--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/decoders/smpeg.c	Thu Feb 21 19:43:05 2002 +0000
@@ -0,0 +1,284 @@
+/*
+ * 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
+ */
+
+/*
+ * MPEG-1 Layer 3, or simply, "MP3", decoder for SDL_sound.
+ *
+ * This driver handles all those highly compressed songs you stole through
+ *  Napster.  :)  It depends on the SMPEG library for decoding, which can
+ *  be grabbed from: http://www.lokigames.com/development/smpeg.php3
+ *
+ * This should also be able to extract the audio stream from an MPEG movie.
+ *
+ * There is an alternative MP3 decoder available, called "mpglib", which
+ *  doesn't depend on external libraries (the decoder itself is part of
+ *  SDL_sound), and may be more efficient, but less flexible than SMPEG. YMMV.
+ *
+ * Please see the file COPYING in the source's root directory.
+ *
+ *  This file written by Ryan C. Gordon. (icculus@clutteredmind.org)
+ */
+
+#if HAVE_CONFIG_H
+#  include <config.h>
+#endif
+
+#ifdef SOUND_SUPPORTS_SMPEG
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <assert.h>
+
+#include "SDL_sound.h"
+
+#define __SDL_SOUND_INTERNAL__
+#include "SDL_sound_internal.h"
+
+#include "smpeg.h"
+#include "extra_rwops.h"
+
+
+static int _SMPEG_init(void);
+static void _SMPEG_quit(void);
+static int _SMPEG_open(Sound_Sample *sample, const char *ext);
+static void _SMPEG_close(Sound_Sample *sample);
+static Uint32 _SMPEG_read(Sound_Sample *sample);
+static int _SMPEG_rewind(Sound_Sample *sample);
+
+static const char *extensions_smpeg[] = { "MP3", "MPEG", "MPG", NULL };
+const Sound_DecoderFunctions __Sound_DecoderFunctions_SMPEG =
+{
+    {
+        extensions_smpeg,
+        "MPEG-1 Layer 3 audio through SMPEG",
+        "Ryan C. Gordon <icculus@clutteredmind.org>",
+        "http://icculus.org/smpeg/"
+    },
+
+    _SMPEG_init,       /*   init() method */
+    _SMPEG_quit,       /*   quit() method */
+    _SMPEG_open,       /*   open() method */
+    _SMPEG_close,      /*  close() method */
+    _SMPEG_read,       /*   read() method */
+    _SMPEG_rewind      /* rewind() method */
+};
+
+
+static int _SMPEG_init(void)
+{
+    return(1);  /* always succeeds. */
+} /* _SMPEG_init */
+
+
+static void _SMPEG_quit(void)
+{
+    /* it's a no-op. */
+} /* _SMPEG_quit */
+
+
+static __inline__ void output_version(void)
+{
+    static int first_time = 1;
+
+    if (first_time)
+    {
+        SMPEG_version v;
+        SMPEG_VERSION(&v);
+        SNDDBG(("SMPEG: Compiled against SMPEG v%d.%d.%d.\n",
+                    v.major, v.minor, v.patch));
+        first_time = 0;
+    } /* if */
+} /* output_version */
+
+
+static int _SMPEG_open(Sound_Sample *sample, const char *ext)
+{
+    SMPEG *smpeg;
+    SMPEG_Info smpeg_info;
+    SDL_AudioSpec spec;
+    Sound_SampleInternal *internal = (Sound_SampleInternal *) sample->opaque;
+    SDL_RWops *refCounter;
+
+    output_version();
+
+       /*
+        * If I understand things correctly, MP3 files don't really have any
+        * magic header we can check for. The MP3 player is expected to just
+        * pick the first thing that looks like a valid frame and start
+        * playing from there.
+        *
+        * So here's what we do: If the caller insists that this is really
+        * MP3 we'll take his word for it. Otherwise, use the same test as
+        * SDL_mixer does and check if the stream starts with something that
+        * looks like a frame.
+        *
+        * A frame begins with 11 bits of frame sync (all bits must be set),
+        * followed by a two-bit MPEG Audio version ID:
+        *
+        *   00 - MPEG Version 2.5 (later extension of MPEG 2)
+        *   01 - reserved
+        *   10 - MPEG Version 2 (ISO/IEC 13818-3)
+        *   11 - MPEG Version 1 (ISO/IEC 11172-3)
+        *
+        * Apparently we don't handle MPEG Version 2.5.
+        */
+    if (__Sound_strcasecmp(ext, "MP3") != 0)
+    {
+        Uint8 mp3_magic[2];
+
+        if (SDL_RWread(internal->rw, mp3_magic, sizeof (mp3_magic), 1) != 1)
+        {
+            Sound_SetError("SMPEG: Could not read MP3 magic.");
+            return(0);
+        } /*if */
+
+        if (mp3_magic[0] != 0xFF || (mp3_magic[1] & 0xF0) != 0xF0)
+        {
+            Sound_SetError("SMPEG: Not an MP3 stream.");
+            return(0);
+        } /* if */
+
+            /* !!! FIXME: If the seek fails, we'll probably miss a frame */
+        SDL_RWseek(internal->rw, -sizeof (mp3_magic), SEEK_CUR);
+    } /* if */
+
+    refCounter = RWops_RWRefCounter_new(internal->rw);
+    if (refCounter == NULL)
+    {
+        SNDDBG(("SMPEG: Failed to create reference counting RWops.\n"));
+        return(0);
+    } /* if */
+
+    /* replace original RWops. This is safe. Honest. :) */
+    internal->rw = refCounter;
+
+    /*
+     * increment the refcount, since SMPEG will nuke the RWops if it can't
+     *  accept the contained data...
+     */
+    RWops_RWRefCounter_addRef(refCounter);
+    smpeg = SMPEG_new_rwops(refCounter, &smpeg_info, 0);
+
+    if (SMPEG_error(smpeg))
+    {
+        Sound_SetError(SMPEG_error(smpeg));
+        SMPEG_delete(smpeg);
+        return(0);
+    } /* if */
+
+    if (!smpeg_info.has_audio)
+    {
+        Sound_SetError("SMPEG: No audio stream found in data.");
+        SMPEG_delete(smpeg);
+        return(0);
+    } /* if */
+
+    SNDDBG(("SMPEG: Accepting data stream.\n"));
+    SNDDBG(("SMPEG: has_audio == {%s}.\n", smpeg_info.has_audio ? "TRUE" : "FALSE"));
+    SNDDBG(("SMPEG: has_video == {%s}.\n", smpeg_info.has_video ? "TRUE" : "FALSE"));
+    SNDDBG(("SMPEG: width == (%d).\n", smpeg_info.width));
+    SNDDBG(("SMPEG: height == (%d).\n", smpeg_info.height));
+    SNDDBG(("SMPEG: current_frame == (%d).\n", smpeg_info.current_frame));
+    SNDDBG(("SMPEG: current_fps == (%f).\n", smpeg_info.current_fps));
+    SNDDBG(("SMPEG: audio_string == [%s].\n", smpeg_info.audio_string));
+    SNDDBG(("SMPEG: audio_current_frame == (%d).\n", smpeg_info.audio_current_frame));
+    SNDDBG(("SMPEG: current_offset == (%d).\n", smpeg_info.current_offset));
+    SNDDBG(("SMPEG: total_size == (%d).\n", smpeg_info.total_size));
+    SNDDBG(("SMPEG: current_time == (%f).\n", smpeg_info.current_time));
+    SNDDBG(("SMPEG: total_time == (%f).\n", smpeg_info.total_time));
+
+    SMPEG_enablevideo(smpeg, 0);
+    SMPEG_enableaudio(smpeg, 1);
+    SMPEG_loop(smpeg, 0);
+
+    SMPEG_wantedSpec(smpeg, &spec);
+
+        /*
+         * One of the MP3s I tried wouldn't work unless I added this line
+         * to tell SMPEG that yes, it may have the spec it wants.
+         */
+    SMPEG_actualSpec(smpeg, &spec);
+    sample->actual.format = spec.format;
+    sample->actual.rate = spec.freq;
+    sample->actual.channels = spec.channels;
+    sample->flags = SOUND_SAMPLEFLAG_NONE;
+    internal->decoder_private = smpeg;
+
+    SMPEG_play(smpeg);
+    return(1);
+} /* _SMPEG_open */
+
+
+static void _SMPEG_close(Sound_Sample *sample)
+{
+    Sound_SampleInternal *internal = (Sound_SampleInternal *) sample->opaque;
+    SMPEG_delete((SMPEG *) internal->decoder_private);
+} /* _SMPEG_close */
+
+
+static Uint32 _SMPEG_read(Sound_Sample *sample)
+{
+    Uint32 retval;
+    Sound_SampleInternal *internal = (Sound_SampleInternal *) sample->opaque;
+    SMPEG *smpeg = (SMPEG *) internal->decoder_private;
+
+        /*
+         * We have to clear the buffer because apparently SMPEG_playAudio()
+         * will mix the decoded audio with whatever's already in it. Nasty.
+         */
+    memset(internal->buffer, '\0', internal->buffer_size);
+    retval = SMPEG_playAudio(smpeg, internal->buffer, internal->buffer_size);
+    if (retval < internal->buffer_size)
+    {
+        char *errMsg = SMPEG_error(smpeg);
+        if (errMsg == NULL)
+            sample->flags |= SOUND_SAMPLEFLAG_EOF;
+        else
+        {
+            Sound_SetError(errMsg);
+            sample->flags |= SOUND_SAMPLEFLAG_ERROR;
+        } /* else */
+    } /* if */
+
+    return(retval);
+} /* _SMPEG_read */
+
+
+static int _SMPEG_rewind(Sound_Sample *sample)
+{
+    Sound_SampleInternal *internal = (Sound_SampleInternal *) sample->opaque;
+    SMPEG *smpeg = (SMPEG *) internal->decoder_private;
+    SMPEGstatus status;
+
+        /*
+         * SMPEG_rewind() really means "stop and rewind", so we may have to
+         * restart it afterwards.
+         */
+    status = SMPEG_status(smpeg);
+    SMPEG_rewind(smpeg);
+    if (status == SMPEG_PLAYING)
+        SMPEG_play(smpeg);
+    return(1);
+} /* _SMPEG_rewind */
+
+#endif /* SOUND_SUPPORTS_SMPEG */
+
+/* end of smpeg.c ... */
+