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/*
* BRLTTY - A background process providing access to the console screen (when in
* text mode) for a blind person using a refreshable braille display.
*
* Copyright (C) 1995-2014 by The BRLTTY Developers.
*
* BRLTTY comes with ABSOLUTELY NO WARRANTY.
*
* This is free software, placed 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. Please see the file LICENSE-GPL for details.
*
* Web Page: http://mielke.cc/brltty/
*
* This software is maintained by Dave Mielke <dave@mielke.cc>.
*/
#include "prologue.h"
#include <string.h>
#include <errno.h>
#include "prefs.h"
#include "log.h"
#include "pcm.h"
#include "notes.h"
char *opt_pcmDevice;
struct NoteDeviceStruct {
PcmDevice *pcm;
int blockSize;
int sampleRate;
int channelCount;
PcmAmplitudeFormat amplitudeFormat;
unsigned char *blockAddress;
size_t blockUsed;
};
static int
pcmFlushBytes (NoteDevice *device) {
int ok = writePcmData(device->pcm, device->blockAddress, device->blockUsed);
if (ok) device->blockUsed = 0;
return ok;
}
static int
pcmWriteBytes (NoteDevice *device, const unsigned char *address, size_t length) {
while (length > 0) {
size_t count = device->blockSize - device->blockUsed;
if (length < count) count = length;
memcpy(&device->blockAddress[device->blockUsed], address, count);
address += count;
length -= count;
if ((device->blockUsed += count) == device->blockSize)
if (!pcmFlushBytes(device))
return 0;
}
return 1;
}
static int
pcmWriteSample (NoteDevice *device, int amplitude) {
PcmAmplitudeFormat format = device->amplitudeFormat;
size_t length = getPcmSampleLength(format);
if (length) {
unsigned char buffer[length];
length = makePcmSample(format, amplitude, buffer, sizeof(buffer));
{
int channel;
for (channel=0; channel<device->channelCount; channel+=1) {
if (!pcmWriteBytes(device, buffer, length)) return 0;
}
}
}
return 1;
}
static int
pcmFlushBlock (NoteDevice *device) {
while (device->blockUsed)
if (!pcmWriteSample(device, 0))
return 0;
return 1;
}
static NoteDevice *
pcmConstruct (int errorLevel) {
NoteDevice *device;
if ((device = malloc(sizeof(*device)))) {
if ((device->pcm = openPcmDevice(errorLevel, opt_pcmDevice))) {
device->blockSize = getPcmBlockSize(device->pcm);
device->sampleRate = getPcmSampleRate(device->pcm);
device->channelCount = getPcmChannelCount(device->pcm);
device->amplitudeFormat = getPcmAmplitudeFormat(device->pcm);
device->blockUsed = 0;
if ((device->blockAddress = malloc(device->blockSize))) {
logMessage(LOG_DEBUG, "PCM enabled: blk=%d rate=%d chan=%d fmt=%d",
device->blockSize, device->sampleRate, device->channelCount, device->amplitudeFormat);
return device;
} else {
logMallocError();
}
closePcmDevice(device->pcm);
}
free(device);
} else {
logMallocError();
}
logMessage(LOG_DEBUG, "PCM not available");
return NULL;
}
static void
pcmDestruct (NoteDevice *device) {
pcmFlushBlock(device);
free(device->blockAddress);
closePcmDevice(device->pcm);
free(device);
logMessage(LOG_DEBUG, "PCM disabled");
}
static int
pcmPlay (NoteDevice *device, unsigned char note, unsigned int duration) {
long int sampleCount = device->sampleRate * duration / 1000;
if (note) {
/* A triangle waveform sounds nice, is lightweight, and avoids
* relying too much on floating-point performance and/or on
* expensive math functions like sin(). Considerations like
* these are especially important on PDAs without any FPU.
*/
int32_t positiveShiftsPerQuarterWave = INT32_MAX / 8;
int32_t negativeShiftsPerQuarterWave = -positiveShiftsPerQuarterWave;
int32_t positiveShiftsPerHalfWave = 2 * positiveShiftsPerQuarterWave;
int32_t negativeSiftsPerHalfWave = -positiveShiftsPerHalfWave;
int32_t positiveShiftsPerFullWave = 2 * positiveShiftsPerHalfWave;
int32_t currentShift = 0;
int32_t shiftsPerSample = (NOTE_FREQUENCY_TYPE)positiveShiftsPerFullWave
/ (NOTE_FREQUENCY_TYPE)device->sampleRate
* GET_NOTE_FREQUENCY(note);
int32_t maximumAmplitude = INT16_MAX * prefs.pcmVolume / 100;
int32_t amplitudeGranularity = positiveShiftsPerQuarterWave / maximumAmplitude;
logMessage(LOG_DEBUG, "tone: msec=%d smct=%lu note=%d",
duration, sampleCount, note);
while (sampleCount > 0) {
do {
{
int32_t normalizedAmplitude = positiveShiftsPerHalfWave - currentShift;
if (normalizedAmplitude > positiveShiftsPerQuarterWave) {
normalizedAmplitude = positiveShiftsPerHalfWave - normalizedAmplitude;
} else if (normalizedAmplitude < negativeShiftsPerQuarterWave) {
normalizedAmplitude = negativeSiftsPerHalfWave - normalizedAmplitude;
}
{
int32_t actualAmplitude = normalizedAmplitude / amplitudeGranularity;
if (!pcmWriteSample(device, actualAmplitude)) return 0;
sampleCount -= 1;
}
}
} while ((currentShift += shiftsPerSample) < positiveShiftsPerFullWave);
do {
currentShift -= positiveShiftsPerFullWave;
} while (currentShift >= positiveShiftsPerFullWave);
}
} else {
logMessage(LOG_DEBUG, "tone: msec=%d smct=%lu note=%d",
duration, sampleCount, note);
while (sampleCount > 0) {
if (!pcmWriteSample(device, 0)) return 0;
--sampleCount;
}
}
return 1;
}
static int
pcmFlush (NoteDevice *device) {
return pcmFlushBlock(device);
}
const NoteMethods pcmNoteMethods = {
.construct = pcmConstruct,
.destruct = pcmDestruct,
.play = pcmPlay,
.flush = pcmFlush
};
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