/*
 * Compresses data to the DEFLATE format.
 * The compressed data is ready to use with inflatemem().
 * Compile using e.g.
 * gcc -O2 -o deflater deflater.c -lz
 *
 * Author: Piotr Fusik <fox@scene.pl>
 */
#include <stdio.h>
#include <stdlib.h>
#include <zlib.h>

#define IN_SIZE_MAX 60000U
#define OUT_SIZE_MAX 60000U

int main(int argc, char* argv[])
{
	FILE* fp;
	char* inbuf;
	char* outbuf;
	size_t inlen;
	size_t outlen;
	z_stream stream;

	/* check command line */
	if (argc != 3) {
		fprintf(stderr,
			"Compresses a file to the DEFLATE format.\n"
			"24 Aug 2002, Piotr Fusik <fox@scene.pl>\n"
			"Usage: deflater input_file deflated_file\n"
		);
		return 3;
	}

	/* alloc buffers */
	inbuf = malloc(IN_SIZE_MAX);
	outbuf = malloc(OUT_SIZE_MAX);
	if (inbuf == NULL || outbuf == NULL) {
		fprintf(stderr, "deflater: Out of memory!\n");
		return 1;
	}

	/* read input file */
	fp = fopen(argv[1], "rb");
	if (fp == NULL) {
		perror(argv[1]);
		return 1;
	}
	inlen = fread(inbuf, 1, IN_SIZE_MAX, fp);
	fclose(fp);

	/* compress */
	stream.next_in = inbuf;
	stream.avail_in = inlen;
	stream.next_out = outbuf;
	stream.avail_out = OUT_SIZE_MAX;
	stream.zalloc = (alloc_func) 0;
	stream.zfree = (free_func) 0;
	if (deflateInit2(&stream, Z_BEST_COMPRESSION, Z_DEFLATED,
		-MAX_WBITS, 9, Z_DEFAULT_STRATEGY) != Z_OK) {
		fprintf(stderr, "deflater: deflateInit2 failed\n");
		return 1;
	}
	if (deflate(&stream, Z_FINISH) != Z_STREAM_END) {
		fprintf(stderr, "deflater: deflate failed\n");
		return 1;
	}
	if (deflateEnd(&stream) != Z_OK) {
		fprintf(stderr, "deflater: deflateEnd failed\n");
		return 1;
	}

	/* write output */
	fp = fopen(argv[2], "wb");
	if (fp == NULL) {
		perror(argv[2]);
		return 1;
	}
	outlen = fwrite(outbuf, 1, stream.total_out, fp);
	fclose(fp);
	if (outlen != stream.total_out) {
		perror(argv[2]);
		return 1;
	}

	/* display summary */
	printf("Compressed %s (%d bytes) to %s (%d bytes)\n",
		argv[1], inlen, argv[2], outlen);
	return 0;
}
