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| 1 /* 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 "cryptlib.h" | |
| 61 #include "bn_lcl.h" | |
| 62 | |
| 63 /* r can == a or b */ | |
| 64 int BN_add(BIGNUM *r, const BIGNUM *a, const BIGNUM *b) | |
| 65 { | |
| 66 const BIGNUM *tmp; | |
| 67 int a_neg = a->neg, ret; | |
| 68 | |
| 69 bn_check_top(a); | |
| 70 bn_check_top(b); | |
| 71 | |
| 72 /* a + b a+b | |
| 73 * a + -b a-b | |
| 74 * -a + b b-a | |
| 75 * -a + -b -(a+b) | |
| 76 */ | |
| 77 if (a_neg ^ b->neg) | |
| 78 { | |
| 79 /* only one is negative */ | |
| 80 if (a_neg) | |
| 81 { tmp=a; a=b; b=tmp; } | |
| 82 | |
| 83 /* we are now a - b */ | |
| 84 | |
| 85 if (BN_ucmp(a,b) < 0) | |
| 86 { | |
| 87 if (!BN_usub(r,b,a)) return(0); | |
| 88 r->neg=1; | |
| 89 } | |
| 90 else | |
| 91 { | |
| 92 if (!BN_usub(r,a,b)) return(0); | |
| 93 r->neg=0; | |
| 94 } | |
| 95 return(1); | |
| 96 } | |
| 97 | |
| 98 ret = BN_uadd(r,a,b); | |
| 99 r->neg = a_neg; | |
| 100 bn_check_top(r); | |
| 101 return ret; | |
| 102 } | |
| 103 | |
| 104 /* unsigned add of b to a */ | |
| 105 int BN_uadd(BIGNUM *r, const BIGNUM *a, const BIGNUM *b) | |
| 106 { | |
| 107 int max,min,dif; | |
| 108 BN_ULONG *ap,*bp,*rp,carry,t1,t2; | |
| 109 const BIGNUM *tmp; | |
| 110 | |
| 111 bn_check_top(a); | |
| 112 bn_check_top(b); | |
| 113 | |
| 114 if (a->top < b->top) | |
| 115 { tmp=a; a=b; b=tmp; } | |
| 116 max = a->top; | |
| 117 min = b->top; | |
| 118 dif = max - min; | |
| 119 | |
| 120 if (bn_wexpand(r,max+1) == NULL) | |
| 121 return 0; | |
| 122 | |
| 123 r->top=max; | |
| 124 | |
| 125 | |
| 126 ap=a->d; | |
| 127 bp=b->d; | |
| 128 rp=r->d; | |
| 129 | |
| 130 carry=bn_add_words(rp,ap,bp,min); | |
| 131 rp+=min; | |
| 132 ap+=min; | |
| 133 bp+=min; | |
| 134 | |
| 135 if (carry) | |
| 136 { | |
| 137 while (dif) | |
| 138 { | |
| 139 dif--; | |
| 140 t1 = *(ap++); | |
| 141 t2 = (t1+1) & BN_MASK2; | |
| 142 *(rp++) = t2; | |
| 143 if (t2) | |
| 144 { | |
| 145 carry=0; | |
| 146 break; | |
| 147 } | |
| 148 } | |
| 149 if (carry) | |
| 150 { | |
| 151 /* carry != 0 => dif == 0 */ | |
| 152 *rp = 1; | |
| 153 r->top++; | |
| 154 } | |
| 155 } | |
| 156 if (dif && rp != ap) | |
| 157 while (dif--) | |
| 158 /* copy remaining words if ap != rp */ | |
| 159 *(rp++) = *(ap++); | |
| 160 r->neg = 0; | |
| 161 bn_check_top(r); | |
| 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,dif; | |
| 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 max = a->top; | |
| 179 min = b->top; | |
| 180 dif = max - min; | |
| 181 | |
| 182 if (dif < 0) /* hmm... should not be happening */ | |
| 183 { | |
| 184 BNerr(BN_F_BN_USUB,BN_R_ARG2_LT_ARG3); | |
| 185 return(0); | |
| 186 } | |
| 187 | |
| 188 if (bn_wexpand(r,max) == NULL) return(0); | |
| 189 | |
| 190 ap=a->d; | |
| 191 bp=b->d; | |
| 192 rp=r->d; | |
| 193 | |
| 194 #if 1 | |
| 195 carry=0; | |
| 196 for (i = min; i != 0; i--) | |
| 197 { | |
| 198 t1= *(ap++); | |
| 199 t2= *(bp++); | |
| 200 if (carry) | |
| 201 { | |
| 202 carry=(t1 <= t2); | |
| 203 t1=(t1-t2-1)&BN_MASK2; | |
| 204 } | |
| 205 else | |
| 206 { | |
| 207 carry=(t1 < t2); | |
| 208 t1=(t1-t2)&BN_MASK2; | |
| 209 } | |
| 210 #if defined(IRIX_CC_BUG) && !defined(LINT) | |
| 211 dummy=t1; | |
| 212 #endif | |
| 213 *(rp++)=t1&BN_MASK2; | |
| 214 } | |
| 215 #else | |
| 216 carry=bn_sub_words(rp,ap,bp,min); | |
| 217 ap+=min; | |
| 218 bp+=min; | |
| 219 rp+=min; | |
| 220 #endif | |
| 221 if (carry) /* subtracted */ | |
| 222 { | |
| 223 if (!dif) | |
| 224 /* error: a < b */ | |
| 225 return 0; | |
| 226 while (dif) | |
| 227 { | |
| 228 dif--; | |
| 229 t1 = *(ap++); | |
| 230 t2 = (t1-1)&BN_MASK2; | |
| 231 *(rp++) = t2; | |
| 232 if (t1) | |
| 233 break; | |
| 234 } | |
| 235 } | |
| 236 #if 0 | |
| 237 memcpy(rp,ap,sizeof(*rp)*(max-i)); | |
| 238 #else | |
| 239 if (rp != ap) | |
| 240 { | |
| 241 for (;;) | |
| 242 { | |
| 243 if (!dif--) break; | |
| 244 rp[0]=ap[0]; | |
| 245 if (!dif--) break; | |
| 246 rp[1]=ap[1]; | |
| 247 if (!dif--) break; | |
| 248 rp[2]=ap[2]; | |
| 249 if (!dif--) break; | |
| 250 rp[3]=ap[3]; | |
| 251 rp+=4; | |
| 252 ap+=4; | |
| 253 } | |
| 254 } | |
| 255 #endif | |
| 256 | |
| 257 r->top=max; | |
| 258 r->neg=0; | |
| 259 bn_correct_top(r); | |
| 260 return(1); | |
| 261 } | |
| 262 | |
| 263 int BN_sub(BIGNUM *r, const BIGNUM *a, const BIGNUM *b) | |
| 264 { | |
| 265 int max; | |
| 266 int add=0,neg=0; | |
| 267 const BIGNUM *tmp; | |
| 268 | |
| 269 bn_check_top(a); | |
| 270 bn_check_top(b); | |
| 271 | |
| 272 /* a - b a-b | |
| 273 * a - -b a+b | |
| 274 * -a - b -(a+b) | |
| 275 * -a - -b b-a | |
| 276 */ | |
| 277 if (a->neg) | |
| 278 { | |
| 279 if (b->neg) | |
| 280 { tmp=a; a=b; b=tmp; } | |
| 281 else | |
| 282 { add=1; neg=1; } | |
| 283 } | |
| 284 else | |
| 285 { | |
| 286 if (b->neg) { add=1; neg=0; } | |
| 287 } | |
| 288 | |
| 289 if (add) | |
| 290 { | |
| 291 if (!BN_uadd(r,a,b)) return(0); | |
| 292 r->neg=neg; | |
| 293 return(1); | |
| 294 } | |
| 295 | |
| 296 /* We are actually doing a - b :-) */ | |
| 297 | |
| 298 max=(a->top > b->top)?a->top:b->top; | |
| 299 if (bn_wexpand(r,max) == NULL) return(0); | |
| 300 if (BN_ucmp(a,b) < 0) | |
| 301 { | |
| 302 if (!BN_usub(r,b,a)) return(0); | |
| 303 r->neg=1; | |
| 304 } | |
| 305 else | |
| 306 { | |
| 307 if (!BN_usub(r,a,b)) return(0); | |
| 308 r->neg=0; | |
| 309 } | |
| 310 bn_check_top(r); | |
| 311 return(1); | |
| 312 } | |
| 313 | |
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Chromium Code Reviews
Issue 2072073002:
Delete bundled copy of OpenSSL and replace with README. (Closed)
Base URL: https://chromium.googlesource.com/chromium/deps/openssl@master