/*
monosynth.h: generic mono related synth functions
copyright 1995-2008 by the mpg123 project - free software under the terms of the LGPL 2.1
see COPYING and AUTHORS files in distribution or http://mpg123.org
initially written by Michael Hipp, generalized by Thomas Orgis
This header is used multiple times to create different variants of these functions.
See decode.c and synth.h .
Hint: BLOCK, MONO_NAME, MONO2STEREO_NAME, SYNTH_NAME and SAMPLE_T do vary.
Thomas looked closely at the decode_1to1, decode_2to1 and decode_4to1 contents, seeing that they are too similar to be separate files.
This is what resulted...
Reason to separate this from synth.h:
There are decoders that have a special synth_1to1 but still can use these generic derivations for the mono stuff.
It generally makes a good deal of sense to set SYNTH_NAME to opt_synth_1to1(fr) (or opt_synth_2to1(fr), etc.).
*/
/* Mono synth, wrapping over SYNTH_NAME */
int MONO_NAME(real *bandPtr, mpg123_handle *fr)
{
SAMPLE_T samples_tmp[BLOCK];
SAMPLE_T *tmp1 = samples_tmp;
int i,ret;
/* save buffer stuff, trick samples_tmp into there, decode, restore */
unsigned char *samples = fr->buffer.data;
int pnt = fr->buffer.fill;
fr->buffer.data = (unsigned char*) samples_tmp;
fr->buffer.fill = 0;
ret = SYNTH_NAME(bandPtr, 0, fr, 0); /* decode into samples_tmp */
fr->buffer.data = samples; /* restore original value */
/* now append samples from samples_tmp */
samples += pnt; /* just the next mem in frame buffer */
for(i=0;i<(BLOCK/2);i++)
{
*( (SAMPLE_T *)samples) = *tmp1;
samples += sizeof(SAMPLE_T);
tmp1 += 2;
}
fr->buffer.fill = pnt + (BLOCK/2)*sizeof(SAMPLE_T);
return ret;
}
/* Mono to stereo synth, wrapping over SYNTH_NAME */
int MONO2STEREO_NAME(real *bandPtr, mpg123_handle *fr)
{
int i,ret;
unsigned char *samples = fr->buffer.data;
ret = SYNTH_NAME(bandPtr,0,fr,1);
samples += fr->buffer.fill - BLOCK*sizeof(SAMPLE_T);
for(i=0;i<(BLOCK/2);i++)
{
((SAMPLE_T *)samples)[1] = ((SAMPLE_T *)samples)[0];
samples+=2*sizeof(SAMPLE_T);
}
return ret;
}