I have written a Windows App in C# that needs to read a text file over the network, starting from the end of the file and reading backwards toward the beginning (looking for the last occurrence of a couple of strings in one line of text). I do not want to read the entire file, as it is very large, on a highly utilized server, and is updated with hundreds of lines of text every second. So since I am reading backwards, I do a seek, then read, then encode the byte array as a string, split the string into an array of lines, then iterate and search through the string array. My problem is that since the first or 0 element of my string array will almost always be an incomplete line, to ensure 100% reliability I need to adjust the next seek so that I read the entire line that was incomplete/truncated on the last read (it would ideally be the final element of the next string array after the read,encode,split). So everything works great except that I can't seem to adjust the Seek to always read the whole truncated line. Most of the time it works, but not 100%, and therefore is useless :). I must be doing something wrong with the counting of the bytes or "\r\n"s. Any reasonable help would be appreciated. Code is below...
- using (FileStream fs = new FileStream(sFullPathAndFileName, FileMode.Open, FileAccess.Read, FileShare.ReadWrite))
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{
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fs.Seek(iBBFileSize+iBytesPerRead, SeekOrigin.Begin);
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byte[] BBLog = new byte[posBytesPerRead];
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System.Text.ASCIIEncoding enc = new System.Text.ASCIIEncoding();
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//lTotalBytes is a negative number used to offset to the position to start read
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//iBytesPerRead is a negative number
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//posBytesPerRead is the positive version of iBytesPerRead
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//iBR represents bytes read
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while (found == 0 && fs.Position>posBytesPerRead)
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{
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iBR = fs.Read(BBLog, 0, posBytesPerRead);
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lTotalBytes -= iBR;
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BBString = enc.GetString(BBLog);
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BBLines = BBString.Split(new string[] { "\r\n" }, StringSplitOptions.None);
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iBBLineCount = BBLines.Length;
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//Removed string array iteration/parsing
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iFirstlinelength = BBLines[0].Length;
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lTotalBytes += iFirstlinelength;
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fs.Seek(iBBFileSize + lTotalBytes + (2*iBBLineCount), SeekOrigin.Begin);
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}
