Update EA-MT API a bit

src/coding/ea_mt_decoder.c

@@ -17,7 +17,12 @@
 #define UTK_MAX(x,y) ((x)>(y)?(x):(y))
 #define UTK_CLAMP(x,min,max) UTK_MIN(UTK_MAX(x,min),max)
 
+#define UTK_BUFFER_SIZE 0x1000
+
 struct ea_mt_codec_data {
+    STREAMFILE *streamfile;
+    uint8_t buffer[UTK_BUFFER_SIZE];
+    off_t offset;
     int pcm_blocks;
     int samples_filled;
     int samples_used;
@@ -27,6 +32,8 @@ struct ea_mt_codec_data {
     void* utk_context;
 };
 
+static size_t ea_mt_read_callback(void *dest, int size, void *arg);
+
 
 ea_mt_codec_data *init_ea_mt(int channels, int pcm_blocks, int reset_sample) {
     ea_mt_codec_data *data = NULL;
@@ -42,6 +49,8 @@ ea_mt_codec_data *init_ea_mt(int channels, int pcm_blocks, int reset_sample) {
 
         data[i].pcm_blocks = pcm_blocks;
         data[i].reset_sample = reset_sample;
+
+        utk_set_callback(data[i].utk_context, data[i].buffer, UTK_BUFFER_SIZE, &data[i], &ea_mt_read_callback);
     }
 
     return data;
@@ -121,7 +130,6 @@ void decode_ea_mt(VGMSTREAM * vgmstream, sample * outbuf, int channelspacing, in
 static void flush_ea_mt_offsets(VGMSTREAM *vgmstream, int is_start, int samples_discard) {
     ea_mt_codec_data *data = vgmstream->codec_data;
     int i;
-    size_t bytes;
 
     if (!data) return;
 
@@ -133,20 +141,16 @@ static void flush_ea_mt_offsets(VGMSTREAM *vgmstream, int is_start, int samples_
     for (i = 0; i < vgmstream->channels; i++) {
         UTKContext* ctx = data[i].utk_context;
 
-        ctx->streamfile = vgmstream->ch[i].streamfile; /* maybe should keep its own STREAMFILE? */
+        data[i].streamfile = vgmstream->ch[i].streamfile; /* maybe should keep its own STREAMFILE? */
         if (is_start)
-            ctx->offset = vgmstream->ch[i].channel_start_offset;
+            data[i].offset = vgmstream->ch[i].channel_start_offset;
         else
-            ctx->offset = vgmstream->ch[i].offset;
-        //todo no need to read, allow to do it manually?
-        bytes = read_streamfile(ctx->buffer,ctx->offset,sizeof(ctx->buffer),ctx->streamfile);
-        ctx->offset = ctx->offset + bytes;
+            data[i].offset = vgmstream->ch[i].offset;
 
-        ctx->ptr = ctx->buffer;
-        ctx->end = ctx->buffer + bytes;
-        ctx->bits_count = 0;
+        utk_set_ptr(ctx, 0, 0); /* reset the buffer reader */
 
         if (is_start) {
+            //utk_reset(ctx); //todo
             ctx->parsed_header = 0;
             data[i].samples_done = 0;
         }
@@ -179,3 +183,16 @@ void free_ea_mt(ea_mt_codec_data *data, int channels) {
     }
     free(data);
 }
+
+/* ********************** */
+
+static size_t ea_mt_read_callback(void *dest, int size, void *arg) {
+    ea_mt_codec_data *ch_data = arg;
+    int bytes_read;
+
+    bytes_read = read_streamfile(dest,ch_data->offset,size,ch_data->streamfile);
+    ch_data->offset += bytes_read;
+
+    return bytes_read;
+
+}

src/coding/ea_mt_decoder_utk.h

@@ -7,11 +7,10 @@
 /* Note: This struct assumes a member alignment of 4 bytes.
 ** This matters when pitch_lag > 216 on the first subframe of any given frame. */
 typedef struct UTKContext {
-    uint8_t buffer[4096]; //vgmstream extra
-    STREAMFILE * streamfile; //vgmstream extra
-    unsigned int offset; //vgmstream extra
-
-    FILE *fp;
+    uint8_t *buffer;
+    size_t buffer_size;
+    void *arg;
+    size_t (*read_callback)(void *dest, int size, void *arg);
     const uint8_t *ptr, *end;
 
     int parsed_header;
@@ -131,14 +130,9 @@ static int utk_read_byte(UTKContext *ctx)
     if (ctx->ptr < ctx->end)
         return *ctx->ptr++;
 
-    //vgmstream extra: this reads from FILE if static buffer was exhausted, now from a context buffer and STREAMFILE instead
-    if (ctx->streamfile) { //if (ctx->fp) {
-        //static uint8_t buffer[4096];
-        //size_t bytes_copied = fread(buffer, 1, sizeof(buffer), ctx->fp);
-        size_t bytes_copied = read_streamfile(ctx->buffer, ctx->offset, sizeof(ctx->buffer), ctx->streamfile);
-
-        ctx->offset += bytes_copied;
-        if (bytes_copied > 0 && bytes_copied <= sizeof(ctx->buffer)) {
+    if (ctx->read_callback) {
+        size_t bytes_copied = ctx->read_callback(ctx->buffer, ctx->buffer_size, ctx->arg);
+        if (bytes_copied > 0 && bytes_copied <= ctx->buffer_size) {
             ctx->ptr = ctx->buffer;
             ctx->end = ctx->buffer + bytes_copied;
             return *ctx->ptr++;
@@ -394,9 +388,10 @@ static void utk_init(UTKContext *ctx)
     memset(ctx, 0, sizeof(*ctx));
 }
 
-static void utk_reset(UTKContext *ctx) //vgmstream extra
+static void utk_reset(UTKContext *ctx)
 {
-    /* resets the internal state, leaving the external config/buffers set */
+    /* resets the internal state, leaving the external config/buffers
+     * untouched (could be reset externally or using utk_set_x) */
     ctx->parsed_header = 0;
     ctx->bits_value = 0;
     ctx->bits_count = 0;
@@ -408,10 +403,14 @@ static void utk_reset(UTKContext *ctx) //vgmstream extra
     memset(ctx->adapt_cb, 0, sizeof(ctx->adapt_cb));
     memset(ctx->decompressed_frame, 0, sizeof(ctx->decompressed_frame));
 }
-#if 0 //vgmstream extra
-static void utk_set_fp(UTKContext *ctx, FILE *fp)
+
+static void utk_set_callback(UTKContext *ctx, uint8_t *buffer, size_t buffer_size, void *arg, size_t (*read_callback)(void *, int , void *))
 {
-    ctx->fp = fp;
+    /* prepares for external reading */
+    ctx->buffer = buffer;
+    ctx->buffer_size = buffer_size;
+    ctx->arg = arg;
+    ctx->read_callback = read_callback;
 
     /* reset the bit reader */
     ctx->bits_count = 0;
@@ -419,13 +418,14 @@ static void utk_set_fp(UTKContext *ctx, FILE *fp)
 
 static void utk_set_ptr(UTKContext *ctx, const uint8_t *ptr, const uint8_t *end)
 {
+    /* sets the pointer to an external data buffer (can also be used to
+     * reset the buffered data if set to ptr/end 0) */
     ctx->ptr = ptr;
     ctx->end = end;
 
     /* reset the bit reader */
     ctx->bits_count = 0;
 }
-#endif
 
 /*
 ** MicroTalk Revision 3 decoding function.
@@ -453,34 +453,17 @@ static int utk_rev3_decode_frame(UTKContext *ctx)
         ** crafted MT5:1 file can crash sx.exe.
         ** We will throw an error instead. */
         if (offset < 0 || offset > 432) {
-            //fprintf(stderr, "error: invalid PCM offset %d\n", offset);
-            //exit(EXIT_FAILURE);
-            return -1; //vgmstream extra
+            return -1; /* invalid PCM offset */
         }
         if (count < 0 || count > 432 - offset) {
-            //fprintf(stderr, "error: invalid PCM count %d\n", count);
-            //exit(EXIT_FAILURE);
-            return -2; //vgmstream extra
+            return -2; /* invalid PCM count */
         }
 
         for (i = 0; i < count; i++)
             ctx->decompressed_frame[offset+i] = (float)utk_read_i16(ctx);
     }
 
-    return 0; //vgmstream extra
+    return 0;
 }
 
-#if 0 //vgmstream extra
-static const char * utk_get_error_string(int error)
-{
-    switch(error) {
-    case -1:
-        return "invalid rev3 PCM offset";
-    case -2:
-        return "invalid rev3 PCM count";
-    default:
-        return "unknown error";
-    }
-}
-#endif
 #endif /* _EA_MT_DECODER_UTK_H_ */