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sm64pc/tools/libmio0.c

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#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#if defined(_WIN32) || defined(_WIN64)
#include <io.h>
#include <fcntl.h>
#endif
#include "libmio0.h"
#include "utils.h"
// defines
#define MIO0_VERSION "0.1"
#define GET_BIT(buf, bit) ((buf)[(bit) / 8] & (1 << (7 - ((bit) % 8))))
// types
typedef struct
{
int *indexes;
int allocated;
int count;
int start;
} lookback;
// functions
#define LOOKBACK_COUNT 256
#define LOOKBACK_INIT_SIZE 128
static lookback *lookback_init(void)
{
lookback *lb = malloc(LOOKBACK_COUNT * sizeof(*lb));
for (int i = 0; i < LOOKBACK_COUNT; i++) {
lb[i].allocated = LOOKBACK_INIT_SIZE;
lb[i].indexes = malloc(lb[i].allocated * sizeof(*lb[i].indexes));
lb[i].count = 0;
lb[i].start = 0;
}
return lb;
}
static void lookback_free(lookback *lb)
{
for (int i = 0; i < LOOKBACK_COUNT; i++) {
free(lb[i].indexes);
}
free(lb);
}
static inline void lookback_push(lookback *lkbk, unsigned char val, int index)
{
lookback *lb = &lkbk[val];
if (lb->count == lb->allocated) {
lb->allocated *= 4;
lb->indexes = realloc(lb->indexes, lb->allocated * sizeof(*lb->indexes));
}
lb->indexes[lb->count++] = index;
}
static void PUT_BIT(unsigned char *buf, int bit, int val)
{
unsigned char mask = 1 << (7 - (bit % 8));
unsigned int offset = bit / 8;
buf[offset] = (buf[offset] & ~(mask)) | (val ? mask : 0);
}
// used to find longest matching stream in buffer
// buf: buffer
// start_offset: offset in buf to look back from
// max_search: max number of bytes to find
// found_offset: returned offset found (0 if none found)
// returns max length of matching stream (0 if none found)
static int find_longest(const unsigned char *buf, int start_offset, int max_search, int *found_offset, lookback *lkbk)
{
int best_length = 0;
int best_offset = 0;
int cur_length;
int search_len;
int farthest, off, i;
int lb_idx;
const unsigned char first = buf[start_offset];
lookback *lb = &lkbk[first];
// buf
// | off start max
// V |+i-> |+i-> |
// |--------------raw-data-----------------|
// |+i-> | |+i->
// +cur_length
// check at most the past 4096 values
farthest = MAX(start_offset - 4096, 0);
// find starting index
for (lb_idx = lb->start; lb_idx < lb->count && lb->indexes[lb_idx] < farthest; lb_idx++) {}
lb->start = lb_idx;
for ( ; lb_idx < lb->count && lb->indexes[lb_idx] < start_offset; lb_idx++) {
off = lb->indexes[lb_idx];
// check at most requested max or up until start
search_len = MIN(max_search, start_offset - off);
for (i = 0; i < search_len; i++) {
if (buf[start_offset + i] != buf[off + i]) {
break;
}
}
cur_length = i;
// if matched up until start, continue matching in already matched parts
if (cur_length == search_len) {
// check at most requested max less current length
search_len = max_search - cur_length;
for (i = 0; i < search_len; i++) {
if (buf[start_offset + cur_length + i] != buf[off + i]) {
break;
}
}
cur_length += i;
}
if (cur_length > best_length) {
best_offset = start_offset - off;
best_length = cur_length;
}
}
// return best reverse offset and length (may be 0)
*found_offset = best_offset;
return best_length;
}
// decode MIO0 header
// returns 1 if valid header, 0 otherwise
int mio0_decode_header(const unsigned char *buf, mio0_header_t *head)
{
if (!memcmp(buf, "MIO0", 4)) {
head->dest_size = read_u32_be(&buf[4]);
head->comp_offset = read_u32_be(&buf[8]);
head->uncomp_offset = read_u32_be(&buf[12]);
return 1;
}
return 0;
}
void mio0_encode_header(unsigned char *buf, const mio0_header_t *head)
{
memcpy(buf, "MIO0", 4);
write_u32_be(&buf[4], head->dest_size);
write_u32_be(&buf[8], head->comp_offset);
write_u32_be(&buf[12], head->uncomp_offset);
}
int mio0_decode(const unsigned char *in, unsigned char *out, unsigned int *end)
{
mio0_header_t head;
unsigned int bytes_written = 0;
int bit_idx = 0;
int comp_idx = 0;
int uncomp_idx = 0;
int valid;
// extract header
valid = mio0_decode_header(in, &head);
// verify MIO0 header
if (!valid) {
return -2;
}
// decode data
while (bytes_written < head.dest_size) {
if (GET_BIT(&in[MIO0_HEADER_LENGTH], bit_idx)) {
// 1 - pull uncompressed data
out[bytes_written] = in[head.uncomp_offset + uncomp_idx];
bytes_written++;
uncomp_idx++;
} else {
// 0 - read compressed data
int idx;
int length;
int i;
const unsigned char *vals = &in[head.comp_offset + comp_idx];
comp_idx += 2;
length = ((vals[0] & 0xF0) >> 4) + 3;
idx = ((vals[0] & 0x0F) << 8) + vals[1] + 1;
for (i = 0; i < length; i++) {
out[bytes_written] = out[bytes_written - idx];
bytes_written++;
}
}
bit_idx++;
}
if (end) {
*end = head.uncomp_offset + uncomp_idx;
}
return bytes_written;
}
int mio0_encode(const unsigned char *in, unsigned int length, unsigned char *out)
{
unsigned char *bit_buf;
unsigned char *comp_buf;
unsigned char *uncomp_buf;
unsigned int bit_length;
unsigned int comp_offset;
unsigned int uncomp_offset;
unsigned int bytes_proc = 0;
int bytes_written;
int bit_idx = 0;
int comp_idx = 0;
int uncomp_idx = 0;
lookback *lookbacks;
// initialize lookback buffer
lookbacks = lookback_init();
// allocate some temporary buffers worst case size
bit_buf = malloc((length + 7) / 8); // 1-bit/byte
comp_buf = malloc(length); // 16-bits/2bytes
uncomp_buf = malloc(length); // all uncompressed
memset(bit_buf, 0, (length + 7) / 8);
// encode data
// special case for first byte
lookback_push(lookbacks, in[0], 0);
uncomp_buf[uncomp_idx] = in[0];
uncomp_idx += 1;
bytes_proc += 1;
PUT_BIT(bit_buf, bit_idx++, 1);
while (bytes_proc < length) {
int offset;
int max_length = MIN(length - bytes_proc, 18);
int longest_match = find_longest(in, bytes_proc, max_length, &offset, lookbacks);
// push current byte before checking next longer match
lookback_push(lookbacks, in[bytes_proc], bytes_proc);
if (longest_match > 2) {
int lookahead_offset;
// lookahead to next byte to see if longer match
int lookahead_length = MIN(length - bytes_proc - 1, 18);
int lookahead_match = find_longest(in, bytes_proc + 1, lookahead_length, &lookahead_offset, lookbacks);
// better match found, use uncompressed + lookahead compressed
if ((longest_match + 1) < lookahead_match) {
// uncompressed byte
uncomp_buf[uncomp_idx] = in[bytes_proc];
uncomp_idx++;
PUT_BIT(bit_buf, bit_idx, 1);
bytes_proc++;
longest_match = lookahead_match;
offset = lookahead_offset;
bit_idx++;
lookback_push(lookbacks, in[bytes_proc], bytes_proc);
}
// first byte already pushed above
for (int i = 1; i < longest_match; i++) {
lookback_push(lookbacks, in[bytes_proc + i], bytes_proc + i);
}
// compressed block
comp_buf[comp_idx] = (((longest_match - 3) & 0x0F) << 4) |
(((offset - 1) >> 8) & 0x0F);
comp_buf[comp_idx + 1] = (offset - 1) & 0xFF;
comp_idx += 2;
PUT_BIT(bit_buf, bit_idx, 0);
bytes_proc += longest_match;
} else {
// uncompressed byte
uncomp_buf[uncomp_idx] = in[bytes_proc];
uncomp_idx++;
PUT_BIT(bit_buf, bit_idx, 1);
bytes_proc++;
}
bit_idx++;
}
// compute final sizes and offsets
// +7 so int division accounts for all bits
bit_length = ((bit_idx + 7) / 8);
// compressed data after control bits and aligned to 4-byte boundary
comp_offset = ALIGN(MIO0_HEADER_LENGTH + bit_length, 4);
uncomp_offset = comp_offset + comp_idx;
bytes_written = uncomp_offset + uncomp_idx;
// output header
memcpy(out, "MIO0", 4);
write_u32_be(&out[4], length);
write_u32_be(&out[8], comp_offset);
write_u32_be(&out[12], uncomp_offset);
// output data
memcpy(&out[MIO0_HEADER_LENGTH], bit_buf, bit_length);
memcpy(&out[comp_offset], comp_buf, comp_idx);
memcpy(&out[uncomp_offset], uncomp_buf, uncomp_idx);
// free allocated buffers
free(bit_buf);
free(comp_buf);
free(uncomp_buf);
lookback_free(lookbacks);
return bytes_written;
}
static FILE *mio0_open_out_file(const char *out_file) {
if (strcmp(out_file, "-") == 0) {
#if defined(_WIN32) || defined(_WIN64)
_setmode(_fileno(stdout), _O_BINARY);
#endif
return stdout;
} else {
return fopen(out_file, "wb");
}
}
int mio0_decode_file(const char *in_file, unsigned long offset, const char *out_file)
{
mio0_header_t head;
FILE *in;
FILE *out;
unsigned char *in_buf = NULL;
unsigned char *out_buf = NULL;
long file_size;
int ret_val = 0;
size_t bytes_read;
int bytes_decoded;
int bytes_written;
int valid;
in = fopen(in_file, "rb");
if (in == NULL) {
return 1;
}
// allocate buffer to read from offset to end of file
fseek(in, 0, SEEK_END);
file_size = ftell(in);
in_buf = malloc(file_size - offset);
fseek(in, offset, SEEK_SET);
// read bytes
bytes_read = fread(in_buf, 1, file_size - offset, in);
if (bytes_read != file_size - offset) {
ret_val = 2;
goto free_all;
}
// verify header
valid = mio0_decode_header(in_buf, &head);
if (!valid) {
ret_val = 3;
goto free_all;
}
out_buf = malloc(head.dest_size);
// decompress MIO0 encoded data
bytes_decoded = mio0_decode(in_buf, out_buf, NULL);
if (bytes_decoded < 0) {
ret_val = 3;
goto free_all;
}
// open output file
out = mio0_open_out_file(out_file);
if (out == NULL) {
ret_val = 4;
goto free_all;
}
// write data to file
bytes_written = fwrite(out_buf, 1, bytes_decoded, out);
if (bytes_written != bytes_decoded) {
ret_val = 5;
}
// clean up
if (out != stdout) {
fclose(out);
}
free_all:
if (out_buf) {
free(out_buf);
}
if (in_buf) {
free(in_buf);
}
fclose(in);
return ret_val;
}
int mio0_encode_file(const char *in_file, const char *out_file)
{
FILE *in;
FILE *out;
unsigned char *in_buf = NULL;
unsigned char *out_buf = NULL;
size_t file_size;
size_t bytes_read;
int bytes_encoded;
int bytes_written;
int ret_val = 0;
in = fopen(in_file, "rb");
if (in == NULL) {
return 1;
}
// allocate buffer to read entire contents of files
fseek(in, 0, SEEK_END);
file_size = ftell(in);
fseek(in, 0, SEEK_SET);
in_buf = malloc(file_size);
// read bytes
bytes_read = fread(in_buf, 1, file_size, in);
if (bytes_read != file_size) {
ret_val = 2;
goto free_all;
}
// allocate worst case length
out_buf = malloc(MIO0_HEADER_LENGTH + ((file_size+7)/8) + file_size);
// compress data in MIO0 format
bytes_encoded = mio0_encode(in_buf, file_size, out_buf);
// open output file
out = mio0_open_out_file(out_file);
if (out == NULL) {
ret_val = 4;
goto free_all;
}
// write data to file
bytes_written = fwrite(out_buf, 1, bytes_encoded, out);
if (bytes_written != bytes_encoded) {
ret_val = 5;
}
// clean up
if (out != stdout) {
fclose(out);
}
free_all:
if (out_buf) {
free(out_buf);
}
if (in_buf) {
free(in_buf);
}
fclose(in);
return ret_val;
}
// mio0 standalone executable
#ifdef MIO0_STANDALONE
typedef struct
{
char *in_filename;
char *out_filename;
unsigned int offset;
int compress;
} arg_config;
static arg_config default_config =
{
NULL,
NULL,
0,
1
};
static void print_usage(void)
{
ERROR("Usage: mio0 [-c / -d] [-o OFFSET] FILE [OUTPUT]\n"
"\n"
"mio0 v" MIO0_VERSION ": MIO0 compression and decompression tool\n"
"\n"
"Optional arguments:\n"
" -c compress raw data into MIO0 (default: compress)\n"
" -d decompress MIO0 into raw data\n"
" -o OFFSET starting offset in FILE (default: 0)\n"
"\n"
"File arguments:\n"
" FILE input file\n"
" [OUTPUT] output file (default: FILE.out), \"-\" for stdout\n");
exit(1);
}
// parse command line arguments
static void parse_arguments(int argc, char *argv[], arg_config *config)
{
int i;
int file_count = 0;
if (argc < 2) {
print_usage();
exit(1);
}
for (i = 1; i < argc; i++) {
if (argv[i][0] == '-' && argv[i][1] != '\0') {
switch (argv[i][1]) {
case 'c':
config->compress = 1;
break;
case 'd':
config->compress = 0;
break;
case 'o':
if (++i >= argc) {
print_usage();
}
config->offset = strtoul(argv[i], NULL, 0);
break;
default:
print_usage();
break;
}
} else {
switch (file_count) {
case 0:
config->in_filename = argv[i];
break;
case 1:
config->out_filename = argv[i];
break;
default: // too many
print_usage();
break;
}
file_count++;
}
}
if (file_count < 1) {
print_usage();
}
}
int main(int argc, char *argv[])
{
char out_filename[FILENAME_MAX];
arg_config config;
int ret_val;
// get configuration from arguments
config = default_config;
parse_arguments(argc, argv, &config);
if (config.out_filename == NULL) {
config.out_filename = out_filename;
sprintf(config.out_filename, "%s.out", config.in_filename);
}
// operation
if (config.compress) {
ret_val = mio0_encode_file(config.in_filename, config.out_filename);
} else {
ret_val = mio0_decode_file(config.in_filename, config.offset, config.out_filename);
}
switch (ret_val) {
case 1:
ERROR("Error opening input file \"%s\"\n", config.in_filename);
break;
case 2:
ERROR("Error reading from input file \"%s\"\n", config.in_filename);
break;
case 3:
ERROR("Error decoding MIO0 data. Wrong offset (0x%X)?\n", config.offset);
break;
case 4:
ERROR("Error opening output file \"%s\"\n", config.out_filename);
break;
case 5:
ERROR("Error writing bytes to output file \"%s\"\n", config.out_filename);
break;
}
return ret_val;
}
#endif // MIO0_STANDALONE
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