Package net.sf.saxon.tree.tiny

Class CompressedWhitespace

  • All Implemented Interfaces:
    CharSequence
    public class CompressedWhitespace
extends Object
implements CharSequence
    This class provides a compressed representation of a sequence of whitespace characters. The representation is a sequence of bytes: in each byte the top two bits indicate which whitespace character is used (x9, xA, xD, or x20) and the bottom six bits indicate the number of such characters. A zero byte is a filler. We don't compress the sequence if it would occupy more than 8 bytes, because that's the space we've got available in the TinyTree arrays.

    • Constructor Detail

      • CompressedWhitespace

        public CompressedWhitespace​(long compressedValue)

    • Method Detail

      • compress

        public static CharSequence compress​(CharSequence in)
        Attempt to compress a CharSequence
        Parameters:
        in - the CharSequence to be compressed
        Returns:
        the compressed sequence if it can be compressed; or the original CharSequence otherwise

      • uncompress

        public FastStringBuffer uncompress​(FastStringBuffer buffer)
        Uncompress the whitespace to a FastStringBuffer
        Parameters:
        buffer - the buffer to which the whitespace is to be appended. The parameter may be null, in which case a new buffer is created.
        Returns:
        the FastStringBuffer to which the whitespace has been appended. If a buffer was supplied in the argument, this will be the same buffer.

      • uncompress

        public static void uncompress​(long value,
                              FastStringBuffer buffer)

      • getCompressedValue

        public long getCompressedValue()

      • charAt

        public char charAt​(int index)
        Returns the char value at the specified index. An index ranges from zero to length() - 1. The first char value of the sequence is at index zero, the next at index one, and so on, as for array indexing.

        If the char value specified by the index is a surrogate, the surrogate value is returned.

        Specified by:
        charAt in interface CharSequence
        Parameters:
        index - the index of the char value to be returned
        Returns:
        the specified char value
        Throws:
        IndexOutOfBoundsException - if the index argument is negative or not less than length()

      • subSequence

        public CharSequence subSequence​(int start,
                                int end)
        Returns a new CharSequence that is a subsequence of this sequence. The subsequence starts with the char value at the specified index and ends with the char value at index end - 1. The length (in chars) of the returned sequence is end - start, so if start == end then an empty sequence is returned.
        Specified by:
        subSequence in interface CharSequence
        Parameters:
        start - the start index, inclusive
        end - the end index, exclusive
        Returns:
        the specified subsequence
        Throws:
        IndexOutOfBoundsException - if start or end are negative, if end is greater than length(), or if start is greater than end

      • equals

        public boolean equals​(Object obj)
        Indicates whether some other object is "equal to" this one.
        Overrides:
        equals in class Object

      • hashCode

        public int hashCode()
        Returns a hash code value for the object.
        Overrides:
        hashCode in class Object

      • write

        public void write​(Writer writer)
           throws IOException
        Write the value to a Writer
        Parameters:
        writer - the writer to write to
        Throws:
        IOException - if an error occurs downstream

      • writeEscape

        public void writeEscape​(boolean[] specialChars,
                        Writer writer)
                 throws IOException
        Write the value to a Writer with escaping of special characters
        Parameters:
        specialChars - identifies which characters are considered special
        writer - the writer to write to
        Throws:
        IOException - if an error occurs downstream