File indexing completed on 2024-05-12 04:45:13

 /*
 Copyright (C) 1999-2007 The Botan Project. All rights reserved.
 
 Redistribution and use in source and binary forms, for any use, with or without
 modification, is permitted provided that the following conditions are met:
 
 1. Redistributions of source code must retain the above 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.
 
 THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) "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(S) OR CONTRIBUTOR(S) 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.
 */
 // LICENSEHEADER_END
 namespace QCA { // WRAPNS_LINE
 /*************************************************
  * BigInt Assignment Operators Source File        *
  * (C) 1999-2007 The Botan Project                *
  *************************************************/
 
 } // WRAPNS_LINE
 #include <botan/bigint.h>
 namespace QCA { // WRAPNS_LINE
 } // WRAPNS_LINE
 #include <botan/numthry.h>
 namespace QCA { // WRAPNS_LINE
 } // WRAPNS_LINE
 #include <botan/mp_core.h>
 namespace QCA { // WRAPNS_LINE
 } // WRAPNS_LINE
 #include <botan/bit_ops.h>
 namespace QCA { // WRAPNS_LINE
 } // WRAPNS_LINE
 #include <botan/util.h>
 namespace QCA { // WRAPNS_LINE
 } // WRAPNS_LINE
 #include <algorithm>
 namespace QCA { // WRAPNS_LINE
 
 namespace Botan {
 
 /*************************************************
  * Addition Operator                              *
  *************************************************/
 BigInt &BigInt::operator+=(const BigInt &y)
 {
     const u32bit x_sw = sig_words(), y_sw = y.sig_words();
 
 #ifdef BOTAN_TYPES_QT
     const u32bit reg_size = qMax(x_sw, y_sw) + 1;
 #else
     const u32bit reg_size = std::max(x_sw, y_sw) + 1;
 #endif
     grow_to(reg_size);
 
     if ((sign() == y.sign()))
         bigint_add2(get_reg(), reg_size - 1, y.data(), y_sw);
     else {
         s32bit relative_size = bigint_cmp(data(), x_sw, y.data(), y_sw);
 
         if (relative_size < 0) {
             SecureVector<word> z(reg_size - 1);
             bigint_sub3(z, y.data(), reg_size - 1, data(), x_sw);
             copy_mem(reg.begin(), z.begin(), z.size());
             set_sign(y.sign());
         } else if (relative_size == 0) {
             reg.clear();
             set_sign(Positive);
         } else if (relative_size > 0)
             bigint_sub2(get_reg(), x_sw, y.data(), y_sw);
     }
 
     return (*this);
 }
 
 /*************************************************
  * Subtraction Operator                           *
  *************************************************/
 BigInt &BigInt::operator-=(const BigInt &y)
 {
     const u32bit x_sw = sig_words(), y_sw = y.sig_words();
 
     s32bit relative_size = bigint_cmp(data(), x_sw, y.data(), y_sw);
 
 #ifdef BOTAN_TYPES_QT
     const u32bit reg_size = qMax(x_sw, y_sw) + 1;
 #else
     const u32bit reg_size = std::max(x_sw, y_sw) + 1;
 #endif
     grow_to(reg_size);
 
     if (relative_size < 0) {
         if (sign() == y.sign()) {
             SecureVector<word> z(reg_size - 1);
             bigint_sub3(z, y.data(), reg_size - 1, data(), x_sw);
             copy_mem(reg.begin(), z.begin(), z.size());
         } else
             bigint_add2(get_reg(), reg_size - 1, y.data(), y_sw);
 
         set_sign(y.reverse_sign());
     } else if (relative_size == 0) {
         if (sign() == y.sign()) {
             reg.clear();
             set_sign(Positive);
         } else
             bigint_shl1(get_reg(), x_sw, 0, 1);
     } else if (relative_size > 0) {
         if (sign() == y.sign())
             bigint_sub2(get_reg(), x_sw, y.data(), y_sw);
         else
             bigint_add2(get_reg(), reg_size - 1, y.data(), y_sw);
     }
 
     return (*this);
 }
 
 /*************************************************
  * Multiplication Operator                        *
  *************************************************/
 BigInt &BigInt::operator*=(const BigInt &y)
 {
     const u32bit x_sw = sig_words(), y_sw = y.sig_words();
     set_sign((sign() == y.sign()) ? Positive : Negative);
 
     if (x_sw == 0 || y_sw == 0) {
         reg.clear();
         set_sign(Positive);
     } else if (x_sw == 1 && y_sw) {
         grow_to(y_sw + 2);
         bigint_linmul3(get_reg(), y.data(), y_sw, word_at(0));
     } else if (y_sw == 1 && x_sw) {
         grow_to(x_sw + 2);
         bigint_linmul2(get_reg(), x_sw, y.word_at(0));
     } else {
         grow_to(size() + y.size());
 
         SecureVector<word> z(data(), x_sw);
         SecureVector<word> workspace(size());
 
         bigint_mul(get_reg(), size(), workspace, z, z.size(), x_sw, y.data(), y.size(), y_sw);
     }
 
     return (*this);
 }
 
 /*************************************************
  * Division Operator                              *
  *************************************************/
 BigInt &BigInt::operator/=(const BigInt &y)
 {
     if (y.sig_words() == 1 && power_of_2(y.word_at(0)))
         (*this) >>= (y.bits() - 1);
     else
         (*this) = (*this) / y;
     return (*this);
 }
 
 /*************************************************
  * Modulo Operator                                *
  *************************************************/
 BigInt &BigInt::operator%=(const BigInt &mod)
 {
     return (*this = (*this) % mod);
 }
 
 /*************************************************
  * Modulo Operator                                *
  *************************************************/
 word BigInt::operator%=(word mod)
 {
     if (mod == 0)
         throw BigInt::DivideByZero();
     if (power_of_2(mod)) {
         word result = (word_at(0) & (mod - 1));
         clear();
         grow_to(2);
         reg[0] = result;
         return result;
     }
 
     word remainder = 0;
 
     for (u32bit j = sig_words(); j > 0; --j)
         remainder = bigint_modop(remainder, word_at(j - 1), mod);
     clear();
     grow_to(2);
 
     if (remainder && sign() == BigInt::Negative)
         reg[0] = mod - remainder;
     else
         reg[0] = remainder;
 
     set_sign(BigInt::Positive);
 
     return word_at(0);
 }
 
 /*************************************************
  * Left Shift Operator                            *
  *************************************************/
 BigInt &BigInt::operator<<=(u32bit shift)
 {
     if (shift) {
         const u32bit shift_words = shift / MP_WORD_BITS, shift_bits = shift % MP_WORD_BITS, words = sig_words();
 
         grow_to(words + shift_words + (shift_bits ? 1 : 0));
         bigint_shl1(get_reg(), words, shift_words, shift_bits);
     }
 
     return (*this);
 }
 
 /*************************************************
  * Right Shift Operator                           *
  *************************************************/
 BigInt &BigInt::operator>>=(u32bit shift)
 {
     if (shift) {
         const u32bit shift_words = shift / MP_WORD_BITS, shift_bits = shift % MP_WORD_BITS;
 
         bigint_shr1(get_reg(), sig_words(), shift_words, shift_bits);
 
         if (is_zero())
             set_sign(Positive);
     }
 
     return (*this);
 }
 
 }
 } // WRAPNS_LINE