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d4efd44fb0
git-svn-id: https://zxing.googlecode.com/svn/trunk@1202 59b500cc-1b3d-0410-9834-0bbf25fbcc57
89 lines
3.3 KiB
C#
Executable file
89 lines
3.3 KiB
C#
Executable file
/*
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* Copyright 2008 ZXing authors
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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using System;
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namespace com.google.zxing.common.reedsolomon
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{
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/// <summary> <p>Implements Reed-Solomon enbcoding, as the name implies.</p>
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///
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/// </summary>
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/// <author> Sean Owen
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/// </author>
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/// <author> William Rucklidge
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/// </author>
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/// <author>www.Redivivus.in (suraj.supekar@redivivus.in) - Ported from ZXING Java Source
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/// </author>
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public sealed class ReedSolomonEncoder
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{
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//UPGRADE_NOTE: Final was removed from the declaration of 'field '. "ms-help://MS.VSCC.v80/dv_commoner/local/redirect.htm?index='!DefaultContextWindowIndex'&keyword='jlca1003'"
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private GF256 field;
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//UPGRADE_NOTE: Final was removed from the declaration of 'cachedGenerators '. "ms-help://MS.VSCC.v80/dv_commoner/local/redirect.htm?index='!DefaultContextWindowIndex'&keyword='jlca1003'"
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private System.Collections.ArrayList cachedGenerators;
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public ReedSolomonEncoder(GF256 field)
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{
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if (!GF256.QR_CODE_FIELD.Equals(field))
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{
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throw new System.ArgumentException("Only QR Code is supported at this time");
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}
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this.field = field;
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this.cachedGenerators = System.Collections.ArrayList.Synchronized(new System.Collections.ArrayList(10));
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cachedGenerators.Add(new GF256Poly(field, new int[]{1}));
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}
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private GF256Poly buildGenerator(int degree)
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{
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if (degree >= cachedGenerators.Count)
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{
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GF256Poly lastGenerator = (GF256Poly) cachedGenerators[cachedGenerators.Count - 1];
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for (int d = cachedGenerators.Count; d <= degree; d++)
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{
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GF256Poly nextGenerator = lastGenerator.multiply(new GF256Poly(field, new int[]{1, field.exp(d - 1)}));
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cachedGenerators.Add(nextGenerator);
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lastGenerator = nextGenerator;
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}
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}
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return (GF256Poly) cachedGenerators[degree];
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}
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public void encode(int[] toEncode, int ecBytes)
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{
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if (ecBytes == 0)
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{
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throw new System.ArgumentException("No error correction bytes");
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}
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int dataBytes = toEncode.Length - ecBytes;
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if (dataBytes <= 0)
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{
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throw new System.ArgumentException("No data bytes provided");
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}
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GF256Poly generator = buildGenerator(ecBytes);
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int[] infoCoefficients = new int[dataBytes];
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Array.Copy(toEncode, 0, infoCoefficients, 0, dataBytes);
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GF256Poly info = new GF256Poly(field, infoCoefficients);
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info = info.multiplyByMonomial(ecBytes, 1);
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GF256Poly remainder = info.divide(generator)[1];
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int[] coefficients = remainder.Coefficients;
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int numZeroCoefficients = ecBytes - coefficients.Length;
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for (int i = 0; i < numZeroCoefficients; i++)
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{
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toEncode[dataBytes + i] = 0;
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}
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Array.Copy(coefficients, 0, toEncode, dataBytes + numZeroCoefficients, coefficients.Length);
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}
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}
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} |