REminiscence/cpc_player.cpp

130 lines
3.0 KiB
C++

#include "cpc_player.h"
#include "mixer.h"
#include "util.h"
static const char *_tunes[] = {
"Options.Cpc",
"Jungle.Cpc",
"Subway.Cpc",
"TVshow.Cpc",
"City.Cpc",
"Alien.Cpc"
};
CpcPlayer::CpcPlayer(Mixer *mixer, FileSystem *fs)
: _mix(mixer), _fs(fs) {
}
CpcPlayer::~CpcPlayer() {
}
bool CpcPlayer::playTrack(int num) {
_compression[0] = 0;
const int tuneNum = num - 2;
if (tuneNum >= 0 && tuneNum < ARRAYSIZE(_tunes) && _f.open(_tunes[tuneNum], "rb", _fs)) {
_pos = 0;
_sampleL = _sampleR = 0;
while (nextChunk()) {
if (_compression[0]) {
_restartPos = _nextPos;
_mix->setPremixHook(mixCallback, this);
return true;
}
}
}
return false;
}
void CpcPlayer::stopTrack() {
_f.close();
}
void CpcPlayer::pauseTrack() {
_mix->setPremixHook(0, 0);
}
void CpcPlayer::resumeTrack() {
_mix->setPremixHook(mixCallback, this);
}
bool CpcPlayer::nextChunk() {
bool found = false;
while (!_f.ioErr() && !found) {
const uint32_t pos = _pos;
char tag[4];
_f.read(tag, sizeof(tag));
const uint32_t len = _f.readUint32BE();
_nextPos = pos + len;
if (memcmp(tag, "SNDS", 4) == 0) {
_f.readUint32BE();
_f.readUint32BE();
char type[4];
_f.read(type, sizeof(type));
if (memcmp(type, "SHDR", 4) == 0) {
uint8_t buf[24];
_f.read(buf, sizeof(buf));
const uint32_t rate = _f.readUint32BE();
const uint32_t channels = _f.readUint32BE();
if (channels != 2 || rate != _mix->getSampleRate()) {
warning("Unsupported CPC tune channels %d rate %d", channels, rate);
break;
}
_f.read(_compression, sizeof(_compression) - 1);
_compression[sizeof(_compression) - 1] = 0;
if (strcmp(_compression, "SDX2") != 0) {
warning("Unsupported CPC compression '%s'", _compression);
break;
}
found = true;
} else if (memcmp(type, "SSMP", 4) == 0) {
_samplesLeft = _f.readUint32BE();
found = true;
break;
} else {
warning("Unhandled SNDS chunk '%c%c%c%c'", type[0], type[1], type[2], type[3]);
}
} else if (memcmp(tag, "SHDR", 4) == 0 || memcmp(tag, "FILL", 4) == 0 || memcmp(tag, "CTRL", 4) == 0) {
// ignore
} else {
warning("Unhandled chunk '%c%c%c%c' size %d", tag[0], tag[1], tag[2], tag[3], len);
}
_f.seek(_nextPos);
_pos = _nextPos;
}
return found;
}
static int16_t decodeSDX2(int16_t prev, int8_t data) {
const int sqr = data * ABS(data) * 2;
return (data & 1) != 0 ? prev + sqr : sqr;
}
int8_t CpcPlayer::readSampleData() {
if (_samplesLeft <= 0) {
_f.seek(_nextPos);
_pos = _nextPos;
if (!nextChunk()) {
// rewind
_f.seek(_restartPos);
nextChunk();
}
}
const int8_t data = _f.readByte();
--_samplesLeft;
return data;
}
bool CpcPlayer::mix(int16_t *buf, int len) {
for (int i = 0; i < len; ++i) {
_sampleL = decodeSDX2(_sampleL, readSampleData());
_sampleR = decodeSDX2(_sampleR, readSampleData());
*buf++ = (_sampleL + _sampleR) / 2;
}
return true;
}
bool CpcPlayer::mixCallback(void *param, int16_t *buf, int len) {
return ((CpcPlayer *)param)->mix(buf, len);
}