Add start of C based decoder

This commit is contained in:
James Bowes 2012-07-28 10:51:53 -03:00
parent 427caabb1b
commit a8a7fd57f6
2 changed files with 149 additions and 0 deletions

4
Makefile Normal file
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CFLAGS=`pkg-config --libs --cflags zlib`
unpack: unpack.c
gcc -Wall $(CFLAGS) -o unpack unpack.c

145
unpack.c Normal file
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#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include <zlib.h>
#define CHUNK 1024
struct node {
struct node *next;
unsigned int path;
unsigned int children[];
};
static int
load_dictionary(FILE *source, unsigned char **dictionary) {
int ret;
unsigned have;
z_stream strm;
unsigned char in[CHUNK];
int read = 0;
unsigned char *buf = malloc(sizeof(char) * CHUNK);
*dictionary = buf;
printf("unpacking string dictionary\n");
/* allocate inflate state */
strm.zalloc = Z_NULL;
strm.zfree = Z_NULL;
strm.opaque = Z_NULL;
strm.avail_in = 0;
strm.next_in = Z_NULL;
ret = inflateInit(&strm);
if (ret != Z_OK) {
printf("ERROR\n");
return ret;
}
/* decompress until deflate stream ends or end of file */
do {
strm.avail_in = fread(in, 1, CHUNK, source);
if (ferror(source)) {
(void)inflateEnd(&strm);
return -1;
}
if (strm.avail_in == 0) {
printf("read entire file\n");
break;
}
strm.next_in = in;
/* run inflate() on input until output buffer not full */
do {
strm.avail_out = CHUNK;
strm.next_out = buf;
ret = inflate(&strm, Z_NO_FLUSH);
assert(ret != Z_STREAM_ERROR); /* state not clobbered */
switch (ret) {
case Z_NEED_DICT:
printf("NEED ERROR\n");
ret = Z_DATA_ERROR; /* and fall through */
case Z_DATA_ERROR:
printf("DATA ERROR\n");
case Z_MEM_ERROR:
(void)inflateEnd(&strm);
printf("MEMORY ERROR\n");
return -1;
}
have = CHUNK - strm.avail_out;
read += CHUNK - strm.avail_out;
} while (strm.avail_out == 0);
// read += CHUNK;
/* done when inflate() says it's done */
} while (ret != Z_STREAM_END);
printf("data is:\n");
int i;
for (i=0; i < read; i++) {
if (buf[i] == '\0') {
putchar('\n');
} else {
putchar(buf[i]);
}
}
// rewind back to unused zlib bytes
if (fseek(source, (long) strm.avail_in * -1, SEEK_CUR)) {
printf("Error seeking back in stream\n");
return -1;
}
printf ("dictionary stats:\n");
printf ("\tcompressed size: %zu\n", ftell(source));
printf ("\tuncompressed size: %d\n", read);
inflateEnd(&strm);
return ret == Z_STREAM_END ? 0 : -1;
}
static int
load_node_list(FILE *stream, struct node **list) {
unsigned char buf[CHUNK];
size_t read;
struct node *np = malloc(sizeof(struct node));
*list = np;
read = fread(buf, 1, CHUNK, stream);
printf("Read %zu bytes\n", read);
return 0;
}
int
main(int argc, char **argv) {
FILE *fp;
unsigned char *dictionary;
struct node *list;
if (argc != 2) {
printf("usage: unpack <bin file>\n");
return -1;
}
fp = fopen(argv[1], "r");
if (fp == NULL) {
printf("error: unable to open file: %s\n", argv[1]);
return -1;
}
if (load_dictionary(fp, &dictionary)) {
printf("dictionary inflation failed. exiting\n");
return -1;
}
if (load_node_list(fp, &list)) {
printf("node list parsing failed. exiting\n");
return -1;
}
return 0;
}