pdf/chunk_stream.h

   1 // Copyright (c) 2010 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef PDF_CHUNK_STREAM_H_
   6 #define PDF_CHUNK_STREAM_H_
   7
   8 #include <stddef.h>
   9
  10 #include <map>
  11 #include <vector>
  12
  13 namespace chrome_pdf {
  14
  15 // This class collects a chunks of data into one data stream. Client can check
  16 // if data in certain range is available, and get missing chunks of data.
  17 class ChunkStream {
  18  public:
  19   ChunkStream();
  20   ~ChunkStream();
  21
  22   void Clear();
  23
  24   void Preallocate(size_t stream_size);
  25   size_t GetSize();
  26
  27   bool WriteData(size_t offset, void* buffer, size_t size);
  28   bool ReadData(size_t offset, size_t size, void* buffer) const;
  29
  30   // Returns vector of pairs where first is an offset, second is a size.
  31   bool GetMissedRanges(size_t offset, size_t size,
  32       std::vector<std::pair<size_t, size_t> >* ranges) const;
  33   bool IsRangeAvailable(size_t offset, size_t size) const;
  34   size_t GetFirstMissingByte() const;
  35
  36   size_t GetLastByteBefore(size_t offset) const;
  37   size_t GetFirstByteAfter(size_t offset) const;
  38
  39  private:
  40   std::vector<unsigned char> data_;
  41
  42   // Pair, first - begining of the chunk, second - size of the chunk.
  43   std::map<size_t, size_t> chunks_;
  44 };
  45
  46 };  // namespace chrome_pdf
  47
  48 #endif