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Remove PCM16-XOR decoder and use decryption streamfile instead

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The encryption is built on top of the data, so this way mimics the
actual setup and removes another superfluous decoder
This commit is contained in:
bnnm 2018-03-27 23:24:24 +02:00
parent 0f529ea1a7
commit 1708dcaf63
6 changed files with 84 additions and 66 deletions
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1
src/coding/coding.h
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@ -59,7 +59,6 @@ void decode_ngc_afc(VGMSTREAMCHANNEL * stream, sample * outbuf, int channelspaci
/* pcm_decoder */
void decode_pcm16LE(VGMSTREAMCHANNEL * stream, sample * outbuf, int channelspacing, int32_t first_sample, int32_t samples_to_do);
void decode_pcm16LE_XOR_int(VGMSTREAMCHANNEL * stream, sample * outbuf, int channelspacing, int32_t first_sample, int32_t samples_to_do);
void decode_pcm16BE(VGMSTREAMCHANNEL * stream, sample * outbuf, int channelspacing, int32_t first_sample, int32_t samples_to_do);
void decode_pcm16_int(VGMSTREAMCHANNEL * stream, sample * outbuf, int channelspacing, int32_t first_sample, int32_t samples_to_do, int big_endian);
void decode_pcm8(VGMSTREAMCHANNEL * stream, sample * outbuf, int channelspacing, int32_t first_sample, int32_t samples_to_do);

9
src/coding/pcm_decoder.c
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@ -78,15 +78,6 @@ void decode_pcm16_int(VGMSTREAMCHANNEL * stream, sample * outbuf, int channelspa
}
}
void decode_pcm16LE_XOR_int(VGMSTREAMCHANNEL * stream, sample * outbuf, int channelspacing, int32_t first_sample, int32_t samples_to_do) {
int i;
int32_t sample_count;
for (i=first_sample,sample_count=0; i<first_sample+samples_to_do; i++,sample_count+=channelspacing) {
outbuf[sample_count]=read_16bitLE(stream->offset+i*2*channelspacing,stream->streamfile)^stream->key_xor;
}
}
static int expand_ulaw(uint8_t ulawbyte) {
int sign, segment, quantization, new_sample;
const int bias = 0x84;

1
src/formats.c
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@ -436,7 +436,6 @@ typedef struct {
static const coding_info coding_info_list[] = {
{coding_PCM16LE, "Little Endian 16-bit PCM"},
{coding_PCM16LE_XOR_int, "Little Endian 16-bit PCM with 2 byte interleave and XOR obfuscation"},
{coding_PCM16BE, "Big Endian 16-bit PCM"},
{coding_PCM16_int, "16-bit PCM with 2 byte interleave (block)"},
{coding_PCM8, "8-bit PCM"},

127
src/meta/ps2_jstm.c
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@ -1,63 +1,104 @@
#include "meta.h"
#include "../util.h"
#include "../coding/coding.h"
/* JSTM (.STM (renamed .JSTM) from Tantei Jinguji Saburo - Kind of Blue) */
static STREAMFILE* setup_jstm_streamfile(STREAMFILE *streamFile, off_t start_offset);
/* JSTM - from Tantei Jinguji Saburo - Kind of Blue (PS2) */
VGMSTREAM * init_vgmstream_ps2_jstm(STREAMFILE *streamFile) {
VGMSTREAM * vgmstream = NULL;
off_t start_offset = 0x20;
int loop_flag;
int channel_count;
char filename[PATH_LIMIT];
STREAMFILE *temp_streamFile = NULL;
off_t start_offset;
int loop_flag, channel_count;
/* check extension */
streamFile->get_name(streamFile,filename,sizeof(filename));
if (strcasecmp("stm",filename_extension(filename)) &&
strcasecmp("jstm",filename_extension(filename))) goto fail;
/* check header (JSTM) */
if (read_32bitBE(0x0,streamFile) != 0x4A53544D) goto fail;
/* checks */
/* .stm: original, .jstm: header id */
if (!check_extensions(streamFile, "stm,jstm"))
goto fail;
if (read_32bitBE(0x00,streamFile) != 0x4A53544D) /* "JSTM" */
goto fail;
loop_flag = (read_32bitLE(0x14,streamFile) != 0);
channel_count = read_16bitLE(0x4,streamFile);
// hmm, don't know what 6 is, one is probably bytes per sample and the
// other is channels, but who can say?
if (channel_count != read_16bitLE(0x6,streamFile)) goto fail;
start_offset = 0x20;
channel_count = read_16bitLE(0x04,streamFile);
if (channel_count != read_16bitLE(0x06,streamFile)) /* 0x02, interleave? */
goto fail;
loop_flag = (read_32bitLE(0x14,streamFile) != -1);
/* build the VGMSTREAM */
vgmstream = allocate_vgmstream(channel_count,loop_flag);
if (!vgmstream) goto fail;
/* fill in the statistics vitale */
vgmstream->sample_rate = read_32bitLE(0x8,streamFile);
vgmstream->coding_type = coding_PCM16LE_XOR_int;
vgmstream->num_samples = read_32bitLE(0xC,streamFile)/2/channel_count;
vgmstream->layout_type = layout_none;
vgmstream->sample_rate = read_32bitLE(0x08,streamFile);
vgmstream->num_samples = pcm_bytes_to_samples(read_32bitLE(0x0C,streamFile),channel_count,16);
if (loop_flag) {
vgmstream->loop_start_sample = pcm_bytes_to_samples(read_32bitLE(0x14,streamFile),channel_count,16);
vgmstream->loop_end_sample = vgmstream->num_samples;
}
vgmstream->meta_type = meta_PS2_JSTM;
vgmstream->coding_type = coding_PCM16LE;
vgmstream->layout_type = layout_interleave;
vgmstream->interleave_block_size = 0x02;
if (loop_flag) {
vgmstream->loop_start_sample=read_32bitLE(0x14,streamFile)/2/channel_count;
vgmstream->loop_end_sample=vgmstream->num_samples;
}
/* open the file for reading */
{
int i;
STREAMFILE * file;
file = streamFile->open(streamFile,filename,STREAMFILE_DEFAULT_BUFFER_SIZE);
if (!file) goto fail;
for (i=0; i < channel_count; i++) {
vgmstream->ch[i].streamfile = file;
vgmstream->ch[i].channel_start_offset =
vgmstream->ch[i].offset = start_offset + 2*i;
vgmstream->ch[i].key_xor = 0x5A5A;
}
}
temp_streamFile = setup_jstm_streamfile(streamFile, start_offset);
if (!temp_streamFile) goto fail;
if (!vgmstream_open_stream(vgmstream,temp_streamFile,start_offset))
goto fail;
close_streamfile(temp_streamFile);
return vgmstream;
fail:
if (vgmstream) close_vgmstream(vgmstream);
close_streamfile(temp_streamFile);
close_vgmstream(vgmstream);
return NULL;
}
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) {
//VGM_LOG("xor %x to %x\n", dest[i], dest[i] ^ 0x5A);getchar();
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);
if (!new_streamFile) goto fail;
temp_streamFile = new_streamFile;
return temp_streamFile;
fail:
close_streamfile(temp_streamFile);
return NULL;
}

9
src/vgmstream.c
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@ -963,7 +963,6 @@ int get_vgmstream_samples_per_frame(VGMSTREAM * vgmstream) {
return 1;
case coding_PCM16LE:
case coding_PCM16LE_XOR_int:
case coding_PCM16BE:
case coding_PCM16_int:
case coding_PCM8:
@ -1131,7 +1130,6 @@ int get_vgmstream_frame_size(VGMSTREAM * vgmstream) {
return 0;
case coding_PCM16LE:
case coding_PCM16LE_XOR_int:
case coding_PCM16BE:
case coding_PCM16_int:
return 0x02;
@ -1338,13 +1336,6 @@ void decode_vgmstream(VGMSTREAM * vgmstream, int samples_written, int samples_to
samples_to_do);
}
break;
case coding_PCM16LE_XOR_int:
for (chan=0;chan<vgmstream->channels;chan++) {
decode_pcm16LE_XOR_int(&vgmstream->ch[chan],buffer+samples_written*vgmstream->channels+chan,
vgmstream->channels,vgmstream->samples_into_block,
samples_to_do);
}
break;
case coding_PCM16BE:
for (chan=0;chan<vgmstream->channels;chan++) {
decode_pcm16BE(&vgmstream->ch[chan],buffer+samples_written*vgmstream->channels+chan,

3
src/vgmstream.h
View File

@ -78,7 +78,6 @@ enum { STREAM_NAME_SIZE = 255 }; /* reasonable max */
typedef enum {
/* PCM */
coding_PCM16LE, /* little endian 16-bit PCM */
coding_PCM16LE_XOR_int, /* little endian 16-bit PCM with sample-level xor (for blocks) */
coding_PCM16BE, /* big endian 16-bit PCM */
coding_PCM16_int, /* 16-bit PCM with sample-level interleave (for blocks) */
@ -715,8 +714,6 @@ typedef struct {
uint16_t adx_mult;
uint16_t adx_add;
/* generic encryption */
uint16_t key_xor;
} VGMSTREAMCHANNEL;
/* main vgmstream info */