlice** bufs, int32_t* len) {
    30      // Cap the last buffer's size to the amount that's been written to it.
    31      DBSlice& last = bufs_.back();
    32      last.len = buf_ptr_ - last.data;
    33      *bufs = &bufs_.front();
    34      *len = bufs_.size();
    35    }
    36  
    37    // Get the number of key/value pairs written to this chunkedBuffer.
    38    int Count() const { return count_; }
    39    // Get the number of bytes written to this chunkedBuffer.
    40    int NumBytes() const { return bytes_; }
    41  
    42   private:
    43    void put(const char* data, int len, int next_size_hint);
    44  
    45   private:
    46    std::vector<DBSlice> bufs_;
    47    int64_t count_;
    48    int64_t bytes_;
    49    char* buf_ptr_;
    50  };
    51  
    52  }  // namespace cockroach