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