ref: 2515cb2de68b10eff93b876159dcbf180474f146
dir: /src/gsm.c/
/* * Copyright 1991, 1992, 1993 Guido van Rossum And Sundry Contributors. * This source code is freely redistributable and may be used for * any purpose. This copyright notice must be maintained. * Guido van Rossum And Sundry Contributors are not responsible for * the consequences of using this software. */ /* * GSM 06.10 courtesy Communications and Operating Systems Research Group, * Technische Universitaet Berlin * * More information on this format can be obtained from * http://www.cs.tu-berlin.de/~jutta/toast.html * * Source is available from ftp://ftp.cs.tu-berlin.de/pub/local/kbs/tubmik/gsm * * Written 26 Jan 1995 by Andrew Pam * Portions Copyright (c) 1995 Serious Cybernetics * * July 19, 1998 - Chris Bagwell (cbagwell@sprynet.com) * Added GSM support to SOX from patches floating around with the help * of Dima Barsky (ess2db@ee.surrey.ac.uk). * * Nov. 26, 1999 - Stan Brooks (stabro@megsinet.com) * Rewritten to support multiple channels */ #include "st_i.h" #ifdef EXTERNAL_GSM #include <gsm/gsm.h> #else #include "libgsm/gsm.h" #endif #include <errno.h> #define MAXCHANS 16 /* sizeof(gsm_frame) */ #define FRAMESIZE 33 /* samples per gsm_frame */ #define BLOCKSIZE 160 /* Private data */ struct gsmpriv { int channels; gsm_signal *samples; gsm_signal *samplePtr; gsm_signal *sampleTop; gsm_byte *frames; gsm handle[MAXCHANS]; }; static int gsmstart_rw(ft_t ft, int w) { struct gsmpriv *p = (struct gsmpriv *) ft->priv; int ch; ft->info.encoding = ST_ENCODING_GSM; ft->info.size = ST_SIZE_BYTE; if (!ft->info.rate) ft->info.rate = 8000; if (ft->info.channels == 0) ft->info.channels = 1; p->channels = ft->info.channels; if (p->channels > MAXCHANS || p->channels <= 0) { st_fail_errno(ft,ST_EFMT,"gsm: channels(%d) must be in 1-16", ft->info.channels); return(ST_EOF); } for (ch=0; ch<p->channels; ch++) { p->handle[ch] = gsm_create(); if (!p->handle[ch]) { st_fail_errno(ft,errno,"unable to create GSM stream"); return (ST_EOF); } } p->frames = (gsm_byte*) malloc(p->channels*FRAMESIZE); p->samples = (gsm_signal*) malloc(BLOCKSIZE * (p->channels+1) * sizeof(gsm_signal)); p->sampleTop = p->samples + BLOCKSIZE*p->channels; p->samplePtr = (w)? p->samples : p->sampleTop; return (ST_SUCCESS); } static int st_gsmstartread(ft_t ft) { return gsmstart_rw(ft,0); } static int st_gsmstartwrite(ft_t ft) { return gsmstart_rw(ft,1); } /* * Read up to len samples from file. * Convert to signed longs. * Place in buf[]. * Return number of samples read. */ static st_size_t st_gsmread(ft_t ft, st_sample_t *buf, st_size_t samp) { size_t done = 0; int r, ch, chans; gsm_signal *gbuff; struct gsmpriv *p = (struct gsmpriv *) ft->priv; chans = p->channels; while (done < samp) { while (p->samplePtr < p->sampleTop && done < samp) buf[done++] = ST_SIGNED_WORD_TO_SAMPLE(*(p->samplePtr)++,); if (done>=samp) break; r = st_readbuf(ft, p->frames, p->channels*FRAMESIZE, 1); if (r != 1) break; p->samplePtr = p->samples; for (ch=0; ch<chans; ch++) { int i; gsm_signal *gsp; gbuff = p->sampleTop; if (gsm_decode(p->handle[ch], p->frames + ch*FRAMESIZE, gbuff) < 0) { st_fail_errno(ft,errno,"error during GSM decode"); return (0); } gsp = p->samples + ch; for (i=0; i<BLOCKSIZE; i++) { *gsp = *gbuff++; gsp += chans; } } } return done; } static int gsmflush(ft_t ft) { int r, ch, chans; gsm_signal *gbuff; struct gsmpriv *p = (struct gsmpriv *) ft->priv; chans = p->channels; /* zero-fill samples as needed */ while (p->samplePtr < p->sampleTop) *(p->samplePtr)++ = 0; gbuff = p->sampleTop; for (ch=0; ch<chans; ch++) { int i; gsm_signal *gsp; gsp = p->samples + ch; for (i=0; i<BLOCKSIZE; i++) { gbuff[i] = *gsp; gsp += chans; } gsm_encode(p->handle[ch], gbuff, p->frames); r = st_writebuf(ft, p->frames, FRAMESIZE, 1); if (r != 1) { st_fail_errno(ft,errno,"write error"); return(ST_EOF); } } p->samplePtr = p->samples; return (ST_SUCCESS); } static st_size_t st_gsmwrite(ft_t ft, const st_sample_t *buf, st_size_t samp) { size_t done = 0; struct gsmpriv *p = (struct gsmpriv *) ft->priv; while (done < samp) { while ((p->samplePtr < p->sampleTop) && (done < samp)) *(p->samplePtr)++ = ST_SAMPLE_TO_SIGNED_WORD(buf[done++], ft->clippedCount); if (p->samplePtr == p->sampleTop) { if(gsmflush(ft)) { return 0; } } } return done; } static int st_gsmstopread(ft_t ft) { struct gsmpriv *p = (struct gsmpriv *) ft->priv; int ch; for (ch=0; ch<p->channels; ch++) gsm_destroy(p->handle[ch]); free(p->samples); free(p->frames); return (ST_SUCCESS); } static int st_gsmstopwrite(ft_t ft) { int rc; struct gsmpriv *p = (struct gsmpriv *) ft->priv; if (p->samplePtr > p->samples) { rc = gsmflush(ft); if (rc) return rc; } return st_gsmstopread(ft); /* destroy handles and free buffers */ } /* GSM 06.10 */ static const char *gsmnames[] = { "gsm", NULL }; static st_format_t st_gsm_format = { gsmnames, NULL, 0, st_gsmstartread, st_gsmread, st_gsmstopread, st_gsmstartwrite, st_gsmwrite, st_gsmstopwrite, st_format_nothing_seek }; const st_format_t *st_gsm_format_fn(void) { return &st_gsm_format; }