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1 /* crypto/bn/bn_lib.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 #ifndef BN_DEBUG
60 # undef NDEBUG /* avoid conflicting definitions */
61 # define NDEBUG
62 #endif
63
64 #include <assert.h>
65 #include <limits.h>
66 #include <stdio.h>
67 #include "cryptlib.h"
68 #include "bn_lcl.h"
69
70 const char *BN_version="Big Number" OPENSSL_VERSION_PTEXT;
71
72 /* This stuff appears to be completely unused, so is deprecated */
73 #ifndef OPENSSL_NO_DEPRECATED
74 /* For a 32 bit machine
75 * 2 - 4 == 128
76 * 3 - 8 == 256
77 * 4 - 16 == 512
78 * 5 - 32 == 1024
79 * 6 - 64 == 2048
80 * 7 - 128 == 4096
81 * 8 - 256 == 8192
82 */
83 static int bn_limit_bits=0;
84 static int bn_limit_num=8; /* (1<<bn_limit_bits) */
85 static int bn_limit_bits_low=0;
86 static int bn_limit_num_low=8; /* (1<<bn_limit_bits_low) */
87 static int bn_limit_bits_high=0;
88 static int bn_limit_num_high=8; /* (1<<bn_limit_bits_high) */
89 static int bn_limit_bits_mont=0;
90 static int bn_limit_num_mont=8; /* (1<<bn_limit_bits_mont) */
91
92 void BN_set_params(int mult, int high, int low, int mont)
93 {
94 if (mult >= 0)
95 {
96 if (mult > (int)(sizeof(int)*8)-1)
97 mult=sizeof(int)*8-1;
98 bn_limit_bits=mult;
99 bn_limit_num=1<<mult;
100 }
101 if (high >= 0)
102 {
103 if (high > (int)(sizeof(int)*8)-1)
104 high=sizeof(int)*8-1;
105 bn_limit_bits_high=high;
106 bn_limit_num_high=1<<high;
107 }
108 if (low >= 0)
109 {
110 if (low > (int)(sizeof(int)*8)-1)
111 low=sizeof(int)*8-1;
112 bn_limit_bits_low=low;
113 bn_limit_num_low=1<<low;
114 }
115 if (mont >= 0)
116 {
117 if (mont > (int)(sizeof(int)*8)-1)
118 mont=sizeof(int)*8-1;
119 bn_limit_bits_mont=mont;
120 bn_limit_num_mont=1<<mont;
121 }
122 }
123
124 int BN_get_params(int which)
125 {
126 if (which == 0) return(bn_limit_bits);
127 else if (which == 1) return(bn_limit_bits_high);
128 else if (which == 2) return(bn_limit_bits_low);
129 else if (which == 3) return(bn_limit_bits_mont);
130 else return(0);
131 }
132 #endif
133
134 const BIGNUM *BN_value_one(void)
135 {
136 static BN_ULONG data_one=1L;
137 static BIGNUM const_one={&data_one,1,1,0,BN_FLG_STATIC_DATA};
138
139 return(&const_one);
140 }
141
142 char *BN_options(void)
143 {
144 static int init=0;
145 static char data[16];
146
147 if (!init)
148 {
149 init++;
150 #ifdef BN_LLONG
151 BIO_snprintf(data,sizeof data,"bn(%d,%d)",
152 (int)sizeof(BN_ULLONG)*8,(int)sizeof(BN_ULONG)*8);
153 #else
154 BIO_snprintf(data,sizeof data,"bn(%d,%d)",
155 (int)sizeof(BN_ULONG)*8,(int)sizeof(BN_ULONG)*8);
156 #endif
157 }
158 return(data);
159 }
160
161 int BN_num_bits_word(BN_ULONG l)
162 {
163 static const char bits[256]={
164 0,1,2,2,3,3,3,3,4,4,4,4,4,4,4,4,
165 5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,
166 6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,
167 6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,
168 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
169 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
170 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
171 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
172 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
173 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
174 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
175 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
176 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
177 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
178 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
179 8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
180 };
181
182 #if defined(SIXTY_FOUR_BIT_LONG)
183 if (l & 0xffffffff00000000L)
184 {
185 if (l & 0xffff000000000000L)
186 {
187 if (l & 0xff00000000000000L)
188 {
189 return(bits[(int)(l>>56)]+56);
190 }
191 else return(bits[(int)(l>>48)]+48);
192 }
193 else
194 {
195 if (l & 0x0000ff0000000000L)
196 {
197 return(bits[(int)(l>>40)]+40);
198 }
199 else return(bits[(int)(l>>32)]+32);
200 }
201 }
202 else
203 #else
204 #ifdef SIXTY_FOUR_BIT
205 if (l & 0xffffffff00000000LL)
206 {
207 if (l & 0xffff000000000000LL)
208 {
209 if (l & 0xff00000000000000LL)
210 {
211 return(bits[(int)(l>>56)]+56);
212 }
213 else return(bits[(int)(l>>48)]+48);
214 }
215 else
216 {
217 if (l & 0x0000ff0000000000LL)
218 {
219 return(bits[(int)(l>>40)]+40);
220 }
221 else return(bits[(int)(l>>32)]+32);
222 }
223 }
224 else
225 #endif
226 #endif
227 {
228 #if defined(THIRTY_TWO_BIT) || defined(SIXTY_FOUR_BIT) || defined(SIXTY_FOUR_BIT_LONG)
229 if (l & 0xffff0000L)
230 {
231 if (l & 0xff000000L)
232 return(bits[(int)(l>>24L)]+24);
233 else return(bits[(int)(l>>16L)]+16);
234 }
235 else
236 #endif
237 {
238 #if defined(SIXTEEN_BIT) || defined(THIRTY_TWO_BIT) || defined(SIXTY_FOUR_BIT) || defined(SIXTY_FOUR_BIT_LONG)
239 if (l & 0xff00L)
240 return(bits[(int)(l>>8)]+8);
241 else
242 #endif
243 return(bits[(int)(l )] );
244 }
245 }
246 }
247
248 int BN_num_bits(const BIGNUM *a)
249 {
250 int i = a->top - 1;
251 bn_check_top(a);
252
253 if (BN_is_zero(a)) return 0;
254 return ((i*BN_BITS2) + BN_num_bits_word(a->d[i]));
255 }
256
257 void BN_clear_free(BIGNUM *a)
258 {
259 int i;
260
261 if (a == NULL) return;
262 bn_check_top(a);
263 if (a->d != NULL)
264 {
265 OPENSSL_cleanse(a->d,a->dmax*sizeof(a->d[0]));
266 if (!(BN_get_flags(a,BN_FLG_STATIC_DATA)))
267 OPENSSL_free(a->d);
268 }
269 i=BN_get_flags(a,BN_FLG_MALLOCED);
270 OPENSSL_cleanse(a,sizeof(BIGNUM));
271 if (i)
272 OPENSSL_free(a);
273 }
274
275 void BN_free(BIGNUM *a)
276 {
277 if (a == NULL) return;
278 bn_check_top(a);
279 if ((a->d != NULL) && !(BN_get_flags(a,BN_FLG_STATIC_DATA)))
280 OPENSSL_free(a->d);
281 if (a->flags & BN_FLG_MALLOCED)
282 OPENSSL_free(a);
283 else
284 {
285 #ifndef OPENSSL_NO_DEPRECATED
286 a->flags|=BN_FLG_FREE;
287 #endif
288 a->d = NULL;
289 }
290 }
291
292 void BN_init(BIGNUM *a)
293 {
294 memset(a,0,sizeof(BIGNUM));
295 bn_check_top(a);
296 }
297
298 BIGNUM *BN_new(void)
299 {
300 BIGNUM *ret;
301
302 if ((ret=(BIGNUM *)OPENSSL_malloc(sizeof(BIGNUM))) == NULL)
303 {
304 BNerr(BN_F_BN_NEW,ERR_R_MALLOC_FAILURE);
305 return(NULL);
306 }
307 ret->flags=BN_FLG_MALLOCED;
308 ret->top=0;
309 ret->neg=0;
310 ret->dmax=0;
311 ret->d=NULL;
312 bn_check_top(ret);
313 return(ret);
314 }
315
316 /* This is used both by bn_expand2() and bn_dup_expand() */
317 /* The caller MUST check that words > b->dmax before calling this */
318 static BN_ULONG *bn_expand_internal(const BIGNUM *b, int words)
319 {
320 BN_ULONG *A,*a = NULL;
321 const BN_ULONG *B;
322 int i;
323
324 bn_check_top(b);
325
326 if (words > (INT_MAX/(4*BN_BITS2)))
327 {
328 BNerr(BN_F_BN_EXPAND_INTERNAL,BN_R_BIGNUM_TOO_LONG);
329 return NULL;
330 }
331 if (BN_get_flags(b,BN_FLG_STATIC_DATA))
332 {
333 BNerr(BN_F_BN_EXPAND_INTERNAL,BN_R_EXPAND_ON_STATIC_BIGNUM_DATA);
334 return(NULL);
335 }
336 a=A=(BN_ULONG *)OPENSSL_malloc(sizeof(BN_ULONG)*words);
337 if (A == NULL)
338 {
339 BNerr(BN_F_BN_EXPAND_INTERNAL,ERR_R_MALLOC_FAILURE);
340 return(NULL);
341 }
342 #if 1
343 B=b->d;
344 /* Check if the previous number needs to be copied */
345 if (B != NULL)
346 {
347 for (i=b->top>>2; i>0; i--,A+=4,B+=4)
348 {
349 /*
350 * The fact that the loop is unrolled
351 * 4-wise is a tribute to Intel. It's
352 * the one that doesn't have enough
353 * registers to accomodate more data.
354 * I'd unroll it 8-wise otherwise:-)
355 *
356 * <appro@fy.chalmers.se>
357 */
358 BN_ULONG a0,a1,a2,a3;
359 a0=B[0]; a1=B[1]; a2=B[2]; a3=B[3];
360 A[0]=a0; A[1]=a1; A[2]=a2; A[3]=a3;
361 }
362 switch (b->top&3)
363 {
364 case 3: A[2]=B[2];
365 case 2: A[1]=B[1];
366 case 1: A[0]=B[0];
367 case 0: /* workaround for ultrix cc: without 'case 0', the optimizer does
368 * the switch table by doing a=top&3; a--; goto jump_table[a];
369 * which fails for top== 0 */
370 ;
371 }
372 }
373
374 #else
375 memset(A,0,sizeof(BN_ULONG)*words);
376 memcpy(A,b->d,sizeof(b->d[0])*b->top);
377 #endif
378
379 return(a);
380 }
381
382 /* This is an internal function that can be used instead of bn_expand2()
383 * when there is a need to copy BIGNUMs instead of only expanding the
384 * data part, while still expanding them.
385 * Especially useful when needing to expand BIGNUMs that are declared
386 * 'const' and should therefore not be changed.
387 * The reason to use this instead of a BN_dup() followed by a bn_expand2()
388 * is memory allocation overhead. A BN_dup() followed by a bn_expand2()
389 * will allocate new memory for the BIGNUM data twice, and free it once,
390 * while bn_dup_expand() makes sure allocation is made only once.
391 */
392
393 #ifndef OPENSSL_NO_DEPRECATED
394 BIGNUM *bn_dup_expand(const BIGNUM *b, int words)
395 {
396 BIGNUM *r = NULL;
397
398 bn_check_top(b);
399
400 /* This function does not work if
401 * words <= b->dmax && top < words
402 * because BN_dup() does not preserve 'dmax'!
403 * (But bn_dup_expand() is not used anywhere yet.)
404 */
405
406 if (words > b->dmax)
407 {
408 BN_ULONG *a = bn_expand_internal(b, words);
409
410 if (a)
411 {
412 r = BN_new();
413 if (r)
414 {
415 r->top = b->top;
416 r->dmax = words;
417 r->neg = b->neg;
418 r->d = a;
419 }
420 else
421 {
422 /* r == NULL, BN_new failure */
423 OPENSSL_free(a);
424 }
425 }
426 /* If a == NULL, there was an error in allocation in
427 bn_expand_internal(), and NULL should be returned */
428 }
429 else
430 {
431 r = BN_dup(b);
432 }
433
434 bn_check_top(r);
435 return r;
436 }
437 #endif
438
439 /* This is an internal function that should not be used in applications.
440 * It ensures that 'b' has enough room for a 'words' word number
441 * and initialises any unused part of b->d with leading zeros.
442 * It is mostly used by the various BIGNUM routines. If there is an error,
443 * NULL is returned. If not, 'b' is returned. */
444
445 BIGNUM *bn_expand2(BIGNUM *b, int words)
446 {
447 bn_check_top(b);
448
449 if (words > b->dmax)
450 {
451 BN_ULONG *a = bn_expand_internal(b, words);
452 if(!a) return NULL;
453 if(b->d) OPENSSL_free(b->d);
454 b->d=a;
455 b->dmax=words;
456 }
457
458 /* None of this should be necessary because of what b->top means! */
459 #if 0
460 /* NB: bn_wexpand() calls this only if the BIGNUM really has to grow */
461 if (b->top < b->dmax)
462 {
463 int i;
464 BN_ULONG *A = &(b->d[b->top]);
465 for (i=(b->dmax - b->top)>>3; i>0; i--,A+=8)
466 {
467 A[0]=0; A[1]=0; A[2]=0; A[3]=0;
468 A[4]=0; A[5]=0; A[6]=0; A[7]=0;
469 }
470 for (i=(b->dmax - b->top)&7; i>0; i--,A++)
471 A[0]=0;
472 assert(A == &(b->d[b->dmax]));
473 }
474 #endif
475 bn_check_top(b);
476 return b;
477 }
478
479 BIGNUM *BN_dup(const BIGNUM *a)
480 {
481 BIGNUM *t;
482
483 if (a == NULL) return NULL;
484 bn_check_top(a);
485
486 t = BN_new();
487 if (t == NULL) return NULL;
488 if(!BN_copy(t, a))
489 {
490 BN_free(t);
491 return NULL;
492 }
493 bn_check_top(t);
494 return t;
495 }
496
497 BIGNUM *BN_copy(BIGNUM *a, const BIGNUM *b)
498 {
499 int i;
500 BN_ULONG *A;
501 const BN_ULONG *B;
502
503 bn_check_top(b);
504
505 if (a == b) return(a);
506 if (bn_wexpand(a,b->top) == NULL) return(NULL);
507
508 #if 1
509 A=a->d;
510 B=b->d;
511 for (i=b->top>>2; i>0; i--,A+=4,B+=4)
512 {
513 BN_ULONG a0,a1,a2,a3;
514 a0=B[0]; a1=B[1]; a2=B[2]; a3=B[3];
515 A[0]=a0; A[1]=a1; A[2]=a2; A[3]=a3;
516 }
517 switch (b->top&3)
518 {
519 case 3: A[2]=B[2];
520 case 2: A[1]=B[1];
521 case 1: A[0]=B[0];
522 case 0: ; /* ultrix cc workaround, see comments in bn_expand_internal */
523 }
524 #else
525 memcpy(a->d,b->d,sizeof(b->d[0])*b->top);
526 #endif
527
528 a->top=b->top;
529 a->neg=b->neg;
530 bn_check_top(a);
531 return(a);
532 }
533
534 BIGNUM *BN_ncopy(BIGNUM *a, const BIGNUM *b, size_t n)
535 {
536 int i, min;
537 BN_ULONG *A;
538 const BN_ULONG *B;
539
540 bn_check_top(b);
541 if (a == b)
542 return a;
543
544 min = (b->top < (int)n)? b->top: (int)n;
545 if (!min)
546 {
547 BN_zero(a);
548 return a;
549 }
550 if (bn_wexpand(a, min) == NULL)
551 return NULL;
552
553 A=a->d;
554 B=b->d;
555 for (i=min>>2; i>0; i--, A+=4, B+=4)
556 {
557 BN_ULONG a0,a1,a2,a3;
558 a0=B[0]; a1=B[1]; a2=B[2]; a3=B[3];
559 A[0]=a0; A[1]=a1; A[2]=a2; A[3]=a3;
560 }
561 switch (min&3)
562 {
563 case 3: A[2]=B[2];
564 case 2: A[1]=B[1];
565 case 1: A[0]=B[0];
566 case 0: ;
567 }
568 a->top = min;
569 a->neg = b->neg;
570 bn_correct_top(a);
571 return(a);
572 }
573
574 void BN_swap(BIGNUM *a, BIGNUM *b)
575 {
576 int flags_old_a, flags_old_b;
577 BN_ULONG *tmp_d;
578 int tmp_top, tmp_dmax, tmp_neg;
579
580 bn_check_top(a);
581 bn_check_top(b);
582
583 flags_old_a = a->flags;
584 flags_old_b = b->flags;
585
586 tmp_d = a->d;
587 tmp_top = a->top;
588 tmp_dmax = a->dmax;
589 tmp_neg = a->neg;
590
591 a->d = b->d;
592 a->top = b->top;
593 a->dmax = b->dmax;
594 a->neg = b->neg;
595
596 b->d = tmp_d;
597 b->top = tmp_top;
598 b->dmax = tmp_dmax;
599 b->neg = tmp_neg;
600
601 a->flags = (flags_old_a & BN_FLG_MALLOCED) | (flags_old_b & BN_FLG_STATIC_DATA);
602 b->flags = (flags_old_b & BN_FLG_MALLOCED) | (flags_old_a & BN_FLG_STATIC_DATA);
603 bn_check_top(a);
604 bn_check_top(b);
605 }
606
607 void BN_clear(BIGNUM *a)
608 {
609 bn_check_top(a);
610 if (a->d != NULL)
611 memset(a->d,0,a->dmax*sizeof(a->d[0]));
612 a->top=0;
613 a->neg=0;
614 }
615
616 BN_ULONG BN_get_word(const BIGNUM *a)
617 {
618 if (a->top > 1)
619 return BN_MASK2;
620 else if (a->top == 1)
621 return a->d[0];
622 /* a->top == 0 */
623 return 0;
624 }
625
626 int BN_set_word(BIGNUM *a, BN_ULONG w)
627 {
628 bn_check_top(a);
629 if (bn_expand(a,(int)sizeof(BN_ULONG)*8) == NULL) return(0);
630 a->neg = 0;
631 a->d[0] = w;
632 a->top = (w ? 1 : 0);
633 bn_check_top(a);
634 return(1);
635 }
636
637 BIGNUM *BN_bin2bn(const unsigned char *s, int len, BIGNUM *ret)
638 {
639 unsigned int i,m;
640 unsigned int n;
641 BN_ULONG l;
642 BIGNUM *bn = NULL;
643
644 if (ret == NULL)
645 ret = bn = BN_new();
646 if (ret == NULL) return(NULL);
647 bn_check_top(ret);
648 l=0;
649 n=len;
650 if (n == 0)
651 {
652 ret->top=0;
653 return(ret);
654 }
655 i=((n-1)/BN_BYTES)+1;
656 m=((n-1)%(BN_BYTES));
657 if (bn_wexpand(ret, (int)i) == NULL)
658 {
659 if (bn) BN_free(bn);
660 return NULL;
661 }
662 ret->top=i;
663 ret->neg=0;
664 while (n--)
665 {
666 l=(l<<8L)| *(s++);
667 if (m-- == 0)
668 {
669 ret->d[--i]=l;
670 l=0;
671 m=BN_BYTES-1;
672 }
673 }
674 /* need to call this due to clear byte at top if avoiding
675 * having the top bit set (-ve number) */
676 bn_correct_top(ret);
677 return(ret);
678 }
679
680 /* ignore negative */
681 int BN_bn2bin(const BIGNUM *a, unsigned char *to)
682 {
683 int n,i;
684 BN_ULONG l;
685
686 bn_check_top(a);
687 n=i=BN_num_bytes(a);
688 while (i--)
689 {
690 l=a->d[i/BN_BYTES];
691 *(to++)=(unsigned char)(l>>(8*(i%BN_BYTES)))&0xff;
692 }
693 return(n);
694 }
695
696 int BN_ucmp(const BIGNUM *a, const BIGNUM *b)
697 {
698 int i;
699 BN_ULONG t1,t2,*ap,*bp;
700
701 bn_check_top(a);
702 bn_check_top(b);
703
704 i=a->top-b->top;
705 if (i != 0) return(i);
706 ap=a->d;
707 bp=b->d;
708 for (i=a->top-1; i>=0; i--)
709 {
710 t1= ap[i];
711 t2= bp[i];
712 if (t1 != t2)
713 return((t1 > t2) ? 1 : -1);
714 }
715 return(0);
716 }
717
718 int BN_cmp(const BIGNUM *a, const BIGNUM *b)
719 {
720 int i;
721 int gt,lt;
722 BN_ULONG t1,t2;
723
724 if ((a == NULL) || (b == NULL))
725 {
726 if (a != NULL)
727 return(-1);
728 else if (b != NULL)
729 return(1);
730 else
731 return(0);
732 }
733
734 bn_check_top(a);
735 bn_check_top(b);
736
737 if (a->neg != b->neg)
738 {
739 if (a->neg)
740 return(-1);
741 else return(1);
742 }
743 if (a->neg == 0)
744 { gt=1; lt= -1; }
745 else { gt= -1; lt=1; }
746
747 if (a->top > b->top) return(gt);
748 if (a->top < b->top) return(lt);
749 for (i=a->top-1; i>=0; i--)
750 {
751 t1=a->d[i];
752 t2=b->d[i];
753 if (t1 > t2) return(gt);
754 if (t1 < t2) return(lt);
755 }
756 return(0);
757 }
758
759 int BN_set_bit(BIGNUM *a, int n)
760 {
761 int i,j,k;
762
763 if (n < 0)
764 return 0;
765
766 i=n/BN_BITS2;
767 j=n%BN_BITS2;
768 if (a->top <= i)
769 {
770 if (bn_wexpand(a,i+1) == NULL) return(0);
771 for(k=a->top; k<i+1; k++)
772 a->d[k]=0;
773 a->top=i+1;
774 }
775
776 a->d[i]|=(((BN_ULONG)1)<<j);
777 bn_check_top(a);
778 return(1);
779 }
780
781 int BN_clear_bit(BIGNUM *a, int n)
782 {
783 int i,j;
784
785 bn_check_top(a);
786 if (n < 0) return 0;
787
788 i=n/BN_BITS2;
789 j=n%BN_BITS2;
790 if (a->top <= i) return(0);
791
792 a->d[i]&=(~(((BN_ULONG)1)<<j));
793 bn_correct_top(a);
794 return(1);
795 }
796
797 int BN_is_bit_set(const BIGNUM *a, int n)
798 {
799 int i,j;
800
801 bn_check_top(a);
802 if (n < 0) return 0;
803 i=n/BN_BITS2;
804 j=n%BN_BITS2;
805 if (a->top <= i) return 0;
806 return((a->d[i]&(((BN_ULONG)1)<<j))?1:0);
807 }
808
809 int BN_mask_bits(BIGNUM *a, int n)
810 {
811 int b,w;
812
813 bn_check_top(a);
814 if (n < 0) return 0;
815
816 w=n/BN_BITS2;
817 b=n%BN_BITS2;
818 if (w >= a->top) return 0;
819 if (b == 0)
820 a->top=w;
821 else
822 {
823 a->top=w+1;
824 a->d[w]&= ~(BN_MASK2<<b);
825 }
826 bn_correct_top(a);
827 return(1);
828 }
829
830 int bn_cmp_words(const BN_ULONG *a, const BN_ULONG *b, int n)
831 {
832 int i;
833 BN_ULONG aa,bb;
834
835 aa=a[n-1];
836 bb=b[n-1];
837 if (aa != bb) return((aa > bb)?1:-1);
838 for (i=n-2; i>=0; i--)
839 {
840 aa=a[i];
841 bb=b[i];
842 if (aa != bb) return((aa > bb)?1:-1);
843 }
844 return(0);
845 }
846
847 /* Here follows a specialised variants of bn_cmp_words(). It has the
848 property of performing the operation on arrays of different sizes.
849 The sizes of those arrays is expressed through cl, which is the
850 common length ( basicall, min(len(a),len(b)) ), and dl, which is the
851 delta between the two lengths, calculated as len(a)-len(b).
852 All lengths are the number of BN_ULONGs... */
853
854 int bn_cmp_part_words(const BN_ULONG *a, const BN_ULONG *b,
855 int cl, int dl)
856 {
857 int n,i;
858 n = cl-1;
859
860 if (dl < 0)
861 {
862 for (i=dl; i<0; i++)
863 {
864 if (b[n-i] != 0)
865 return -1; /* a < b */
866 }
867 }
868 if (dl > 0)
869 {
870 for (i=dl; i>0; i--)
871 {
872 if (a[n+i] != 0)
873 return 1; /* a > b */
874 }
875 }
876 return bn_cmp_words(a,b,cl);
877 }
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