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Code cleanups and fix codecPCM16 for big-endian systems (they seem rare these days)

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This commit is contained in:
Erik Hofman 2016-03-28 15:08:28 +02:00
parent 2e1f01a86a
commit 63b2b04977
1 changed files with 34 additions and 35 deletions
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69
simgear/sound/readwav.cxx
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@ -77,50 +77,49 @@ namespace
{
}
void codecPCM16 (Buffer* buf)
void codecPCM16BE (Buffer* buf)
{
// always byte-swaps here; is this a good idea?
uint16_t *d = (uint16_t *) buf->data;
size_t i, l = buf->length / 2;
for (i = 0; i < l; i++) {
*d = sg_bswap_16(*d);
*d = sg_bswap_16(*d); ++d;
}
}
/*
* From: http://www.multimedia.cx/simpleaudio.html#tth_sEc6.1
*/
int16_t mulaw2linear (uint8_t mulawbyte)
{
static const int16_t exp_lut[8] = {
0, 132, 396, 924, 1980, 4092, 8316, 16764
};
int16_t sign, exponent, mantissa, sample;
mulawbyte = ~mulawbyte;
sign = (mulawbyte & 0x80);
exponent = (mulawbyte >> 4) & 0x07;
mantissa = mulawbyte & 0x0F;
sample = exp_lut[exponent] + (mantissa << (exponent + 3));
return sign ? -sample : sample;
int16_t mulaw2linear (uint8_t mulawbyte)
{
static const int16_t exp_lut[8] = {
0, 132, 396, 924, 1980, 4092, 8316, 16764
};
int16_t sign, exponent, mantissa, sample;
mulawbyte = ~mulawbyte;
sign = (mulawbyte & 0x80);
exponent = (mulawbyte >> 4) & 0x07;
mantissa = mulawbyte & 0x0F;
sample = exp_lut[exponent] + (mantissa << (exponent + 3));
return sign ? -sample : sample;
}
void codecULaw (Buffer* b)
{
uint8_t *d = (uint8_t *) b->data;
size_t newLength = b->length * 2;
int16_t *buf = (int16_t *) malloc(newLength);
if (buf == NULL)
throw sg_exception("malloc failed decoing ULaw WAV file");
uint8_t *d = (uint8_t *) b->data;
size_t newLength = b->length * 2;
int16_t *buf = (int16_t *) malloc(newLength);
if (buf == NULL)
throw sg_exception("malloc failed decoing ULaw WAV file");
for (ALsizei i = 0; i < b->length; i++) {
buf[i] = mulaw2linear(d[i]);
for (ALsizei i = 0; i < b->length; i++) {
buf[i] = mulaw2linear(d[i]);
}
free(b->data);
b->data = buf;
b->length = newLength;
}
free(b->data);
b->data = buf;
b->length = newLength;
}
bool gzSkip(gzFile fd, int skipCount)
{
int r = gzseek(fd, skipCount, SEEK_CUR);
@ -213,10 +212,10 @@ int16_t mulaw2linear (uint8_t mulawbyte)
switch (audioFormat)
{
case 1: /* PCM */
codec = (bitsPerSample == 8 || sgIsLittleEndian()) ? codecLinear : codecPCM16;
codec = (bitsPerSample == 8 || sgIsLittleEndian()) ? codecLinear : codecPCM16BE;
break;
case 7: /* uLaw */
bitsPerSample *= 2; /* ToDo: ??? */
bitsPerSample *= 2; /* uLaw is 16-bit packed into 8 bits */
codec = codecULaw;
break;
default:
@ -263,7 +262,7 @@ ALvoid* loadWAVFromFile(const SGPath& path, ALenum& format, ALsizei& size, ALflo
}
Buffer b;
b.path = path;
b.path = path;
gzFile fd;
fd = gzopen(path.c_str(), "rb");
@ -271,12 +270,12 @@ ALvoid* loadWAVFromFile(const SGPath& path, ALenum& format, ALsizei& size, ALflo
throw sg_io_exception("loadWAVFromFile: unable to open file", path);
}
loadWavFile(fd, &b);
loadWavFile(fd, &b);
ALvoid* data = b.data;
b.data = NULL; // don't free when Buffer does out of scope
format = b.format;
size = b.length;
freqf = b.frequency;
b.data = NULL; // don't free when Buffer does out of scope
format = b.format;
size = b.length;
freqf = b.frequency;
gzclose(fd);
return data;