GZipStream.Write 方法

定義

命名空間:

System.IO.Compression

組件:

netstandard.dll, System.IO.Compression.dll

多載

名稱	Description
Write(ReadOnlySpan<Byte>)	從只讀位元組區間寫入一串位元組到目前 GZip 串流，並依照寫入位元組數將當前位置往前推進。
Write(Byte[], Int32, Int32)	從指定的位元組陣列將壓縮的位元組寫入底層的 GZip 串流。

Write(ReadOnlySpan<Byte>)

來源:

GZipStream.cs

從只讀位元組區間寫入一串位元組到目前 GZip 串流，並依照寫入位元組數將當前位置往前推進。

public:
 override void Write(ReadOnlySpan<System::Byte> buffer);

public override void Write(ReadOnlySpan<byte> buffer);

override this.Write : ReadOnlySpan<byte> -> unit

Public Overrides Sub Write (buffer As ReadOnlySpan(Of Byte))

參數

buffer

ReadOnlySpan<Byte>

一個記憶區域。 此方法會將該區域的內容複製到目前的 GZip 串流中。

備註

利用該 CanWrite 屬性判斷目前實例是否支援寫入。 使用該 WriteAsync 方法非同步寫入目前串流。

若寫入操作成功，GZip 串流中的位置會依寫入位元組數前進。 若發生例外，GZip 串流中的位置保持不變。

Write(Byte[], Int32, Int32)

來源:

GZipStream.cs

從指定的位元組陣列將壓縮的位元組寫入底層的 GZip 串流。

public:
 override void Write(cli::array <System::Byte> ^ buffer, int offset, int count);

public override void Write(byte[] buffer, int offset, int count);

override this.Write : byte[] * int * int -> unit

Public Overrides Sub Write (buffer As Byte(), offset As Integer, count As Integer)

參數

buffer

Byte[]

就是包含要壓縮資料的緩衝區。

offset

Int32

位元組將被讀取的位元組偏移量。

count

Int32

最大可寫入位元組數。

例外狀況

ObjectDisposedException

寫入操作無法執行，因為串流是封閉的。

範例

以下範例展示了如何使用 Read and Write 方法來壓縮和解壓位元組。

using System;
using System.IO;
using System.IO.Compression;
using System.Text;

public static class MemoryWriteReadExample
{
    private const string Message = "Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.";
    private static readonly byte[] s_messageBytes = Encoding.ASCII.GetBytes(Message);

    public static void Run()
    {
        Console.WriteLine($"The original string length is {s_messageBytes.Length} bytes.");
        using var stream = new MemoryStream();
        CompressBytesToStream(stream);
        Console.WriteLine($"The compressed stream length is {stream.Length} bytes.");
        int decompressedLength = DecompressStreamToBytes(stream);
        Console.WriteLine($"The decompressed string length is {decompressedLength} bytes, same as the original length.");
        /*
         Output:
            The original string length is 445 bytes.
            The compressed stream length is 282 bytes.
            The decompressed string length is 445 bytes, same as the original length.
        */
    }

    private static void CompressBytesToStream(Stream stream)
    {
        using var compressor = new GZipStream(stream, CompressionLevel.SmallestSize, leaveOpen: true);
        compressor.Write(s_messageBytes, 0, s_messageBytes.Length);
    }

    private static int DecompressStreamToBytes(Stream stream)
    {
        stream.Position = 0;
        int bufferSize = 512;
        byte[] buffer = new byte[bufferSize];
        using var gzipStream = new GZipStream(stream, CompressionMode.Decompress);

        int totalRead = 0;
        while (totalRead < buffer.Length)
        {
            int bytesRead = gzipStream.Read(buffer.AsSpan(totalRead));
            if (bytesRead == 0) break;
            totalRead += bytesRead;
        }

        return totalRead;
    }
}

open System.IO
open System.IO.Compression
open System.Text

let message =
    "Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum."

let s_messageBytes = Encoding.ASCII.GetBytes message

let compressBytesToStream stream =
    use compressor =
        new GZipStream(stream, CompressionLevel.SmallestSize, leaveOpen = true)

    compressor.Write(s_messageBytes, 0, s_messageBytes.Length)

let decompressStreamToBytes (stream: Stream) =
    stream.Position <- 0
    let bufferSize = 512
    let decompressedBytes = Array.zeroCreate bufferSize
    use decompressor = new GZipStream(stream, CompressionMode.Decompress)
    decompressor.Read(decompressedBytes, 0, bufferSize)

[<EntryPoint>]
let main _ =
    printfn $"The original string length is {s_messageBytes.Length} bytes."
    use stream = new MemoryStream()
    compressBytesToStream stream
    printfn $"The compressed stream length is {stream.Length} bytes."
    let decompressedLength = decompressStreamToBytes stream
    printfn $"The decompressed string length is {decompressedLength} bytes, same as the original length."
    0

// Output:
//     The original string length is 445 bytes.
//     The compressed stream length is 282 bytes.
//     The decompressed string length is 445 bytes, same as the original length.

Imports System.IO
Imports System.IO.Compression
Imports System.Text

Module MemoryWriteReadExample
    Private Const Message As String = "Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum."
    Private ReadOnly s_messageBytes As Byte() = Encoding.ASCII.GetBytes(Message)

    Sub Main()
        Console.WriteLine($"The original string length is {s_messageBytes.Length} bytes.")

        Using stream = New MemoryStream()
            CompressBytesToStream(stream)
            Console.WriteLine($"The compressed stream length is {stream.Length} bytes.")
            Dim decompressedLength As Integer = DecompressStreamToBytes(stream)
            Console.WriteLine($"The decompressed string length is {decompressedLength} bytes, same as the original length.")
        End Using
        ' Output:
        '   The original string length is 445 bytes.
        '   The compressed stream length is 282 bytes.
        '   The decompressed string length is 445 bytes, same as the original length.
    End Sub

    Private Sub CompressBytesToStream(ByVal stream As Stream)
        Using compressor = New GZipStream(stream, CompressionLevel.SmallestSize, leaveOpen:=True)
            compressor.Write(s_messageBytes, 0, s_messageBytes.Length)
        End Using
    End Sub

    Private Function DecompressStreamToBytes(ByVal stream As Stream) As Integer
        stream.Position = 0
        Dim bufferSize As Integer = 512
        Dim decompressedBytes As Byte() = New Byte(bufferSize - 1) {}
        Using decompressor = New GZipStream(stream, CompressionMode.Decompress)
            Dim length As Integer = decompressor.Read(decompressedBytes, 0, bufferSize)
            Return length
        End Using
    End Function
End Module

備註

寫入操作可能不會立即發生，但會被緩衝直到達到緩衝區大小或 Flush 呼叫 or Close 方法為止。