www.pudn.com > sha1.zip > shacmp.cpp

/* 
 *	shacmp.cpp 
 * 
 *	Copyright (C) 1998 
 *	Paul E. Jones  
 *	All Rights Reserved 
 * 
 ***************************************************************************** 
 *	$Id: shacmp.cpp,v 1.5 2004/03/27 18:09:09 paulej Exp $ 
 ***************************************************************************** 
 * 
 *	Description: 
 * 		This utility will compare two files by producing a message digest 
 * 		for each file using the Secure Hashing Algorithm and comparing 
 * 		the message digests.  This function will return 0 if they 
 * 		compare or 1 if they do not or if there is an error. 
 * 		Errors result in a return code higher than 1. 
 * 
 *	Portability Issues: 
 *		none. 
 * 
 */ 
 
#include  
#include  
#include "sha1.h" 
 
/* 
 *	Return codes 
 */ 
#define SHA1_COMPARE		0 
#define SHA1_NO_COMPARE		1 
#define SHA1_USAGE_ERROR	2 
#define SHA1_FILE_ERROR		3 
 
/* 
 *	Function prototype 
 */ 
void usage(); 
 
/*	 
 *	main 
 * 
 *	Description: 
 *		This is the entry point for the program 
 * 
 *	Parameters: 
 *		argc: [in] 
 *			This is the count of arguments in the argv array 
 *		argv: [in] 
 *			This is an array of filenames for which to compute message digests 
 * 
 *	Returns: 
 *		Nothing. 
 * 
 *	Comments: 
 * 
 */ 
int main(int argc, char *argv[]) 
{ 
	SHA1		sha;						// SHA-1 class 
	FILE		*fp;						// File pointer for reading files 
	char		c;							// Character read from file 
	unsigned	message_digest[2][5];		// Message digest for files 
	int			i;							// Counter 
	bool		message_match;				// Message digest match flag 
	int			returncode; 
 
	/* 
	 *	If we have two arguments, we will assume they are filenames.  If 
	 *	we do not have to arguments, call usage() and exit. 
	 */ 
	if (argc != 3) 
	{ 
		usage(); 
		return SHA1_USAGE_ERROR; 
	} 
 
	/* 
	 *	Get the message digests for each file 
	 */ 
	for(i = 1; i <= 2; i++) 
	{ 
		sha.Reset(); 
 
		if (!(fp = fopen(argv[i],"rb"))) 
		{ 
			fprintf(stderr, "sha: unable to open file %s\n", argv[i]); 
			return SHA1_FILE_ERROR; 
		} 
 
		c = fgetc(fp); 
		while(!feof(fp)) 
		{ 
			sha.Input(c); 
			c = fgetc(fp); 
		} 
 
		fclose(fp); 
 
		if (!sha.Result(message_digest[i-1])) 
		{ 
			fprintf(stderr,"shacmp: could not compute message digest for %s\n", 
			  		argv[i]); 
			return SHA1_FILE_ERROR; 
		} 
	} 
 
	/* 
	 *	Compare the message digest values 
	 */ 
	message_match = true; 
	for(i = 0; i < 5; i++) 
	{ 
		if (message_digest[0][i] != message_digest[1][i]) 
		{ 
			message_match = false; 
			break; 
		} 
	} 
 
	if (message_match) 
	{ 
		printf("Fingerprints match:\n"); 
		returncode = SHA1_COMPARE; 
	} 
	else 
	{ 
		printf("Fingerprints do not match:\n"); 
		returncode = SHA1_NO_COMPARE; 
	} 
 
	printf(	"\t%08X %08X %08X %08X %08X\n", 
			message_digest[0][0], 
			message_digest[0][1], 
			message_digest[0][2], 
			message_digest[0][3], 
			message_digest[0][4]); 
	printf(	"\t%08X %08X %08X %08X %08X\n", 
			message_digest[1][0], 
			message_digest[1][1], 
			message_digest[1][2], 
			message_digest[1][3], 
			message_digest[1][4]); 
 
	return returncode; 
} 
 
/*	 
 *	usage 
 * 
 *	Description: 
 *		This function will display program usage information to the user. 
 * 
 *	Parameters: 
 *		None. 
 * 
 *	Returns: 
 *		Nothing. 
 * 
 *	Comments: 
 * 
 */ 
void usage() 
{ 
	printf("usage: shacmp  \n"); 
	printf("\tThis program will compare the message digests (fingerprints)\n"); 
	printf("\tfor two files using the Secure Hashing Algorithm (SHA-1).\n"); 
}