// SPDX-License-Identifier: WTFPL
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>

typedef uint32_t UW;
typedef int32_t W;
typedef uint8_t UB;
#define IMPORT extern

#include "bzcomp.h"	/* use $(BD)/include/bzcomp.h */

static size_t filesize;
static UB *buf;

static int loadfile(char *filename)
{
	FILE *fp;

	fp = fopen(filename, "r");
	if (fp == NULL) {
		printf("loadfile: %s open error\n", filename);
		return -1;
	}

	fseek(fp, 0, SEEK_END);
	filesize = ftell(fp);
	fseek(fp, 0, SEEK_SET);

	buf = malloc(filesize);
	if (buf == NULL) goto fin0;

	fread(buf, filesize, 1, fp);
fin0:
	fclose(fp);

	return 0;
}

static int savefile(char *filename, void *buffer, size_t size)
{
	FILE *fp;  

	fp = fopen(filename, "w");
	if (fp == NULL) {
		printf("savefile: %s open error\n", filename);
		return -1;
	}

	fwrite(buffer, size, 1, fp);
	fclose(fp);
	return 0;
}

int main(int argc, char *argv[])
{
	UB *out;
	Bz_HDR *h;

	if (argc < 3) {
		printf("%s: usage [infile] [outfile]\n", argv[0]);
		goto fin0;
	}

	if (loadfile(argv[1]) < 0 || buf == NULL) {
		printf("file read error\n");
		goto fin0;
	}

	h = (Bz_HDR *)buf;
	if ((h->magic1 != BzMAGIC1 && h->magic1 != BzMAGIC1S) ||
	    h->magic2 != BzMAGIC2 || h->magic3 != BzMAGIC3) {
		printf("invalid file header\n");
		goto fin0;
	}

	if ((out = malloc(h->expsz)) == NULL) {
		printf("malloc failed (out)\n");
		goto fin1;
	}

	bz_uncompress(out, buf + sizeof(Bz_HDR),
		      h->expsz, filesize - sizeof(Bz_HDR));

	savefile(argv[2], out, h->expsz);

	free(out);
fin1:
	free(buf);
fin0:
	return 0;
}