A small program to dump the contents of a binary file in hex or to a C header

xdmp.c

/*
* $ gcc -o xdmp.exe xdmp.c
*/
#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#include <unistd.h>

unsigned char *read_file(const char *fname, size_t *plen) {
	FILE *f;
	size_t len,r;
	unsigned char *bytes;

	if(plen)
		*plen = 0;

	if(!(f = fopen(fname, "rb")))
		return NULL;

	fseek(f, 0, SEEK_END);
	len = ftell(f);
	rewind(f);

	if(!(bytes = malloc(len+2)))
		return NULL;
	r = fread(bytes, 1, len, f);

	if(r != len) {
		free(bytes);
		return NULL;
	}

	fclose(f);
	bytes[len] = '\0';

	if(plen)
		*plen = len;

	return bytes;
}

void usage(const char *exe) {
	fprintf(stderr, "Usage: %s [-c] file...\n", exe);
	fprintf(stderr, "Where:\n");
	fprintf(stderr, "     -c    - outputs file as C code\n");
}

void dump_file_x(const char *name, unsigned char *bytes, size_t len) {
	printf("** File: %s; Size: %u bytes\n", name, len);
	size_t i, j;
	for(i = 0; i < (len >> 4) + 1; i++) {
		if(len > 0xFFFF)
			printf("%08X: ", i << 4);
		else
			printf("%04X: ", i << 4);

		for(j = 0; j < 16; j++) {
			size_t a = (i << 4) + j;
			if(a >= len) break;
			if(j == 8)
				printf(" ");
			printf("%02X ", bytes[a]);
		}

		for(; j < 16; j++) {
			fputs("   ", stdout);
		}

		fputs(" ", stdout);
		for(j = 0; j < 16; j++) {
			size_t a = (i << 4) + j;
			if(a >= len) break;
			if(j == 8)
				printf(" ");
			printf("%c", isprint(bytes[a])?bytes[a]:'.');
		}
		printf("\n");
	}
}

void dump_file_code(const char *name, unsigned char *bytes, size_t len) {
	char varname[50];
	snprintf(varname, sizeof varname, "%s", name);
	size_t i, j;
	for(i = 0; varname[i]; i++) {
		if(!isalnum(varname[i]))
			varname[i] = '_';
	}

	printf("/* File: %s; Size: %u bytes */\n", name, len);
	printf("static const unsigned char %s[] = {\n", varname);
	for(i = 0; i < (len >> 4) + 1; i++) {
		for(j = 0; j < 16; j++) {
			size_t a = (i << 4) + j;
			if(a >= len) break;
			if(j == 8)
				printf(" ");
			printf("0x%02X, ", bytes[a]);
		}
		printf("\n");
	}
	printf("};\nstatic long %s_len = %u;\n", varname, len);
}

int main(int argc, char *argv[]) {

	int opt, code_mode = 0;

	while((opt = getopt(argc, argv, "c?")) != -1) {
		switch(opt) {
			case 'c': {
				code_mode = 1;
			} break;
			case '?' : {
				usage(argv[0]);
				return 1;
			}
		}
	}

	if(optind >= argc) {
		usage(argv[0]);
		return 1;
	}
	int f;
	for(f = optind; f < argc; f++) {
		size_t len;

		unsigned char *bytes = read_file(argv[f], &len);
		if(!bytes) {
			fprintf(stderr, "error: unable to read '%s'\n", argv[f]);
			return 1;
		}

		if(f > 1) fputs("\n", stdout);
		if(code_mode)
			dump_file_code(argv[f], bytes, len);
		else
			dump_file_x(argv[f], bytes, len);

		free(bytes);
	}

	return 0;
}