--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/decoders/oggtremor.c	Wed Apr 27 19:37:16 2011 -0700
@@ -0,0 +1,377 @@
+/*
+ * 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
+ */
+
+/*
+ * Ogg Vorbis decoder for SDL_sound.
+ *
+ * This driver handles .OGG audio files, and depends on libvorbisfile to
+ *  do the actual decoding work. libvorbisfile is part of libvorbis, which
+ *  is part of the Ogg Vorbis project.
+ *
+ *   Ogg Vorbis: http://www.xiph.org/ogg/vorbis/
+ *   vorbisfile documentation: http://www.xiph.org/ogg/vorbis/doc/vorbisfile/
+ *
+ * Please see the file LICENSE.txt in the source's root directory.
+ *
+ *  This file written by Ryan C. Gordon. (icculus@icculus.org)
+ */
+
+#if HAVE_CONFIG_H
+#  include <config.h>
+#endif
+
+#ifdef SOUND_SUPPORTS_OGG
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <math.h>
+
+#include "SDL_sound.h"
+
+#define __SDL_SOUND_INTERNAL__
+#include "SDL_sound_internal.h"
+
+//#include <vorbis/codec.h>
+#include <ivorbisfile.h>
+#define ERR_IO_ERROR "I/O error"
+
+
+static int OGG_init(void);
+static void OGG_quit(void);
+static int OGG_open(Sound_Sample *sample, const char *ext);
+static void OGG_close(Sound_Sample *sample);
+static Uint32 OGG_read(Sound_Sample *sample);
+static int OGG_rewind(Sound_Sample *sample);
+static int OGG_seek(Sound_Sample *sample, Uint32 ms);
+
+static const char *extensions_ogg[] = { "OGG", NULL };
+const Sound_DecoderFunctions __Sound_DecoderFunctions_OGG =
+{
+    {
+        extensions_ogg,
+        "Ogg Vorbis audio through VorbisFile",
+        "Ryan C. Gordon <icculus@icculus.org>",
+        "http://www.icculus.org/SDL_sound/"
+    },
+
+    OGG_init,       /*   init() method */
+    OGG_quit,       /*   quit() method */
+    OGG_open,       /*   open() method */
+    OGG_close,      /*  close() method */
+    OGG_read,       /*   read() method */
+    OGG_rewind,     /* rewind() method */
+    OGG_seek        /*   seek() method */
+};
+
+
+static int OGG_init(void)
+{
+    return(1);  /* always succeeds. */
+} /* OGG_init */
+
+
+static void OGG_quit(void)
+{
+    /* it's a no-op. */
+} /* OGG_quit */
+
+
+
+    /*
+     * These are callbacks from vorbisfile that let them read data from
+     *  a RWops...
+     */
+
+static size_t RWops_ogg_read(void *ptr, size_t size, size_t nmemb, void *datasource)
+{
+    return((size_t) SDL_RWread((SDL_RWops *) datasource, ptr, size, nmemb));
+} /* RWops_ogg_read */
+
+static int RWops_ogg_seek(void *datasource, ogg_int64_t offset, int whence)
+{
+    return(SDL_RWseek((SDL_RWops *) datasource, offset, whence));
+} /* RWops_ogg_seek */
+
+static int RWops_ogg_close(void *datasource)
+{
+    /* do nothing; SDL_sound will delete the RWops at a higher level. */
+    return(0);  /* this is success in fclose(), so I guess that's okay. */
+} /* RWops_ogg_close */
+
+static long RWops_ogg_tell(void *datasource)
+{
+    return((long) SDL_RWtell((SDL_RWops *) datasource));
+} /* RWops_ogg_tell */
+
+static const ov_callbacks RWops_ogg_callbacks =
+{
+    RWops_ogg_read,
+    RWops_ogg_seek,
+    RWops_ogg_close,
+    RWops_ogg_tell
+};
+
+
+    /* Return a human readable version of an VorbisFile error code... */
+#if (defined DEBUG_CHATTER)
+static const char *ogg_error(int errnum)
+{
+    switch(errnum)
+    {
+        case OV_EREAD:
+            return("i/o error");
+        case OV_ENOTVORBIS:
+            return("not a vorbis file");
+        case OV_EVERSION:
+            return("Vorbis version mismatch");
+        case OV_EBADHEADER:
+            return("invalid Vorbis bitstream header");
+        case OV_EFAULT:
+            return("internal logic fault in Vorbis library");
+    } /* switch */
+
+    return("unknown error");
+} /* ogg_error */
+#endif
+
+static __inline__ void output_ogg_comments(OggVorbis_File *vf)
+{
+#if (defined DEBUG_CHATTER)
+    int i;
+    vorbis_comment *vc = ov_comment(vf, -1);
+
+    if (vc == NULL)
+        return;
+
+    SNDDBG(("OGG: vendor == [%s].\n", vc->vendor));
+    for (i = 0; i < vc->comments; i++)
+    {
+        SNDDBG(("OGG: user comment [%s].\n", vc->user_comments[i]));
+    } /* for */
+#endif
+} /* output_ogg_comments */
+
+
+static int OGG_open(Sound_Sample *sample, const char *ext)
+{
+    int rc;
+    double total_time;
+    OggVorbis_File *vf;
+    vorbis_info *info;
+    Sound_SampleInternal *internal = (Sound_SampleInternal *) sample->opaque;
+
+    vf = (OggVorbis_File *) malloc(sizeof (OggVorbis_File));
+    BAIL_IF_MACRO(vf == NULL, ERR_OUT_OF_MEMORY, 0);
+
+    rc = ov_open_callbacks(internal->rw, vf, NULL, 0, RWops_ogg_callbacks);
+    if (rc != 0)
+    {
+        SNDDBG(("OGG: can't grok data. reason: [%s].\n", ogg_error(rc)));
+        free(vf);
+        BAIL_MACRO("OGG: Not valid Ogg Vorbis data.", 0);
+    } /* if */
+
+    info = ov_info(vf, -1);
+    if (info == NULL)
+    {
+        ov_clear(vf);
+        free(vf);
+        BAIL_MACRO("OGG: failed to retrieve bitstream info", 0);
+    } /* if */
+
+    SNDDBG(("OGG: Accepting data stream.\n"));
+
+    output_ogg_comments(vf);
+    SNDDBG(("OGG: bitstream version == (%d).\n", info->version));
+    SNDDBG(("OGG: bitstream channels == (%d).\n", info->channels));
+    SNDDBG(("OGG: bitstream sampling rate == (%ld).\n", info->rate));
+    SNDDBG(("OGG: seekable == {%s}.\n", ov_seekable(vf) ? "TRUE" : "FALSE"));
+    SNDDBG(("OGG: number of logical bitstreams == (%ld).\n", ov_streams(vf)));
+    SNDDBG(("OGG: serial number == (%ld).\n", ov_serialnumber(vf, -1)));
+    SNDDBG(("OGG: total seconds of sample == (%f).\n", ov_time_total(vf, -1)));
+
+    internal->decoder_private = vf;
+    sample->flags = SOUND_SAMPLEFLAG_CANSEEK;
+    sample->actual.rate = (Uint32) info->rate;
+    sample->actual.channels = (Uint8) info->channels;
+    total_time = ov_time_total(vf, -1);
+    if (OV_EINVAL == total_time)
+      internal->total_time = -1;
+    else
+      internal->total_time = (Sint32)(total_time * 1000.0 + 0.5);
+
+
+    /*
+     * Since we might have more than one logical bitstream in the OGG file,
+     *  and these bitstreams may be in different formats, we might be
+     *  converting two or three times: once in vorbisfile, once again in
+     *  SDL_sound, and perhaps a third time to get it to the sound device's
+     *  format. That's wickedly inefficient.
+     *
+     * To combat this a little, if the user specified a desired format, we
+     *  claim that to be the "actual" format of the collection of logical
+     *  bitstreams. This means that VorbisFile will do a conversion as
+     *  necessary, and SDL_sound will not. If the user didn't specify a
+     *  desired format, then we pretend the "actual" format is something that
+     *  OGG files are apparently commonly encoded in.
+     */
+    sample->actual.format = (sample->desired.format == 0) ?
+                             AUDIO_S16SYS : sample->desired.format;
+    return(1);
+} /* OGG_open */
+
+
+static void OGG_close(Sound_Sample *sample)
+{
+    Sound_SampleInternal *internal = (Sound_SampleInternal *) sample->opaque;
+    OggVorbis_File *vf = (OggVorbis_File *) internal->decoder_private;
+    ov_clear(vf);
+    free(vf);
+} /* OGG_close */
+
+/* Note: According to the Vorbis documentation:
+ * "ov_read() will  decode at most one vorbis packet per invocation, 
+ * so the value returned will generally be less than length."
+ * Due to this, for buffer sizes like 16384, SDL_Sound was always getting
+ * an underfilled buffer and always setting the EAGAIN flag.
+ * Since the SDL_Sound API implies that the entire buffer
+ * should be filled unless EOF, additional code has been added
+ * to this function to call ov_read() until the buffer is filled.
+ * However, there may still be some corner cases where the buffer
+ * cannot be entirely filled. So be aware.
+ */
+static Uint32 OGG_read(Sound_Sample *sample)
+{
+    int rc;
+    int bitstream;
+	Sound_SampleInternal *internal = (Sound_SampleInternal *) sample->opaque;
+    OggVorbis_File *vf = (OggVorbis_File *) internal->decoder_private;
+    
+    rc = ov_read(vf, internal->buffer, internal->buffer_size,
+            &bitstream);
+
+        /* Make sure the read went smoothly... */
+    if (rc == 0)
+        sample->flags |= SOUND_SAMPLEFLAG_EOF;
+        
+    else if (rc < 0)
+        sample->flags |= SOUND_SAMPLEFLAG_ERROR;
+
+    /* If the buffer isn't filled, keep trying to fill it
+     * until no more data can be grabbed */
+    else if ((Uint32) rc < internal->buffer_size)
+	{
+        /* Creating a pointer to the buffer that denotes where to start
+         * writing new data. */
+        Uint8* buffer_start_point = NULL;
+        int total_bytes_read = rc;
+        int bytes_remaining = internal->buffer_size - rc;
+
+        /* Keep grabbing data until something prevents
+         * us from getting more. (Could be EOF,
+         * packets are too large to fit in remaining
+         * space, or an error.)
+         */
+        while( (rc > 0) && (bytes_remaining > 0) )
+        {
+        /* Set buffer pointer to end of last write */
+        /* All the messiness is to get rid of the warning for
+         * dereferencing a void*
+         */
+            buffer_start_point = &(((Uint8*)internal->buffer)[total_bytes_read]);
+            rc = ov_read(vf, buffer_start_point, bytes_remaining,
+                &bitstream);
+            /* Make sure rc > 0 because we don't accidently want
+             * to change the counters if there was an error
+             */
+            if(rc > 0)
+            {
+                total_bytes_read += rc;
+                bytes_remaining = bytes_remaining - rc;
+            }
+	    }
+        /* I think the minimum read size is 2, though I'm
+         * not sure about this. (I've hit cases where I
+         * couldn't read less than 4.) What I don't want to do is
+         * accidently claim we hit EOF when the reason rc == 0
+         * is because the requested amount of data was smaller
+         * than the minimum packet size.
+         * For now, I will be conservative
+         * and not set the EOF flag, and let the next call to 
+         * this function figure it out.
+         * I think the ERROR flag is safe to set because 
+         * it looks like OGG simply returns 0 if the 
+         * read size is too small. 
+         * And in most cases for sensible buffer sizes, 
+         * this fix will fill the buffer,
+         * so we can set the EAGAIN flag without worrying
+         * that it will always be set.
+         */
+        if(rc < 0)
+	    {
+            sample->flags |= SOUND_SAMPLEFLAG_ERROR;
+        }
+        else if(rc == 0)
+        {
+            /* Do nothing for now until there is a better solution */
+            /* sample->flags |= SOUND_SAMPLEFLAG_EOF; */
+        }
+
+        /* Test for a buffer underrun. It should occur less frequently
+         * now, but it still may happen and not necessarily mean
+         * anything useful. */
+        if ((Uint32) total_bytes_read < internal->buffer_size)
+        {
+            sample->flags |= SOUND_SAMPLEFLAG_EAGAIN;
+        }
+        /* change rc to the total bytes read so function
+         * can return the correct value.
+         */
+        rc = total_bytes_read;
+    }
+
+    return((Uint32) rc);
+} /* OGG_read */
+
+
+static int OGG_rewind(Sound_Sample *sample)
+{
+    Sound_SampleInternal *internal = (Sound_SampleInternal *) sample->opaque;
+    OggVorbis_File *vf = (OggVorbis_File *) internal->decoder_private;
+
+    BAIL_IF_MACRO(ov_raw_seek(vf, 0) < 0, ERR_IO_ERROR, 0);
+    return(1);
+} /* OGG_rewind */
+
+
+static int OGG_seek(Sound_Sample *sample, Uint32 ms)
+{
+    Sound_SampleInternal *internal = (Sound_SampleInternal *) sample->opaque;
+    OggVorbis_File *vf = (OggVorbis_File *) internal->decoder_private;
+    double timepos = (((double) ms) / 1000.0);
+    BAIL_IF_MACRO(ov_time_seek(vf, timepos) < 0, ERR_IO_ERROR, 0);
+    return(1);
+} /* OGG_seek */
+
+#endif /* SOUND_SUPPORTS_OGG */
+
+
+/* end of ogg.c ... */
+