74 lines
2.6 KiB
C#
74 lines
2.6 KiB
C#
using System;
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using System.IO;
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/*
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* Reference arithmetic coding
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* Copyright (c) Project Nayuki
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*
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* https://www.nayuki.io/page/reference-arithmetic-coding
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* https://github.com/nayuki/Reference-arithmetic-coding
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*/
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/// <summary>
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/// Compression application using adaptive arithmetic coding.
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/// <para>Usage: java AdaptiveArithmeticCompress InputFile OutputFile</para>
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/// <para>Then use the corresponding "AdaptiveArithmeticDecompress" application to recreate the original input file.</para>
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/// <para>Note that the application starts with a flat frequency table of 257 symbols (all set to a frequency of 1),
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/// and updates it after each byte encoded. The corresponding decompressor program also starts with a flat
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/// frequency table and updates it after each byte decoded. It is by design that the compressor and
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/// decompressor have synchronized states, so that the data can be decompressed properly.</para>
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/// </summary>
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public class AdaptiveArithmeticCompress
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{
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//JAVA TO C# CONVERTER WARNING: Method 'throws' clauses are not available in C#:
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//ORIGINAL LINE: public static void main(String[] args) throws java.io.IOException
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public static void Main(string[] args)
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{
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/* @@@@ PORT
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// Handle command line arguments
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if (args.Length != 2)
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{
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Console.Error.WriteLine("Usage: java AdaptiveArithmeticCompress InputFile OutputFile");
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Environment.Exit(1);
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return;
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}
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File inputFile = new File(args[0]);
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File outputFile = new File(args[1]);
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// Perform file compression
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using (Stream @in = new BufferedInputStream(new FileStream(inputFile, FileMode.Open, FileAccess.Read)), BitOutputStream @out = new BitOutputStream(new BufferedOutputStream(new FileStream(outputFile, FileMode.Create, FileAccess.Write))))
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{
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compress(@in, @out);
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}
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*/
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}
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// To allow unit testing, this method is package-private instead of private.
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//JAVA TO C# CONVERTER WARNING: Method 'throws' clauses are not available in C#:
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//ORIGINAL LINE: static void compress(java.io.InputStream in, BitOutputStream out) throws java.io.IOException
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internal static void compress(Stream @in, BitOutputStream @out)
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{
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FlatFrequencyTable initFreqs = new FlatFrequencyTable(257);
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FrequencyTable freqs = new SimpleFrequencyTable(initFreqs);
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ArithmeticEncoder enc = new ArithmeticEncoder(32, @out);
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while (true)
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{
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// Read and encode one byte
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int symbol = @in.ReadByte();
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if (symbol == -1)
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{
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break;
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}
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enc.write(freqs, symbol);
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freqs.increment(symbol);
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}
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enc.write(freqs, 256); // EOF
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enc.finish(); // Flush remaining code bits
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}
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}
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