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Date: Sat, 16 Feb 2008 20:59:24 +0100
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From: Tilman Sauerbeck
Subject: [PATCH] Allow SDL_mixer to open wave streams via SDL_rwops

the current version of SDL_mixer can only load WAVE streams directly
from files. In my application I have the need to load them from an
SDL_RWops structure. The attached patch adds that feature to SDL_mixer.
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@slouken
slouken committed Feb 26, 2008
1 parent 3e1278b commit c0d0164
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Showing 4 changed files with 66 additions and 60 deletions.
4 changes: 4 additions & 0 deletions CHANGES
View file
@@ -1,3 +1,7 @@
1.2.9:
Tilman Sauerbeck - Tue Feb 26 03:44:47 PST 2008
* Added support for streaming WAV files with Mix_LoadMUS_RW()

1.2.8:
Sam Lantinga - Wed Jul 18 09:45:54 PDT 2007
* Improved detection of Ogg Vorbis and Tremor libraries
Expand Down
22 changes: 20 additions & 2 deletions music.c
View file
Expand Up @@ -1416,11 +1416,13 @@ MODULE *MikMod_LoadSongRW(SDL_RWops *rw, int maxchan)
}
# endif

Mix_Music *Mix_LoadMUS_RW(SDL_RWops *rw) {
Mix_Music *Mix_LoadMUS_RW(SDL_RWops *rw)
{
Uint8 magic[5]; /*Apparently there is no way to check if the file is really a MOD,*/
/* or there are too many formats supported by MikMod or MikMod does */
/* this check by itself. If someone implements other formats (e.g. MP3) */
/* the check can be uncommented */
Uint8 moremagic[9];
Mix_Music *music;
int start;

Expand All @@ -1431,12 +1433,14 @@ Mix_Music *Mix_LoadMUS_RW(SDL_RWops *rw) {

/* Figure out what kind of file this is */
start = SDL_RWtell(rw);
if (SDL_RWread(rw,magic,1,4)!=4) {
if ( SDL_RWread(rw,magic,1,4) != 4 ||
SDL_RWread(rw,moremagic,1,8) != 8 ) {
Mix_SetError("Couldn't read from RWops");
return NULL;
}
SDL_RWseek(rw, start, SEEK_SET);
magic[4]='\0';
moremagic[8] = '\0';

/* Allocate memory for the music structure */
music=(Mix_Music *)malloc(sizeof(Mix_Music));
Expand All @@ -1446,6 +1450,20 @@ Mix_Music *Mix_LoadMUS_RW(SDL_RWops *rw) {
}
music->error = 0;

#ifdef WAV_MUSIC
/* WAVE files have the magic four bytes "RIFF"
AIFF files have the magic 12 bytes "FORM" XXXX "AIFF"
*/
if ( ((strcmp((char *)magic, "RIFF") == 0) && (strcmp((char *)(moremagic+4), "WAVE") == 0)) ||
(strcmp((char *)magic, "FORM") == 0) ) {
music->type = MUS_WAV;
music->data.wave = WAVStream_LoadSong_RW(rw, (char *)magic);
if ( music->data.wave == NULL ) {
music->error = 1;
}

} else
#endif
#ifdef OGG_MUSIC
/* Ogg Vorbis files have the magic four bytes "OggS" */
if ( strcmp((char *)magic, "OggS") == 0 ) {
Expand Down
94 changes: 37 additions & 57 deletions wavestream.c
View file
Expand Up @@ -95,9 +95,9 @@ static SDL_AudioSpec mixer;
static int wavestream_volume = MIX_MAX_VOLUME;

/* Function to load the WAV/AIFF stream */
static FILE *LoadWAVStream (const char *file, SDL_AudioSpec *spec,
static SDL_RWops *LoadWAVStream (SDL_RWops *rw, SDL_AudioSpec *spec,
long *start, long *stop);
static FILE *LoadAIFFStream (const char *file, SDL_AudioSpec *spec,
static SDL_RWops *LoadAIFFStream (SDL_RWops *rw, SDL_AudioSpec *spec,
long *start, long *stop);

/* Initialize the WAVStream player, with the given mixer settings
Expand All @@ -114,8 +114,26 @@ void WAVStream_SetVolume(int volume)
wavestream_volume = volume;
}

/* Load a WAV stream from the given file */
WAVStream *WAVStream_LoadSong(const char *file, const char *magic)
{
SDL_RWops *rw;
WAVStream *wave;

rw = SDL_RWFromFile(file, "rb");
if ( rw == NULL ) {
SDL_SetError("Couldn't open %s", file);
return NULL;
}
wave = WAVStream_LoadSong_RW(rw, magic);
if ( wave == NULL ) {
SDL_FreeRW(rw);
return NULL;
}
return wave;
}

/* Load a WAV stream from the given file */
WAVStream *WAVStream_LoadSong_RW(SDL_RWops *rw, const char *magic)
{
WAVStream *wave;
SDL_AudioSpec wavespec;
Expand All @@ -128,16 +146,16 @@ WAVStream *WAVStream_LoadSong(const char *file, const char *magic)
if ( wave ) {
memset(wave, 0, (sizeof *wave));
if ( strcmp(magic, "RIFF") == 0 ) {
wave->wavefp = LoadWAVStream(file, &wavespec,
wave->rw = LoadWAVStream(rw, &wavespec,
&wave->start, &wave->stop);
} else
if ( strcmp(magic, "FORM") == 0 ) {
wave->wavefp = LoadAIFFStream(file, &wavespec,
wave->rw = LoadAIFFStream(rw, &wavespec,
&wave->start, &wave->stop);
} else {
Mix_SetError("Unknown WAVE format");
}
if ( wave->wavefp == NULL ) {
if ( wave->rw == NULL ) {
free(wave);
return(NULL);
}
Expand All @@ -151,8 +169,7 @@ WAVStream *WAVStream_LoadSong(const char *file, const char *magic)
/* Start playback of a given WAV stream */
void WAVStream_Start(WAVStream *wave)
{
clearerr(wave->wavefp);
fseek(wave->wavefp, wave->start, SEEK_SET);
SDL_RWseek (wave->rw, wave->start, SEEK_SET);
music = wave;
}

Expand All @@ -161,7 +178,7 @@ void WAVStream_PlaySome(Uint8 *stream, int len)
{
long pos;

if ( music && ((pos=ftell(music->wavefp)) < music->stop) ) {
if ( music && ((pos=SDL_RWtell(music->rw)) < music->stop) ) {
if ( music->cvt.needed ) {
int original_len;

Expand All @@ -181,7 +198,7 @@ void WAVStream_PlaySome(Uint8 *stream, int len)
if ( (music->stop - pos) < original_len ) {
original_len = (music->stop - pos);
}
original_len = fread(music->cvt.buf,1,original_len,music->wavefp);
original_len = SDL_RWread(music->rw, music->cvt.buf,1,original_len);
/* At least at the time of writing, SDL_ConvertAudio()
does byte-order swapping starting at the end of the
buffer. Thus, if we are reading 16-bit samples, we
Expand All @@ -202,7 +219,7 @@ void WAVStream_PlaySome(Uint8 *stream, int len)
data = SDL_stack_alloc(Uint8, len);
if (data)
{
fread(data, len, 1, music->wavefp);
SDL_RWread(music->rw, data, len, 1);
SDL_MixAudio(stream, data, len, wavestream_volume);
SDL_stack_free(data);
}
Expand All @@ -221,8 +238,8 @@ void WAVStream_FreeSong(WAVStream *wave)
{
if ( wave ) {
/* Clean up associated data */
if ( wave->wavefp ) {
fclose(wave->wavefp);
if ( wave->freerw ) {
SDL_FreeRW(wave->rw);
}
if ( wave->cvt.buf ) {
free(wave->cvt.buf);
Expand All @@ -237,7 +254,7 @@ int WAVStream_Active(void)
int active;

active = 0;
if ( music && (ftell(music->wavefp) < music->stop) ) {
if ( music && (SDL_RWtell(music->rw) < music->stop) ) {
active = 1;
}
return(active);
Expand All @@ -264,12 +281,10 @@ static int ReadChunk(SDL_RWops *src, Chunk *chunk, int read_data)
return(chunk->length);
}

static FILE *LoadWAVStream (const char *file, SDL_AudioSpec *spec,
static SDL_RWops *LoadWAVStream (SDL_RWops *src, SDL_AudioSpec *spec,
long *start, long *stop)
{
int was_error;
FILE *wavefp;
SDL_RWops *src;
Chunk chunk;
int lenread;

Expand All @@ -281,17 +296,7 @@ static FILE *LoadWAVStream (const char *file, SDL_AudioSpec *spec,
/* FMT chunk */
WaveFMT *format = NULL;

/* Make sure we are passed a valid data source */
was_error = 0;
wavefp = fopen(file, "rb");
src = NULL;
if ( wavefp ) {
src = SDL_RWFromFP(wavefp, 0);
}
if ( src == NULL ) {
was_error = 1;
goto done;
}

/* Check the magic header */
RIFFchunk = SDL_ReadLE32(src);
Expand Down Expand Up @@ -367,16 +372,10 @@ static FILE *LoadWAVStream (const char *file, SDL_AudioSpec *spec,
if ( format != NULL ) {
free(format);
}
if ( src ) {
SDL_RWclose(src);
}
if ( was_error ) {
if ( wavefp ) {
fclose(wavefp);
wavefp = NULL;
}
return NULL;
}
return(wavefp);
return(src);
}

/* I couldn't get SANE_to_double() to work, so I stole this from libsndfile.
Expand Down Expand Up @@ -405,14 +404,12 @@ static Uint32 SANE_to_Uint32 (Uint8 *sanebuf)
| (sanebuf[5] >> 1)) >> (29 - sanebuf[1]);
}

static FILE *LoadAIFFStream (const char *file, SDL_AudioSpec *spec,
static SDL_RWops *LoadAIFFStream (SDL_RWops *src, SDL_AudioSpec *spec,
long *start, long *stop)
{
int was_error;
int found_SSND;
int found_COMM;
FILE *wavefp;
SDL_RWops *src;

Uint32 chunk_type;
Uint32 chunk_length;
Expand All @@ -431,18 +428,7 @@ static FILE *LoadAIFFStream (const char *file, SDL_AudioSpec *spec,
Uint8 sane_freq[10];
Uint32 frequency = 0;


/* Make sure we are passed a valid data source */
was_error = 0;
wavefp = fopen(file, "rb");
src = NULL;
if ( wavefp ) {
src = SDL_RWFromFP(wavefp, 0);
}
if ( src == NULL ) {
was_error = 1;
goto done;
}

/* Check the magic header */
FORMchunk = SDL_ReadLE32(src);
Expand Down Expand Up @@ -531,15 +517,9 @@ static FILE *LoadAIFFStream (const char *file, SDL_AudioSpec *spec,
spec->samples = 4096; /* Good default buffer size */

done:
if ( src ) {
SDL_RWclose(src);
}
if ( was_error ) {
if ( wavefp ) {
fclose(wavefp);
wavefp = NULL;
}
return NULL;
}
return(wavefp);
return(src);
}

6 changes: 5 additions & 1 deletion wavestream.h
View file
Expand Up @@ -27,7 +27,8 @@
#include <stdio.h>

typedef struct {
FILE *wavefp;
SDL_RWops *rw;
SDL_bool freerw;
long start;
long stop;
SDL_AudioCVT cvt;
Expand All @@ -44,6 +45,9 @@ extern void WAVStream_SetVolume(int volume);
/* Load a WAV stream from the given file */
extern WAVStream *WAVStream_LoadSong(const char *file, const char *magic);

/* Load a WAV stream from an SDL_RWops object */
extern WAVStream *WAVStream_LoadSong_RW(SDL_RWops *rw, const char *magic);

/* Start playback of a given WAV stream */
extern void WAVStream_Start(WAVStream *wave);

Expand Down

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