查找任何文件编码的有效方法 [英] Effective way to find any file's Encoding

问题描述

是的，这是一个最常见的问题，这个问题对我来说很模糊，因为我对此知之甚少.

Yes is a most frequent question, and this matter is vague for me and since I don't know much about it.

但我想要一种非常精确的方法来查找文件编码.像 Notepad++ 一样精确.

But i would like a very precise way to find a files Encoding. So precise as Notepad++ is.

推荐答案

StreamReader.CurrentEncoding 属性很少为我返回正确的文本文件编码.通过分析文件的字节顺序标记 (BOM)，我在确定文件的字节序方面取得了更大的成功.如果文件没有 BOM，则无法确定文件的编码.

The StreamReader.CurrentEncoding property rarely returns the correct text file encoding for me. I've had greater success determining a file's endianness, by analyzing its byte order mark (BOM). If the file does not have a BOM, this cannot determine the file's encoding.

*更新 4/08/2020 以包含 UTF-32LE 检测并返回正确的 UTF-32BE 编码

*UPDATED 4/08/2020 to include UTF-32LE detection and return correct encoding for UTF-32BE

/// <summary>
/// Determines a text file's encoding by analyzing its byte order mark (BOM).
/// Defaults to ASCII when detection of the text file's endianness fails.
/// </summary>
/// <param name="filename">The text file to analyze.</param>
/// <returns>The detected encoding.</returns>
public static Encoding GetEncoding(string filename)
{
    // Read the BOM
    var bom = new byte[4];
    using (var file = new FileStream(filename, FileMode.Open, FileAccess.Read))
    {
        file.Read(bom, 0, 4);
    }

    // Analyze the BOM
    if (bom[0] == 0x2b && bom[1] == 0x2f && bom[2] == 0x76) return Encoding.UTF7;
    if (bom[0] == 0xef && bom[1] == 0xbb && bom[2] == 0xbf) return Encoding.UTF8;
    if (bom[0] == 0xff && bom[1] == 0xfe && bom[2] == 0 && bom[3] == 0) return Encoding.UTF32; //UTF-32LE
    if (bom[0] == 0xff && bom[1] == 0xfe) return Encoding.Unicode; //UTF-16LE
    if (bom[0] == 0xfe && bom[1] == 0xff) return Encoding.BigEndianUnicode; //UTF-16BE
    if (bom[0] == 0 && bom[1] == 0 && bom[2] == 0xfe && bom[3] == 0xff) return new UTF32Encoding(true, true);  //UTF-32BE

    // We actually have no idea what the encoding is if we reach this point, so
    // you may wish to return null instead of defaulting to ASCII
    return Encoding.ASCII;
}

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