Package com.thirdpartylabs.xmlscalpel.io.reader

Class ByteTrackingReader

java.lang.Object
java.io.Reader
java.io.FilterReader
com.thirdpartylabs.xmlscalpel.io.reader.ByteTrackingReader
All Implemented Interfaces:
java.io.Closeable, java.lang.AutoCloseable, java.lang.Readable
public class ByteTrackingReader
extends java.io.FilterReader
FilterReader that tracks byte progress as chars are read.

Char offsets are mapped to byte offsets, so that known char offsets can be used to determine byte offsets. Only a certain number (set in charMemoryDepth, currently 8192) of the most recent offsets are remembered. This reader is specifically intended to be used in conjunction with the Woodstox streaming reader, which seems to read 2048 chars ahead of the reported progress, so we need to account for that, and accommodate potentially large tag names, since the end tag plus the read-ahead determine the length of memory we need.

  • Field Summary

    Fields inherited from class java.io.FilterReader

    in

    Fields inherited from class java.io.Reader

    lock

  • Constructor Summary

    Constructors 
    Modifier Constructor Description
    protected ByteTrackingReader​(java.io.Reader in)
    Creates a new byte tracking filtered reader.

  • Method Summary

    Modifier and Type Method Description
    long getByteOffsetForCharOffset​(long charOffset)
    Return the byte offset for the provided char offset
    int read()
    Read a char and count the bytes
    int read​(char[] buffer, int off, int len)
    Read and count the bytes in the chars that are read
    long skip​(long n)
    We read and count the bytes in chars we're skipping over

    Methods inherited from class java.io.FilterReader

    close, mark, markSupported, ready, reset

    Methods inherited from class java.io.Reader

    nullReader, read, read, transferTo

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • Constructor Details

    • ByteTrackingReader

      protected ByteTrackingReader​(java.io.Reader in)
      Creates a new byte tracking filtered reader.
      Parameters:
      in - a Reader object providing the underlying stream.
      Throws:
      java.lang.NullPointerException - if in is null

  • Method Details

    • skip

      public long skip​(long n) throws java.io.IOException
      We read and count the bytes in chars we're skipping over
      Overrides:
      skip in class java.io.FilterReader
      Parameters:
      n - Number of chars to skip
      Returns:
      Number of chars actually skipped
      Throws:
      java.io.IOException

    • read

      public int read​(char[] buffer, int off, int len) throws java.io.IOException
      Read and count the bytes in the chars that are read
      Overrides:
      read in class java.io.FilterReader
      Parameters:
      buffer - Char array to be filled
      off - The buffer will be filled starting at this offset
      len - The number of chars to read
      Returns:
      the number of chars read
      Throws:
      java.io.IOException

    • read

      public int read() throws java.io.IOException
      Read a char and count the bytes
      Overrides:
      read in class java.io.FilterReader
      Returns:
      A single char read from the file
      Throws:
      java.io.IOException

    • getByteOffsetForCharOffset

      public long getByteOffsetForCharOffset​(long charOffset)
      Return the byte offset for the provided char offset
      Parameters:
      charOffset - A character offset
      Returns:
      -1 if if the charOffset is negative, or if the offset is outside the bounds of our memory