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