bnprint.c

著名的加密软件的应用于电子邮件中

/*
* bnprint.c - Print a bignum, for debugging purposes.
*
* Copyright (C) 1995-1997 Pretty Good Privacy, Inc. All rights reserved.
*
* Written by Colin Plumb.
*
* $Id: bnprint.c,v 1.17.2.1 1997/06/07 09:49:41 mhw Exp $
*/
#ifndef HAVE_CONFIG_H
#define HAVE_CONFIG_H 0
#endif
#if HAVE_CONFIG_H
#include "config.h"
#endif

/*
* Some compilers complain about #if FOO if FOO isn't defined,
* so do the ANSI-mandated thing explicitly...
*/
#ifndef NO_STRING_H
#define NO_STRING_H 0
#endif
#ifndef HAVE_STRINGS_H
#define HAVE_STRINGS_H 0
#endif

#include <stdio.h>

#if !NO_STRING_H
#include <string.h>
#elif HAVE_STRINGS_H
#include <strings.h>
#endif

#include "bn.h"
#include "bnprint.h"

#include "bnkludge.h"

int
bnPrint(FILE *f, char const *prefix, struct BigNum const *bn,
			char const *suffix)
	{
			unsigned char temp[32];	/* How much to print on one line */
			unsigned len;
			size_t i;

			if (prefix && fputs(prefix, f) < 0)
				 return EOF;

			len = (bnBits(bn) + 7)/ 8;

			if (!len) {
				 if (putc('0', f) < 0)
				 	return EOF;
			} else {
				 while (len > sizeof(temp)) {
							len -= sizeof(temp);
							bnExtractBigBytes(bn, temp, len, sizeof(temp));
							for (i = 0; i < sizeof(temp); i++)
								 if (fprintf(f, "%02X", temp[i]) < 0)
								 	return EOF;
							if (putc('\\', f) < 0 || putc('\n', f) < 0)
								 return EOF;
							if (prefix) {
									i = strlen(prefix);
									while (i--)
										if (putc(' ', f) < 0)
											 return EOF;
							}
					}
					bnExtractBigBytes(bn, temp, 0, len);
					for (i = 0; i < len; i++)
						if (fprintf(f, "%02X", temp[i]) < 0)
							 return EOF;
			}
			return suffix ?	fputs(suffix, f) : 0;
	}


	int
bnPrint10(FILE *f, char const *prefix, struct BigNum const *bn,
			char const *suffix)
	{
			struct BigNum pbig, pbig1;
			struct BigNum ten, zero, rem;
			char buf[3000];		 		/* up to 9000 bits */
			int bufi = sizeof(buf)-1;
			int n;

			buf[bufi] = '\0';
			bnBegin (&pbig);
			bnBegin (&pbig1);
			bnBegin (&rem);
		
			bnBegin (&ten);
			bnAddQ (&ten, 10);
			bnBegin (&zero);

			bnCopy (&pbig, bn);
		
			while (bnCmp (&pbig, &zero) != 0) {
					bnDivMod (&pbig1, &rem, &pbig, &ten);
					bnCopy (&pbig, &pbig1);
					n = bnLSWord (&rem);
					buf[--bufi] = n + '0';
			}

			bnEnd (&pbig);
			bnEnd (&pbig1);
			bnEnd (&rem);

			if (prefix && fputs(prefix, f) < 0)
				 return EOF;

fputs (buf+bufi, f);
memset (buf, 0, sizeof(buf));

return suffix ?	fputs(suffix, f) : 0;
}