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Diffstat (limited to 'tools/source/generic/bigint.cxx')
-rw-r--r-- | tools/source/generic/bigint.cxx | 852 |
1 files changed, 852 insertions, 0 deletions
diff --git a/tools/source/generic/bigint.cxx b/tools/source/generic/bigint.cxx new file mode 100644 index 0000000000..51810cab17 --- /dev/null +++ b/tools/source/generic/bigint.cxx @@ -0,0 +1,852 @@ +/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */ +/* + * This file is part of the LibreOffice project. + * + * This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at http://mozilla.org/MPL/2.0/. + * + * This file incorporates work covered by the following license notice: + * + * Licensed to the Apache Software Foundation (ASF) under one or more + * contributor license agreements. See the NOTICE file distributed + * with this work for additional information regarding copyright + * ownership. The ASF licenses this file to you under the Apache + * License, Version 2.0 (the "License"); you may not use this file + * except in compliance with the License. You may obtain a copy of + * the License at http://www.apache.org/licenses/LICENSE-2.0 . + */ + +#include <math.h> + +#include <osl/diagnose.h> +#include <tools/bigint.hxx> + +#include <algorithm> +#include <string.h> + +/** + * The range in which we can perform add/sub without fear of overflow + */ +const sal_Int32 MY_MAXLONG = 0x3fffffff; +const sal_Int32 MY_MINLONG = -MY_MAXLONG; + +/* + * The algorithms for Addition, Subtraction, Multiplication and Division + * of large numbers originate from SEMINUMERICAL ALGORITHMS by + * DONALD E. KNUTH in the series The Art of Computer Programming: + * chapter 4.3.1. The Classical Algorithms. + */ + +// TODO: Needs conversion to sal_uInt16/INT16/sal_uInt32/sal_Int32 +void BigInt::MakeBigInt( const BigInt& rVal ) +{ + if ( rVal.nLen != 0 ) + { + memcpy( static_cast<void*>(this), static_cast<const void*>(&rVal), sizeof( BigInt ) ); + while ( nLen > 1 && nNum[nLen-1] == 0 ) + nLen--; + } + else + { + nVal = rVal.nVal; + sal_uInt32 nTmp; + if (nVal < 0) + { + bIsNeg = true; + nTmp = -static_cast<sal_Int64>(nVal); + } + else + { + bIsNeg = false; + nTmp = nVal; + } + + nNum[0] = static_cast<sal_uInt16>(nTmp & 0xffffL); + nNum[1] = static_cast<sal_uInt16>(nTmp >> 16); + if ( nTmp & 0xffff0000L ) + nLen = 2; + else + nLen = 1; + } +} + +void BigInt::Normalize() +{ + if ( nLen != 0 ) + { + while ( nLen > 1 && nNum[nLen-1] == 0 ) + nLen--; + + if ( nLen < 3 ) + { + sal_Int32 newVal; + if ( nLen < 2 ) + newVal = nNum[0]; + else if ( nNum[1] & 0x8000 ) + return; + else + newVal = (static_cast<sal_Int32>(nNum[1]) << 16) + nNum[0]; + + nLen = 0; + nVal = newVal; + + if ( bIsNeg ) + nVal = -nVal; + } + // else nVal is undefined !!! W.P. + } + // why? nVal is undefined ??? W.P. + else if ( nVal & 0xFFFF0000L ) + nLen = 2; + else + nLen = 1; +} + +void BigInt::Mult( const BigInt &rVal, sal_uInt16 nMul ) +{ + sal_uInt16 nK = 0; + for ( int i = 0; i < rVal.nLen; i++ ) + { + sal_uInt32 nTmp = static_cast<sal_uInt32>(rVal.nNum[i]) * static_cast<sal_uInt32>(nMul) + nK; + nK = static_cast<sal_uInt16>(nTmp >> 16); + nNum[i] = static_cast<sal_uInt16>(nTmp); + } + + if ( nK ) + { + nNum[rVal.nLen] = nK; + nLen = rVal.nLen + 1; + } + else + nLen = rVal.nLen; + + bIsNeg = rVal.bIsNeg; +} + +void BigInt::Div( sal_uInt16 nDiv, sal_uInt16& rRem ) +{ + sal_uInt32 nK = 0; + for ( int i = nLen - 1; i >= 0; i-- ) + { + sal_uInt32 nTmp = static_cast<sal_uInt32>(nNum[i]) + (nK << 16); + nNum[i] = static_cast<sal_uInt16>(nTmp / nDiv); + nK = nTmp % nDiv; + } + rRem = static_cast<sal_uInt16>(nK); + + if ( nNum[nLen-1] == 0 ) + nLen -= 1; +} + +bool BigInt::IsLess( const BigInt& rVal ) const +{ + if ( rVal.nLen < nLen) + return true; + if ( rVal.nLen > nLen ) + return false; + + int i; + for ( i = nLen - 1; i > 0 && nNum[i] == rVal.nNum[i]; i-- ) + { + } + return rVal.nNum[i] < nNum[i]; +} + +void BigInt::AddLong( BigInt& rB, BigInt& rErg ) +{ + if ( bIsNeg == rB.bIsNeg ) + { + int i; + char len; + + // if length of the two values differ, fill remaining positions + // of the smaller value with zeros. + if (nLen >= rB.nLen) + { + len = nLen; + for (i = rB.nLen; i < len; i++) + rB.nNum[i] = 0; + } + else + { + len = rB.nLen; + for (i = nLen; i < len; i++) + nNum[i] = 0; + } + + // Add numerals, starting from the back + sal_Int32 k; + sal_Int32 nZ = 0; + for (i = 0, k = 0; i < len; i++) { + nZ = static_cast<sal_Int32>(nNum[i]) + static_cast<sal_Int32>(rB.nNum[i]) + k; + if (nZ & 0xff0000L) + k = 1; + else + k = 0; + rErg.nNum[i] = static_cast<sal_uInt16>(nZ & 0xffffL); + } + // If an overflow occurred, add to solution + if (nZ & 0xff0000L) // or if(k) + { + rErg.nNum[i] = 1; + len++; + } + // Set length and sign + rErg.nLen = len; + rErg.bIsNeg = bIsNeg && rB.bIsNeg; + } + // If one of the values is negative, perform subtraction instead + else if (bIsNeg) + { + bIsNeg = false; + rB.SubLong(*this, rErg); + bIsNeg = true; + } + else + { + rB.bIsNeg = false; + SubLong(rB, rErg); + rB.bIsNeg = true; + } +} + +void BigInt::SubLong( BigInt& rB, BigInt& rErg ) +{ + if ( bIsNeg == rB.bIsNeg ) + { + int i; + char len; + sal_Int32 nZ, k; + + // if length of the two values differ, fill remaining positions + // of the smaller value with zeros. + if (nLen >= rB.nLen) + { + len = nLen; + for (i = rB.nLen; i < len; i++) + rB.nNum[i] = 0; + } + else + { + len = rB.nLen; + for (i = nLen; i < len; i++) + nNum[i] = 0; + } + + if ( IsLess(rB) ) + { + for (i = 0, k = 0; i < len; i++) + { + nZ = static_cast<sal_Int32>(nNum[i]) - static_cast<sal_Int32>(rB.nNum[i]) + k; + if (nZ < 0) + k = -1; + else + k = 0; + rErg.nNum[i] = static_cast<sal_uInt16>(nZ & 0xffffL); + } + rErg.bIsNeg = bIsNeg; + } + else + { + for (i = 0, k = 0; i < len; i++) + { + nZ = static_cast<sal_Int32>(rB.nNum[i]) - static_cast<sal_Int32>(nNum[i]) + k; + if (nZ < 0) + k = -1; + else + k = 0; + rErg.nNum[i] = static_cast<sal_uInt16>(nZ & 0xffffL); + } + // if a < b, revert sign + rErg.bIsNeg = !bIsNeg; + } + rErg.nLen = len; + } + // If one of the values is negative, perform addition instead + else if (bIsNeg) + { + bIsNeg = false; + AddLong(rB, rErg); + bIsNeg = true; + rErg.bIsNeg = true; + } + else + { + rB.bIsNeg = false; + AddLong(rB, rErg); + rB.bIsNeg = true; + rErg.bIsNeg = false; + } +} + +void BigInt::MultLong( const BigInt& rB, BigInt& rErg ) const +{ + int i, j; + sal_uInt32 nZ, k; + + rErg.bIsNeg = bIsNeg != rB.bIsNeg; + rErg.nLen = nLen + rB.nLen; + + for (i = 0; i < rErg.nLen; i++) + rErg.nNum[i] = 0; + + for (j = 0; j < rB.nLen; j++) + { + for (i = 0, k = 0; i < nLen; i++) + { + nZ = static_cast<sal_uInt32>(nNum[i]) * static_cast<sal_uInt32>(rB.nNum[j]) + + static_cast<sal_uInt32>(rErg.nNum[i + j]) + k; + rErg.nNum[i + j] = static_cast<sal_uInt16>(nZ & 0xffffU); + k = nZ >> 16; + } + rErg.nNum[i + j] = static_cast<sal_uInt16>(k); + } +} + +void BigInt::DivLong( const BigInt& rB, BigInt& rErg ) const +{ + int i, j; + sal_uInt16 nK, nQ, nMult; + sal_uInt16 nLenB = rB.nLen; + sal_uInt16 nLenB1 = rB.nLen - 1; + BigInt aTmpA, aTmpB; + + nMult = static_cast<sal_uInt16>(0x10000L / (static_cast<sal_Int32>(rB.nNum[nLenB1]) + 1)); + + aTmpA.Mult( *this, nMult ); + if ( aTmpA.nLen == nLen ) + { + aTmpA.nNum[aTmpA.nLen] = 0; + aTmpA.nLen++; + } + + aTmpB.Mult( rB, nMult ); + + for (j = aTmpA.nLen - 1; j >= nLenB; j--) + { // guess divisor + sal_uInt32 nTmp = ( static_cast<sal_uInt32>(aTmpA.nNum[j]) << 16 ) + aTmpA.nNum[j - 1]; + if (aTmpA.nNum[j] == aTmpB.nNum[nLenB1]) + nQ = 0xFFFF; + else + nQ = static_cast<sal_uInt16>(nTmp / aTmpB.nNum[nLenB1]); + + if ( (static_cast<sal_uInt32>(aTmpB.nNum[nLenB1 - 1]) * nQ) > + ((nTmp - static_cast<sal_uInt32>(aTmpB.nNum[nLenB1]) * nQ) << 16) + aTmpA.nNum[j - 2]) + nQ--; + // Start division + nK = 0; + for (i = 0; i < nLenB; i++) + { + nTmp = static_cast<sal_uInt32>(aTmpA.nNum[j - nLenB + i]) + - (static_cast<sal_uInt32>(aTmpB.nNum[i]) * nQ) + - nK; + aTmpA.nNum[j - nLenB + i] = static_cast<sal_uInt16>(nTmp); + nK = static_cast<sal_uInt16>(nTmp >> 16); + if ( nK ) + nK = static_cast<sal_uInt16>(0x10000U - nK); + } + sal_uInt16& rNum( aTmpA.nNum[j - nLenB + i] ); + rNum -= nK; + if (aTmpA.nNum[j - nLenB + i] == 0) + rErg.nNum[j - nLenB] = nQ; + else + { + rErg.nNum[j - nLenB] = nQ - 1; + nK = 0; + for (i = 0; i < nLenB; i++) + { + nTmp = aTmpA.nNum[j - nLenB + i] + aTmpB.nNum[i] + nK; + aTmpA.nNum[j - nLenB + i] = static_cast<sal_uInt16>(nTmp & 0xFFFFL); + if (nTmp & 0xFFFF0000L) + nK = 1; + else + nK = 0; + } + } + } + + rErg.bIsNeg = bIsNeg != rB.bIsNeg; + rErg.nLen = nLen - rB.nLen + 1; +} + +void BigInt::ModLong( const BigInt& rB, BigInt& rErg ) const +{ + sal_uInt16 i, j; + sal_uInt16 nK, nQ, nMult; + sal_Int16 nLenB = rB.nLen; + sal_Int16 nLenB1 = rB.nLen - 1; + BigInt aTmpA, aTmpB; + + nMult = static_cast<sal_uInt16>(0x10000L / (static_cast<sal_Int32>(rB.nNum[nLenB1]) + 1)); + + aTmpA.Mult( *this, nMult); + if ( aTmpA.nLen == nLen ) + { + aTmpA.nNum[aTmpA.nLen] = 0; + aTmpA.nLen++; + } + + aTmpB.Mult( rB, nMult); + + for (j = aTmpA.nLen - 1; j >= nLenB; j--) + { // Guess divisor + sal_uInt32 nTmp = ( static_cast<sal_uInt32>(aTmpA.nNum[j]) << 16 ) + aTmpA.nNum[j - 1]; + if (aTmpA.nNum[j] == aTmpB.nNum[nLenB1]) + nQ = 0xFFFF; + else + nQ = static_cast<sal_uInt16>(nTmp / aTmpB.nNum[nLenB1]); + + if ( (static_cast<sal_uInt32>(aTmpB.nNum[nLenB1 - 1]) * nQ) > + ((nTmp - aTmpB.nNum[nLenB1] * nQ) << 16) + aTmpA.nNum[j - 2]) + nQ--; + // Start division + nK = 0; + for (i = 0; i < nLenB; i++) + { + nTmp = static_cast<sal_uInt32>(aTmpA.nNum[j - nLenB + i]) + - (static_cast<sal_uInt32>(aTmpB.nNum[i]) * nQ) + - nK; + aTmpA.nNum[j - nLenB + i] = static_cast<sal_uInt16>(nTmp); + nK = static_cast<sal_uInt16>(nTmp >> 16); + if ( nK ) + nK = static_cast<sal_uInt16>(0x10000U - nK); + } + sal_uInt16& rNum( aTmpA.nNum[j - nLenB + i] ); + rNum = rNum - nK; + if (aTmpA.nNum[j - nLenB + i] == 0) + rErg.nNum[j - nLenB] = nQ; + else + { + rErg.nNum[j - nLenB] = nQ - 1; + nK = 0; + for (i = 0; i < nLenB; i++) { + nTmp = aTmpA.nNum[j - nLenB + i] + aTmpB.nNum[i] + nK; + aTmpA.nNum[j - nLenB + i] = static_cast<sal_uInt16>(nTmp & 0xFFFFL); + if (nTmp & 0xFFFF0000L) + nK = 1; + else + nK = 0; + } + } + } + + rErg = aTmpA; + rErg.Div( nMult, nQ ); +} + +bool BigInt::ABS_IsLess( const BigInt& rB ) const +{ + if (nLen != 0 || rB.nLen != 0) + { + BigInt nA, nB; + nA.MakeBigInt( *this ); + nB.MakeBigInt( rB ); + if (nA.nLen == nB.nLen) + { + int i; + for (i = nA.nLen - 1; i > 0 && nA.nNum[i] == nB.nNum[i]; i--) + { + } + return nA.nNum[i] < nB.nNum[i]; + } + else + return nA.nLen < nB.nLen; + } + if ( nVal < 0 ) + if ( rB.nVal < 0 ) + return nVal > rB.nVal; + else + return nVal > -rB.nVal; + else + if ( rB.nVal < 0 ) + return nVal < -rB.nVal; + else + return nVal < rB.nVal; +} + +BigInt::BigInt( const BigInt& rBigInt ) + : nLen(0) + , bIsNeg(false) +{ + if ( rBigInt.nLen != 0 ) + memcpy( static_cast<void*>(this), static_cast<const void*>(&rBigInt), sizeof( BigInt ) ); + else + nVal = rBigInt.nVal; +} + +BigInt::BigInt( std::u16string_view rString ) + : nLen(0) +{ + bIsNeg = false; + nVal = 0; + + bool bNeg = false; + auto p = rString.begin(); + auto pEnd = rString.end(); + if (p == pEnd) + return; + if ( *p == '-' ) + { + bNeg = true; + p++; + } + if (p == pEnd) + return; + while( p != pEnd && *p >= '0' && *p <= '9' ) + { + *this *= 10; + *this += *p - '0'; + p++; + } + if ( nLen != 0 ) + bIsNeg = bNeg; + else if( bNeg ) + nVal = -nVal; +} + +BigInt::BigInt( double nValue ) + : nVal(0) +{ + if ( nValue < 0 ) + { + nValue *= -1; + bIsNeg = true; + } + else + { + bIsNeg = false; + } + + if ( nValue < 1 ) + { + nVal = 0; + nLen = 0; + } + else + { + int i=0; + + while ( ( nValue > 65536.0 ) && ( i < MAX_DIGITS ) ) + { + nNum[i] = static_cast<sal_uInt16>(fmod( nValue, 65536.0 )); + nValue -= nNum[i]; + nValue /= 65536.0; + i++; + } + if ( i < MAX_DIGITS ) + nNum[i++] = static_cast<sal_uInt16>(nValue); + + nLen = i; + + if ( i < 3 ) + Normalize(); + } +} + +BigInt::BigInt( sal_uInt32 nValue ) + : nVal(0) +{ + if ( nValue & 0x80000000U ) + { + bIsNeg = false; + nNum[0] = static_cast<sal_uInt16>(nValue & 0xffffU); + nNum[1] = static_cast<sal_uInt16>(nValue >> 16); + nLen = 2; + } + else + { + bIsNeg = false; + nVal = nValue; + nLen = 0; + } +} + +BigInt::BigInt( sal_Int64 nValue ) + : nVal(0) +{ + bIsNeg = nValue < 0; + nLen = 0; + + if ((nValue >= SAL_MIN_INT32) && (nValue <= SAL_MAX_INT32)) + { + nVal = static_cast<sal_Int32>(nValue); + } + else + { + sal_uInt64 nUValue = static_cast<sal_uInt64>(bIsNeg ? -nValue : nValue); + for (int i = 0; (i != sizeof(sal_uInt64) / 2) && (nUValue != 0); ++i) + { + nNum[i] = static_cast<sal_uInt16>(nUValue & 0xffffUL); + nUValue = nUValue >> 16; + ++nLen; + } + } +} + +BigInt::operator double() const +{ + if ( nLen == 0 ) + return static_cast<double>(nVal); + else + { + int i = nLen-1; + double nRet = static_cast<double>(static_cast<sal_uInt32>(nNum[i])); + + while ( i ) + { + nRet *= 65536.0; + i--; + nRet += static_cast<double>(static_cast<sal_uInt32>(nNum[i])); + } + + if ( bIsNeg ) + nRet *= -1; + + return nRet; + } +} + +BigInt& BigInt::operator=( const BigInt& rBigInt ) +{ + if (this == &rBigInt) + return *this; + + if ( rBigInt.nLen != 0 ) + memcpy( static_cast<void*>(this), static_cast<const void*>(&rBigInt), sizeof( BigInt ) ); + else + { + nLen = 0; + nVal = rBigInt.nVal; + } + return *this; +} + +BigInt& BigInt::operator+=( const BigInt& rVal ) +{ + if ( nLen == 0 && rVal.nLen == 0 ) + { + if( nVal <= MY_MAXLONG && rVal.nVal <= MY_MAXLONG + && nVal >= MY_MINLONG && rVal.nVal >= MY_MINLONG ) + { // No overflows may occur here + nVal += rVal.nVal; + return *this; + } + + if( (nVal < 0) != (rVal.nVal < 0) ) + { // No overflows may occur here + nVal += rVal.nVal; + return *this; + } + } + + BigInt aTmp1, aTmp2; + aTmp1.MakeBigInt( *this ); + aTmp2.MakeBigInt( rVal ); + aTmp1.AddLong( aTmp2, *this ); + Normalize(); + return *this; +} + +BigInt& BigInt::operator-=( const BigInt& rVal ) +{ + if ( nLen == 0 && rVal.nLen == 0 ) + { + if ( nVal <= MY_MAXLONG && rVal.nVal <= MY_MAXLONG && + nVal >= MY_MINLONG && rVal.nVal >= MY_MINLONG ) + { // No overflows may occur here + nVal -= rVal.nVal; + return *this; + } + + if ( (nVal < 0) == (rVal.nVal < 0) ) + { // No overflows may occur here + nVal -= rVal.nVal; + return *this; + } + } + + BigInt aTmp1, aTmp2; + aTmp1.MakeBigInt( *this ); + aTmp2.MakeBigInt( rVal ); + aTmp1.SubLong( aTmp2, *this ); + Normalize(); + return *this; +} + +BigInt& BigInt::operator*=( const BigInt& rVal ) +{ + static const sal_Int32 MY_MAXSHORT = 0x00007fff; + static const sal_Int32 MY_MINSHORT = -MY_MAXSHORT; + + if ( nLen == 0 && rVal.nLen == 0 + && nVal <= MY_MAXSHORT && rVal.nVal <= MY_MAXSHORT + && nVal >= MY_MINSHORT && rVal.nVal >= MY_MINSHORT ) + // TODO: not optimal !!! W.P. + { // No overflows may occur here + nVal *= rVal.nVal; + } + else + { + BigInt aTmp1, aTmp2; + aTmp1.MakeBigInt( rVal ); + aTmp2.MakeBigInt( *this ); + aTmp1.MultLong(aTmp2, *this); + Normalize(); + } + return *this; +} + +BigInt& BigInt::operator/=( const BigInt& rVal ) +{ + if ( rVal.nLen == 0 ) + { + if ( rVal.nVal == 0 ) + { + OSL_FAIL( "BigInt::operator/ --> divide by zero" ); + return *this; + } + + if ( nLen == 0 ) + { + // No overflows may occur here + nVal /= rVal.nVal; + return *this; + } + + if ( rVal.nVal == 1 ) + return *this; + + if ( rVal.nVal == -1 ) + { + bIsNeg = !bIsNeg; + return *this; + } + + if ( rVal.nVal <= 0xFFFF && rVal.nVal >= -0xFFFF ) + { + // Divide BigInt with an sal_uInt16 + sal_uInt16 nTmp; + if ( rVal.nVal < 0 ) + { + nTmp = static_cast<sal_uInt16>(-rVal.nVal); + bIsNeg = !bIsNeg; + } + else + nTmp = static_cast<sal_uInt16>(rVal.nVal); + + Div( nTmp, nTmp ); + Normalize(); + return *this; + } + } + + if ( ABS_IsLess( rVal ) ) + { + *this = BigInt( 0 ); + return *this; + } + + // Divide BigInt with BigInt + BigInt aTmp1, aTmp2; + aTmp1.MakeBigInt( *this ); + aTmp2.MakeBigInt( rVal ); + aTmp1.DivLong(aTmp2, *this); + Normalize(); + return *this; +} + +BigInt& BigInt::operator%=( const BigInt& rVal ) +{ + if ( rVal.nLen == 0 ) + { + if ( rVal.nVal == 0 ) + { + OSL_FAIL( "BigInt::operator/ --> divide by zero" ); + return *this; + } + + if ( nLen == 0 ) + { + // No overflows may occur here + nVal %= rVal.nVal; + return *this; + } + + if ( rVal.nVal <= 0xFFFF && rVal.nVal >= -0xFFFF ) + { + // Divide Bigint by int16 + sal_uInt16 nTmp; + if ( rVal.nVal < 0 ) + { + nTmp = static_cast<sal_uInt16>(-rVal.nVal); + bIsNeg = !bIsNeg; + } + else + nTmp = static_cast<sal_uInt16>(rVal.nVal); + + Div( nTmp, nTmp ); + *this = BigInt( nTmp ); + return *this; + } + } + + if ( ABS_IsLess( rVal ) ) + return *this; + + // Divide BigInt with BigInt + BigInt aTmp1, aTmp2; + aTmp1.MakeBigInt( *this ); + aTmp2.MakeBigInt( rVal ); + aTmp1.ModLong(aTmp2, *this); + Normalize(); + return *this; +} + +bool operator==( const BigInt& rVal1, const BigInt& rVal2 ) +{ + if (rVal1.nLen == 0 && rVal2.nLen == 0) + return rVal1.nVal == rVal2.nVal; + + BigInt nA, nB; + nA.MakeBigInt(rVal1); + nB.MakeBigInt(rVal2); + return nA.bIsNeg == nB.bIsNeg && nA.nLen == nB.nLen + && std::equal(nA.nNum, nA.nNum + nA.nLen, nB.nNum); +} + +bool operator<( const BigInt& rVal1, const BigInt& rVal2 ) +{ + if (rVal1.nLen == 0 && rVal2.nLen == 0) + return rVal1.nVal < rVal2.nVal; + + BigInt nA, nB; + nA.MakeBigInt(rVal1); + nB.MakeBigInt(rVal2); + if (nA.bIsNeg != nB.bIsNeg) + return !nB.bIsNeg; + if (nA.nLen != nB.nLen) + return nA.bIsNeg ? (nA.nLen > nB.nLen) : (nA.nLen < nB.nLen); + int i = nA.nLen - 1; + while (i > 0 && nA.nNum[i] == nB.nNum[i]) + --i; + return nA.bIsNeg ? (nA.nNum[i] > nB.nNum[i]) : (nA.nNum[i] < nB.nNum[i]); +} + +tools::Long BigInt::Scale( tools::Long nVal, tools::Long nMul, tools::Long nDiv ) +{ + BigInt aVal( nVal ); + + aVal *= nMul; + + if ( aVal.IsNeg() != ( nDiv < 0 ) ) + aVal -= nDiv / 2; // for correct rounding + else + aVal += nDiv / 2; // for correct rounding + + aVal /= nDiv; + + return tools::Long( aVal ); +} + +/* vim:set shiftwidth=4 softtabstop=4 expandtab: */ |