com.google.gwt.dev.util.editdistance

Class PatternBitmap

java.lang.Object

com.google.gwt.dev.util.editdistance.PatternBitmap

public class PatternBitmap
extends Object

A bitmap array generator for the positions that a given character appears within a pattern. The array of bitmaps is indexed by a CharIndex that represents the alphabet for the pattern. One bitmap is produced for each character. The bitmap for a character "c" has the (1< bit set for each position "i" where that character appears in the pattern. Several implementations are provided for different string sizes: int, long, int[]. The caller provides a (zeroed) array of the desired type, sized according to the CharIndex; the array is returned as a convenience.

Method Summary

Modifier and Type	Method and Description
static int[]	map(CharSequence s, CharIndex idx, int[] result) Computes a pattern bitmap for a short character sequence.
static int[][]	map(CharSequence s, CharIndex idx, int[][] result, int width) Computes a pattern bitmap for a character sequence of any length.
static long[]	map(CharSequence s, CharIndex idx, long[] result) Computes a pattern bitmap for a medium character sequence.

Methods inherited from class java.lang.Object

equals, finalize, getClass, hashCode, toString

Method Detail

map

public static int[] map(CharSequence s,
                        CharIndex idx,
                        int[] result)

Computes a pattern bitmap for a short character sequence. For each character in the alphabet (represented by a CharIndex), bits are set where that character appears in the sequence. For this generator, the pattern must fit in an "int": the character sequence must not be longer than Integer.SIZE.

Parameters:

s - the character sequence defining the bits to be set

idx - the alphabet for which bitmaps should be produced

result - an array (of size idx.size() or greater) to hold the resulting bitmaps

Returns:

the result array passed as a parameter, for convenience

map

public static int[][] map(CharSequence s,
                          CharIndex idx,
                          int[][] result,
                          int width)

Computes a pattern bitmap for a character sequence of any length. For each character in the alphabet (represented by a CharIndex), bits are set where that character appears in the sequence. Each (per-character) bitmap is represented by an "int[]".

Parameters:

s - the character sequence defining the bits to be set

idx - the alphabet for which bitmaps should be produced

result - an array (of size idx.size() or greater) to hold the resulting bitmaps

width - how many bits to be use in each word, no more than Integer.SIZE

Returns:

the result array passed as a parameter, for convenience

map

public static long[] map(CharSequence s,
                         CharIndex idx,
                         long[] result)

Computes a pattern bitmap for a medium character sequence. For each character in the alphabet (represented by a CharIndex), bits are set where that character appears in the sequence. For this generator, the pattern must fit in a "long": the character sequence must not be longer than Long.SIZE.

Parameters:

s - the character sequence defining the bits to be set

idx - the alphabet for which bitmaps should be produced

result - an array (of size idx.size() or greater) to hold the resulting bitmaps

Returns:

the result array passed as a parameter, for convenience