[C/C#/C++] MD5 Hash Generator

/* Name: MD5Sum 
 * Author: Fallen Angel 
 * Usage: md5sum(.exe) [File,...]
 * Description: Generates the MD5 Hash of the File(s)
 * OS: Windows, Unix/Linux
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <windows.h>
#include "md5.h"

static void print_sig(const unsigned char *sig);
static void read_file(const char *filename);
static void print_intr(void);

int main(int argc, char *argv[])
{
 if(argc < 2 || strcmp(argv[1], "-h") == 0 || strcmp(argv[1],"--help") == 0)
 {
 printf("usage: %s [File,...]",argv[0]);
 exit(EXIT_FAILURE); 
 }

 print_intr(); 
 while(*++argv)
 {
 read_file(*argv); 
 }
 
 printf("\t[+] Hash successfully Generated\n");
 return EXIT_SUCCESS; 
}

static void read_file(const char *filename) 
{
 unsigned char sig[MD5_SIZE];
 char buffer[4096];
 md5_t md5;
 int ret;
 FILE *stream;
 
 if (strcmp(filename, "-") == 0) {
 stream = stdin;
 }
 else {
 stream = fopen(filename, "r");
 if (stream == NULL) {
 perror(filename);
 exit(1);
 }
 }
 
 md5_init(&md5);
 
 while (1) {
 
 ret = fread(buffer, sizeof(char), sizeof(buffer), stream);
 if (ret <= 0)
 break;
 
 md5_process(&md5, buffer, ret);
 }
 
 md5_finish(&md5, sig); 
 
 if (stream != stdin) {
 (void)fclose(stream);
 }
 
 (void)printf("\t|MD5-Hash");
 printf("(%s): '",filename);
 print_sig(sig);
 (void)printf("'\n");
}

static void print_sig(const unsigned char *sig)
{
 const unsigned char *sig_p;
 
 for (sig_p = sig; sig_p < sig + MD5_SIZE; sig_p++) {
 (void)printf("%02x", *sig_p);
 }
}

static void print_intr(void)
{
 printf("\t---- Little MD5 Hash Creator ----\n");
 printf("\n\t[!] Generating Hash\n");
 Sleep(155); 
}