60 lines
1.7 KiB
C#
60 lines
1.7 KiB
C#
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using System;
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using System.IO;
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using System.Runtime.InteropServices;
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namespace Quik.Stb
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{
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public unsafe class StbiStreamWrapper : IDisposable
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{
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private Stream _stream;
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private bool _keepOpen;
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private bool _isDisposed;
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private delegate int ReadProc(void *userdata, byte* buffer, int count);
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private delegate void SkipProc(void *userdata, int count);
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private delegate int Eof(void *userdata);
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public StbiStreamWrapper(Stream stream, bool keepOpen = false)
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{
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if (stream == null) throw new ArgumentNullException(nameof(stream));
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_stream = stream;
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_keepOpen = keepOpen;
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}
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public void CreateCallbacks(out stbi_io_callbacks cb)
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{
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cb = default;
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cb.read = Marshal.GetFunctionPointerForDelegate<ReadProc>(ReadCb);
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cb.skip = Marshal.GetFunctionPointerForDelegate<SkipProc>(SkipCb);
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cb.eof = Marshal.GetFunctionPointerForDelegate<Eof>(EofCb);
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}
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private int ReadCb(void *userdata, byte* buffer, int count)
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{
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Span<byte> bytes = new Span<byte>(buffer, count);
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return _stream.Read(bytes);
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}
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private void SkipCb(void *userdata, int count)
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{
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_stream.Seek(count, SeekOrigin.Current);
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}
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private int EofCb(void *userdata)
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{
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if (!_stream.CanRead || _stream.Position == _stream.Length)
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return 1;
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return 0;
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}
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public void Dispose()
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{
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if (_isDisposed) return;
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if (!_keepOpen) _stream.Dispose();
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_isDisposed = true;
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}
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}
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}
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