Stream，byte[]，LZMA

最新推荐文章于 2025-06-18 11:14:32 发布

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最新推荐文章于 2025-06-18 11:14:32 发布

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本文详细介绍了C#中如何将二进制数据转换为图片，并提供了byte[]与string间的转换方法，以及Stream与byte[]之间的转换技巧。此外，还讲解了如何将Stream写入文件及从文件读取Stream的方法。

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//转自瓦里奥

一. 二进制转换成图片

MemoryStream ms =
new MemoryStream(bytes);
ms.Position = 0;
Image img = Image.FromStream(ms);
ms.Close();
this.pictureBox1.Image

二. C#中byte[]与string的转换代码

System.Text.UnicodeEncoding converter =
new System.Text.UnicodeEncoding();
　　byte[] inputBytes =converter.GetBytes(inputString);
　　string
inputString = converter.GetString(inputBytes);

string 
inputString = System.Convert.ToBase64String(inputBytes);
　　byte[] inputBytes = System.Convert.FromBase64String(inputString);
FileStream fileStream =
new FileStream(fileName, FileMode.Open, FileAccess.Read, FileShare.Read);

三. C# Stream 和 byte[] 之间的转换

/// 将 Stream 转成 byte[]
 
public 
byte[] StreamToBytes(Stream stream)
{
    byte[] bytes =
new byte[stream.Length];
    stream.Read(bytes, 0, bytes.Length);
    // 设置当前流的位置为流的开始
    stream.Seek(0, SeekOrigin.Begin);
    return
bytes;
}
 
/// 将 byte[] 转成 Stream
 
public
Stream BytesToStream(byte[] bytes)
{
    Stream stream =
new MemoryStream(bytes);
    return
stream;
}

四. Stream 和文件之间的转换

将 Stream 写入文件

public 
void StreamToFile(Stream stream,string
fileName)
{
    // 把 Stream 转换成 byte[]
    byte[] bytes =
new byte[stream.Length];
    stream.Read(bytes, 0, bytes.Length);
    // 设置当前流的位置为流的开始
    stream.Seek(0, SeekOrigin.Begin);
    // 把 byte[] 写入文件
    FileStream fs =
new FileStream(fileName, FileMode.Create);
    BinaryWriter bw =
new BinaryWriter(fs);
    bw.Write(bytes);
    bw.Close();
    fs.Close();
}

五. 从文件读取 Stream

public 
Stream FileToStream(string 
fileName)
{            
    // 打开文件
    FileStream fileStream =
new FileStream(fileName, FileMode.Open, FileAccess.Read, FileShare.Read);
    // 读取文件的 byte[]
    byte[] bytes =
new byte[fileStream.Length];
    fileStream.Read(bytes, 0, bytes.Length);
    fileStream.Close();
    // 把 byte[] 转换成 Stream
    Stream stream =
new MemoryStream(bytes);
    return
stream;
 
 
}

六

//Bitmap 转化为 Byte[]
                Bitmap BitReturn =
new Bitmap();
                byte[] bReturn =
null;
                MemoryStream ms =
new MemoryStream();
                BitReturn.Save(ms, System.Drawing.Imaging.ImageFormat.Png);
                bReturn = ms.GetBuffer();

//from stackoverflow

private static void CompressFileLZMA(string inFile, string outFile) { SevenZip.Compression.LZMA.Encoder coder = new SevenZip.Compression.LZMA.Encoder(); FileStream input = new FileStream(inFile, FileMode.Open); FileStream output = new FileStream(outFile, FileMode.Create); // Write the encoder properties coder.WriteCoderProperties(output); // Write the decompressed file size. output.Write(BitConverter.GetBytes(input.Length), 0, 8); // Encode the file. coder.Code(input, output, input.Length, -1, null); output.Flush(); output.Close(); } private static void DecompressFileLZMA(string inFile, string outFile) { SevenZip.Compression.LZMA.Decoder coder = new SevenZip.Compression.LZMA.Decoder(); FileStream input = new FileStream(inFile, FileMode.Open); FileStream output = new FileStream(outFile, FileMode.Create); // Read the decoder properties byte[] properties = new byte[5]; input.Read(properties, 0, 5); // Read in the decompress file size. byte [] fileLengthBytes = new byte[8]; input.Read(fileLengthBytes, 0, 8); long fileLength = BitConverter.ToInt64(fileLengthBytes, 0); coder.SetDecoderProperties(properties); coder.Code(input, output, input.Length, fileLength, null); output.Flush(); output.Close(); }

public static void Decompress(Stream inStream, Stream outStream){ byte[] properties = new byte[5]; inStream.Read(properties, 0, 5); SevenZip.Compression.LZMA.Decoder decoder = new SevenZip.Compression.LZMA.Decoder(); decoder.SetDecoderProperties(properties); long outSize = 0; for (int i = 0; i < 8; i++) { int v = inStream.ReadByte(); outSize |= ((long)(byte)v) << (8 * i); } long compressedSize = inStream.Length - inStream.Position; decoder.Code(inStream, outStream, compressedSize, outSize, null);}public static string DecompressLzma(string inputstring){ if (!string.IsNullOrEmpty(inputstring)) { byte[] myInts = Array.ConvertAll(inputstring.Split(','), s => (byte)int.Parse(s)); var stream = new MemoryStream(myInts); var outputStream = new MemoryStream(); Decompress(stream, outputStream); using (var reader = new StreamReader(outputStream)) { outputStream.Position = 0; string output = reader.ReadToEnd(); return output; } } return "";}

public static string CompressLzma(string inputstring){ if (!string.IsNullOrEmpty(inputstring)) { var stream = new MemoryStream(Encoding.Unicode.GetBytes(inputstring ?? "")); var outputStream = new MemoryStream(); Compress(stream, outputStream); byte[] bytes = outputStream.ToArray(); } return "";}public static void Compress(MemoryStream inStream, MemoryStream outStream){ CoderPropID[] propIDs; object[] properties; PrepareEncoder(out propIDs, out properties); SevenZip.Compression.LZMA.Encoder encoder = new SevenZip.Compression.LZMA.Encoder(); encoder.SetCoderProperties(propIDs, properties); encoder.WriteCoderProperties(outStream); Int64 fileSize = inStream.Length; for (int i = 0; i < 8; i++) { outStream.WriteByte((Byte)(fileSize >> (8 * i))); } encoder.Code(inStream, outStream, -1, -1, null);}public static void PrepareEncoder(out CoderPropID[] propIDs, out object[] properties){ bool eos = true; Int32 dictionary = 1 << 16; Int32 posStateBits = 2; Int32 litContextBits = 3; // for normal files // UInt32 litContextBits = 0; // for 32-bit data Int32 litPosBits = 0; // UInt32 litPosBits = 2; // for 32-bit data Int32 algorithm = 2; Int32 numFastBytes = 32; string mf = "bt2"; propIDs = new CoderPropID[] { CoderPropID.DictionarySize, CoderPropID.PosStateBits, CoderPropID.LitContextBits, CoderPropID.LitPosBits, CoderPropID.Algorithm, CoderPropID.NumFastBytes, CoderPropID.MatchFinder, CoderPropID.EndMarker }; properties = new object[] { dictionary, posStateBits, litContextBits, litPosBits, algorithm, numFastBytes, mf, eos };}

public static string CompressLzma(string inputstring){ if (!string.IsNullOrEmpty(inputstring)) { var stream = new MemoryStream(Encoding.UTF8.GetBytes(inputstring ?? "")); var outputStream = new MemoryStream(); Compress(stream, outputStream); byte[] bytes = outputStream.ToArray(); var result = string.Join(",", Array.ConvertAll(bytes, v => signedInt((int)v))); return result; } return "";}public static void PrepareEncoder(out CoderPropID[] propIDs, out object[] properties){ bool eos = true; Int32 dictionary = 1 << 16; Int32 posStateBits = 2; Int32 litContextBits = 3; // for normal files // UInt32 litContextBits = 0; // for 32-bit data Int32 litPosBits = 0; // UInt32 litPosBits = 2; // for 32-bit data Int32 algorithm = 2; Int32 numFastBytes = 64; string mf = "bt4"; propIDs = new CoderPropID[] { CoderPropID.DictionarySize, CoderPropID.PosStateBits, CoderPropID.LitContextBits, CoderPropID.LitPosBits, CoderPropID.Algorithm, CoderPropID.NumFastBytes, CoderPropID.MatchFinder, CoderPropID.EndMarker }; properties = new object[] { dictionary, posStateBits, litContextBits, litPosBits, algorithm, numFastBytes, mf, eos };}private static int signedInt(int unsignedInt){ return unsignedInt >= 128 ? Math.Abs(128 - unsignedInt) - 128 : unsignedInt;}public static void Compress(MemoryStream inStream, MemoryStream outStream){ CoderPropID[] propIDs; object[] properties; PrepareEncoder(out propIDs, out properties); SevenZip.Compression.LZMA.Encoder encoder = new SevenZip.Compression.LZMA.Encoder(); encoder.SetCoderProperties(propIDs, properties); encoder.WriteCoderProperties(outStream); Int64 fileSize = inStream.Length; for (int i = 0; i < 8; i++) { outStream.WriteByte((Byte)(fileSize >> (8 * i))); } encoder.Code(inStream, outStream, -1, -1, null);}