47 lines
1.3 KiB
C
47 lines
1.3 KiB
C
#ifndef _SSCF_ENCRYPTED_H_
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#define _SSCF_ENCRYPTED_H_
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#include "../streamfile.h"
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typedef struct {
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uint8_t key[0x800];
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} sscf_io;
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static size_t sscf_io_read(STREAMFILE* sf, uint8_t* dest, off_t offset, size_t length, sscf_io* io) {
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int i;
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size_t bytes = read_streamfile(dest, offset, length, sf);
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for (i = 0; i < bytes; i++) {
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dest[i] ^= io->key[(offset + i) % sizeof(io->key)];
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}
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return bytes;
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}
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/* Decrypts SSCF streams */
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static STREAMFILE* setup_sscf_streamfile(STREAMFILE* sf, uint32_t xorkey) {
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STREAMFILE *new_sf = NULL;
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sscf_io io = {0};
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int i;
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uint32_t stream_offset = 0x80;
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uint32_t stream_size = get_streamfile_size(sf) - stream_offset;
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/* setup key */
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xorkey = (xorkey >> 21) | (xorkey << 11);
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for (i = 0; i < sizeof(io.key); i += 4) {
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put_u32le(io.key + i, xorkey);
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xorkey += (xorkey >> 29) | (xorkey << 3);
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}
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new_sf = open_wrap_streamfile(sf);
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new_sf = open_io_streamfile_f(new_sf, &io, sizeof(sscf_io), sscf_io_read, NULL);
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if (new_sf) {
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stream_size = read_u32le(0x84, new_sf) + 0x08; /* RIFF size */
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}
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new_sf = open_clamp_streamfile_f(new_sf, stream_offset, stream_size);
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new_sf = open_fakename_streamfile_f(new_sf, NULL, "xma");
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return new_sf;
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}
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#endif
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