--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/decoders/voc.c	Tue Sep 18 11:01:48 2001 +0000
@@ -0,0 +1,486 @@
+/*
+ * 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
+ */
+
+/*
+ * VOC decoder for SDL_sound.
+ *
+ * This driver handles Creative Labs VOC audio data...this is a legacy format,
+ *  but there's some game ports that could make use of such a decoder. Plus,
+ *  VOC is fairly straightforward to decode, so this is a more complex, but
+ *  still palatable example of an SDL_sound decoder. Y'know, in case the
+ *  RAW decoder didn't do it for you.  :)
+ *
+ * This code was ripped from a decoder I had written for SDL_mixer, which was
+ *  largely ripped from sox v12.17.1's voc.c.
+ *
+ *    SDL_mixer: http://www.libsdl.org/projects/SDL_mixer/
+ *    sox: http://www.freshmeat.net/projects/sox/
+ *
+ * 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 <assert.h>
+
+#include "SDL.h"
+#include "SDL_endian.h"
+#include "SDL_sound.h"
+
+#define __SDL_SOUND_INTERNAL__
+#include "SDL_sound_internal.h"
+
+#if (!defined SOUND_SUPPORTS_VOC)
+#error SOUND_SUPPORTS_VOC must be defined.
+#endif
+
+
+static int VOC_open(Sound_Sample *sample, const char *ext);
+static void VOC_close(Sound_Sample *sample);
+static Uint32 VOC_read(Sound_Sample *sample);
+
+const Sound_DecoderFunctions __Sound_DecoderFunctions_VOC =
+{
+    {
+        "VOC",
+        "Creative Labs Voice format",
+        "Ryan C. Gordon <icculus@clutteredmind.org>",
+        "http://www.icculus.org/SDL_sound/"
+    },
+
+    VOC_open,       /* open() method       */
+    VOC_close,      /* close() method       */
+    VOC_read        /* read() method       */
+};
+
+
+/* Private data for VOC file */
+typedef struct vocstuff {
+    Uint32	rest;           /* bytes remaining in current block */
+    Uint32	rate;           /* rate code (byte) of this chunk */
+    int 	silent;         /* sound or silence? */
+    Uint32	srate;			/* rate code (byte) of silence */
+    Uint32	blockseek;		/* start of current output block */
+    Uint32	samples;		/* number of samples output */
+    Uint32	size;           /* word length of data */
+    int 	channels;       /* number of sound channels */
+    int     extended;       /* Has an extended block been read? */
+    Uint32  bufpos;         /* byte position in internal->buffer. */
+} vs_t;
+
+/* Size field */
+/* SJB: note that the 1st 3 are sometimes used as sizeof(type) */
+#define ST_SIZE_BYTE     1
+#define ST_SIZE_8BIT     1
+#define ST_SIZE_WORD     2
+#define ST_SIZE_16BIT    2
+#define ST_SIZE_DWORD    4
+#define ST_SIZE_32BIT    4
+#define ST_SIZE_FLOAT    5
+#define ST_SIZE_DOUBLE   6
+#define ST_SIZE_IEEE     7   /* IEEE 80-bit floats. */
+
+/* Style field */
+#define ST_ENCODING_UNSIGNED  1 /* unsigned linear: Sound Blaster */
+#define ST_ENCODING_SIGN2     2 /* signed linear 2's comp: Mac */
+#define ST_ENCODING_ULAW      3 /* U-law signed logs: US telephony, SPARC */
+#define ST_ENCODING_ALAW      4 /* A-law signed logs: non-US telephony */
+#define ST_ENCODING_ADPCM     5 /* Compressed PCM */
+#define ST_ENCODING_IMA_ADPCM 6 /* Compressed PCM */
+#define ST_ENCODING_GSM       7 /* GSM 6.10 33-byte frame lossy compression */
+
+#define VOC_TERM      0
+#define VOC_DATA      1
+#define VOC_CONT      2
+#define VOC_SILENCE   3
+#define VOC_MARKER    4
+#define VOC_TEXT      5
+#define VOC_LOOP      6
+#define VOC_LOOPEND   7
+#define VOC_EXTENDED  8
+#define VOC_DATA_16   9
+
+
+static __inline__ int voc_check_header(SDL_RWops *src)
+{
+    /* VOC magic header */
+    Uint8  signature[20];  /* "Creative Voice File\032" */
+    Uint16 datablockofs;
+
+    if (SDL_RWread(src, signature, sizeof (signature), 1) != 1)
+        return(0);
+
+    if (memcmp(signature, "Creative Voice File\032", sizeof (signature)) != 0) {
+        Sound_SetError("Unrecognized file type (not VOC)");
+        return(0);
+    }
+
+        /* get the offset where the first datablock is located */
+    if (SDL_RWread(src, &datablockofs, sizeof (Uint16), 1) != 1)
+        return(0);
+
+    datablockofs = SDL_SwapLE16(datablockofs);
+
+    if (SDL_RWseek(src, datablockofs, SEEK_SET) != datablockofs)
+        return(0);
+
+    return(1);  /* success! */
+} /* voc_check_header */
+
+/* !!! FIXME : Add a flag to vs_t that distinguishes EOF and Error conditions. */
+
+/* Read next block header, save info, leave position at start of data */
+static int voc_get_block(Sound_Sample *sample)
+{
+    Sound_SampleInternal *internal = (Sound_SampleInternal *) sample->opaque;
+    SDL_RWops *src = internal->rw;
+    vs_t *v = (vs_t *) internal->decoder_private;
+    Uint8 bits24[3];
+    Uint8 uc, block;
+    Uint32 sblen;
+    Uint16 new_rate_short;
+    Uint32 new_rate_long;
+    Uint8 trash[6];
+    Uint16 period;
+    int i;
+
+    v->silent = 0;
+    while (v->rest == 0)
+    {
+        if (SDL_RWread(src, &block, sizeof (block), 1) != 1)
+            return 1;  /* assume that's the end of the file. */
+
+        if (block == VOC_TERM)
+            return 1;
+
+        if (SDL_RWread(src, bits24, sizeof (bits24), 1) != 1)
+            return 1;  /* assume that's the end of the file. */
+
+        /* Size is an 24-bit value. Ugh. */
+        sblen = ( (bits24[0]) | (bits24[1] << 8) | (bits24[2] << 16) );
+
+        switch(block)
+        {
+            case VOC_DATA:
+                if (SDL_RWread(src, &uc, sizeof (uc), 1) != 1)
+                    return 0;
+
+                /* When DATA block preceeded by an EXTENDED     */
+                /* block, the DATA blocks rate value is invalid */
+                if (!v->extended)
+                {
+                    if (uc == 0)
+                    {
+                        Sound_SetError("VOC Sample rate is zero?");
+                        return 0;
+                    }
+
+                    if ((v->rate != -1) && (uc != v->rate))
+                    {
+                        Sound_SetError("VOC sample rate codes differ");
+                        return 0;
+                    }
+
+                    v->rate = uc;
+                    sample->actual.rate = 1000000.0/(256 - v->rate);
+                    v->channels = 1;
+                }
+
+                if (SDL_RWread(src, &uc, sizeof (uc), 1) != 1)
+                    return 0;
+
+                if (uc != 0)
+                {
+                    Sound_SetError("VOC decoder only interprets 8-bit data");
+                    return 0;
+                }
+
+                v->extended = 0;
+                v->rest = sblen - 2;
+                v->size = ST_SIZE_BYTE;
+                return 1;
+
+            case VOC_DATA_16:
+                if (SDL_RWread(src, &new_rate_long, sizeof (new_rate_long), 1) != 1)
+                    return 0;
+                new_rate_long = SDL_SwapLE32(new_rate_long);
+                if (new_rate_long == 0)
+                {
+                    Sound_SetError("VOC Sample rate is zero?");
+                    return 0;
+                }
+                if ((v->rate != -1) && (new_rate_long != v->rate))
+                {
+                    Sound_SetError("VOC sample rate codes differ");
+                    return 0;
+                }
+                v->rate = new_rate_long;
+                sample->actual.rate = new_rate_long;
+
+                if (SDL_RWread(src, &uc, sizeof (uc), 1) != 1)
+                    return 0;
+
+                switch (uc)
+                {
+                    case 8:  v->size = ST_SIZE_BYTE; break;
+                    case 16: v->size = ST_SIZE_WORD; break;
+                    default:
+                        Sound_SetError("VOC with unknown data size");
+                        return 0;
+                }
+
+                if (SDL_RWread(src, &v->channels, sizeof (Uint8), 1) != 1)
+                    return 0;
+
+                if (SDL_RWread(src, trash, sizeof (Uint8), 6) != 6)
+                    return 0;
+
+                v->rest = sblen - 12;
+                return 1;
+
+            case VOC_CONT:
+                v->rest = sblen;
+                return 1;
+
+            case VOC_SILENCE:
+                if (SDL_RWread(src, &period, sizeof (period), 1) != 1)
+                    return 0;
+                period = SDL_SwapLE16(period);
+
+                if (SDL_RWread(src, &uc, sizeof (uc), 1) != 1)
+                    return 0;
+                if (uc == 0)
+                {
+                    Sound_SetError("VOC silence sample rate is zero");
+                    return 0;
+                }
+
+                /*
+                 * Some silence-packed files have gratuitously
+                 * different sample rate codes in silence.
+                 * Adjust period.
+                 */
+                if ((v->rate != -1) && (uc != v->rate))
+                    period = (period * (256 - uc))/(256 - v->rate);
+                else
+                    v->rate = uc;
+                v->rest = period;
+                v->silent = 1;
+                return 1;
+
+            case VOC_LOOP:
+            case VOC_LOOPEND:
+                for(i = 0; i < sblen; i++)   /* skip repeat loops. */
+                {
+                    if (SDL_RWread(src, trash, sizeof (Uint8), 1) != 1)
+                        return 0;
+                }
+                break;
+
+            case VOC_EXTENDED:
+                /* An Extended block is followed by a data block */
+                /* Set this byte so we know to use the rate      */
+                /* value from the extended block and not the     */
+                /* data block.                     */
+                v->extended = 1;
+                if (SDL_RWread(src, &new_rate_short, sizeof (new_rate_short), 1) != 1)
+                    return 0;
+                new_rate_short = SDL_SwapLE16(new_rate_short);
+                if (new_rate_short == 0)
+                {
+                   Sound_SetError("VOC sample rate is zero");
+                   return 0;
+                }
+                if ((v->rate != -1) && (new_rate_short != v->rate))
+                {
+                   Sound_SetError("VOC sample rate codes differ");
+                   return 0;
+                }
+                v->rate = new_rate_short;
+
+                if (SDL_RWread(src, &uc, sizeof (uc), 1) != 1)
+                    return 0;
+
+                if (uc != 0)
+                {
+                    Sound_SetError("VOC decoder only interprets 8-bit data");
+                    return 0;
+                }
+
+                if (SDL_RWread(src, &uc, sizeof (uc), 1) != 1)
+                    return 0;
+
+                if (uc)
+                    sample->actual.channels = 2;  /* Stereo */
+                /* Needed number of channels before finishing
+                   compute for rate */
+                sample->actual.rate =
+                     (256000000L/(65536L - v->rate)) / sample->actual.channels;
+                /* An extended block must be followed by a data */
+                /* block to be valid so loop back to top so it  */
+                /* can be grabed.                */
+                continue;
+
+            case VOC_MARKER:
+                if (SDL_RWread(src, trash, sizeof (Uint8), 2) != 2)
+                    return 0;
+
+                /* Falling! Falling! */
+
+            default:  /* text block or other krapola. */
+                for(i = 0; i < sblen; i++)
+                {
+                    if (SDL_RWread(src, &trash, sizeof (Uint8), 1) != 1)
+                        return 0;
+                }
+
+                if (block == VOC_TEXT)
+                    continue;    /* get next block */
+        }
+    }
+
+    return 1;
+}
+
+
+static int voc_read(Sound_Sample *sample)
+{
+    Sound_SampleInternal *internal = (Sound_SampleInternal *) sample->opaque;
+    SDL_RWops *src = internal->rw;
+    vs_t *v = (vs_t *) internal->decoder_private;
+    int done = 0;
+    Uint8 silence = 0x80;
+    Uint8 *buf = internal->buffer;
+
+    if (v->rest == 0)
+    {
+        if (!voc_get_block(sample))
+            return 0;
+    }
+
+    if (v->rest == 0)
+        return 0;
+
+    if (v->silent)
+    {
+        if (v->size == ST_SIZE_WORD)
+            silence = 0x00;
+
+        /* Fill in silence */
+        memset(buf, silence, v->rest);
+        done = v->rest;
+        v->rest = 0;
+    }
+
+    else
+    {
+        Uint32 max = (v->rest < internal->buffer_size) ?
+                        v->rest : internal->buffer_size;
+        done = SDL_RWread(src, buf + v->bufpos, 1, max);
+        v->rest -= done;
+        v->bufpos += done;
+        if (v->size == ST_SIZE_WORD)
+        {
+            #if (SDL_BYTEORDER == SDL_BIG_ENDIAN)
+                for (; v->rest > 0; v->rest -= 2)
+                {
+                    *((Uint16 *) buf) = SDL_SwapLE16(*((Uint16 *) buf));
+                    ((Uint16 *) buf)++;
+                }
+            #endif
+        }
+    }
+
+    return done;
+} /* voc_read */
+
+
+static int VOC_open(Sound_Sample *sample, const char *ext)
+{
+    Sound_SampleInternal *internal = (Sound_SampleInternal *) sample->opaque;
+    vs_t *v = NULL;
+
+    if (!voc_check_header(internal->rw))
+        return(0);
+
+    v = (vs_t *) malloc(sizeof (vs_t));
+    BAIL_IF_MACRO(v == NULL, ERR_OUT_OF_MEMORY, 0);
+    memset(v, '\0', sizeof (vs_t));
+    internal->decoder_private = v;
+
+    v->rate = -1;
+    if (!voc_get_block(sample))
+    {
+        free(v);
+        return(0);
+    } /* if */
+
+    if (v->rate == -1)
+    {
+        Sound_SetError("VOC data had no sound!");
+        free(v);
+        return(0);
+    } /* if */
+
+    _D(("VOC: Accepting data stream.\n"));
+    sample->actual.format = (v->size == ST_SIZE_WORD) ? AUDIO_S16LSB:AUDIO_U8;
+    sample->actual.channels = v->channels;
+    sample->flags = SOUND_SAMPLEFLAG_NONE;
+    return(1);
+} /* VOC_open */
+
+
+static void VOC_close(Sound_Sample *sample)
+{
+    Sound_SampleInternal *internal = (Sound_SampleInternal *) sample->opaque;
+    free(internal->decoder_private);
+} /* VOC_close */
+
+
+static Uint32 VOC_read(Sound_Sample *sample)
+{
+    Sound_SampleInternal *internal = (Sound_SampleInternal *) sample->opaque;
+    vs_t *v = (vs_t *) internal->decoder_private;
+
+    v->bufpos = 0;
+    while (v->bufpos < internal->buffer_size)
+    {
+        Uint32 rc = voc_read(sample);
+        if (rc == 0)  /* !!! FIXME: Could be an error... */
+        {
+            sample->flags |= SOUND_SAMPLEFLAG_EOF;
+            break;
+        } /* if */
+
+        if (!voc_get_block(sample))
+        {
+            sample->flags |= SOUND_SAMPLEFLAG_ERROR;
+            break;
+        } /* if */
+    } /* while */
+
+    return(v->bufpos);
+} /* VOC_read */
+
+
+/* end of voc.c ... */
+