vgmstream/src/meta/jstm_streamfile.h
2019-07-28 15:11:17 +02:00

52 lines
1.4 KiB
C

#ifndef _JSTM_STREAMFILE_H_
#define _JSTM_STREAMFILE_H_
#include "../streamfile.h"
typedef struct {
off_t start_offset;
} jstm_decryption_data;
static size_t jstm_decryption_read(STREAMFILE *streamfile, uint8_t *dest, off_t offset, size_t length, jstm_decryption_data* data) {
size_t bytes_read;
int i;
bytes_read = streamfile->read(streamfile, dest, offset, length);
/* decrypt data (xor) */
for (i = 0; i < bytes_read; i++) {
if (offset+i >= data->start_offset) {
dest[i] = dest[i] ^ 0x5A;
}
}
return bytes_read;
}
static STREAMFILE* setup_jstm_streamfile(STREAMFILE *streamFile, off_t start_offset) {
STREAMFILE *temp_streamFile = NULL, *new_streamFile = NULL;
jstm_decryption_data io_data = {0};
size_t io_data_size = sizeof(jstm_decryption_data);
/* setup decryption */
io_data.start_offset = start_offset;
/* setup custom streamfile */
new_streamFile = open_wrap_streamfile(streamFile);
if (!new_streamFile) goto fail;
temp_streamFile = new_streamFile;
new_streamFile = open_io_streamfile(temp_streamFile, &io_data,io_data_size, jstm_decryption_read,NULL);
if (!new_streamFile) goto fail;
temp_streamFile = new_streamFile;
return temp_streamFile;
fail:
close_streamfile(temp_streamFile);
return NULL;
}
#endif /* _JSTM_STREAMFILE_H_ */