mirror of
https://github.com/vgmstream/vgmstream.git
synced 2024-12-19 18:05:52 +01:00
127 lines
3.8 KiB
C
127 lines
3.8 KiB
C
#ifndef _NUS3BANK_STREAMFILE_H_
|
|
#define _NUS3BANK_STREAMFILE_H_
|
|
#include "../streamfile.h"
|
|
|
|
|
|
static uint32_t swap_endian32(uint32_t v) {
|
|
return ((v & 0xff000000) >> 24u) |
|
|
((v & 0x00ff0000) >> 8u) |
|
|
((v & 0x0000ff00) << 8u) |
|
|
((v & 0x000000ff) << 24u);
|
|
}
|
|
|
|
|
|
#define KEY_MAX_SIZE 0x1000
|
|
|
|
typedef struct {
|
|
uint8_t key[KEY_MAX_SIZE];
|
|
int key_len;
|
|
} io_data_t;
|
|
|
|
static size_t io_read(STREAMFILE *sf, uint8_t *dest, off_t offset, size_t length, io_data_t *data) {
|
|
int i;
|
|
size_t bytes = read_streamfile(dest, offset, length, sf);
|
|
|
|
/* decrypt data (xor) */
|
|
if (offset < data->key_len) {
|
|
for (i = 0; i < bytes; i++) {
|
|
if (offset + i < data->key_len)
|
|
dest[i] ^= data->key[offset + i];
|
|
}
|
|
}
|
|
|
|
return bytes;
|
|
}
|
|
|
|
/* decrypts RIFF streams in NUS3BANK */
|
|
static STREAMFILE* setup_nus3bank_streamfile(STREAMFILE *sf, off_t start) {
|
|
STREAMFILE *new_sf = NULL;
|
|
io_data_t io_data = {0};
|
|
|
|
/* setup key */
|
|
{
|
|
uint32_t base_key, chunk_key;
|
|
uint8_t buf[KEY_MAX_SIZE];
|
|
uint32_t chunk_type, chunk_size;
|
|
int pos, data_pos, bytes;
|
|
|
|
/* Header is XORed with a base key and a derived chunk type/size key, while chunk data is XORed with
|
|
* unencrypted data itself, so we need to find where "data" starts then do another pass to properly set key.
|
|
* Original code handles RIFF's "data" and also BNSF's "sdat" too, encrypted BNSF aren't known though. */
|
|
|
|
bytes = read_streamfile(buf, start, sizeof(buf), sf);
|
|
if (bytes < 0x800) goto fail; /* files of 1 XMA block do exist, but not less */
|
|
|
|
base_key = 0x0763E951;
|
|
chunk_type = get_u32be(buf + 0x00) ^ base_key;
|
|
chunk_size = get_u32be(buf + 0x04) ^ base_key;
|
|
if (chunk_type != 0x52494646) /* "RIFF" */
|
|
goto fail;
|
|
|
|
chunk_key = base_key ^ (((chunk_size >> 16u) & 0x0000FFFF) | ((chunk_size << 16u) & 0xFFFF0000)); /* ROTr 16 size */
|
|
|
|
/* find "data" */
|
|
pos = 0x0c;
|
|
while(pos < sizeof(buf)) {
|
|
chunk_type = get_u32be(buf + pos + 0x00) ^ chunk_key;
|
|
chunk_size = get_u32be(buf + pos + 0x04) ^ chunk_key;
|
|
chunk_size = swap_endian32(chunk_size);
|
|
pos += 0x08;
|
|
|
|
if (chunk_type == 0x64617461) { /* "data" */
|
|
data_pos = pos;
|
|
break;
|
|
}
|
|
|
|
if (pos + chunk_size > sizeof(buf) - 0x08) {
|
|
VGM_LOG("NUS3 SF: header too big\n");
|
|
goto fail; /* max around 0x400 */
|
|
}
|
|
|
|
pos += chunk_size;
|
|
}
|
|
|
|
|
|
/* setup key */
|
|
put_u32be(io_data.key + 0x00, base_key);
|
|
put_u32be(io_data.key + 0x04, base_key);
|
|
put_u32be(io_data.key + 0x08, chunk_key);
|
|
pos = 0x0c; /* after WAVE */
|
|
|
|
while (pos < data_pos) {
|
|
chunk_type = get_u32be(buf + pos + 0x00) ^ chunk_key;
|
|
chunk_size = get_u32be(buf + pos + 0x04) ^ chunk_key;
|
|
chunk_size = swap_endian32(chunk_size);
|
|
|
|
put_u32be(io_data.key + pos + 0x00, chunk_key);
|
|
put_u32be(io_data.key + pos + 0x04, chunk_key);
|
|
pos += 0x08;
|
|
|
|
if (pos >= data_pos)
|
|
break;
|
|
|
|
/* buf must contain data of at least chunk_size */
|
|
if (data_pos + chunk_size >= sizeof(buf)) {
|
|
VGM_LOG("NUS3 SF: chunk too big\n");
|
|
goto fail;
|
|
}
|
|
|
|
memcpy(io_data.key + pos, buf + data_pos, chunk_size);
|
|
|
|
pos += chunk_size;
|
|
}
|
|
|
|
io_data.key_len = data_pos;
|
|
}
|
|
|
|
|
|
new_sf = open_wrap_streamfile(sf);
|
|
new_sf = open_io_streamfile(new_sf, &io_data, sizeof(io_data_t), io_read, NULL);
|
|
return new_sf;
|
|
fail:
|
|
close_streamfile(sf);
|
|
return NULL;
|
|
}
|
|
|
|
#endif /* _NUS3BANK_STREAMFILE_H_ */
|