99 lines
2.6 KiB
C#
99 lines
2.6 KiB
C#
#region Copyright & License Information
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/*
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* Copyright 2007-2015 The OpenRA Developers (see AUTHORS)
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* This file is part of OpenRA, which is free software. It is made
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* available to you under the terms of the GNU General Public License
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* as published by the Free Software Foundation. For more information,
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* see COPYING.
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*/
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#endregion
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using System.IO;
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namespace OpenRA.FileFormats
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{
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struct ImaAdpcmChunk
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{
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public int CompressedSize;
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public int OutputSize;
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public static ImaAdpcmChunk Read(Stream s)
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{
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ImaAdpcmChunk c;
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c.CompressedSize = s.ReadUInt16();
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c.OutputSize = s.ReadUInt16();
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if (s.ReadUInt32() != 0xdeaf)
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throw new InvalidDataException("Chunk header is bogus");
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return c;
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}
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}
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public static class ImaAdpcmLoader
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{
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static readonly int[] IndexAdjust = { -1, -1, -1, -1, 2, 4, 6, 8 };
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static readonly int[] StepTable =
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{
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7, 8, 9, 10, 11, 12, 13, 14, 16,
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17, 19, 21, 23, 25, 28, 31, 34, 37,
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41, 45, 50, 55, 60, 66, 73, 80, 88,
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97, 107, 118, 130, 143, 157, 173, 190, 209,
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230, 253, 279, 307, 337, 371, 408, 449, 494,
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544, 598, 658, 724, 796, 876, 963, 1060, 1166,
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1282, 1411, 1552, 1707, 1878, 2066, 2272, 2499, 2749,
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3024, 3327, 3660, 4026, 4428, 4871, 5358, 5894, 6484,
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7132, 7845, 8630, 9493, 10442, 11487, 12635, 13899, 15289,
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16818, 18500, 20350, 22385, 24623, 27086, 29794, 32767
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};
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static short DecodeImaAdpcmSample(byte b, ref int index, ref int current)
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{
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var sb = (b & 8) != 0;
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b &= 7;
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var delta = (StepTable[index] * b) / 4 + StepTable[index] / 8;
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if (sb) delta = -delta;
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current += delta;
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if (current > short.MaxValue) current = short.MaxValue;
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if (current < short.MinValue) current = short.MinValue;
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index += IndexAdjust[b];
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if (index < 0) index = 0;
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if (index > 88) index = 88;
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return (short)current;
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}
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public static byte[] LoadImaAdpcmSound(byte[] raw, ref int index)
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{
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var currentSample = 0;
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return LoadImaAdpcmSound(raw, ref index, ref currentSample);
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}
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public static byte[] LoadImaAdpcmSound(byte[] raw, ref int index, ref int currentSample)
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{
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var s = new MemoryStream(raw);
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var dataSize = raw.Length;
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var outputSize = raw.Length * 4;
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var output = new byte[outputSize];
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var offset = 0;
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while (dataSize-- > 0)
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{
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var b = s.ReadUInt8();
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var t = DecodeImaAdpcmSample(b, ref index, ref currentSample);
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output[offset++] = (byte)t;
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output[offset++] = (byte)(t >> 8);
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t = DecodeImaAdpcmSample((byte)(b >> 4), ref index, ref currentSample);
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output[offset++] = (byte)t;
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output[offset++] = (byte)(t >> 8);
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}
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return output;
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}
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}
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}
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