rdesktop/crypto/bn_add.c

/* crypto/bn/bn_add.c */
/* 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 "bn_lcl.h"

/* r can == a or b */
int BN_add(BIGNUM *r, const BIGNUM *a, const BIGNUM *b)
        {
        const BIGNUM *tmp;

        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);
                }

        if (a->neg) /* both are neg */
                r->neg=1;
        else
                r->neg=0;

        if (!BN_uadd(r,a,b)) return(0);
        return(1);
        }

/* unsigned add of b to a, r must be large enough */
int BN_uadd(BIGNUM *r, const BIGNUM *a, const BIGNUM *b)
        {
        register int i;
        int max,min;
        BN_ULONG *ap,*bp,*rp,carry,t1;
        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;

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

        r->top=max;


        ap=a->d;
        bp=b->d;
        rp=r->d;
        carry=0;

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

        if (carry)
                {
                while (i < max)
                        {
                        i++;
                        t1= *(ap++);
                        if ((*(rp++)=(t1+1)&BN_MASK2) >= t1)
                                {
                                carry=0;
                                break;
                                }
                        }
                if ((i >= max) && carry)
                        {
                        *(rp++)=1;
                        r->top++;
                        }
                }
        if (rp != ap)
                {
                for (; i<max; i++)
                        *(rp++)= *(ap++);
                }
        /* memcpy(rp,ap,sizeof(*ap)*(max-i));*/
        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;
        register BN_ULONG t1,t2,*ap,*bp,*rp;
        int i,carry;
#if defined(IRIX_CC_BUG) && !defined(LINT)
        int dummy;
#endif

        bn_check_top(a);
        bn_check_top(b);

        if (a->top < b->top) /* hmm... should not be happening */
                {
                BNerr(BN_F_BN_USUB,BN_R_ARG2_LT_ARG3);
                return(0);
                }

        max=a->top;
        min=b->top;
        if (bn_wexpand(r,max) == NULL) return(0);

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

#if 1
        carry=0;
        for (i=0; i<min; 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;
                        }
#if defined(IRIX_CC_BUG) && !defined(LINT)
                dummy=t1;
#endif
                *(rp++)=t1&BN_MASK2;
                }
#else
        carry=bn_sub_words(rp,ap,bp,min);
        ap+=min;
        bp+=min;
        rp+=min;
        i=min;
#endif
        if (carry) /* subtracted */
                {
                while (i < max)
                        {
                        i++;
                        t1= *(ap++);
                        t2=(t1-1)&BN_MASK2;
                        *(rp++)=t2;
                        if (t1 > t2) break;
                        }
                }
#if 0
        memcpy(rp,ap,sizeof(*rp)*(max-i));
#else
        if (rp != ap)
                {
                for (;;)
                        {
                        if (i++ >= max) break;
                        rp[0]=ap[0];
                        if (i++ >= max) break;
                        rp[1]=ap[1];
                        if (i++ >= max) break;
                        rp[2]=ap[2];
                        if (i++ >= max) break;
                        rp[3]=ap[3];
                        rp+=4;
                        ap+=4;
                        }
                }
#endif

        r->top=max;
        bn_fix_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;
                }
        return(1);
        }

1	matty	32	/* crypto/bn/bn_add.c */
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			#include "bn_lcl.h"
61
62			/* r can == a or b */
63			int BN_add(BIGNUM r, const BIGNUM a, const BIGNUM *b)
64			{
65			const BIGNUM *tmp;
66
67			bn_check_top(a);
68			bn_check_top(b);
69
70			/* a + b a+b
71			* a + -b a-b
72			* -a + b b-a
73			* -a + -b -(a+b)
74			*/
75			if (a->neg ^ b->neg)
76			{
77			/* only one is negative */
78			if (a->neg)
79			{ tmp=a; a=b; b=tmp; }
80
81			/* we are now a - b */
82
83			if (BN_ucmp(a,b) < 0)
84			{
85			if (!BN_usub(r,b,a)) return(0);
86			r->neg=1;
87			}
88			else
89			{
90			if (!BN_usub(r,a,b)) return(0);
91			r->neg=0;
92			}
93			return(1);
94			}
95
96			if (a->neg) /* both are neg */
97			r->neg=1;
98			else
99			r->neg=0;
100
101			if (!BN_uadd(r,a,b)) return(0);
102			return(1);
103			}
104
105			/* unsigned add of b to a, r must be large enough */
106			int BN_uadd(BIGNUM r, const BIGNUM a, const BIGNUM *b)
107			{
108			register int i;
109			int max,min;
110			BN_ULONG ap,bp,*rp,carry,t1;
111			const BIGNUM *tmp;
112
113			bn_check_top(a);
114			bn_check_top(b);
115
116			if (a->top < b->top)
117			{ tmp=a; a=b; b=tmp; }
118			max=a->top;
119			min=b->top;
120
121			if (bn_wexpand(r,max+1) == NULL)
122			return(0);
123
124			r->top=max;
125
126
127			ap=a->d;
128			bp=b->d;
129			rp=r->d;
130			carry=0;
131
132			carry=bn_add_words(rp,ap,bp,min);
133			rp+=min;
134			ap+=min;
135			bp+=min;
136			i=min;
137
138			if (carry)
139			{
140			while (i < max)
141			{
142			i++;
143			t1= *(ap++);
144			if ((*(rp++)=(t1+1)&BN_MASK2) >= t1)
145			{
146			carry=0;
147			break;
148			}
149			}
150			if ((i >= max) && carry)
151			{
152			*(rp++)=1;
153			r->top++;
154			}
155			}
156			if (rp != ap)
157			{
158			for (; i<max; i++)
159			(rp++)= (ap++);
160			}
161			/* memcpy(rp,ap,sizeof(ap)(max-i));*/
162			return(1);
163			}
164
165			/* unsigned subtraction of b from a, a must be larger than b. */
166			int BN_usub(BIGNUM r, const BIGNUM a, const BIGNUM *b)
167			{
168			int max,min;
169			register BN_ULONG t1,t2,ap,bp,*rp;
170			int i,carry;
171			#if defined(IRIX_CC_BUG) && !defined(LINT)
172			int dummy;
173			#endif
174
175			bn_check_top(a);
176			bn_check_top(b);
177
178			if (a->top < b->top) /* hmm... should not be happening */
179			{
180			BNerr(BN_F_BN_USUB,BN_R_ARG2_LT_ARG3);
181			return(0);
182			}
183
184			max=a->top;
185			min=b->top;
186			if (bn_wexpand(r,max) == NULL) return(0);
187
188			ap=a->d;
189			bp=b->d;
190			rp=r->d;
191
192			#if 1
193			carry=0;
194			for (i=0; i<min; i++)
195			{
196			t1= *(ap++);
197			t2= *(bp++);
198			if (carry)
199			{
200			carry=(t1 <= t2);
201			t1=(t1-t2-1)&BN_MASK2;
202			}
203			else
204			{
205			carry=(t1 < t2);
206			t1=(t1-t2)&BN_MASK2;
207			}
208			#if defined(IRIX_CC_BUG) && !defined(LINT)
209			dummy=t1;
210			#endif
211			*(rp++)=t1&BN_MASK2;
212			}
213			#else
214			carry=bn_sub_words(rp,ap,bp,min);
215			ap+=min;
216			bp+=min;
217			rp+=min;
218			i=min;
219			#endif
220			if (carry) /* subtracted */
221			{
222			while (i < max)
223			{
224			i++;
225			t1= *(ap++);
226			t2=(t1-1)&BN_MASK2;
227			*(rp++)=t2;
228			if (t1 > t2) break;
229			}
230			}
231			#if 0
232			memcpy(rp,ap,sizeof(rp)(max-i));
233			#else
234			if (rp != ap)
235			{
236			for (;;)
237			{
238			if (i++ >= max) break;
239			rp[0]=ap[0];
240			if (i++ >= max) break;
241			rp[1]=ap[1];
242			if (i++ >= max) break;
243			rp[2]=ap[2];
244			if (i++ >= max) break;
245			rp[3]=ap[3];
246			rp+=4;
247			ap+=4;
248			}
249			}
250			#endif
251
252			r->top=max;
253			bn_fix_top(r);
254			return(1);
255			}
256
257			int BN_sub(BIGNUM r, const BIGNUM a, const BIGNUM *b)
258			{
259			int max;
260			int add=0,neg=0;
261			const BIGNUM *tmp;
262
263			bn_check_top(a);
264			bn_check_top(b);
265
266			/* a - b a-b
267			* a - -b a+b
268			* -a - b -(a+b)
269			* -a - -b b-a
270			*/
271			if (a->neg)
272			{
273			if (b->neg)
274			{ tmp=a; a=b; b=tmp; }
275			else
276			{ add=1; neg=1; }
277			}
278			else
279			{
280			if (b->neg) { add=1; neg=0; }
281			}
282
283			if (add)
284			{
285			if (!BN_uadd(r,a,b)) return(0);
286			r->neg=neg;
287			return(1);
288			}
289
290			/* We are actually doing a - b :-) */
291
292			max=(a->top > b->top)?a->top:b->top;
293			if (bn_wexpand(r,max) == NULL) return(0);
294			if (BN_ucmp(a,b) < 0)
295			{
296			if (!BN_usub(r,b,a)) return(0);
297			r->neg=1;
298			}
299			else
300			{
301			if (!BN_usub(r,a,b)) return(0);
302			r->neg=0;
303			}
304			return(1);
305			}
306