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output/alsa: move class PeriodBuffer to lib/alsa/PeriodBuffer.hxx

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This commit is contained in:
Max Kellermann 2017-10-26 09:27:36 +02:00
parent 034bb13e1c
commit b08cb148ae
3 changed files with 141 additions and 104 deletions
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1
Makefile.am
View File

@ -258,6 +258,7 @@ UPNP_SOURCES = \
ALSA_SOURCES = \
src/lib/alsa/Version.cxx src/lib/alsa/Version.hxx \
src/lib/alsa/PeriodBuffer.hxx \
src/lib/alsa/NonBlock.cxx src/lib/alsa/NonBlock.hxx
#

138
src/lib/alsa/PeriodBuffer.hxx Normal file
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@ -0,0 +1,138 @@
/*
* Copyright 2003-2017 The Music Player Daemon Project
* http://www.musicpd.org
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#ifndef MPD_ALSA_PERIOD_BUFFER_HXX
#define MPD_ALSA_PERIOD_BUFFER_HXX
#include "check.h"
#include <alsa/asoundlib.h>
#include <algorithm>
#include <stdint.h>
namespace Alsa {
class PeriodBuffer {
size_t capacity, head, tail;
uint8_t *buffer;
public:
PeriodBuffer() = default;
PeriodBuffer(const PeriodBuffer &) = delete;
PeriodBuffer &operator=(const PeriodBuffer &) = delete;
void Allocate(size_t n_frames, size_t frame_size) noexcept {
capacity = n_frames * frame_size;
/* reserve space for one more (partial) frame,
to be able to fill the buffer with silence,
after moving an unfinished frame to the
end */
buffer = new uint8_t[capacity + frame_size - 1];
head = tail = 0;
}
void Free() noexcept {
delete[] buffer;
}
bool IsEmpty() const noexcept {
return head == tail;
}
bool IsFull() const noexcept {
return tail >= capacity;
}
uint8_t *GetTail() noexcept {
return buffer + tail;
}
size_t GetSpaceBytes() const noexcept {
assert(tail <= capacity);
return capacity - tail;
}
void AppendBytes(size_t n) noexcept {
assert(n <= capacity);
assert(tail <= capacity - n);
tail += n;
}
void FillWithSilence(const uint8_t *_silence,
const size_t frame_size) noexcept {
size_t partial_frame = tail % frame_size;
auto *dest = GetTail() - partial_frame;
/* move the partial frame to the end */
std::copy(dest, GetTail(), buffer + capacity);
size_t silence_size = capacity - tail - partial_frame;
std::copy_n(_silence, silence_size, dest);
tail = capacity + partial_frame;
}
const uint8_t *GetHead() const noexcept {
return buffer + head;
}
snd_pcm_uframes_t GetFrames(size_t frame_size) const noexcept {
return (tail - head) / frame_size;
}
void ConsumeBytes(size_t n) noexcept {
head += n;
assert(head <= capacity);
if (head >= capacity) {
tail -= head;
/* copy the partial frame (if any)
back to the beginning */
std::copy_n(GetHead(), tail, buffer);
head = 0;
}
}
void ConsumeFrames(snd_pcm_uframes_t n, size_t frame_size) noexcept {
ConsumeBytes(n * frame_size);
}
snd_pcm_uframes_t GetPeriodPosition(size_t frame_size) const noexcept {
return head / frame_size;
}
void Rewind() noexcept {
head = 0;
}
void Clear() noexcept {
head = tail = 0;
}
};
} // namespace Alsa
#endif

106
src/output/plugins/AlsaOutputPlugin.cxx
View File

@ -20,6 +20,7 @@
#include "config.h"
#include "AlsaOutputPlugin.hxx"
#include "lib/alsa/NonBlock.hxx"
#include "lib/alsa/PeriodBuffer.hxx"
#include "lib/alsa/Version.hxx"
#include "../OutputAPI.hxx"
#include "mixer/MixerList.hxx"
@ -153,110 +154,7 @@ class AlsaOutput final
*/
boost::lockfree::spsc_queue<uint8_t> *ring_buffer;
class PeriodBuffer {
size_t capacity, head, tail;
uint8_t *buffer;
public:
PeriodBuffer() = default;
PeriodBuffer(const PeriodBuffer &) = delete;
PeriodBuffer &operator=(const PeriodBuffer &) = delete;
void Allocate(size_t n_frames, size_t frame_size) noexcept {
capacity = n_frames * frame_size;
/* reserve space for one more (partial) frame,
to be able to fill the buffer with silence,
after moving an unfinished frame to the
end */
buffer = new uint8_t[capacity + frame_size - 1];
head = tail = 0;
}
void Free() noexcept {
delete[] buffer;
}
bool IsEmpty() const noexcept {
return head == tail;
}
bool IsFull() const noexcept {
return tail >= capacity;
}
uint8_t *GetTail() noexcept {
return buffer + tail;
}
size_t GetSpaceBytes() const noexcept {
assert(tail <= capacity);
return capacity - tail;
}
void AppendBytes(size_t n) noexcept {
assert(n <= capacity);
assert(tail <= capacity - n);
tail += n;
}
void FillWithSilence(const uint8_t *_silence,
const size_t frame_size) noexcept {
size_t partial_frame = tail % frame_size;
auto *dest = GetTail() - partial_frame;
/* move the partial frame to the end */
std::copy(dest, GetTail(), buffer + capacity);
size_t silence_size = capacity - tail - partial_frame;
std::copy_n(_silence, silence_size, dest);
tail = capacity + partial_frame;
}
const uint8_t *GetHead() const noexcept {
return buffer + head;
}
snd_pcm_uframes_t GetFrames(size_t frame_size) const noexcept {
return (tail - head) / frame_size;
}
void ConsumeBytes(size_t n) noexcept {
head += n;
assert(head <= capacity);
if (head >= capacity) {
tail -= head;
/* copy the partial frame (if any)
back to the beginning */
std::copy_n(GetHead(), tail, buffer);
head = 0;
}
}
void ConsumeFrames(snd_pcm_uframes_t n, size_t frame_size) noexcept {
ConsumeBytes(n * frame_size);
}
snd_pcm_uframes_t GetPeriodPosition(size_t frame_size) const noexcept {
return head / frame_size;
}
void Rewind() noexcept {
head = 0;
}
void Clear() noexcept {
head = tail = 0;
}
};
PeriodBuffer period_buffer;
Alsa::PeriodBuffer period_buffer;
/**
* Protects #cond, #error, #drain.