82f014aa0b
BUG=1669 R=andrew@webrtc.org, fischman@webrtc.org, niklas.enbom@webrtc.org Review URL: https://webrtc-codereview.appspot.com/2032004 git-svn-id: http://webrtc.googlecode.com/svn/trunk@4719 4adac7df-926f-26a2-2b94-8c16560cd09d
87 lines
2.6 KiB
C++
87 lines
2.6 KiB
C++
/*
|
|
* Copyright (c) 2013 The WebRTC project authors. All Rights Reserved.
|
|
*
|
|
* Use of this source code is governed by a BSD-style license
|
|
* that can be found in the LICENSE file in the root of the source
|
|
* tree. An additional intellectual property rights grant can be found
|
|
* in the file PATENTS. All contributing project authors may
|
|
* be found in the AUTHORS file in the root of the source tree.
|
|
*/
|
|
|
|
#include "webrtc/modules/audio_device/android/single_rw_fifo.h"
|
|
|
|
#if !defined(__ARMEL__)
|
|
// ARM specific due to the implementation of MemoryBarrier.
|
|
#error trying to compile ARM code for non-ARM target
|
|
#endif
|
|
|
|
static int UpdatePos(int pos, int capacity) {
|
|
return (pos + 1) % capacity;
|
|
}
|
|
|
|
namespace webrtc {
|
|
|
|
namespace subtle {
|
|
|
|
// From http://src.chromium.org/viewvc/chrome/trunk/src/base/atomicops_internals_arm_gcc.h
|
|
// Note that it is only the MemoryBarrier function that makes this class arm
|
|
// specific. Borrowing other MemoryBarrier implementations, this class could
|
|
// be extended to more platforms.
|
|
inline void MemoryBarrier() {
|
|
// Note: This is a function call, which is also an implicit compiler
|
|
// barrier.
|
|
typedef void (*KernelMemoryBarrierFunc)();
|
|
((KernelMemoryBarrierFunc)0xffff0fa0)();
|
|
}
|
|
|
|
} // namespace subtle
|
|
|
|
SingleRwFifo::SingleRwFifo(int capacity)
|
|
: capacity_(capacity),
|
|
size_(0),
|
|
read_pos_(0),
|
|
write_pos_(0) {
|
|
queue_.reset(new int8_t*[capacity_]);
|
|
}
|
|
|
|
SingleRwFifo::~SingleRwFifo() {
|
|
}
|
|
|
|
void SingleRwFifo::Push(int8_t* mem) {
|
|
assert(mem);
|
|
|
|
// Ensure that there is space for the new data in the FIFO.
|
|
// Note there is only one writer meaning that the other thread is guaranteed
|
|
// only to decrease the size.
|
|
const int free_slots = capacity() - size();
|
|
if (free_slots <= 0) {
|
|
// Size can be queried outside of the Push function. The caller is assumed
|
|
// to ensure that Push will be successful before calling it.
|
|
assert(false);
|
|
return;
|
|
}
|
|
queue_[write_pos_] = mem;
|
|
// Memory barrier ensures that |size_| is updated after the size has changed.
|
|
subtle::MemoryBarrier();
|
|
++size_;
|
|
write_pos_ = UpdatePos(write_pos_, capacity());
|
|
}
|
|
|
|
int8_t* SingleRwFifo::Pop() {
|
|
int8_t* ret_val = NULL;
|
|
if (size() <= 0) {
|
|
// Size can be queried outside of the Pop function. The caller is assumed
|
|
// to ensure that Pop will be successfull before calling it.
|
|
assert(false);
|
|
return ret_val;
|
|
}
|
|
ret_val = queue_[read_pos_];
|
|
// Memory barrier ensures that |size_| is updated after the size has changed.
|
|
subtle::MemoryBarrier();
|
|
--size_;
|
|
read_pos_ = UpdatePos(read_pos_, capacity());
|
|
return ret_val;
|
|
}
|
|
|
|
} // namespace webrtc
|