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1 /*
2  *  Copyright (c) 2015 The WebRTC project authors. All Rights Reserved.
3  *
4  *  Use of this source code is governed by a BSD-style license
5  *  that can be found in the LICENSE file in the root of the source
6  *  tree. An additional intellectual property rights grant can be found
7  *  in the file PATENTS.  All contributing project authors may
8  *  be found in the AUTHORS file in the root of the source tree.
9  */
10 
11 #include "common_video/include/i420_buffer_pool.h"
12 
13 #include <limits>
14 
15 #include "rtc_base/checks.h"
16 
17 namespace webrtc {
18 
I420BufferPool()19 I420BufferPool::I420BufferPool() : I420BufferPool(false) {}
I420BufferPool(bool zero_initialize)20 I420BufferPool::I420BufferPool(bool zero_initialize)
21     : I420BufferPool(zero_initialize, std::numeric_limits<size_t>::max()) {}
I420BufferPool(bool zero_initialize,size_t max_number_of_buffers)22 I420BufferPool::I420BufferPool(bool zero_initialize,
23                                size_t max_number_of_buffers)
24     : zero_initialize_(zero_initialize),
25       max_number_of_buffers_(max_number_of_buffers) {}
26 I420BufferPool::~I420BufferPool() = default;
27 
Release()28 void I420BufferPool::Release() {
29   buffers_.clear();
30 }
31 
Resize(size_t max_number_of_buffers)32 bool I420BufferPool::Resize(size_t max_number_of_buffers) {
33   RTC_DCHECK_RUNS_SERIALIZED(&race_checker_);
34   size_t used_buffers_count = 0;
35   for (const rtc::scoped_refptr<PooledI420Buffer>& buffer : buffers_) {
36     // If the buffer is in use, the ref count will be >= 2, one from the list we
37     // are looping over and one from the application. If the ref count is 1,
38     // then the list we are looping over holds the only reference and it's safe
39     // to reuse.
40     if (!buffer->HasOneRef()) {
41       used_buffers_count++;
42     }
43   }
44   if (used_buffers_count > max_number_of_buffers) {
45     return false;
46   }
47   max_number_of_buffers_ = max_number_of_buffers;
48 
49   size_t buffers_to_purge = buffers_.size() - max_number_of_buffers_;
50   auto iter = buffers_.begin();
51   while (iter != buffers_.end() && buffers_to_purge > 0) {
52     if ((*iter)->HasOneRef()) {
53       iter = buffers_.erase(iter);
54       buffers_to_purge--;
55     } else {
56       ++iter;
57     }
58   }
59   return true;
60 }
61 
CreateBuffer(int width,int height)62 rtc::scoped_refptr<I420Buffer> I420BufferPool::CreateBuffer(int width,
63                                                             int height) {
64   // Default stride_y is width, default uv stride is width / 2 (rounding up).
65   return CreateBuffer(width, height, width, (width + 1) / 2, (width + 1) / 2);
66 }
67 
CreateBuffer(int width,int height,int stride_y,int stride_u,int stride_v)68 rtc::scoped_refptr<I420Buffer> I420BufferPool::CreateBuffer(int width,
69                                                             int height,
70                                                             int stride_y,
71                                                             int stride_u,
72                                                             int stride_v) {
73   RTC_DCHECK_RUNS_SERIALIZED(&race_checker_);
74   // Release buffers with wrong resolution.
75   for (auto it = buffers_.begin(); it != buffers_.end();) {
76     const auto& buffer = *it;
77     if (buffer->width() != width || buffer->height() != height ||
78         buffer->StrideY() != stride_y || buffer->StrideU() != stride_u ||
79         buffer->StrideV() != stride_v) {
80       it = buffers_.erase(it);
81     } else {
82       ++it;
83     }
84   }
85   // Look for a free buffer.
86   for (const rtc::scoped_refptr<PooledI420Buffer>& buffer : buffers_) {
87     // If the buffer is in use, the ref count will be >= 2, one from the list we
88     // are looping over and one from the application. If the ref count is 1,
89     // then the list we are looping over holds the only reference and it's safe
90     // to reuse.
91     if (buffer->HasOneRef())
92       return buffer;
93   }
94 
95   if (buffers_.size() >= max_number_of_buffers_)
96     return nullptr;
97   // Allocate new buffer.
98   rtc::scoped_refptr<PooledI420Buffer> buffer =
99       new PooledI420Buffer(width, height, stride_y, stride_u, stride_v);
100   if (zero_initialize_)
101     buffer->InitializeData();
102   buffers_.push_back(buffer);
103   return buffer;
104 }
105 
106 }  // namespace webrtc
107