87 lines
3.1 KiB
C
87 lines
3.1 KiB
C
#include "vorbis_custom_decoder.h"
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#ifdef VGM_USE_VORBIS
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#include <vorbis/codec.h>
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/* **************************************************************************** */
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/* EXTERNAL API */
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/* **************************************************************************** */
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/**
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* AWC removes the Ogg layer and uses 32b frame sizes for headers and 16b frame sizes for data
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*/
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int vorbis_custom_setup_init_awc(STREAMFILE* sf, off_t start_offset, vorbis_custom_codec_data* data) {
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off_t offset = data->config.header_offset;
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size_t packet_size;
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/* read 3 packets with triad (id/comment/setup), each with an AWC header */
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/* normal identificacion packet */
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packet_size = read_u32le(offset, sf);
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if (packet_size > data->buffer_size) goto fail;
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data->op.bytes = read_streamfile(data->buffer, offset + 0x04, packet_size, sf);
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if (vorbis_synthesis_headerin(&data->vi, &data->vc, &data->op) != 0)
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goto fail;
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offset += 0x04 + packet_size;
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/* normal comment packet */
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packet_size = read_u32le(offset, sf);
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if (packet_size > data->buffer_size) goto fail;
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data->op.bytes = read_streamfile(data->buffer, offset + 0x04, packet_size, sf);
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if (vorbis_synthesis_headerin(&data->vi, &data->vc, &data->op) !=0)
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goto fail;
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offset += 0x04 + packet_size;
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/* normal setup packet */
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packet_size = read_u32le(offset, sf);
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if (packet_size > data->buffer_size) goto fail;
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data->op.bytes = read_streamfile(data->buffer, offset + 0x04, packet_size, sf);
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if (vorbis_synthesis_headerin(&data->vi, &data->vc, &data->op) != 0)
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goto fail;
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offset += 0x04 + packet_size;
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/* data starts separate */
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data->config.data_start_offset = start_offset;
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return 1;
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fail:
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return 0;
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}
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/* as AWC was coded by wackos, frames are forced to fit 0x800 chunks and rest is padded, in both sfx and music/blocked modes
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* (ex. read frame until 0x7A0 + next frame is size 0x140 > pads 0x60 and last goes to next chunk) */
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static inline off_t find_padding_awc(off_t offset, vorbis_custom_codec_data* data) {
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offset = offset - data->config.data_start_offset;
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return 0x800 - (offset % 0x800);
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}
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int vorbis_custom_parse_packet_awc(VGMSTREAMCHANNEL* stream, vorbis_custom_codec_data* data) {
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size_t bytes;
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/* get next packet size from the AWC 16b header, except between chunks */
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data->op.bytes = read_u16le(stream->offset, stream->streamfile);
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if (data->op.bytes == 0) { // || (stream->offset - start & 0x800) < 0x01 //todo could pad near block end?
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stream->offset += find_padding_awc(stream->offset, data);
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data->op.bytes = read_u16le(stream->offset, stream->streamfile);
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}
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stream->offset += 0x02;
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if (data->op.bytes == 0 || data->op.bytes == 0xFFFF || data->op.bytes > data->buffer_size)
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goto fail; /* EOF or end padding */
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/* read raw block */
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bytes = read_streamfile(data->buffer, stream->offset, data->op.bytes, stream->streamfile);
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stream->offset += data->op.bytes;
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if (bytes != data->op.bytes) goto fail; /* wrong packet? */
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return 1;
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fail:
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return 0;
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}
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#endif
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