Simplify STREAMFILE handling in scd_int_layout

It's not the easiest thing to follow so here is what's going on with
STREAMFILEs:
- external player opens base-streamfile, with a base FILE
- meta scd parses stuff, then per DSP channel/layer:
  - open temp-streamfile, which does custom IO with base-streamfile
(doesn't open any FILE)
  - pass temp-streamfile to init_vgmstream_ngc_dsp_std
  - init parses ok, and re-opens temp-streamfile (with custom IO) as its
own dsp-vgmstream-streamfile; internally it does fopen/fdopen the
original FILE from base-streamfile
  - scd_int_layout stores the newly created VGMSTREAM (internally has
the dsp-vgmstream-streamfile too)
  - close temp-streamfile, that doesn't close base-streamfile as it's
wrapped to avoid doing so, nor affects dsp-vgmstream-streamfile in any
way.
- meta parsing is done, so external player closes base-streamfile (but
the re-fopen'ed dsp-vgmstream-streamfile FILE remains)
- vgmstream renders pcm buffers, etc
- finally player calls close_vgmstream
  - scd_int_layout calls close_vgmstream for each stored VGMSTREAM
  - the VGMSTREAM internally closes the dsp-vgmstream-streamfile, which
in turn closes its own FILE

So ultimately all FILEs, STREAMFILEs and their clones should be properly
handled and closed.

src/meta/sqex_scd.c

@@ -11,7 +11,6 @@ static void scd_ogg_v3_decryption_callback(void *ptr, size_t size, size_t nmemb,
 /* SCD - Square-Enix games (FF XIII, XIV) */
 VGMSTREAM * init_vgmstream_sqex_scd(STREAMFILE *streamFile) {
     VGMSTREAM * vgmstream = NULL;
-    char filename[PATH_LIMIT];
     off_t start_offset, tables_offset, meta_offset, extradata_offset, name_offset = 0;
     int32_t stream_size, extradata_size, loop_start, loop_end;
 
@@ -26,7 +25,6 @@ VGMSTREAM * init_vgmstream_sqex_scd(STREAMFILE *streamFile) {
     /* check extension, case insensitive */
     if ( !check_extensions(streamFile, "scd") )
         goto fail;
-    streamFile->get_name(streamFile,filename,sizeof(filename));
 
     /** main header **/
     if (read_32bitBE(0x00,streamFile) != 0x53454442 &&  /* "SEDB" */
@@ -281,7 +279,6 @@ VGMSTREAM * init_vgmstream_sqex_scd(STREAMFILE *streamFile) {
 
         case 0x0A:      /* DSP ADPCM [Dragon Quest X (Wii)] */
         case 0x15: {    /* DSP ADPCM [Dragon Quest X (Wii U)] (no apparent differences except higher sample rate) */
-            STREAMFILE * file;
             int i;
             const off_t interleave_size = 0x800;
             const off_t stride_size = interleave_size * channel_count;
@@ -308,28 +305,22 @@ VGMSTREAM * init_vgmstream_sqex_scd(STREAMFILE *streamFile) {
                 }
             }
 
-            /* the primary streamfile we'll be using */
-            file = streamFile->open(streamFile,filename,stride_size);
-            if (!file) goto fail;
-
-            vgmstream->ch[0].streamfile = file;
-
             data = malloc(sizeof(scd_int_codec_data));
             data->substream_count = channel_count;
             data->substreams = calloc(channel_count, sizeof(VGMSTREAM *));
-            data->intfiles = calloc(channel_count, sizeof(STREAMFILE *));
 
             vgmstream->codec_data = data;
 
             for (i=0;i<channel_count;i++) {
-                STREAMFILE * intfile = setup_scd_dsp_streamfile(file, start_offset+interleave_size*i, interleave_size, stride_size, total_size);
-                if (!intfile) goto fail;
+                STREAMFILE* temp_streamFile = setup_scd_dsp_streamfile(streamFile, start_offset+interleave_size*i, interleave_size, stride_size, total_size);
+                if (!temp_streamFile) goto fail;
 
-                data->substreams[i] = init_vgmstream_ngc_dsp_std(intfile);
-                data->intfiles[i] = intfile;
+                data->substreams[i] = init_vgmstream_ngc_dsp_std(temp_streamFile);
+                close_streamfile(temp_streamFile);
                 if (!data->substreams[i]) goto fail;
 
                 /* TODO: only handles mono substreams, though that's all we have with DSP */
+
                 /* save start things so we can restart for seeking/looping */
                 memcpy(data->substreams[i]->start_ch,data->substreams[i]->ch,sizeof(VGMSTREAMCHANNEL)*1);
                 memcpy(data->substreams[i]->start_vgmstream,data->substreams[i],sizeof(VGMSTREAM));

src/vgmstream.c

@@ -804,13 +804,9 @@ void close_vgmstream(VGMSTREAM * vgmstream) {
             if (data->substreams) {
                 int i;
                 for (i=0;i<data->substream_count;i++) {
-                    /* note that the close_streamfile won't do anything but deallocate itself,
-                     * there is only one open file in vgmstream->ch[0].streamfile */
                     close_vgmstream(data->substreams[i]);
-                    if(data->intfiles[i]) close_streamfile(data->intfiles[i]);
                 }
                 free(data->substreams);
-                free(data->intfiles);
             }
 
             free(data);
@@ -2406,7 +2402,7 @@ static STREAMFILE * get_vgmstream_average_bitrate_channel_streamfile(VGMSTREAM *
 
     if (vgmstream->layout_type==layout_scd_int) {
         scd_int_codec_data *data = (scd_int_codec_data *) vgmstream->codec_data;
-        return data->intfiles[channel];
+        return data->substreams[channel]->ch[0].streamfile;
     }
 
     if (vgmstream->coding_type==coding_NWA) {

src/vgmstream.h

@@ -1073,7 +1073,6 @@ typedef struct {
 typedef struct {
     int substream_count;
     VGMSTREAM **substreams;
-    STREAMFILE **intfiles;
 } scd_int_codec_data;
 
 typedef struct {