77 lines
2.2 KiB
C
77 lines
2.2 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[0x1000];
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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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uint32_t start;
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uint32_t max_offset;
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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 *sf, uint8_t *dest, off_t offset, size_t length, ogg_vorbis_io_data* data) {
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static const uint8_t header_swap[4] = { 0x4F,0x67,0x67,0x53 }; /* "OggS" */
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int i;
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size_t bytes = read_streamfile(dest, offset, length, sf);
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if (data->cfg.is_encrypted) {
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int max = bytes;
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int header_end = 0x04;
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//TODO handle data->cfg.start;
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if (data->cfg.max_offset) {
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if (offset > data->cfg.max_offset) {
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max = 0;
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}
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else {
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max = data->cfg.max_offset - offset;
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if (max > bytes)
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max = bytes;
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}
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}
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for (i = 0; i < max; i++) {
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if (data->cfg.is_header_swap && (offset + i) < header_end) {
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dest[i] = header_swap[(offset + i) % 0x04];
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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;
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}
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//todo maybe use generic decryption streamfile
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/* Decrypts Ogg Vorbis streams */
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static STREAMFILE* setup_ogg_vorbis_streamfile(STREAMFILE *sf, ogg_vorbis_io_config_data* cfg) {
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STREAMFILE *new_sf = NULL;
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ogg_vorbis_io_data io_data = {0};
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io_data.cfg = *cfg; /* memcpy */
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new_sf = open_wrap_streamfile(sf);
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new_sf = open_io_streamfile_f(new_sf, &io_data, sizeof(ogg_vorbis_io_data), ogg_vorbis_io_read, NULL);
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//new_sf = open_fakename_streamfile_f(new_sf, NULL, "ogg"); //todo?
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return new_sf;
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}
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#endif /* _OGG_VORBIS_STREAMFILE_H_ */
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