--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/decoders/ogg.c	Wed Sep 19 14:02:56 2001 +0000
@@ -0,0 +1,245 @@
+/*
+ * 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 in the source's root directory.
+ *
+ *  This file written by Ryan C. Gordon. (icculus@clutteredmind.org)
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <math.h>
+#include <assert.h>
+#include "vorbis/codec.h"
+#include "vorbis/vorbisfile.h"
+
+#include "SDL_sound.h"
+
+#define __SDL_SOUND_INTERNAL__
+#include "SDL_sound_internal.h"
+
+#if (!defined SOUND_SUPPORTS_OGG)
+#error SOUND_SUPPORTS_OGG must be defined.
+#endif
+
+
+static int OGG_open(Sound_Sample *sample, const char *ext);
+static void OGG_close(Sound_Sample *sample);
+static Uint32 OGG_read(Sound_Sample *sample);
+
+const Sound_DecoderFunctions __Sound_DecoderFunctions_OGG =
+{
+    {
+        "OGG",
+        "Ogg Vorbis audio through VorbisFile",
+        "Ryan C. Gordon <icculus@clutteredmind.org>",
+        "http://www.icculus.org/SDL_sound/"
+    },
+
+    OGG_open,       /* open() method       */
+    OGG_close,      /* close() method       */
+    OGG_read        /* read() method       */
+};
+
+
+    /*
+     * These are callbacks from vorbisfile that let them read data from
+     *  a RWops...
+     */
+
+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 */
+
+int RWops_ogg_seek(void *datasource, int64_t offset, int whence)
+{
+    return(SDL_RWseek((SDL_RWops *) datasource, offset, whence));
+} /* RWops_ogg_seek */
+
+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 */
+
+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... */
+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 */
+
+
+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;
+
+    _D(("OGG: vendor == [%s].\n", vc->vendor));
+    for (i = 0; i < vc->comments; i++)
+    {
+        _D(("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;
+    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)
+    {
+        _D(("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 */
+
+    _D(("OGG: Accepting data stream.\n"));
+
+    output_ogg_comments(vf);
+    _D(("OGG: bitstream version == (%d).\n", info->version));
+    _D(("OGG: bitstream channels == (%d).\n", info->channels));
+    _D(("OGG: bitstream sampling rate == (%ld).\n", info->rate));
+    _D(("OGG: seekable == {%s}.\n", ov_seekable(vf) ? "TRUE" : "FALSE"));
+    _D(("OGG: number of logical bitstreams == (%ld).\n", ov_streams(vf)));
+    _D(("OGG: serial number == (%ld).\n", ov_serialnumber(vf, -1)));
+    _D(("OGG: total seconds of sample == (%f).\n", ov_time_total(vf, -1)));
+
+    internal->decoder_private = vf;
+    sample->flags = SOUND_SAMPLEFLAG_NONE;
+    sample->actual.rate = (Uint32) info->rate;
+    sample->actual.channels = (Uint8) info->channels;
+
+    /*
+     * 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_S16LSB : 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 */
+
+
+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,
+            ((sample->actual.format & 0x1000) ? 1 : 0), /* bigendian? */
+            ((sample->actual.format & 0xFF) / 8), /* bytes per sample point */
+            ((sample->actual.format & 0x8000) ? 1 : 0), /* signed data? */
+            &bitstream);
+
+        /* Make sure the read went smoothly... */
+    if (rc == 0)
+        sample->flags |= SOUND_SAMPLEFLAG_EOF;
+
+    else if (rc < 0)
+        sample->flags |= SOUND_SAMPLEFLAG_ERROR;
+
+        /* (next call this EAGAIN may turn into an EOF or error.) */
+    else if ((Uint32) rc < internal->buffer_size)
+        sample->flags |= SOUND_SAMPLEFLAG_EAGAIN;
+
+    return((Uint32) rc);
+} /* OGG_read */
+
+/* end of ogg.c ... */
+