# HG changeset patch # User Ryan C. Gordon # Date 1010951296 0 # Node ID 948b62500a548061e52b9355c493ac77535bf05b # Parent 8c2cb920a3838edf80f1b2e3d06cb115a609e10f Initial add. diff -r 8c2cb920a383 -r 948b62500a54 decoders/au.c --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/decoders/au.c Sun Jan 13 19:48:16 2002 +0000 @@ -0,0 +1,294 @@ +/* + * SDL_sound -- An abstract sound format decoding API. + * Copyright (C) 2001 Ryan C. Gordon. + * + * This library is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; either + * version 2.1 of the License, or (at your option) any later version. + * + * This library is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with this library; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + */ + +/* + * Sun/NeXT .au decoder for SDL_sound. + * Formats supported: 8 and 16 bit linear PCM, 8 bit µ-law. + * Files without valid header are assumed to be 8 bit µ-law, 8kHz, mono. + * + * Please see the file COPYING in the source's root directory. + * + * This file written by Mattias Engdegĺrd. (f91-men@nada.kth.se) + */ + +#if HAVE_CONFIG_H +# include +#endif + +#ifdef SOUND_SUPPORTS_AU + +#include +#include +#include +#include + +#include "SDL_sound.h" + +#define __SDL_SOUND_INTERNAL__ +#include "SDL_sound_internal.h" + +static int AU_init(void); +static void AU_quit(void); +static int AU_open(Sound_Sample *sample, const char *ext); +static void AU_close(Sound_Sample *sample); +static Uint32 AU_read(Sound_Sample *sample); + +/* + * Sometimes the extension ".snd" is used for these files (mostly on the NeXT), + * and the magic number comes from this. However it may clash with other + * formats and is somewhat of an anachronism, so only .au is used here. + */ +static const char *extensions_au[] = { "AU", NULL }; +const Sound_DecoderFunctions __Sound_DecoderFunctions_AU = +{ + { + extensions_au, + "Sun/NeXT audio file format", + "Mattias Engdegĺrd ", + "http://www.icculus.org/SDL_sound/" + }, + + AU_init, + AU_quit, + AU_open, + AU_close, + AU_read +}; + +/* no init/deinit needed */ +static int AU_init(void) +{ + return(1); +} + +static void AU_quit(void) +{ + /* no-op. */ +} + +struct au_file_hdr +{ + Uint32 magic; + Uint32 hdr_size; + Uint32 data_size; + Uint32 encoding; + Uint32 sample_rate; + Uint32 channels; +}; + +#define HDR_SIZE 24 + +enum +{ + AU_ENC_ULAW_8 = 1, /* 8-bit ISDN µ-law */ + AU_ENC_LINEAR_8 = 2, /* 8-bit linear PCM */ + AU_ENC_LINEAR_16 = 3, /* 16-bit linear PCM */ + + /* the rest are unsupported (I have never seen them in the wild) */ + AU_ENC_LINEAR_24 = 4, /* 24-bit linear PCM */ + AU_ENC_LINEAR_32 = 5, /* 32-bit linear PCM */ + AU_ENC_FLOAT = 6, /* 32-bit IEEE floating point */ + AU_ENC_DOUBLE = 7, /* 64-bit IEEE floating point */ + /* more Sun formats, not supported either */ + AU_ENC_ADPCM_G721 = 23, + AU_ENC_ADPCM_G722 = 24, + AU_ENC_ADPCM_G723_3 = 25, + AU_ENC_ADPCM_G723_5 = 26, + AU_ENC_ALAW_8 = 27 +}; + +struct audec +{ + unsigned remaining; + int encoding; +}; + + +#define AU_MAGIC 0x646E732E /* ".snd", in ASCII */ + +static int AU_open(Sound_Sample *sample, const char *ext) +{ + Sound_SampleInternal *internal = sample->opaque; + SDL_RWops *rw = internal->rw; + int r, skip, hsize, i; + struct au_file_hdr hdr; + char c; + struct audec *dec = malloc(sizeof *dec); + BAIL_IF_MACRO(dec == NULL, ERR_OUT_OF_MEMORY, 0); + internal->decoder_private = dec; + + r = SDL_RWread(rw, &hdr, 1, HDR_SIZE); + if (r < HDR_SIZE) + { + Sound_SetError("No .au file (bad header)"); + free(dec); + return 0; + } + + if (SDL_SwapLE32(hdr.magic) == AU_MAGIC) + { + /* valid magic */ + dec->encoding = SDL_SwapBE32(hdr.encoding); + switch(dec->encoding) + { + case AU_ENC_ULAW_8: + /* Convert 8-bit µ-law to 16-bit linear on the fly. This is + slightly wasteful if the audio driver must convert them + back, but µ-law only devices are rare (mostly _old_ Suns) */ + sample->actual.format = AUDIO_S16SYS; + break; + + case AU_ENC_LINEAR_8: + sample->actual.format = AUDIO_S8; + break; + + case AU_ENC_LINEAR_16: + sample->actual.format = AUDIO_S16MSB; + break; + + default: + Sound_SetError("Unsupported .au encoding"); + free(dec); + return 0; + } + + sample->actual.rate = SDL_SwapBE32(hdr.sample_rate); + sample->actual.channels = SDL_SwapBE32(hdr.channels); + dec->remaining = SDL_SwapBE32(hdr.data_size); + hsize = SDL_SwapBE32(hdr.hdr_size); + + /* skip remaining part of header (input may be unseekable) */ + for (i = HDR_SIZE; i < hsize; i++) + SDL_RWread(rw, &c, 1, 1); + } + + else if (__Sound_strcasecmp(ext, "au") == 0) + { + /* + * A number of files in the wild have the .au extension but no valid + * header; these are traditionally assumed to be 8kHz µ-law. Handle + * them here only if the extension is recognized. + */ + + SNDDBG(("AU: Invalid header, assuming raw 8kHz µ-law.\n")); + /* if seeking fails, we lose 24 samples. big deal */ + SDL_RWseek(rw, -HDR_SIZE, SEEK_CUR); + dec->encoding = AU_ENC_ULAW_8; + dec->remaining = (Uint32)-1; /* no limit */ + sample->actual.format = AUDIO_S16SYS; + sample->actual.rate = 8000; + sample->actual.channels = 1; + } + + sample->flags = SOUND_SAMPLEFLAG_NONE; + + SNDDBG(("AU: Accepting data stream.\n")); + return 1; +} + + +static void AU_close(Sound_Sample *sample) +{ + Sound_SampleInternal *internal = sample->opaque; + free(internal->decoder_private); +} + +/* table to convert from µ-law encoding to signed 16-bit samples, + generated by a throwaway perl script */ +static Sint16 ulaw_to_linear[256] = { + -32124,-31100,-30076,-29052,-28028,-27004,-25980,-24956, + -23932,-22908,-21884,-20860,-19836,-18812,-17788,-16764, + -15996,-15484,-14972,-14460,-13948,-13436,-12924,-12412, + -11900,-11388,-10876,-10364, -9852, -9340, -8828, -8316, + -7932, -7676, -7420, -7164, -6908, -6652, -6396, -6140, + -5884, -5628, -5372, -5116, -4860, -4604, -4348, -4092, + -3900, -3772, -3644, -3516, -3388, -3260, -3132, -3004, + -2876, -2748, -2620, -2492, -2364, -2236, -2108, -1980, + -1884, -1820, -1756, -1692, -1628, -1564, -1500, -1436, + -1372, -1308, -1244, -1180, -1116, -1052, -988, -924, + -876, -844, -812, -780, -748, -716, -684, -652, + -620, -588, -556, -524, -492, -460, -428, -396, + -372, -356, -340, -324, -308, -292, -276, -260, + -244, -228, -212, -196, -180, -164, -148, -132, + -120, -112, -104, -96, -88, -80, -72, -64, + -56, -48, -40, -32, -24, -16, -8, 0, + 32124, 31100, 30076, 29052, 28028, 27004, 25980, 24956, + 23932, 22908, 21884, 20860, 19836, 18812, 17788, 16764, + 15996, 15484, 14972, 14460, 13948, 13436, 12924, 12412, + 11900, 11388, 10876, 10364, 9852, 9340, 8828, 8316, + 7932, 7676, 7420, 7164, 6908, 6652, 6396, 6140, + 5884, 5628, 5372, 5116, 4860, 4604, 4348, 4092, + 3900, 3772, 3644, 3516, 3388, 3260, 3132, 3004, + 2876, 2748, 2620, 2492, 2364, 2236, 2108, 1980, + 1884, 1820, 1756, 1692, 1628, 1564, 1500, 1436, + 1372, 1308, 1244, 1180, 1116, 1052, 988, 924, + 876, 844, 812, 780, 748, 716, 684, 652, + 620, 588, 556, 524, 492, 460, 428, 396, + 372, 356, 340, 324, 308, 292, 276, 260, + 244, 228, 212, 196, 180, 164, 148, 132, + 120, 112, 104, 96, 88, 80, 72, 64, + 56, 48, 40, 32, 24, 16, 8, 0 +}; + +static Uint32 AU_read(Sound_Sample *sample) +{ + int ret; + Sound_SampleInternal *internal = sample->opaque; + struct audec *dec = internal->decoder_private; + int maxlen; + Uint8 *buf; + + maxlen = internal->buffer_size; + buf = internal->buffer; + if (dec->encoding == AU_ENC_ULAW_8) + { + /* We read µ-law samples into the second half of the buffer, so + we can expand them to 16-bit samples afterwards */ + maxlen >>= 1; + buf += maxlen; + } + + if(maxlen > dec->remaining) + maxlen = dec->remaining; + ret = SDL_RWread(internal->rw, buf, 1, maxlen); + if (ret == 0) + sample->flags |= SOUND_SAMPLEFLAG_EOF; + else if (ret == -1) + sample->flags |= SOUND_SAMPLEFLAG_ERROR; + else + { + dec->remaining -= ret; + if (ret < maxlen) + sample->flags |= SOUND_SAMPLEFLAG_EAGAIN; + + if (dec->encoding == AU_ENC_ULAW_8) + { + int i; + Sint16 *dst = internal->buffer; + for (i = 0; i < ret; i++) + dst[i] = ulaw_to_linear[buf[i]]; + ret <<= 1; /* return twice as much as read */ + } + } + + return ret; +} + +#endif /* SOUND_SUPPORTS_AU */ +