我将如何阅读bittorrent片段？

Question

我目前正在为Ruby开发torrent元信息管理库。

我无法读取文件中的内容。 我只是不明白我应该怎么做。 我知道我应该一次对文件的片段长度字节进行SHA1提取（或者多次读取片段长度字节，或者什么？）

我指望您的帮助。 首选Pseudo / Python / Ruby / PHP代码。

提前致谢。

Answer 1

C＃

// Open the file
using (var file = File.Open(...))
{
    // Move to the relevant place in the file where the piece begins
    file.Seek(piece * pieceLength, SeekOrigin.Begin);

    // Attempt to read up to pieceLength bytes from the file into a buffer
    byte[] buffer = new byte[pieceLength];
    int totalRead = 0;
    while (totalRead < pieceLength)
    {
        var read = stream.Read(buffer, totalRead, pieceLength-totalRead);
        if (read == 0)
        {
            // the piece is smaller than the pieceLength,
            // because it’s the last in the file
            Array.Resize(ref buffer, totalRead);
            break;
        }
        totalRead += read;
    }

    // If you want the raw data for the piece:
    return buffer;

    // If you want the SHA1 hashsum:
    return SHA1.Create().ComputeHash(buffer);
}

Answer 2

请在这里查看此分布：

http://prdownload.berlios.de/torrentparse/TorrentParse.GTK.0.21.zip

用PHP编写，它包含一个Encoder和Decoder以及输入和输出，我相信！