f5fbef7ccc
* Add the instrument to the MIDI channel selector * Reviews Adds support for chained masters Makes the channel UI update on its own when the midi changes (Works with bands too!) * add to admin logs and limit track count * Limit track names by length too * remove left over comment * Requested changes * Reviews
104 lines
2.6 KiB
C#
104 lines
2.6 KiB
C#
using System.IO;
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using System.Text;
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namespace Content.Client.Instruments.MidiParser;
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public sealed class MidiStreamWrapper
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{
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private readonly MemoryStream _stream;
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private byte[] _buffer;
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public long StreamPosition => _stream.Position;
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public MidiStreamWrapper(byte[] data)
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{
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_stream = new MemoryStream(data, writable: false);
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_buffer = new byte[4];
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}
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/// <summary>
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/// Skips X number of bytes in the stream.
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/// </summary>
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/// <param name="count">The number of bytes to skip. If 0, no operations on the stream are performed.</param>
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public void Skip(int count)
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{
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if (count == 0)
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return;
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_stream.Seek(count, SeekOrigin.Current);
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}
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public byte ReadByte()
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{
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var b = _stream.ReadByte();
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if (b == -1)
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throw new Exception("Unexpected end of stream");
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return (byte)b;
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}
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/// <summary>
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/// Reads N bytes using the buffer.
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/// </summary>
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public byte[] ReadBytes(int count)
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{
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if (_buffer.Length < count)
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{
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Array.Resize(ref _buffer, count);
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}
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var read = _stream.Read(_buffer, 0, count);
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if (read != count)
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throw new Exception("Unexpected end of stream");
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return _buffer;
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}
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/// <summary>
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/// Reads a 4 byte big-endian uint.
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/// </summary>
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public uint ReadUInt32()
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{
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var bytes = ReadBytes(4);
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return (uint)((bytes[0] << 24) |
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(bytes[1] << 16) |
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(bytes[2] << 8) |
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(bytes[3]));
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}
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/// <summary>
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/// Reads a 2 byte big-endian ushort.
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/// </summary>
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public ushort ReadUInt16()
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{
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var bytes = ReadBytes(2);
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return (ushort)((bytes[0] << 8) | bytes[1]);
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}
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public string ReadString(int count)
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{
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var bytes = ReadBytes(count);
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return Encoding.UTF8.GetString(bytes, 0, count);
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}
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public uint ReadVariableLengthQuantity()
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{
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uint value = 0;
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// variable-length-quantities encode ints using 7 bits per byte
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// the highest bit (7) is used for a continuation flag. We read until the high bit is 0
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while (true)
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{
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var b = ReadByte();
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value = (value << 7) | (uint)(b & 0x7f); // Shift current value and add 7 bits
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// value << 7, make room for the next 7 bits
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// b & 0x7F mask out the high bit to just get the 7 bit payload
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if ((b & 0x80) == 0)
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break; // This was the last bit.
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}
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return value;
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}
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}
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