vgmstream/src/meta/ast.c

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2.7 KiB
C
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#include "meta.h"
#include "../layout/layout.h"
#include "../util.h"
VGMSTREAM * init_vgmstream_ast(STREAMFILE *streamFile) {
VGMSTREAM * vgmstream = NULL;
char filename[PATH_LIMIT];
coding_t coding_type;
int codec_number;
int channel_count;
int loop_flag;
size_t max_block;
/* check extension, case insensitive */
streamFile->get_name(streamFile,filename,sizeof(filename));
if (strcasecmp("ast",filename_extension(filename))) goto fail;
/* check header */
if ((uint32_t)read_32bitBE(0,streamFile)!=0x5354524D || /* "STRM" */
read_16bitBE(0xa,streamFile)!=0x10 ||
/* check that file = header (0x40) + data */
read_32bitBE(4,streamFile)+0x40!=get_streamfile_size(streamFile))
goto fail;
/* check for a first block */
if (read_32bitBE(0x40,streamFile)!=0x424C434B) /* "BLCK" */
goto fail;
/* check type details */
codec_number = read_16bitBE(8,streamFile);
loop_flag = read_16bitBE(0xe,streamFile);
channel_count = read_16bitBE(0xc,streamFile);
max_block = read_32bitBE(0x20,streamFile);
switch (codec_number) {
case 0:
coding_type = coding_NGC_AFC;
break;
case 1:
coding_type = coding_PCM16BE;
break;
default:
goto fail;
}
/* build the VGMSTREAM */
vgmstream = allocate_vgmstream(channel_count,loop_flag);
if (!vgmstream) goto fail;
/* fill in the vital statistics */
vgmstream->num_samples = read_32bitBE(0x14,streamFile);
vgmstream->sample_rate = read_32bitBE(0x10,streamFile);
/* channels and loop flag are set by allocate_vgmstream */
vgmstream->loop_start_sample = read_32bitBE(0x18,streamFile);
vgmstream->loop_end_sample = read_32bitBE(0x1c,streamFile);
vgmstream->coding_type = coding_type;
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vgmstream->layout_type = layout_blocked_ast;
vgmstream->meta_type = meta_AST;
/* open the file for reading by each channel */
{
int i;
for (i=0;i<channel_count;i++) {
vgmstream->ch[i].streamfile = streamFile->open(streamFile,filename,
(i==0?
max_block+0x20-4: /* first buffer a bit bigger to
read block header without
inefficiency */
max_block
)
);
if (!vgmstream->ch[i].streamfile) goto fail;
}
}
/* start me up */
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block_update_ast(0x40,vgmstream);
return vgmstream;
/* clean up anything we may have opened */
fail:
if (vgmstream) close_vgmstream(vgmstream);
return NULL;
}