/*

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;

}