media/formats/common/offset_byte_queue.cc

   1 // Copyright 2014 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 #include "media/formats/common/offset_byte_queue.h"
   6
   7 #include "base/logging.h"
   8
   9 namespace media {
  10
  11 OffsetByteQueue::OffsetByteQueue() : buf_(NULL), size_(0), head_(0) {}
  12 OffsetByteQueue::~OffsetByteQueue() {}
  13
  14 void OffsetByteQueue::Reset() {
  15   queue_.Reset();
  16   buf_ = NULL;
  17   size_ = 0;
  18   head_ = 0;
  19 }
  20
  21 void OffsetByteQueue::Push(const uint8* buf, int size) {
  22   queue_.Push(buf, size);
  23   Sync();
  24   DVLOG(4) << "Buffer pushed. head=" << head() << " tail=" << tail();
  25 }
  26
  27 void OffsetByteQueue::Peek(const uint8** buf, int* size) {
  28   *buf = size_ > 0 ? buf_ : NULL;
  29   *size = size_;
  30 }
  31
  32 void OffsetByteQueue::Pop(int count) {
  33   queue_.Pop(count);
  34   head_ += count;
  35   Sync();
  36 }
  37
  38 void OffsetByteQueue::PeekAt(int64 offset, const uint8** buf, int* size) {
  39   DCHECK(offset >= head());
  40   if (offset < head() || offset >= tail()) {
  41     *buf = NULL;
  42     *size = 0;
  43     return;
  44   }
  45   *buf = &buf_[offset - head()];
  46   *size = tail() - offset;
  47 }
  48
  49 bool OffsetByteQueue::Trim(int64 max_offset) {
  50   if (max_offset < head_) return true;
  51   if (max_offset > tail()) {
  52     Pop(size_);
  53     return false;
  54   }
  55   Pop(max_offset - head_);
  56   return true;
  57 }
  58
  59 void OffsetByteQueue::Sync() {
  60   queue_.Peek(&buf_, &size_);
  61 }
  62
  63 }  // namespace media