qrazybox/js/jsqrcode/gf256poly.js
2018-05-11 03:30:12 +07:00

230 lines
No EOL
6.3 KiB
JavaScript

/*
Ported to JavaScript by Lazar Laszlo 2011
lazarsoft@gmail.com, www.lazarsoft.info
*/
/*
*
* Copyright 2007 ZXing authors
*
* Licensed 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
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
function GF256Poly(field, coefficients)
{
if (coefficients == null || coefficients.length == 0)
{
throw "System.ArgumentException";
}
this.field = field;
var coefficientsLength = coefficients.length;
if (coefficientsLength > 1 && coefficients[0] == 0)
{
// Leading term must be non-zero for anything except the constant polynomial "0"
var firstNonZero = 1;
while (firstNonZero < coefficientsLength && coefficients[firstNonZero] == 0)
{
firstNonZero++;
}
if (firstNonZero == coefficientsLength)
{
this.coefficients = field.Zero.coefficients;
}
else
{
this.coefficients = new Array(coefficientsLength - firstNonZero);
for(var i=0;i<this.coefficients.length;i++)this.coefficients[i]=0;
//Array.Copy(coefficients, firstNonZero, this.coefficients, 0, this.coefficients.length);
for(var ci=0;ci<this.coefficients.length;ci++)this.coefficients[ci]=coefficients[firstNonZero+ci];
}
}
else
{
this.coefficients = coefficients;
}
this.__defineGetter__("Zero", function()
{
return this.coefficients[0] == 0;
});
this.__defineGetter__("Degree", function()
{
return this.coefficients.length - 1;
});
this.__defineGetter__("Coefficients", function()
{
return this.coefficients;
});
this.getCoefficient=function( degree)
{
return this.coefficients[this.coefficients.length - 1 - degree];
}
this.evaluateAt=function( a)
{
if (a == 0)
{
// Just return the x^0 coefficient
return this.getCoefficient(0);
}
var size = this.coefficients.length;
if (a == 1)
{
// Just the sum of the coefficients
var result = 0;
for (var i = 0; i < size; i++)
{
result = GF256.addOrSubtract(result, this.coefficients[i]);
}
return result;
}
var result2 = this.coefficients[0];
for (var i = 1; i < size; i++)
{
result2 = GF256.addOrSubtract(this.field.multiply(a, result2), this.coefficients[i]);
}
return result2;
}
this.addOrSubtract=function( other)
{
if (this.field != other.field)
{
throw "GF256Polys do not have same GF256 field";
}
if (this.Zero)
{
return other;
}
if (other.Zero)
{
return this;
}
var smallerCoefficients = this.coefficients;
var largerCoefficients = other.coefficients;
if (smallerCoefficients.length > largerCoefficients.length)
{
var temp = smallerCoefficients;
smallerCoefficients = largerCoefficients;
largerCoefficients = temp;
}
var sumDiff = new Array(largerCoefficients.length);
var lengthDiff = largerCoefficients.length - smallerCoefficients.length;
// Copy high-order terms only found in higher-degree polynomial's coefficients
//Array.Copy(largerCoefficients, 0, sumDiff, 0, lengthDiff);
for(var ci=0;ci<lengthDiff;ci++)sumDiff[ci]=largerCoefficients[ci];
for (var i = lengthDiff; i < largerCoefficients.length; i++)
{
sumDiff[i] = GF256.addOrSubtract(smallerCoefficients[i - lengthDiff], largerCoefficients[i]);
}
return new GF256Poly(field, sumDiff);
}
this.multiply1=function( other)
{
if (this.field!=other.field)
{
throw "GF256Polys do not have same GF256 field";
}
if (this.Zero || other.Zero)
{
return this.field.Zero;
}
var aCoefficients = this.coefficients;
var aLength = aCoefficients.length;
var bCoefficients = other.coefficients;
var bLength = bCoefficients.length;
var product = new Array(aLength + bLength - 1);
for (var i = 0; i < aLength; i++)
{
var aCoeff = aCoefficients[i];
for (var j = 0; j < bLength; j++)
{
product[i + j] = GF256.addOrSubtract(product[i + j], this.field.multiply(aCoeff, bCoefficients[j]));
}
}
return new GF256Poly(this.field, product);
}
this.multiply2=function( scalar)
{
if (scalar == 0)
{
return this.field.Zero;
}
if (scalar == 1)
{
return this;
}
var size = this.coefficients.length;
var product = new Array(size);
for (var i = 0; i < size; i++)
{
product[i] = this.field.multiply(this.coefficients[i], scalar);
}
return new GF256Poly(this.field, product);
}
this.multiplyByMonomial=function( degree, coefficient)
{
if (degree < 0)
{
throw "System.ArgumentException";
}
if (coefficient == 0)
{
return this.field.Zero;
}
var size = this.coefficients.length;
var product = new Array(size + degree);
for(var i=0;i<product.length;i++)product[i]=0;
for (var i = 0; i < size; i++)
{
product[i] = this.field.multiply(this.coefficients[i], coefficient);
}
return new GF256Poly(this.field, product);
}
this.divide=function( other)
{
if (this.field!=other.field)
{
throw "GF256Polys do not have same GF256 field";
}
if (other.Zero)
{
throw "Divide by 0";
}
var quotient = this.field.Zero;
var remainder = this;
var denominatorLeadingTerm = other.getCoefficient(other.Degree);
var inverseDenominatorLeadingTerm = this.field.inverse(denominatorLeadingTerm);
while (remainder.Degree >= other.Degree && !remainder.Zero)
{
var degreeDifference = remainder.Degree - other.Degree;
var scale = this.field.multiply(remainder.getCoefficient(remainder.Degree), inverseDenominatorLeadingTerm);
var term = other.multiplyByMonomial(degreeDifference, scale);
var iterationQuotient = this.field.buildMonomial(degreeDifference, scale);
quotient = quotient.addOrSubtract(iterationQuotient);
remainder = remainder.addOrSubtract(term);
}
return new Array(quotient, remainder);
}
}