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https://github.com/vgmstream/vgmstream.git
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67 lines
2.3 KiB
C
67 lines
2.3 KiB
C
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#ifndef _BGW_STREAMFILE_H_
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#define _BGW_STREAMFILE_H_
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#include "../streamfile.h"
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#define BGW_KEY_MAX (0xC0*2)
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typedef struct {
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uint8_t key[BGW_KEY_MAX];
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size_t key_size;
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} bgw_decryption_data;
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/* Encrypted ATRAC3 info from Moogle Toolbox (https://sourceforge.net/projects/mogbox/) */
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static size_t bgw_decryption_read(STREAMFILE *streamfile, uint8_t *dest, off_t offset, size_t length, bgw_decryption_data* data) {
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size_t bytes_read;
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int i;
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bytes_read = streamfile->read(streamfile, dest, offset, length);
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/* decrypt data (xor) */
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for (i = 0; i < bytes_read; i++) {
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dest[i] ^= data->key[(offset + i) % data->key_size];
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}
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//todo: a few files (music069.bgw, music071.bgw, music900.bgw) have the last frames unencrypted,
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// though they are blank and encoder ignores wrongly decrypted frames and outputs blank samples as well
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return bytes_read;
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}
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static STREAMFILE* setup_bgw_atrac3_streamfile(STREAMFILE *streamFile, off_t subfile_offset, size_t subfile_size, size_t frame_size, int channels) {
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STREAMFILE *temp_streamFile = NULL, *new_streamFile = NULL;
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bgw_decryption_data io_data = {0};
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size_t io_data_size = sizeof(bgw_decryption_data);
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int ch;
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/* setup decryption with key (first frame + modified channel header) */
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if (frame_size*channels == 0 || frame_size*channels > BGW_KEY_MAX) goto fail;
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io_data.key_size = read_streamfile(io_data.key, subfile_offset, frame_size*channels, streamFile);
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for (ch = 0; ch < channels; ch++) {
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uint32_t xor = get_32bitBE(io_data.key + frame_size*ch);
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put_32bitBE(io_data.key + frame_size*ch, xor ^ 0xA0024E9F);
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}
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/* setup subfile */
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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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new_streamFile = open_clamp_streamfile(temp_streamFile, subfile_offset,subfile_size);
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if (!new_streamFile) goto fail;
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temp_streamFile = new_streamFile;
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new_streamFile = open_io_streamfile(temp_streamFile, &io_data,io_data_size, bgw_decryption_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 /* _BGW_STREAMFILE_H_ */
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