panorepack.c

#include "crc32.h"
#include "stupidvalve.h"
#include <stdio.h>

int main(int argc, char **argv) {
	if (argc < 4) {
		fprintf(stderr,
		        "Usage: ./panorepack oldfile newcontents outputfile\n");
		exit(1);
	}
	filedata *fd = loadfile(argv[1]);
	if (fd->filetype != SVF) {
		fprintf(stderr, "Error: oldfile must be valid SVF file\n");
		exit(4);
	}
	char *newcontents;
	uint64_t newlen = readintobuf(argv[2], &newcontents);
	svffile_generic *ret = fd->parsed;
	// find the data lump header
	uint32_t i;
	for (i = 0; i < ret->hdr->lumps.count; i++) {
		if (strncmp(ret->lumpheaders[i].tag, "DATA", 4) == 0) {
			break;
		}
	}
	if (i == ret->hdr->lumps.count) {
		fprintf(stderr, "Error: No DATA lump found in input file!\n");
		exit(8);
	}
	uint64_t headerlen = fd->length - ret->lumpheaders[i].length;
	uint64_t newtotallen = headerlen + newlen + 6;
	char *newbuff = (char *)calloc(sizeof(char), newtotallen);
	ret->lumpheaders[i].length = newlen + 6;
	memcpy(newbuff, fd->contents, headerlen);
	memcpy(newbuff + headerlen + 6, newcontents, newlen);
	*(uint32_t *)(newbuff + headerlen) = crc32(0, newcontents, newlen);
	*(uint32_t *)newbuff = newtotallen;
	FILE *of = fopen(argv[3], "w");
	if (of == NULL) {
		fprintf(stderr,
		        "Error: Unable to open output file %s for writing!\n",
		        argv[3]);
		exit(16);
	}
	fwrite(newbuff, sizeof(char), newtotallen, of);
	fclose(of);
	free(newbuff);
	free(newcontents);
	fd_free(fd);
}