531 lines
13 KiB
C
531 lines
13 KiB
C
/*
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SDL_mixer: An audio mixer library based on the SDL library
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Copyright (C) 1997-2009 Sam Lantinga
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This library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Library General Public
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License as published by the Free Software Foundation; either
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version 2 of the License, or (at your option) any later version.
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This library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with this library; if not, write to the Free
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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Sam Lantinga
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slouken@libsdl.org
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*/
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/* $Id: wavestream.c 5214 2009-11-08 17:11:09Z slouken $ */
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/* This file supports streaming WAV files, without volume adjustment */
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#include <stdlib.h>
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#include <string.h>
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#include "SDL_audio.h"
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#include "SDL_mutex.h"
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#include "SDL_rwops.h"
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#include "SDL_endian.h"
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#include "SDL_mixer.h"
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#include "wavestream.h"
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/*
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Taken with permission from SDL_wave.h, part of the SDL library,
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available at: http://www.libsdl.org/
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and placed under the same license as this mixer library.
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*/
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/* WAVE files are little-endian */
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/*******************************************/
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/* Define values for Microsoft WAVE format */
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/*******************************************/
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#define RIFF 0x46464952 /* "RIFF" */
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#define WAVE 0x45564157 /* "WAVE" */
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#define FACT 0x74636166 /* "fact" */
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#define LIST 0x5453494c /* "LIST" */
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#define FMT 0x20746D66 /* "fmt " */
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#define DATA 0x61746164 /* "data" */
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#define PCM_CODE 1
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#define ADPCM_CODE 2
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#define WAVE_MONO 1
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#define WAVE_STEREO 2
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/* Normally, these three chunks come consecutively in a WAVE file */
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typedef struct WaveFMT {
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/* Not saved in the chunk we read:
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Uint32 FMTchunk;
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Uint32 fmtlen;
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*/
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Uint16 encoding;
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Uint16 channels; /* 1 = mono, 2 = stereo */
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Uint32 frequency; /* One of 11025, 22050, or 44100 Hz */
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Uint32 byterate; /* Average bytes per second */
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Uint16 blockalign; /* Bytes per sample block */
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Uint16 bitspersample; /* One of 8, 12, 16, or 4 for ADPCM */
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} WaveFMT;
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/* The general chunk found in the WAVE file */
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typedef struct Chunk {
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Uint32 magic;
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Uint32 length;
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Uint8 *data; /* Data includes magic and length */
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} Chunk;
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/*********************************************/
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/* Define values for AIFF (IFF audio) format */
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/*********************************************/
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#define FORM 0x4d524f46 /* "FORM" */
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#define AIFF 0x46464941 /* "AIFF" */
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#define SSND 0x444e5353 /* "SSND" */
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#define COMM 0x4d4d4f43 /* "COMM" */
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/* Currently we only support a single stream at a time */
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static WAVStream *music = NULL;
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/* This is the format of the audio mixer data */
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static SDL_AudioSpec mixer;
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static int wavestream_volume = MIX_MAX_VOLUME;
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/* Function to load the WAV/AIFF stream */
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static SDL_RWops *LoadWAVStream (SDL_RWops *rw, SDL_AudioSpec *spec,
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long *start, long *stop);
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static SDL_RWops *LoadAIFFStream (SDL_RWops *rw, SDL_AudioSpec *spec,
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long *start, long *stop);
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/* Initialize the WAVStream player, with the given mixer settings
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This function returns 0, or -1 if there was an error.
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*/
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int WAVStream_Init(SDL_AudioSpec *mixerfmt)
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{
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mixer = *mixerfmt;
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return(0);
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}
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void WAVStream_SetVolume(int volume)
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{
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wavestream_volume = volume;
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}
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WAVStream *WAVStream_LoadSong(const char *file, const char *magic)
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{
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SDL_RWops *rw;
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WAVStream *wave;
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rw = SDL_RWFromFile(file, "rb");
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if ( rw == NULL ) {
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SDL_SetError("Couldn't open %s", file);
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return NULL;
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}
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wave = WAVStream_LoadSong_RW(rw, magic);
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if ( wave == NULL ) {
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SDL_FreeRW(rw);
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return NULL;
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}
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return wave;
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}
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/* Load a WAV stream from the given file */
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WAVStream *WAVStream_LoadSong_RW(SDL_RWops *rw, const char *magic)
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{
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WAVStream *wave;
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SDL_AudioSpec wavespec;
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if ( ! mixer.format ) {
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Mix_SetError("WAV music output not started");
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return(NULL);
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}
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wave = (WAVStream *)malloc(sizeof *wave);
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if ( wave ) {
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memset(wave, 0, (sizeof *wave));
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if ( strcmp(magic, "RIFF") == 0 ) {
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wave->rw = LoadWAVStream(rw, &wavespec,
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&wave->start, &wave->stop);
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} else
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if ( strcmp(magic, "FORM") == 0 ) {
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wave->rw = LoadAIFFStream(rw, &wavespec,
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&wave->start, &wave->stop);
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} else {
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Mix_SetError("Unknown WAVE format");
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}
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if ( wave->rw == NULL ) {
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free(wave);
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return(NULL);
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}
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SDL_BuildAudioCVT(&wave->cvt,
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wavespec.format, wavespec.channels, wavespec.freq,
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mixer.format, mixer.channels, mixer.freq);
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}
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return(wave);
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}
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/* Start playback of a given WAV stream */
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void WAVStream_Start(WAVStream *wave)
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{
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SDL_RWseek (wave->rw, wave->start, RW_SEEK_SET);
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music = wave;
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}
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/* Play some of a stream previously started with WAVStream_Start() */
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int WAVStream_PlaySome(Uint8 *stream, int len)
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{
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long pos;
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int left = 0;
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if ( music && ((pos=SDL_RWtell(music->rw)) < music->stop) ) {
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if ( music->cvt.needed ) {
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int original_len;
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original_len=(int)((double)len/music->cvt.len_ratio);
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if ( music->cvt.len != original_len ) {
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int worksize;
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if ( music->cvt.buf != NULL ) {
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free(music->cvt.buf);
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}
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worksize = original_len*music->cvt.len_mult;
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music->cvt.buf=(Uint8 *)malloc(worksize);
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if ( music->cvt.buf == NULL ) {
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return 0;
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}
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music->cvt.len = original_len;
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}
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if ( (music->stop - pos) < original_len ) {
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left = (original_len - (music->stop - pos));
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original_len -= left;
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left = (int)((double)left*music->cvt.len_ratio);
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}
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original_len = SDL_RWread(music->rw, music->cvt.buf,1,original_len);
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/* At least at the time of writing, SDL_ConvertAudio()
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does byte-order swapping starting at the end of the
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buffer. Thus, if we are reading 16-bit samples, we
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had better make damn sure that we get an even
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number of bytes, or we'll get garbage.
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*/
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if ( (music->cvt.src_format & 0x0010) && (original_len & 1) ) {
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original_len--;
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}
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music->cvt.len = original_len;
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SDL_ConvertAudio(&music->cvt);
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SDL_MixAudio(stream, music->cvt.buf, music->cvt.len_cvt, wavestream_volume);
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} else {
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Uint8 *data;
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if ( (music->stop - pos) < len ) {
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left = (len - (music->stop - pos));
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len -= left;
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}
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data = SDL_stack_alloc(Uint8, len);
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if (data)
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{
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SDL_RWread(music->rw, data, len, 1);
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SDL_MixAudio(stream, data, len, wavestream_volume);
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SDL_stack_free(data);
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}
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}
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}
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return left;
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}
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/* Stop playback of a stream previously started with WAVStream_Start() */
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void WAVStream_Stop(void)
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{
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music = NULL;
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}
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/* Close the given WAV stream */
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void WAVStream_FreeSong(WAVStream *wave)
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{
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if ( wave ) {
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/* Clean up associated data */
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if ( wave->freerw ) {
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SDL_FreeRW(wave->rw);
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}
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if ( wave->cvt.buf ) {
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free(wave->cvt.buf);
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}
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free(wave);
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}
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}
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/* Return non-zero if a stream is currently playing */
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int WAVStream_Active(void)
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{
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int active;
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active = 0;
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if ( music && (SDL_RWtell(music->rw) < music->stop) ) {
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active = 1;
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}
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return(active);
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}
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static int ReadChunk(SDL_RWops *src, Chunk *chunk, int read_data)
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{
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chunk->magic = SDL_ReadLE32(src);
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chunk->length = SDL_ReadLE32(src);
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if ( read_data ) {
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chunk->data = (Uint8 *)malloc(chunk->length);
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if ( chunk->data == NULL ) {
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Mix_SetError("Out of memory");
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return(-1);
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}
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if ( SDL_RWread(src, chunk->data, chunk->length, 1) != 1 ) {
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Mix_SetError("Couldn't read chunk");
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free(chunk->data);
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return(-1);
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}
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} else {
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SDL_RWseek(src, chunk->length, RW_SEEK_CUR);
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}
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return(chunk->length);
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}
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static SDL_RWops *LoadWAVStream (SDL_RWops *src, SDL_AudioSpec *spec,
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long *start, long *stop)
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{
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int was_error;
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Chunk chunk;
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int lenread;
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/* WAV magic header */
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Uint32 RIFFchunk;
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Uint32 wavelen;
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Uint32 WAVEmagic;
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/* FMT chunk */
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WaveFMT *format = NULL;
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was_error = 0;
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/* Check the magic header */
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RIFFchunk = SDL_ReadLE32(src);
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wavelen = SDL_ReadLE32(src);
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WAVEmagic = SDL_ReadLE32(src);
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if ( (RIFFchunk != RIFF) || (WAVEmagic != WAVE) ) {
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Mix_SetError("Unrecognized file type (not WAVE)");
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was_error = 1;
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goto done;
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}
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/* Read the audio data format chunk */
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chunk.data = NULL;
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do {
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/* FIXME! Add this logic to SDL_LoadWAV_RW() */
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if ( chunk.data ) {
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free(chunk.data);
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}
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lenread = ReadChunk(src, &chunk, 1);
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if ( lenread < 0 ) {
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was_error = 1;
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goto done;
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}
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} while ( (chunk.magic == FACT) || (chunk.magic == LIST) );
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/* Decode the audio data format */
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format = (WaveFMT *)chunk.data;
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if ( chunk.magic != FMT ) {
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free(chunk.data);
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Mix_SetError("Complex WAVE files not supported");
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was_error = 1;
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goto done;
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}
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switch (SDL_SwapLE16(format->encoding)) {
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case PCM_CODE:
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/* We can understand this */
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break;
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default:
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Mix_SetError("Unknown WAVE data format");
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was_error = 1;
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goto done;
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}
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memset(spec, 0, (sizeof *spec));
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spec->freq = SDL_SwapLE32(format->frequency);
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switch (SDL_SwapLE16(format->bitspersample)) {
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case 8:
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spec->format = AUDIO_U8;
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break;
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case 16:
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spec->format = AUDIO_S16;
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break;
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default:
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Mix_SetError("Unknown PCM data format");
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was_error = 1;
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goto done;
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}
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spec->channels = (Uint8) SDL_SwapLE16(format->channels);
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spec->samples = 4096; /* Good default buffer size */
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/* Set the file offset to the DATA chunk data */
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chunk.data = NULL;
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do {
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*start = SDL_RWtell(src) + 2*sizeof(Uint32);
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lenread = ReadChunk(src, &chunk, 0);
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if ( lenread < 0 ) {
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was_error = 1;
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goto done;
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}
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} while ( chunk.magic != DATA );
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*stop = SDL_RWtell(src);
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done:
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if ( format != NULL ) {
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free(format);
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}
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if ( was_error ) {
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return NULL;
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}
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return(src);
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}
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|
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/* I couldn't get SANE_to_double() to work, so I stole this from libsndfile.
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* I don't pretend to fully understand it.
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*/
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static Uint32 SANE_to_Uint32 (Uint8 *sanebuf)
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{
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/* Negative number? */
|
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if (sanebuf[0] & 0x80)
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return 0;
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|
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/* Less than 1? */
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if (sanebuf[0] <= 0x3F)
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return 1;
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|
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/* Way too big? */
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if (sanebuf[0] > 0x40)
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return 0x4000000;
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|
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/* Still too big? */
|
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if (sanebuf[0] == 0x40 && sanebuf[1] > 0x1C)
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return 800000000;
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|
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return ((sanebuf[2] << 23) | (sanebuf[3] << 15) | (sanebuf[4] << 7)
|
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| (sanebuf[5] >> 1)) >> (29 - sanebuf[1]);
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}
|
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|
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static SDL_RWops *LoadAIFFStream (SDL_RWops *src, SDL_AudioSpec *spec,
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long *start, long *stop)
|
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{
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int was_error;
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int found_SSND;
|
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int found_COMM;
|
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|
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Uint32 chunk_type;
|
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Uint32 chunk_length;
|
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long next_chunk;
|
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|
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/* AIFF magic header */
|
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Uint32 FORMchunk;
|
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Uint32 AIFFmagic;
|
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/* SSND chunk */
|
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Uint32 offset;
|
|
Uint32 blocksize;
|
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/* COMM format chunk */
|
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Uint16 channels = 0;
|
|
Uint32 numsamples = 0;
|
|
Uint16 samplesize = 0;
|
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Uint8 sane_freq[10];
|
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Uint32 frequency = 0;
|
|
|
|
was_error = 0;
|
|
|
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/* Check the magic header */
|
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FORMchunk = SDL_ReadLE32(src);
|
|
chunk_length = SDL_ReadBE32(src);
|
|
AIFFmagic = SDL_ReadLE32(src);
|
|
if ( (FORMchunk != FORM) || (AIFFmagic != AIFF) ) {
|
|
Mix_SetError("Unrecognized file type (not AIFF)");
|
|
was_error = 1;
|
|
goto done;
|
|
}
|
|
|
|
/* From what I understand of the specification, chunks may appear in
|
|
* any order, and we should just ignore unknown ones.
|
|
*
|
|
* TODO: Better sanity-checking. E.g. what happens if the AIFF file
|
|
* contains compressed sound data?
|
|
*/
|
|
|
|
found_SSND = 0;
|
|
found_COMM = 0;
|
|
|
|
do {
|
|
chunk_type = SDL_ReadLE32(src);
|
|
chunk_length = SDL_ReadBE32(src);
|
|
next_chunk = SDL_RWtell(src) + chunk_length;
|
|
|
|
/* Paranoia to avoid infinite loops */
|
|
if (chunk_length == 0)
|
|
break;
|
|
|
|
switch (chunk_type) {
|
|
case SSND:
|
|
found_SSND = 1;
|
|
offset = SDL_ReadBE32(src);
|
|
blocksize = SDL_ReadBE32(src);
|
|
*start = SDL_RWtell(src) + offset;
|
|
break;
|
|
|
|
case COMM:
|
|
found_COMM = 1;
|
|
|
|
/* Read the audio data format chunk */
|
|
channels = SDL_ReadBE16(src);
|
|
numsamples = SDL_ReadBE32(src);
|
|
samplesize = SDL_ReadBE16(src);
|
|
SDL_RWread(src, sane_freq, sizeof(sane_freq), 1);
|
|
frequency = SANE_to_Uint32(sane_freq);
|
|
break;
|
|
|
|
default:
|
|
break;
|
|
}
|
|
} while ((!found_SSND || !found_COMM)
|
|
&& SDL_RWseek(src, next_chunk, RW_SEEK_SET) != -1);
|
|
|
|
if (!found_SSND) {
|
|
Mix_SetError("Bad AIFF file (no SSND chunk)");
|
|
was_error = 1;
|
|
goto done;
|
|
}
|
|
|
|
if (!found_COMM) {
|
|
Mix_SetError("Bad AIFF file (no COMM chunk)");
|
|
was_error = 1;
|
|
goto done;
|
|
}
|
|
|
|
*stop = *start + channels * numsamples * (samplesize / 8);
|
|
|
|
/* Decode the audio data format */
|
|
memset(spec, 0, (sizeof *spec));
|
|
spec->freq = frequency;
|
|
switch (samplesize) {
|
|
case 8:
|
|
spec->format = AUDIO_S8;
|
|
break;
|
|
case 16:
|
|
spec->format = AUDIO_S16MSB;
|
|
break;
|
|
default:
|
|
Mix_SetError("Unknown samplesize in data format");
|
|
was_error = 1;
|
|
goto done;
|
|
}
|
|
spec->channels = (Uint8) channels;
|
|
spec->samples = 4096; /* Good default buffer size */
|
|
|
|
done:
|
|
if ( was_error ) {
|
|
return NULL;
|
|
}
|
|
return(src);
|
|
}
|
|
|