path-packer-c/unpack.c

#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;
}