mirror of
https://github.com/vgmstream/vgmstream.git
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77 lines
2.3 KiB
C
77 lines
2.3 KiB
C
#ifndef _OGG_VORBIS_STREAMFILE_H_
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#define _OGG_VORBIS_STREAMFILE_H_
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#include "../streamfile.h"
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typedef struct {
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int is_encrypted;
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uint8_t key[0x100];
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size_t key_len;
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int is_nibble_swap;
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int is_header_swap;
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} ogg_vorbis_io_config_data;
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typedef struct {
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/* config */
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ogg_vorbis_io_config_data cfg;
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} ogg_vorbis_io_data;
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static size_t ogg_vorbis_io_read(STREAMFILE *streamfile, uint8_t *dest, off_t offset, size_t length, ogg_vorbis_io_data* data) {
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size_t bytes_read;
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int i;
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static const uint8_t header_swap[4] = { 0x4F,0x67,0x67,0x53 }; /* "OggS" */
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static const size_t header_size = 0x04;
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bytes_read = streamfile->read(streamfile, dest, offset, length);
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if (data->cfg.is_encrypted) {
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for (i = 0; i < bytes_read; i++) {
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if (data->cfg.is_header_swap && (offset + i) < header_size) {
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dest[i] = header_swap[(offset + i) % header_size];
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}
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else {
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if (!data->cfg.key_len && !data->cfg.is_nibble_swap)
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break;
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if (data->cfg.key_len)
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dest[i] ^= data->cfg.key[(offset + i) % data->cfg.key_len];
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if (data->cfg.is_nibble_swap)
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dest[i] = ((dest[i] << 4) & 0xf0) | ((dest[i] >> 4) & 0x0f);
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}
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}
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}
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return bytes_read;
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}
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//todo maybe use generic decryption streamfile
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static STREAMFILE* setup_ogg_vorbis_streamfile(STREAMFILE *streamFile, ogg_vorbis_io_config_data cfg) {
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STREAMFILE *temp_streamFile = NULL, *new_streamFile = NULL;
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ogg_vorbis_io_data io_data = {0};
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size_t io_data_size = sizeof(ogg_vorbis_io_data);
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/* setup decryption */
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io_data.cfg = cfg; /* memcpy */
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/* setup custom streamfile */
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new_streamFile = open_wrap_streamfile(streamFile);
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if (!new_streamFile) goto fail;
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temp_streamFile = new_streamFile;
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//todo extension .ogg?
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new_streamFile = open_io_streamfile(temp_streamFile, &io_data,io_data_size, ogg_vorbis_io_read,NULL);
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if (!new_streamFile) goto fail;
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temp_streamFile = new_streamFile;
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return temp_streamFile;
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fail:
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close_streamfile(temp_streamFile);
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return NULL;
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}
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#endif /* _OGG_VORBIS_STREAMFILE_H_ */
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