Head

GCC Code Coverage Report

Directory:	./		Exec	Total	Coverage
File:	lib/libcrypto/bn/bn_add.c	Lines:	104	115	90.4 %
Date:	2017-11-07	Branches:	73	84	86.9 %


/* $OpenBSD: bn_add.c,v 1.11 2017/01/29 17:49:22 beck Exp $ */
/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
 * All rights reserved.
 *
 * This package is an SSL implementation written
 * by Eric Young (eay@cryptsoft.com).
 * The implementation was written so as to conform with Netscapes SSL.
 *
 * This library is free for commercial and non-commercial use as long as
 * the following conditions are aheared to.  The following conditions
 * apply to all code found in this distribution, be it the RC4, RSA,
 * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
 * included with this distribution is covered by the same copyright terms
 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
 *
 * Copyright remains Eric Young's, and as such any Copyright notices in
 * the code are not to be removed.
 * If this package is used in a product, Eric Young should be given attribution
 * as the author of the parts of the library used.
 * This can be in the form of a textual message at program startup or
 * in documentation (online or textual) provided with the package.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *    "This product includes cryptographic software written by
 *     Eric Young (eay@cryptsoft.com)"
 *    The word 'cryptographic' can be left out if the rouines from the library
 *    being used are not cryptographic related :-).
 * 4. If you include any Windows specific code (or a derivative thereof) from
 *    the apps directory (application code) you must include an acknowledgement:
 *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
 *
 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * The licence and distribution terms for any publically available version or
 * derivative of this code cannot be changed.  i.e. this code cannot simply be
 * copied and put under another distribution licence
 * [including the GNU Public Licence.]
 */

#include <stdio.h>

#include <openssl/err.h>

#include "bn_lcl.h"

/* r can == a or b */
int
BN_add(BIGNUM *r, const BIGNUM *a, const BIGNUM *b)
{
	const BIGNUM *tmp;
	int a_neg = a->neg, ret;

	bn_check_top(a);
	bn_check_top(b);

	/*  a +  b	a+b
	 *  a + -b	a-b
	 * -a +  b	b-a
	 * -a + -b	-(a+b)
	 */
	if (a_neg ^ b->neg) {
		/* only one is negative */
		if (a_neg)
				{ tmp = a;
			a = b;
			b = tmp;
		}

		/* we are now a - b */

		if (BN_ucmp(a, b) < 0) {
			if (!BN_usub(r, b, a))
				return (0);
			r->neg = 1;
		} else {
			if (!BN_usub(r, a, b))
				return (0);
			r->neg = 0;
		}
		return (1);
	}

	ret = BN_uadd(r, a, b);
	r->neg = a_neg;
	bn_check_top(r);
	return ret;
}

/* unsigned add of b to a */
int
BN_uadd(BIGNUM *r, const BIGNUM *a, const BIGNUM *b)
{
	int max, min, dif;
	BN_ULONG *ap, *bp, *rp, carry, t1, t2;
	const BIGNUM *tmp;

	bn_check_top(a);
	bn_check_top(b);

	if (a->top < b->top) {
		tmp = a;
		a = b;
		b = tmp;
	}
	max = a->top;
	min = b->top;
	dif = max - min;

	if (bn_wexpand(r, max + 1) == NULL)
		return 0;

	r->top = max;

	ap = a->d;
	bp = b->d;
	rp = r->d;

	carry = bn_add_words(rp, ap, bp, min);
	rp += min;
	ap += min;
	bp += min;

	if (carry) {
		while (dif) {
			dif--;
			t1 = *(ap++);
			t2 = (t1 + 1) & BN_MASK2;
			*(rp++) = t2;
			if (t2) {
				carry = 0;
				break;
			}
		}
		if (carry) {
			/* carry != 0 => dif == 0 */
			*rp = 1;
			r->top++;
		}
	}
	if (dif && rp != ap)
		while (dif--)
			/* copy remaining words if ap != rp */
			*(rp++) = *(ap++);
	r->neg = 0;
	bn_check_top(r);
	return 1;
}

/* unsigned subtraction of b from a, a must be larger than b. */
int
BN_usub(BIGNUM *r, const BIGNUM *a, const BIGNUM *b)
{
	int max, min, dif;
	BN_ULONG t1, t2, *ap, *bp, *rp;
	int i, carry;

	bn_check_top(a);
	bn_check_top(b);

	max = a->top;
	min = b->top;
	dif = max - min;

	if (dif < 0)	/* hmm... should not be happening */
	{
		BNerror(BN_R_ARG2_LT_ARG3);
		return (0);
	}

	if (bn_wexpand(r, max) == NULL)
		return (0);

	ap = a->d;
	bp = b->d;
	rp = r->d;

#if 1
	carry = 0;
	for (i = min; i != 0; i--) {
		t1= *(ap++);
		t2= *(bp++);
		if (carry) {
			carry = (t1 <= t2);
			t1 = (t1 - t2 - 1)&BN_MASK2;
		} else {
			carry = (t1 < t2);
			t1 = (t1 - t2)&BN_MASK2;
		}
		*(rp++) = t1&BN_MASK2;
	}
#else
	carry = bn_sub_words(rp, ap, bp, min);
	ap += min;
	bp += min;
	rp += min;
#endif
	if (carry) /* subtracted */
	{
		if (!dif)
			/* error: a < b */
			return 0;
		while (dif) {
			dif--;
			t1 = *(ap++);
			t2 = (t1 - 1)&BN_MASK2;
			*(rp++) = t2;
			if (t1)
				break;
		}
	}
#if 0
	memcpy(rp, ap, sizeof(*rp)*(max - i));
#else
	if (rp != ap) {
		for (;;) {
			if (!dif--)
				break;
			rp[0] = ap[0];
			if (!dif--)
				break;
			rp[1] = ap[1];
			if (!dif--)
				break;
			rp[2] = ap[2];
			if (!dif--)
				break;
			rp[3] = ap[3];
			rp += 4;
			ap += 4;
		}
	}
#endif

	r->top = max;
	r->neg = 0;
	bn_correct_top(r);
	return (1);
}

int
BN_sub(BIGNUM *r, const BIGNUM *a, const BIGNUM *b)
{
	int max;
	int add = 0, neg = 0;
	const BIGNUM *tmp;

	bn_check_top(a);
	bn_check_top(b);

	/*  a -  b	a-b
	 *  a - -b	a+b
	 * -a -  b	-(a+b)
	 * -a - -b	b-a
	 */
	if (a->neg) {
		if (b->neg) {
			tmp = a;
			a = b;
			b = tmp;
		} else {
			add = 1;
			neg = 1;
		}
	} else {
		if (b->neg) {
			add = 1;
			neg = 0;
		}
	}

	if (add) {
		if (!BN_uadd(r, a, b))
			return (0);
		r->neg = neg;
		return (1);
	}

	/* We are actually doing a - b :-) */

	max = (a->top > b->top) ? a->top : b->top;
	if (bn_wexpand(r, max) == NULL)
		return (0);
	if (BN_ucmp(a, b) < 0) {
		if (!BN_usub(r, b, a))
			return (0);
		r->neg = 1;
	} else {
		if (!BN_usub(r, a, b))
			return (0);
		r->neg = 0;
	}
	bn_check_top(r);
	return (1);
}


Generated by: GCOVR (Version 3.3)

Line	Branch	Exec	Source
1			/* $OpenBSD: bn_add.c,v 1.11 2017/01/29 17:49:22 beck Exp $ */
2			/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
3			* All rights reserved.
4			*
5			* This package is an SSL implementation written
6			* by Eric Young (eay@cryptsoft.com).
7			* The implementation was written so as to conform with Netscapes SSL.
8			*
9			* This library is free for commercial and non-commercial use as long as
10			* the following conditions are aheared to. The following conditions
11			* apply to all code found in this distribution, be it the RC4, RSA,
12			* lhash, DES, etc., code; not just the SSL code. The SSL documentation
13			* included with this distribution is covered by the same copyright terms
14			* except that the holder is Tim Hudson (tjh@cryptsoft.com).
15			*
16			* Copyright remains Eric Young's, and as such any Copyright notices in
17			* the code are not to be removed.
18			* If this package is used in a product, Eric Young should be given attribution
19			* as the author of the parts of the library used.
20			* This can be in the form of a textual message at program startup or
21			* in documentation (online or textual) provided with the package.
22			*
23			* Redistribution and use in source and binary forms, with or without
24			* modification, are permitted provided that the following conditions
25			* are met:
26			* 1. Redistributions of source code must retain the copyright
27			* notice, this list of conditions and the following disclaimer.
28			* 2. Redistributions in binary form must reproduce the above copyright
29			* notice, this list of conditions and the following disclaimer in the
30			* documentation and/or other materials provided with the distribution.
31			* 3. All advertising materials mentioning features or use of this software
32			* must display the following acknowledgement:
33			* "This product includes cryptographic software written by
34			* Eric Young (eay@cryptsoft.com)"
35			* The word 'cryptographic' can be left out if the rouines from the library
36			* being used are not cryptographic related :-).
37			* 4. If you include any Windows specific code (or a derivative thereof) from
38			* the apps directory (application code) you must include an acknowledgement:
39			* "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
40			*
41			* THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
42			* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
43			* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
44			* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
45			* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
46			* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
47			* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
48			* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
49			* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
50			* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
51			* SUCH DAMAGE.
52			*
53			* The licence and distribution terms for any publically available version or
54			* derivative of this code cannot be changed. i.e. this code cannot simply be
55			* copied and put under another distribution licence
56			* [including the GNU Public Licence.]
57			*/
58
59			#include <stdio.h>
60
61			#include <openssl/err.h>
62
63			#include "bn_lcl.h"
64
65			/* r can == a or b */
66			int
67			BN_add(BIGNUM r, const BIGNUM a, const BIGNUM *b)
68			{
69			const BIGNUM *tmp;
70		20231226	int a_neg = a->neg, ret;
71
72			bn_check_top(a);
73			bn_check_top(b);
74
75			/* a + b a+b
76			* a + -b a-b
77			* -a + b b-a
78			* -a + -b -(a+b)
79			*/
80	✓✓	10115613	if (a_neg ^ b->neg) {
81			/* only one is negative */
82	✓✓	3930268	if (a_neg)
83			{ tmp = a;
84			a = b;
85			b = tmp;
86		3929462	}
87
88			/* we are now a - b */
89
90	✓✓	3930268	if (BN_ucmp(a, b) < 0) {
91	✗✓	510	if (!BN_usub(r, b, a))
92			return (0);
93			r->neg = 1;
94		510	} else {
95	✗✓	3929758	if (!BN_usub(r, a, b))
96			return (0);
97			r->neg = 0;
98			}
99		3930268	return (1);
100			}
101
102		6185345	ret = BN_uadd(r, a, b);
103		6185345	r->neg = a_neg;
104			bn_check_top(r);
105		6185345	return ret;
106		10115613	}
107
108			/* unsigned add of b to a */
109			int
110			BN_uadd(BIGNUM r, const BIGNUM a, const BIGNUM *b)
111			{
112			int max, min, dif;
113			BN_ULONG ap, bp, *rp, carry, t1, t2;
114			const BIGNUM *tmp;
115
116			bn_check_top(a);
117			bn_check_top(b);
118
119	✓✓	20156948	if (a->top < b->top) {
120			tmp = a;
121			a = b;
122			b = tmp;
123		83930	}
124		10078474	max = a->top;
125		10078474	min = b->top;
126		10078474	dif = max - min;
127
128	✓✓✗✓	20198816	if (bn_wexpand(r, max + 1) == NULL)
129			return 0;
130
131		10078474	r->top = max;
132
133		10078474	ap = a->d;
134		10078474	bp = b->d;
135		10078474	rp = r->d;
136
137		10078474	carry = bn_add_words(rp, ap, bp, min);
138		10078474	rp += min;
139		10078474	ap += min;
140			bp += min;
141
142	✓✓	10078474	if (carry) {
143	✓✓	1302542	while (dif) {
144		58313	dif--;
145		58313	t1 = *(ap++);
146		58313	t2 = (t1 + 1) & BN_MASK2;
147		58313	*(rp++) = t2;
148	✓✓	58313	if (t2) {
149			carry = 0;
150		56870	break;
151			}
152			}
153	✓✓	1301099	if (carry) {
154			/* carry != 0 => dif == 0 */
155		1244229	*rp = 1;
156		1244229	r->top++;
157		1244229	}
158			}
159	✓✓✓✓	11662748	if (dif && rp != ap)
160	✓✓	1401640	while (dif--)
161			/* copy remaining words if ap != rp */
162		644432	(rp++) = (ap++);
163		10078474	r->neg = 0;
164			bn_check_top(r);
165		10078474	return 1;
166		10078474	}
167
168			/* unsigned subtraction of b from a, a must be larger than b. */
169			int
170			BN_usub(BIGNUM r, const BIGNUM a, const BIGNUM *b)
171			{
172			int max, min, dif;
173			BN_ULONG t1, t2, ap, bp, *rp;
174			int i, carry;
175
176			bn_check_top(a);
177			bn_check_top(b);
178
179		43838262	max = a->top;
180		21919131	min = b->top;
181		21919131	dif = max - min;
182
183	✗✓	21919131	if (dif < 0) /* hmm... should not be happening */
184			{
185			BNerror(BN_R_ARG2_LT_ARG3);
186			return (0);
187			}
188
189	✓✓✗✓	43839224	if (bn_wexpand(r, max) == NULL)
190			return (0);
191
192		21919131	ap = a->d;
193		21919131	bp = b->d;
194		21919131	rp = r->d;
195
196			#if 1
197			carry = 0;
198	✓✓	275525748	for (i = min; i != 0; i--) {
199		115843743	t1= *(ap++);
200		115843743	t2= *(bp++);
201	✓✓	115843743	if (carry) {
202		44607797	carry = (t1 <= t2);
203		44607797	t1 = (t1 - t2 - 1)&BN_MASK2;
204		44607797	} else {
205		71235946	carry = (t1 < t2);
206		71235946	t1 = (t1 - t2)&BN_MASK2;
207			}
208		115843743	*(rp++) = t1&BN_MASK2;
209			}
210			#else
211			carry = bn_sub_words(rp, ap, bp, min);
212			ap += min;
213			bp += min;
214			rp += min;
215			#endif
216	✓✓	21919131	if (carry) /* subtracted */
217			{
218	✗✓	5317357	if (!dif)
219			/* error: a < b */
220			return 0;
221	✓✗	10635101	while (dif) {
222		5317744	dif--;
223		5317744	t1 = *(ap++);
224		5317744	t2 = (t1 - 1)&BN_MASK2;
225		5317744	*(rp++) = t2;
226	✓✓	10635488	if (t1)
227			break;
228			}
229			}
230			#if 0
231			memcpy(rp, ap, sizeof(rp)(max - i));
232			#else
233	✓✓	21919131	if (rp != ap) {
234		9454	for (;;) {
235	✓✓	11695711	if (!dif--)
236			break;
237		21598	rp[0] = ap[0];
238	✓✓	21598	if (!dif--)
239			break;
240		14806	rp[1] = ap[1];
241	✓✓	14806	if (!dif--)
242			break;
243		11442	rp[2] = ap[2];
244	✓✓	11442	if (!dif--)
245			break;
246		9454	rp[3] = ap[3];
247		9454	rp += 4;
248		9454	ap += 4;
249			}
250			}
251			#endif
252
253		21919131	r->top = max;
254		21919131	r->neg = 0;
255	✓✓✓✓ ✓✓	144837207	bn_correct_top(r);
256		21919131	return (1);
257		21919131	}
258
259			int
260			BN_sub(BIGNUM r, const BIGNUM a, const BIGNUM *b)
261			{
262			int max;
263			int add = 0, neg = 0;
264			const BIGNUM *tmp;
265
266			bn_check_top(a);
267			bn_check_top(b);
268
269			/* a - b a-b
270			* a - -b a+b
271			* -a - b -(a+b)
272			* -a - -b b-a
273			*/
274	✓✓	28859976	if (a->neg) {
275	✓✓	4056	if (b->neg) {
276			tmp = a;
277			a = b;
278			b = tmp;
279		3006	} else {
280			add = 1;
281			neg = 1;
282			}
283			} else {
284	✓✓	14425932	if (b->neg) {
285			add = 1;
286			neg = 0;
287		299	}
288			}
289
290	✓✓	14429988	if (add) {
291	✗✓	1349	if (!BN_uadd(r, a, b))
292			return (0);
293		1349	r->neg = neg;
294		1349	return (1);
295			}
296
297			/* We are actually doing a - b :-) */
298
299		14428639	max = (a->top > b->top) ? a->top : b->top;
300	✓✓✗✓	28936168	if (bn_wexpand(r, max) == NULL)
301			return (0);
302	✓✓	14428639	if (BN_ucmp(a, b) < 0) {
303	✗✓	3938734	if (!BN_usub(r, b, a))
304			return (0);
305			r->neg = 1;
306		3938734	} else {
307	✗✓	10489905	if (!BN_usub(r, a, b))
308			return (0);
309			r->neg = 0;
310			}
311			bn_check_top(r);
312		14428639	return (1);
313		14429988	}