273 lines
6.8 KiB
C
273 lines
6.8 KiB
C
|
|
#include <stdio.h>
|
|
#include <stdlib.h>
|
|
|
|
#include "lz.h"
|
|
|
|
enum { MinMatchLength = 4 };
|
|
|
|
int
|
|
uxn_lz_compress(void *output, int output_size, const void *input, int input_size)
|
|
{
|
|
int dict_len, match_len, i, string_len, match_ctl;
|
|
unsigned char *out = output, *combine = 0;
|
|
const unsigned char *dict, *dict_best = 0, *in = input, *start = in,
|
|
*end = in + input_size;
|
|
while(in != end) {
|
|
dict_len = (int)(in - start); /* Get available dictionary size (history of
|
|
original output) */
|
|
if(dict_len > 256)
|
|
dict_len = 256; /* Limit history lookback to 256 bytes */
|
|
dict = in - dict_len; /* Start of dictionary */
|
|
string_len = (int)(end - in); /* Size of the string to search for */
|
|
if(string_len > 0x3FFF + MinMatchLength)
|
|
string_len = 0x3FFF + MinMatchLength;
|
|
/* ^ Limit string length to what we can fit in 14 bits, plus the minimum
|
|
* match length */
|
|
match_len = 0; /* This will hold the length of our best match */
|
|
for(; dict_len;
|
|
dict += 1, dict_len -= 1) /* Iterate through the dictionary */
|
|
{
|
|
for(i = 0;; i++) /* Find common prefix length with the string */
|
|
{
|
|
if(i == string_len) {
|
|
match_len = i;
|
|
dict_best = dict;
|
|
goto done_search;
|
|
}
|
|
/* ^ If we reach the end of the string, this is the best possible match.
|
|
* End. */
|
|
if(in[i] != dict[i % dict_len])
|
|
break; /* Dictionary repeats if we hit the end */
|
|
}
|
|
if(i > match_len) {
|
|
match_len = i;
|
|
dict_best = dict;
|
|
}
|
|
}
|
|
done_search:
|
|
if(match_len >= MinMatchLength) /* Long enough? Use dictionary match */
|
|
{
|
|
if((output_size -= 2) < 0)
|
|
goto overflow;
|
|
match_ctl =
|
|
match_len -
|
|
MinMatchLength; /* More numeric range: treat 0 as 4, 1 as 5, etc. */
|
|
if(match_ctl >
|
|
0x3F) /* Match is long enough to use 2 bytes for the size */
|
|
{
|
|
if((output_size -= 1) < 0)
|
|
goto overflow;
|
|
*out++ = match_ctl >> 8 | 0x40 |
|
|
0x80; /* High byte of the size, with both flags set */
|
|
*out++ = match_ctl; /* Low byte of the size */
|
|
} else /* Use 1 byte for the size */
|
|
{
|
|
*out++ = match_ctl | 0x80; /* Set the "dictionary" flag */
|
|
}
|
|
*out++ = in - dict_best -
|
|
1; /* Write offset into history. (0 is -1, 1 is -2, ...) */
|
|
in += match_len; /* Advance input by size of the match */
|
|
combine = 0; /* Disable combining previous literal, if any */
|
|
continue;
|
|
}
|
|
if(combine) /* Combine with previous literal */
|
|
{
|
|
if((output_size -= 1) < 0)
|
|
goto overflow;
|
|
if(++*combine == 127)
|
|
combine = 0; /* If the literal hits its size limit, terminate it. */
|
|
} else /* Start a new literal */
|
|
{
|
|
if((output_size -= 2) < 0)
|
|
goto overflow;
|
|
combine = out++; /* Store this address, and later use it to increment the
|
|
literal size. */
|
|
*combine = 0; /* The 0 here means literal of length 1. */
|
|
}
|
|
*out++ = *in++; /* Write 1 literal byte from the input to the output. */
|
|
}
|
|
return (int)(out - (unsigned char *)output);
|
|
overflow:
|
|
return -1;
|
|
}
|
|
|
|
int
|
|
uxn_lz_expand(void *output, int output_size, const void *input, int input_size)
|
|
{
|
|
int num, offset, written = 0;
|
|
unsigned char *out = output;
|
|
const unsigned char *from, *in = input;
|
|
while(input_size) {
|
|
num = *in++;
|
|
if(num > 127) /* Dictionary */
|
|
{
|
|
if((input_size -= 1) < 0)
|
|
goto malformed;
|
|
num &= 0x7F;
|
|
if(num & 0x40) {
|
|
if((input_size -= 1) < 0)
|
|
goto malformed;
|
|
num = *in++ | num << 8 & 0x3FFF;
|
|
}
|
|
num += MinMatchLength;
|
|
offset = *in++ + 1;
|
|
if(offset > written)
|
|
goto malformed;
|
|
from = out + written - offset;
|
|
} else /* Literal */
|
|
{
|
|
input_size -= ++num;
|
|
if(input_size < 0)
|
|
goto malformed;
|
|
from = in, in += num;
|
|
}
|
|
if(written + num > output_size)
|
|
goto overflow;
|
|
while(num--)
|
|
out[written++] = *from++;
|
|
}
|
|
return written;
|
|
overflow:
|
|
malformed:
|
|
return -1;
|
|
}
|
|
|
|
int
|
|
uxn_lz_expand_stream(struct uxn_lz_expand_t *a)
|
|
{
|
|
/* Copy struct to stack variables for compiler optimizations */
|
|
unsigned char *next_in = a->next_in, *next_out = a->next_out;
|
|
int avail_in = a->avail_in, avail_out = a->avail_out;
|
|
int dict_len = a->dict_len, copy_num = a->copy_num;
|
|
unsigned char dict_read_pos = a->dict_read_pos,
|
|
dict_write_pos = a->dict_write_pos, *dict = a->dict;
|
|
int result = 0;
|
|
switch(a->state) {
|
|
case 0:
|
|
for(; avail_in;) {
|
|
copy_num = *next_in++;
|
|
avail_in--;
|
|
if(copy_num > 127) /* Dictionary */
|
|
{
|
|
copy_num &= 0x7F;
|
|
if(copy_num & 0x40) {
|
|
case 1:
|
|
if(!avail_in) {
|
|
a->state = 1;
|
|
goto need_more;
|
|
}
|
|
avail_in--;
|
|
copy_num = *next_in++ | copy_num << 8 & 0x3FFF;
|
|
}
|
|
copy_num += MinMatchLength;
|
|
case 2:
|
|
if(!avail_in) {
|
|
a->state = 2;
|
|
goto need_more;
|
|
}
|
|
avail_in--;
|
|
dict_read_pos = *next_in++ + 1;
|
|
if(dict_read_pos > dict_len) {
|
|
a->state = 5;
|
|
result = -1;
|
|
goto flush;
|
|
} /* Malformed */
|
|
dict_read_pos = dict_write_pos - dict_read_pos;
|
|
if((dict_len += copy_num) > 256)
|
|
dict_len = 256;
|
|
case 3:
|
|
do {
|
|
if(!avail_out) {
|
|
a->state = 3;
|
|
goto need_more;
|
|
}
|
|
*next_out++ = dict[dict_write_pos++] = dict[dict_read_pos++];
|
|
avail_out--;
|
|
} while(--copy_num);
|
|
} else /* Literal */
|
|
{
|
|
copy_num++;
|
|
if((dict_len += copy_num) > 256)
|
|
dict_len = 256;
|
|
case 4:
|
|
do {
|
|
if(!avail_in || !avail_out) {
|
|
a->state = 4;
|
|
goto need_more;
|
|
}
|
|
*next_out++ = dict[dict_write_pos++] = *next_in++;
|
|
avail_in--, avail_out--;
|
|
} while(--copy_num);
|
|
}
|
|
}
|
|
a->state = 0;
|
|
case 5:;
|
|
}
|
|
need_more:
|
|
flush:
|
|
/* Flush stack variables back to struct */
|
|
a->next_in = next_in, a->next_out = next_out;
|
|
a->avail_in = avail_in, a->avail_out = avail_out;
|
|
a->dict_len = dict_len, a->copy_num = copy_num;
|
|
a->dict_read_pos = dict_read_pos, a->dict_write_pos = dict_write_pos;
|
|
return result;
|
|
}
|
|
|
|
unsigned int
|
|
uxn_checksum(unsigned int seed, void *bytes, unsigned int bytes_size)
|
|
{
|
|
unsigned int x = seed >> 16, y = seed, c;
|
|
unsigned char *in = bytes, *end = in + bytes_size;
|
|
for(; in != end; in++) {
|
|
c = *in << 8 | *in;
|
|
x = x * 0x2443 + c;
|
|
y = y * 0x118d + c;
|
|
}
|
|
return x << 16 | (y & 0xFFFF);
|
|
}
|
|
|
|
// cc lz_main.c -o main && ./main
|
|
|
|
int
|
|
main(int argc, char *argv[])
|
|
{
|
|
int enc;
|
|
char *s;
|
|
|
|
char *my_byte_buffer = malloc(1000000);
|
|
FILE *fp = fopen("example.txt", "rb");
|
|
char buffer[1000000];
|
|
size_t i;
|
|
|
|
for(i = 0; i < 1000000; ++i) {
|
|
int c = getc(fp);
|
|
if(c == EOF) {
|
|
buffer[i] = 0x00;
|
|
break;
|
|
}
|
|
buffer[i] = c;
|
|
}
|
|
|
|
int res = uxn_lz_compress(my_byte_buffer, 1000000, &buffer, i);
|
|
if(res < 0)
|
|
printf("ERROR\n");
|
|
printf("!!!%d -> %d\n", i, res);
|
|
|
|
FILE *out_file;
|
|
out_file = fopen("compressed.bin", "wb");
|
|
fwrite(my_byte_buffer, 1, res, out_file);
|
|
fclose(out_file);
|
|
|
|
// Other way
|
|
|
|
char *output2 = malloc(1000000);
|
|
int res2 = uxn_lz_expand(output2, 1000000, &buffer, i);
|
|
|
|
printf("!!!%d -> %d\n", res, res2);
|
|
|
|
//
|
|
|
|
return 0;
|
|
}
|