有没有办法知道byte []是否被gzipstream压缩？ [英] Is there a way to know if the byte[] has been compressed by gzipstream?

问题描述

有没有办法知道byte []是否被 GzipStream .net类压缩（或未压缩）？

Is there a way to know if the byte[] has been compressed (or not) by GzipStream .net class?

编辑：
只是想知道byte []数组是否已经压缩（因为我将始终使用GzipStream压缩和解压缩）

Just want to know if the byte[] array has been compressed (since I will always be using GzipStream to compress and decompress)

推荐答案

A GZipStream 是一个 DeflateStream 添加一个标题和尾部。

A GZipStream is a DeflateStream with an additional header and trailer.

格式在 RFC 1952 。

.NET 4.0 GZipStream 类别将以下字节写为标题：

The .NET 4.0 GZipStream class writes the following bytes as header:

byte[] headerBytes = new byte[] { 0x1f, 0x8b, 8, 0, 0, 0, 0, 0, 4, 0 };
if (compressionLevel == 10)
{
    headerBytes[8] = 2;
}

预告片包含 CRC32 校验和和未压缩数据的长度。

The trailer consists of a CRC32 checksum and the length of the uncompressed data.

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