119 lines
3.2 KiB
C
119 lines
3.2 KiB
C
#include <stdio.h>
|
|
#include <stdlib.h>
|
|
|
|
/* cc ulzenc.c -o ulzenc && ./ulzenc a.bin b.ulz */
|
|
|
|
static int
|
|
error(const char *name, const char *msg)
|
|
{
|
|
fprintf(stderr, "%s: %s\n", name, msg);
|
|
return 0;
|
|
}
|
|
|
|
enum { MinMatchLength = 4 };
|
|
|
|
unsigned char *raw, *mem;
|
|
|
|
int
|
|
uxn_lz_compress(const void *input, int input_size)
|
|
{
|
|
int i, dict_len, match_len, string_len, match_ctl;
|
|
unsigned char *output_ptr = mem, *combine = 0;
|
|
const unsigned char *dict, *dict_best = 0;
|
|
const unsigned char *in = input, *start = in, *end = in + input_size;
|
|
while(in != end) {
|
|
/* Get available dictionary size (history of original output) */
|
|
dict_len = (int)(in - start);
|
|
if(dict_len > 256)
|
|
dict_len = 256;
|
|
/* Size of the string to search for */
|
|
/* Limit string length to what we can fit in 14 bits, plus the minimum match length */
|
|
string_len = (int)(end - in);
|
|
if(string_len > 0x3FFF + MinMatchLength)
|
|
string_len = 0x3FFF + MinMatchLength;
|
|
/* Iterate through the dictionary */
|
|
match_len = 0;
|
|
dict = in - dict_len;
|
|
for(; dict_len; dict++, dict_len--) {
|
|
/* Find common prefix length with the string */
|
|
/* If we reach the end of the string, this is the best possible match. End. */
|
|
for(i = 0;; i++) {
|
|
if(i == string_len) {
|
|
match_len = i;
|
|
dict_best = dict;
|
|
goto done_search;
|
|
}
|
|
/* Dictionary repeats if we hit the end */
|
|
if(in[i] != dict[i % dict_len])
|
|
break;
|
|
}
|
|
if(i > match_len) {
|
|
match_len = i;
|
|
dict_best = dict;
|
|
}
|
|
}
|
|
done_search:
|
|
/* CPY */
|
|
if(match_len >= MinMatchLength) {
|
|
/* More numeric range: treat 0 as 4, 1 as 5, etc. */
|
|
match_ctl = match_len - MinMatchLength;
|
|
/* CPY2 */
|
|
if(match_ctl > 0x3F) {
|
|
*output_ptr++ = match_ctl >> 8 | 0xc0; /* High byte of the length, with both flags set */
|
|
*output_ptr++ = match_ctl; /* Low byte of the length */
|
|
} else
|
|
*output_ptr++ = match_ctl | 0x80;
|
|
/* offset(0 is -1, 1 is -2, ...) */
|
|
*output_ptr++ = in - dict_best - 1;
|
|
in += match_len; /* Advance input by size of the match */
|
|
combine = 0; /* Disable combining previous literal, if any */
|
|
}
|
|
/* LIT */
|
|
else {
|
|
/* Combine with previous literal */
|
|
if(combine) {
|
|
if(++*combine == 127)
|
|
combine = 0;
|
|
}
|
|
/* Start a new literal */
|
|
else {
|
|
/* Store this address, and later use it to increment the literal size. */
|
|
combine = output_ptr++;
|
|
/* The 0 here means literal of length 1. */
|
|
*combine = 0;
|
|
}
|
|
|
|
/* Write 1 literal byte from the input to the output. */
|
|
*output_ptr++ = *in++;
|
|
}
|
|
}
|
|
return (int)(output_ptr - mem);
|
|
}
|
|
|
|
int
|
|
encode_ulz(FILE *src)
|
|
{
|
|
int length = 0;
|
|
mem = malloc(0x10000), raw = malloc(0x10000);
|
|
while(fread(raw + length, 1, 1, src)) ++length;
|
|
return uxn_lz_compress(raw, length);
|
|
}
|
|
|
|
int
|
|
main(int argc, char *argv[])
|
|
{
|
|
int res;
|
|
FILE *src, *dst;
|
|
if(argv[1][0] == '-' && argv[1][1] == 'v')
|
|
return !fprintf(stdout, "Ulzenc - ULZ Encoder, 15 Nov 2023.\n");
|
|
if(argc != 3)
|
|
return error("usage", "ulzenc [-v] a.bin b.ulz ");
|
|
if(!(src = fopen(argv[1], "rb")))
|
|
return !error("Invalid input file", argv[1]);
|
|
res = encode_ulz(src);
|
|
if(!(dst = fopen(argv[2], "wb")))
|
|
return !error("Invalid output file", argv[1]);
|
|
fwrite(mem, res, 1, dst);
|
|
printf("Compressed %s -> %s(%d bytes).\n", argv[1], argv[2], res);
|
|
return 0;
|
|
} |