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1 // Copyright (c) 2012 The Chromium Authors. All rights reserved. | 1 // Copyright (c) 2012 The Chromium Authors. All rights reserved. |
2 // Use of this source code is governed by a BSD-style license that can be | 2 // Use of this source code is governed by a BSD-style license that can be |
3 // found in the LICENSE file. | 3 // found in the LICENSE file. |
4 | 4 |
5 #include "media/base/seekable_buffer.h" | 5 #include "media/base/seekable_buffer.h" |
6 | 6 |
7 #include <algorithm> | 7 #include <algorithm> |
8 | 8 |
9 #include "base/logging.h" | 9 #include "base/logging.h" |
10 #include "media/base/data_buffer.h" | 10 #include "media/base/data_buffer.h" |
11 | 11 |
12 namespace media { | 12 namespace media { |
13 | 13 |
14 SeekableBuffer::SeekableBuffer(int backward_capacity, | 14 SeekableBuffer::SeekableBuffer(int backward_capacity, int forward_capacity) |
15 int forward_capacity) | |
16 : current_buffer_offset_(0), | 15 : current_buffer_offset_(0), |
17 backward_capacity_(backward_capacity), | 16 backward_capacity_(backward_capacity), |
18 backward_bytes_(0), | 17 backward_bytes_(0), |
19 forward_capacity_(forward_capacity), | 18 forward_capacity_(forward_capacity), |
20 forward_bytes_(0), | 19 forward_bytes_(0), |
21 current_time_(kNoTimestamp()) { | 20 current_time_(kNoTimestamp()) { |
22 current_buffer_ = buffers_.begin(); | 21 current_buffer_ = buffers_.begin(); |
23 } | 22 } |
24 | 23 |
25 SeekableBuffer::~SeekableBuffer() { | 24 SeekableBuffer::~SeekableBuffer() {} |
26 } | |
27 | 25 |
28 void SeekableBuffer::Clear() { | 26 void SeekableBuffer::Clear() { |
29 buffers_.clear(); | 27 buffers_.clear(); |
30 current_buffer_ = buffers_.begin(); | 28 current_buffer_ = buffers_.begin(); |
31 current_buffer_offset_ = 0; | 29 current_buffer_offset_ = 0; |
32 backward_bytes_ = 0; | 30 backward_bytes_ = 0; |
33 forward_bytes_ = 0; | 31 forward_bytes_ = 0; |
34 current_time_ = kNoTimestamp(); | 32 current_time_ = kNoTimestamp(); |
35 } | 33 } |
36 | 34 |
37 int SeekableBuffer::Read(uint8* data, int size) { | 35 int SeekableBuffer::Read(uint8* data, int size) { |
38 DCHECK(data); | 36 DCHECK(data); |
39 return InternalRead(data, size, true, 0); | 37 return InternalRead(data, size, true, 0); |
40 } | 38 } |
41 | 39 |
42 int SeekableBuffer::Peek(uint8* data, int size, int forward_offset) { | 40 int SeekableBuffer::Peek(uint8* data, int size, int forward_offset) { |
43 DCHECK(data); | 41 DCHECK(data); |
44 return InternalRead(data, size, false, forward_offset); | 42 return InternalRead(data, size, false, forward_offset); |
45 } | 43 } |
46 | 44 |
47 bool SeekableBuffer::GetCurrentChunk(const uint8** data, int* size) const { | 45 bool SeekableBuffer::GetCurrentChunk(const uint8** data, int* size) const { |
48 BufferQueue::iterator current_buffer = current_buffer_; | 46 BufferQueue::iterator current_buffer = current_buffer_; |
49 int current_buffer_offset = current_buffer_offset_; | 47 int current_buffer_offset = current_buffer_offset_; |
50 // Advance position if we are in the end of the current buffer. | 48 // Advance position if we are in the end of the current buffer. |
51 while (current_buffer != buffers_.end() && | 49 while (current_buffer != buffers_.end() && |
52 current_buffer_offset >= (*current_buffer)->GetDataSize()) { | 50 current_buffer_offset >= (*current_buffer)->get_data_size()) { |
53 ++current_buffer; | 51 ++current_buffer; |
54 current_buffer_offset = 0; | 52 current_buffer_offset = 0; |
55 } | 53 } |
56 if (current_buffer == buffers_.end()) | 54 if (current_buffer == buffers_.end()) return false; |
57 return false; | 55 *data = (*current_buffer)->get_data() + current_buffer_offset; |
58 *data = (*current_buffer)->GetData() + current_buffer_offset; | 56 *size = (*current_buffer)->get_data_size() - current_buffer_offset; |
59 *size = (*current_buffer)->GetDataSize() - current_buffer_offset; | |
60 return true; | 57 return true; |
61 } | 58 } |
62 | 59 |
63 bool SeekableBuffer::Append(const scoped_refptr<DataBuffer>& buffer_in) { | 60 bool SeekableBuffer::Append(const scoped_refptr<DataBuffer>& buffer_in) { |
64 if (buffers_.empty() && buffer_in->GetTimestamp() != kNoTimestamp()) { | 61 if (buffers_.empty() && buffer_in->get_timestamp() != kNoTimestamp()) { |
65 current_time_ = buffer_in->GetTimestamp(); | 62 current_time_ = buffer_in->get_timestamp(); |
66 } | 63 } |
67 | 64 |
68 // Since the forward capacity is only used to check the criteria for buffer | 65 // Since the forward capacity is only used to check the criteria for buffer |
69 // full, we always append data to the buffer. | 66 // full, we always append data to the buffer. |
70 buffers_.push_back(buffer_in); | 67 buffers_.push_back(buffer_in); |
71 | 68 |
72 // After we have written the first buffer, update |current_buffer_| to point | 69 // After we have written the first buffer, update |current_buffer_| to point |
73 // to it. | 70 // to it. |
74 if (current_buffer_ == buffers_.end()) { | 71 if (current_buffer_ == buffers_.end()) { |
75 DCHECK_EQ(0, forward_bytes_); | 72 DCHECK_EQ(0, forward_bytes_); |
76 current_buffer_ = buffers_.begin(); | 73 current_buffer_ = buffers_.begin(); |
77 } | 74 } |
78 | 75 |
79 // Update the |forward_bytes_| counter since we have more bytes. | 76 // Update the |forward_bytes_| counter since we have more bytes. |
80 forward_bytes_ += buffer_in->GetDataSize(); | 77 forward_bytes_ += buffer_in->get_data_size(); |
81 | 78 |
82 // Advise the user to stop append if the amount of forward bytes exceeds | 79 // Advise the user to stop append if the amount of forward bytes exceeds |
83 // the forward capacity. A false return value means the user should stop | 80 // the forward capacity. A false return value means the user should stop |
84 // appending more data to this buffer. | 81 // appending more data to this buffer. |
85 if (forward_bytes_ >= forward_capacity_) | 82 if (forward_bytes_ >= forward_capacity_) return false; |
86 return false; | |
87 return true; | 83 return true; |
88 } | 84 } |
89 | 85 |
90 bool SeekableBuffer::Append(const uint8* data, int size) { | 86 bool SeekableBuffer::Append(const uint8* data, int size) { |
91 if (size > 0) { | 87 if (size > 0) { |
92 scoped_refptr<DataBuffer> data_buffer = DataBuffer::CopyFrom(data, size); | 88 scoped_refptr<DataBuffer> data_buffer = DataBuffer::copy_from(data, size); |
93 return Append(data_buffer); | 89 return Append(data_buffer); |
94 } else { | 90 } else { |
95 // Return true if we have forward capacity. | 91 // Return true if we have forward capacity. |
96 return forward_bytes_ < forward_capacity_; | 92 return forward_bytes_ < forward_capacity_; |
97 } | 93 } |
98 } | 94 } |
99 | 95 |
100 bool SeekableBuffer::Seek(int32 offset) { | 96 bool SeekableBuffer::Seek(int32 offset) { |
101 if (offset > 0) | 97 if (offset > 0) |
102 return SeekForward(offset); | 98 return SeekForward(offset); |
103 else if (offset < 0) | 99 else if (offset < 0) |
104 return SeekBackward(-offset); | 100 return SeekBackward(-offset); |
105 return true; | 101 return true; |
106 } | 102 } |
107 | 103 |
108 bool SeekableBuffer::SeekForward(int size) { | 104 bool SeekableBuffer::SeekForward(int size) { |
109 // Perform seeking forward only if we have enough bytes in the queue. | 105 // Perform seeking forward only if we have enough bytes in the queue. |
110 if (size > forward_bytes_) | 106 if (size > forward_bytes_) return false; |
111 return false; | |
112 | 107 |
113 // Do a read of |size| bytes. | 108 // Do a read of |size| bytes. |
114 int taken = InternalRead(NULL, size, true, 0); | 109 int taken = InternalRead(NULL, size, true, 0); |
115 DCHECK_EQ(taken, size); | 110 DCHECK_EQ(taken, size); |
116 return true; | 111 return true; |
117 } | 112 } |
118 | 113 |
119 bool SeekableBuffer::SeekBackward(int size) { | 114 bool SeekableBuffer::SeekBackward(int size) { |
120 if (size > backward_bytes_) | 115 if (size > backward_bytes_) return false; |
121 return false; | |
122 // Record the number of bytes taken. | 116 // Record the number of bytes taken. |
123 int taken = 0; | 117 int taken = 0; |
124 // Loop until we taken enough bytes and rewind by the desired |size|. | 118 // Loop until we taken enough bytes and rewind by the desired |size|. |
125 while (taken < size) { | 119 while (taken < size) { |
126 // |current_buffer_| can never be invalid when we are in this loop. It can | 120 // |current_buffer_| can never be invalid when we are in this loop. It can |
127 // only be invalid before any data is appended. The invalid case should be | 121 // only be invalid before any data is appended. The invalid case should be |
128 // handled by checks before we enter this loop. | 122 // handled by checks before we enter this loop. |
129 DCHECK(current_buffer_ != buffers_.end()); | 123 DCHECK(current_buffer_ != buffers_.end()); |
130 | 124 |
131 // We try to consume at most |size| bytes in the backward direction. We also | 125 // We try to consume at most |size| bytes in the backward direction. We also |
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143 | 137 |
144 // Forward bytes increases and backward bytes decreases by the amount | 138 // Forward bytes increases and backward bytes decreases by the amount |
145 // consumed in the current buffer. | 139 // consumed in the current buffer. |
146 forward_bytes_ += consumed; | 140 forward_bytes_ += consumed; |
147 backward_bytes_ -= consumed; | 141 backward_bytes_ -= consumed; |
148 DCHECK_GE(backward_bytes_, 0); | 142 DCHECK_GE(backward_bytes_, 0); |
149 | 143 |
150 // The current buffer pointed by current iterator has been consumed. Move | 144 // The current buffer pointed by current iterator has been consumed. Move |
151 // the iterator backward so it points to the previous buffer. | 145 // the iterator backward so it points to the previous buffer. |
152 if (current_buffer_offset_ == 0) { | 146 if (current_buffer_offset_ == 0) { |
153 if (current_buffer_ == buffers_.begin()) | 147 if (current_buffer_ == buffers_.begin()) break; |
154 break; | |
155 // Move the iterator backward. | 148 // Move the iterator backward. |
156 --current_buffer_; | 149 --current_buffer_; |
157 // Set the offset into the current buffer to be the buffer size as we | 150 // Set the offset into the current buffer to be the buffer size as we |
158 // are preparing for rewind for next iteration. | 151 // are preparing for rewind for next iteration. |
159 current_buffer_offset_ = (*current_buffer_)->GetDataSize(); | 152 current_buffer_offset_ = (*current_buffer_)->get_data_size(); |
160 } | 153 } |
161 } | 154 } |
162 | 155 |
163 UpdateCurrentTime(current_buffer_, current_buffer_offset_); | 156 UpdateCurrentTime(current_buffer_, current_buffer_offset_); |
164 | 157 |
165 DCHECK_EQ(taken, size); | 158 DCHECK_EQ(taken, size); |
166 return true; | 159 return true; |
167 } | 160 } |
168 | 161 |
169 void SeekableBuffer::EvictBackwardBuffers() { | 162 void SeekableBuffer::EvictBackwardBuffers() { |
170 // Advances the iterator until we hit the current pointer. | 163 // Advances the iterator until we hit the current pointer. |
171 while (backward_bytes_ > backward_capacity_) { | 164 while (backward_bytes_ > backward_capacity_) { |
172 BufferQueue::iterator i = buffers_.begin(); | 165 BufferQueue::iterator i = buffers_.begin(); |
173 if (i == current_buffer_) | 166 if (i == current_buffer_) break; |
174 break; | |
175 scoped_refptr<DataBuffer> buffer = *i; | 167 scoped_refptr<DataBuffer> buffer = *i; |
176 backward_bytes_ -= buffer->GetDataSize(); | 168 backward_bytes_ -= buffer->get_data_size(); |
177 DCHECK_GE(backward_bytes_, 0); | 169 DCHECK_GE(backward_bytes_, 0); |
178 | 170 |
179 buffers_.erase(i); | 171 buffers_.erase(i); |
180 } | 172 } |
181 } | 173 } |
182 | 174 |
183 int SeekableBuffer::InternalRead(uint8* data, int size, | 175 int SeekableBuffer::InternalRead(uint8* data, int size, bool advance_position, |
184 bool advance_position, | |
185 int forward_offset) { | 176 int forward_offset) { |
186 // Counts how many bytes are actually read from the buffer queue. | 177 // Counts how many bytes are actually read from the buffer queue. |
187 int taken = 0; | 178 int taken = 0; |
188 | 179 |
189 BufferQueue::iterator current_buffer = current_buffer_; | 180 BufferQueue::iterator current_buffer = current_buffer_; |
190 int current_buffer_offset = current_buffer_offset_; | 181 int current_buffer_offset = current_buffer_offset_; |
191 | 182 |
192 int bytes_to_skip = forward_offset; | 183 int bytes_to_skip = forward_offset; |
193 while (taken < size) { | 184 while (taken < size) { |
194 // |current_buffer| is valid since the first time this buffer is appended | 185 // |current_buffer| is valid since the first time this buffer is appended |
195 // with data. | 186 // with data. |
196 if (current_buffer == buffers_.end()) | 187 if (current_buffer == buffers_.end()) break; |
197 break; | |
198 | 188 |
199 scoped_refptr<DataBuffer> buffer = *current_buffer; | 189 scoped_refptr<DataBuffer> buffer = *current_buffer; |
200 | 190 |
201 int remaining_bytes_in_buffer = | 191 int remaining_bytes_in_buffer = |
202 buffer->GetDataSize() - current_buffer_offset; | 192 buffer->get_data_size() - current_buffer_offset; |
203 | 193 |
204 if (bytes_to_skip == 0) { | 194 if (bytes_to_skip == 0) { |
205 // Find the right amount to copy from the current buffer referenced by | 195 // Find the right amount to copy from the current buffer referenced by |
206 // |buffer|. We shall copy no more than |size| bytes in total and each | 196 // |buffer|. We shall copy no more than |size| bytes in total and each |
207 // single step copied no more than the current buffer size. | 197 // single step copied no more than the current buffer size. |
208 int copied = std::min(size - taken, remaining_bytes_in_buffer); | 198 int copied = std::min(size - taken, remaining_bytes_in_buffer); |
209 | 199 |
210 // |data| is NULL if we are seeking forward, so there's no need to copy. | 200 // |data| is NULL if we are seeking forward, so there's no need to copy. |
211 if (data) | 201 if (data) |
212 memcpy(data + taken, buffer->GetData() + current_buffer_offset, copied); | 202 memcpy(data + taken, buffer->get_data() + current_buffer_offset, |
| 203 copied); |
213 | 204 |
214 // Increase total number of bytes copied, which regulates when to end this | 205 // Increase total number of bytes copied, which regulates when to end this |
215 // loop. | 206 // loop. |
216 taken += copied; | 207 taken += copied; |
217 | 208 |
218 // We have read |copied| bytes from the current buffer. Advances the | 209 // We have read |copied| bytes from the current buffer. Advances the |
219 // offset. | 210 // offset. |
220 current_buffer_offset += copied; | 211 current_buffer_offset += copied; |
221 } else { | 212 } else { |
222 int skipped = std::min(remaining_bytes_in_buffer, bytes_to_skip); | 213 int skipped = std::min(remaining_bytes_in_buffer, bytes_to_skip); |
223 current_buffer_offset += skipped; | 214 current_buffer_offset += skipped; |
224 bytes_to_skip -= skipped; | 215 bytes_to_skip -= skipped; |
225 } | 216 } |
226 | 217 |
227 // The buffer has been consumed. | 218 // The buffer has been consumed. |
228 if (current_buffer_offset == buffer->GetDataSize()) { | 219 if (current_buffer_offset == buffer->get_data_size()) { |
229 if (advance_position) { | 220 if (advance_position) { |
230 // Next buffer may not have timestamp, so we need to update current | 221 // Next buffer may not have timestamp, so we need to update current |
231 // timestamp before switching to the next buffer. | 222 // timestamp before switching to the next buffer. |
232 UpdateCurrentTime(current_buffer, current_buffer_offset); | 223 UpdateCurrentTime(current_buffer, current_buffer_offset); |
233 } | 224 } |
234 | 225 |
235 BufferQueue::iterator next = current_buffer; | 226 BufferQueue::iterator next = current_buffer; |
236 ++next; | 227 ++next; |
237 // If we are at the last buffer, don't advance. | 228 // If we are at the last buffer, don't advance. |
238 if (next == buffers_.end()) | 229 if (next == buffers_.end()) break; |
239 break; | |
240 | 230 |
241 // Advances the iterator. | 231 // Advances the iterator. |
242 current_buffer = next; | 232 current_buffer = next; |
243 current_buffer_offset = 0; | 233 current_buffer_offset = 0; |
244 } | 234 } |
245 } | 235 } |
246 | 236 |
247 if (advance_position) { | 237 if (advance_position) { |
248 // We have less forward bytes and more backward bytes. Updates these | 238 // We have less forward bytes and more backward bytes. Updates these |
249 // counters by |taken|. | 239 // counters by |taken|. |
250 forward_bytes_ -= taken; | 240 forward_bytes_ -= taken; |
251 backward_bytes_ += taken; | 241 backward_bytes_ += taken; |
252 DCHECK_GE(forward_bytes_, 0); | 242 DCHECK_GE(forward_bytes_, 0); |
253 DCHECK(current_buffer_ != buffers_.end() || forward_bytes_ == 0); | 243 DCHECK(current_buffer_ != buffers_.end() || forward_bytes_ == 0); |
254 | 244 |
255 current_buffer_ = current_buffer; | 245 current_buffer_ = current_buffer; |
256 current_buffer_offset_ = current_buffer_offset; | 246 current_buffer_offset_ = current_buffer_offset; |
257 | 247 |
258 UpdateCurrentTime(current_buffer_, current_buffer_offset_); | 248 UpdateCurrentTime(current_buffer_, current_buffer_offset_); |
259 EvictBackwardBuffers(); | 249 EvictBackwardBuffers(); |
260 } | 250 } |
261 | 251 |
262 return taken; | 252 return taken; |
263 } | 253 } |
264 | 254 |
265 void SeekableBuffer::UpdateCurrentTime(BufferQueue::iterator buffer, | 255 void SeekableBuffer::UpdateCurrentTime(BufferQueue::iterator buffer, |
266 int offset) { | 256 int offset) { |
267 // Garbage values are unavoidable, so this check will remain. | 257 // Garbage values are unavoidable, so this check will remain. |
268 if (buffer != buffers_.end() && (*buffer)->GetTimestamp() != kNoTimestamp()) { | 258 if (buffer != buffers_.end() && |
269 int64 time_offset = ((*buffer)->GetDuration().InMicroseconds() * | 259 (*buffer)->get_timestamp() != kNoTimestamp()) { |
270 offset) / (*buffer)->GetDataSize(); | 260 int64 time_offset = ((*buffer)->get_duration().InMicroseconds() * offset) / |
| 261 (*buffer)->get_data_size(); |
271 | 262 |
272 current_time_ = (*buffer)->GetTimestamp() + | 263 current_time_ = (*buffer)->get_timestamp() + |
273 base::TimeDelta::FromMicroseconds(time_offset); | 264 base::TimeDelta::FromMicroseconds(time_offset); |
274 } | 265 } |
275 } | 266 } |
276 | 267 |
277 } // namespace media | 268 } // namespace media |
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