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https://github.com/vgmstream/vgmstream.git
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40 lines
1.1 KiB
C
40 lines
1.1 KiB
C
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#ifndef _LP_STREAMFILE_H_
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#define _LP_STREAMFILE_H_
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#include "../streamfile.h"
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typedef struct {
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off_t start;
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} lp_io_data;
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static size_t lp_io_read(STREAMFILE *sf, uint8_t *dest, off_t offset, size_t length, lp_io_data* data) {
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int i;
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size_t bytes = read_streamfile(dest, offset, length, sf);
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/* PCM16LE frames are ROL'ed (or lower bit is ignored?) so this only works if reads are aligned
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* to sizeof(uint16_t); maybe could be a new decoder but seems like a waste */
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for (i = 0; i < bytes / 2 * 2; i += 2) {
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if (offset + i >= data->start) {
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uint16_t v = get_u16le(dest + i);
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v = (v << 1) | ((v >> 15) & 0x0001);
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put_u16le(dest + i, v);
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}
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}
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return bytes;
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}
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/* decrypts Enthusia "LP" PCM streams */
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static STREAMFILE* setup_lp_streamfile(STREAMFILE* sf, off_t start) {
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STREAMFILE* new_sf = NULL;
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lp_io_data io_data = {0};
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io_data.start = start;
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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(lp_io_data), lp_io_read, NULL);
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return new_sf;
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}
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#endif /* _LP_STREAMFILE_H_ */
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