c# - 读取包含不规则换行符的文件

Question

我正在尝试用 C# 读取一个格式如下的文本文件:

this is a line\r\n
this is a line\r
\r\n
this is a line\r
\r\n
this is a line\r
\r\n
this is a line\r\n
this is a line\r
\r\n
etc...

我正在读取文件中的每一行

StreamReader.ReadLine()

但这不会保留换行符。我需要知道/检测有什么样的换行符，因为我正在计算每行的字节数。例如:

如果行以字符 \r 结尾，行包括:((nr-of-bytes-in-line) + 1 byte) 字节(取决于当然是关于编码类型)，如果行以 \r\n 结尾，则行包括:((nr-of-bytes-in-line) + 2 bytes) 字节。

编辑:

我有解决方案，基于israel altar 的回答。顺便说一句:Jon Skeet 也建议这样做。我已经实现了 ReadLine 的覆盖版本，因此它会包含换行符。这是重写函数的代码:

    public override String ReadLine()
    {
        StringBuilder sb = new StringBuilder();
        while (true)
        {
            int ch = Read();
            if (ch == -1)
            {
                break;
            }
            if (ch == '\r' || ch == '\n')
            {
                if (ch == '\r' && Peek() == '\n')
                {
                    sb.Append('\r');
                    sb.Append('\n');
                    Read();
                    break;
                }
                else if(ch == '\r' && Peek() == '\r')
                {
                    sb.Append('\r');
                    break;
                }
            }
            sb.Append((char)ch);
        }
        if (sb.Length > 0)
        {
            return sb.ToString();
        }
        return null;
    }

Answer 1

根据.net资源，readline是这样实现的:

// Reads a line. A line is defined as a sequence of characters followed by
        // a carriage return ('\r'), a line feed ('\n'), or a carriage return
        // immediately followed by a line feed. The resulting string does not
        // contain the terminating carriage return and/or line feed. The returned
        // value is null if the end of the input stream has been reached.
        //
        public virtual String ReadLine() 
        {
            StringBuilder sb = new StringBuilder();
            while (true) {
                int ch = Read();
                if (ch == -1) break;
                if (ch == '\r' || ch == '\n') 
                {
                    if (ch == '\r' && Peek() == '\n') Read();
                    return sb.ToString();
                }
                sb.Append((char)ch);
            }
            if (sb.Length > 0) return sb.ToString();
            return null;
        }

如您所见，您可以添加一个 if 语句，如下所示:

 if (ch == '\r') 
{
  //add the amount of bytes wanted
}
if  (ch == '\n')
{
  //add the amount of bytes wanted
}

或者做任何你想要的操作。