diff --git a/Aaru.Compression/Aaru.Compression.csproj b/Aaru.Compression/Aaru.Compression.csproj index 842bc603b..0e20d4f51 100644 --- a/Aaru.Compression/Aaru.Compression.csproj +++ b/Aaru.Compression/Aaru.Compression.csproj @@ -105,6 +105,7 @@ + diff --git a/Aaru.Compression/Zip/BlastStream.cs b/Aaru.Compression/Zip/BlastStream.cs new file mode 100644 index 000000000..5670b6c59 --- /dev/null +++ b/Aaru.Compression/Zip/BlastStream.cs @@ -0,0 +1,111 @@ +using System; +using System.IO; +using System.Runtime.InteropServices; + +// ReSharper disable LocalizableElement + +namespace Aaru.Compression.Zip; + +public partial class BlastStream : Stream +{ + readonly byte[] _decoded; + readonly long _length; + long _position; + + public BlastStream(Stream compressedStream, long decompressedLength) + { + if(compressedStream == null) throw new ArgumentNullException(nameof(compressedStream)); + if(!compressedStream.CanRead) throw new ArgumentException("Stream must be readable", nameof(compressedStream)); + if(decompressedLength < 0) throw new ArgumentOutOfRangeException(nameof(decompressedLength)); + + // Read full compressed data into memory + compressedStream.Position = 0; + var inBuf = new byte[compressedStream.Length]; + compressedStream.ReadExactly(inBuf, 0, inBuf.Length); + + // Allocate output buffer + _decoded = new byte[decompressedLength]; + var outLen = (nint)decompressedLength; + + // Call native decompressor + int err = AARU_zip_blast_decode_buffer(_decoded, ref outLen, inBuf, inBuf.Length); + + if(err != 0) throw new InvalidOperationException("Blast decompression failed"); + + // Adjust actual length in case it differs + _length = outLen; + _position = 0; + } + + public override bool CanRead => true; + public override bool CanSeek => true; + public override bool CanWrite => false; + public override long Length => _length; + + public override long Position + { + get => _position; + set => Seek(value, SeekOrigin.Begin); + } + + [LibraryImport("libAaru.Compression.Native")] + public static partial int AARU_zip_blast_decode_buffer(byte[] dst_buffer, ref nint dst_size, byte[] src_buffer, + nint src_size); + + public override void Flush() + { + // no-op + } + + /// + /// Reads up to bytes from the decompressed buffer + /// into , starting at . + /// + public override int Read(byte[] buffer, int offset, int count) + { + if(buffer == null) throw new ArgumentNullException(nameof(buffer)); + if(offset < 0) throw new ArgumentOutOfRangeException(nameof(offset)); + if(count < 0) throw new ArgumentOutOfRangeException(nameof(count)); + if(offset + count > buffer.Length) throw new ArgumentException("offset+count exceeds buffer length"); + + long remaining = _length - _position; + + if(remaining <= 0) return 0; + + var toRead = (int)Math.Min(count, remaining); + Array.Copy(_decoded, _position, buffer, offset, toRead); + _position += toRead; + + return toRead; + } + + /// + /// Sets the current position within the decompressed buffer. + /// + public override long Seek(long offset, SeekOrigin origin) + { + long newPos = origin switch + { + SeekOrigin.Begin => offset, + SeekOrigin.Current => _position + offset, + SeekOrigin.End => _length + offset, + _ => throw new ArgumentException("Invalid SeekOrigin", nameof(origin)) + }; + + if(newPos < 0 || newPos > _length) throw new IOException("Attempt to seek outside the buffer"); + + _position = newPos; + + return _position; + } + + public override void SetLength(long value) + { + throw new NotSupportedException("Cannot resize decompressed buffer"); + } + + public override void Write(byte[] buffer, int offset, int count) + { + throw new NotSupportedException("Stream is read-only"); + } +} \ No newline at end of file