Module org.eclipse.jetty.util

Package org.eclipse.jetty.util

Class SearchPattern

java.lang.Object

org.eclipse.jetty.util.SearchPattern

public class SearchPattern
extends Object

Fast search for patterns within strings, arrays of bytes and ByteBuffers.

Uses an implementation of the Boyer–Moore–Horspool algorithm with a 256 character alphabet.

The algorithm has an average-case complexity of O(n) on random text and O(nm) in the worst case, where m = pattern length and n = length of data to search.

Method Summary

Modifier and Type	Method	Description
static SearchPattern	compile(byte[] pattern)	Creates a SearchPattern instance which can be used to find matches of the pattern in data.
static SearchPattern	compile(String pattern)	Creates a SearchPattern instance which can be used to find matches of the pattern in data.
int	endsWith(byte[] data, int offset, int length)	Search for a partial match of the pattern at the end of the data.
int	endsWith(ByteBuffer buffer)	Searches for a partial match of the pattern at the end of the ByteBuffer.
int	getLength()
byte[]	getPattern()
int	match(byte[] data, int offset, int length)	Search for a complete match of the pattern within the data
int	match(ByteBuffer buffer)	Searches for a full match of the pattern in the ByteBuffer.
int	startsWith(byte[] data, int offset, int length, int matched)	Search for a possibly partial match of the pattern at the start of the data.
int	startsWith(ByteBuffer buffer, int matched)	Searches for a partial match of the pattern at the beginning of the ByteBuffer.

Methods inherited from class java.lang.Object

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

Method Details

compile

public static SearchPattern compile(byte[] pattern)

Creates a SearchPattern instance which can be used to find matches of the pattern in data.

Parameters:

pattern - byte array containing the pattern to search

Returns:

a new SearchPattern instance using the given pattern

compile

public static SearchPattern compile(String pattern)

Creates a SearchPattern instance which can be used to find matches of the pattern in data.

The pattern string must only contain ASCII characters.

Parameters:

pattern - string containing the pattern to search

Returns:

a new SearchPattern instance using the given pattern

getPattern

public byte[] getPattern()

Returns:

the pattern to search.

match

public int match(byte[] data,
 int offset,
 int length)

Search for a complete match of the pattern within the data

Parameters:

data - The data in which to search for. The data may be arbitrary binary data, but the pattern will always be StandardCharsets.US_ASCII encoded.

offset - The offset within the data to start the search

length - The length of the data to search

Returns:

The index within the data array at which the first instance of the pattern or -1 if not found

match

public int match(ByteBuffer buffer)

Searches for a full match of the pattern in the ByteBuffer.

The ByteBuffer may contain arbitrary binary data, but the pattern will always be StandardCharsets.US_ASCII encoded.

The position and limit of the ByteBuffer are not changed.

Parameters:

buffer - the ByteBuffer to search into

Returns:

the number of bytes after the buffer's position at which the full pattern was found, or -1 if the full pattern was not found

endsWith

public int endsWith(byte[] data,
 int offset,
 int length)

Search for a partial match of the pattern at the end of the data.

Parameters:

data - The data in which to search for. The data may be arbitrary binary data, but the pattern will always be StandardCharsets.US_ASCII encoded.

offset - The offset within the data to start the search

length - The length of the data to search

Returns:

the length of the partial pattern matched and 0 for no match.

endsWith

public int endsWith(ByteBuffer buffer)

Searches for a partial match of the pattern at the end of the ByteBuffer.

The ByteBuffer may contain arbitrary binary data, but the pattern will always be StandardCharsets.US_ASCII encoded.

The position and limit of the ByteBuffer are not changed.

Parameters:

buffer - the ByteBuffer to search into

Returns:

how many bytes of the pattern were matched at the end of the ByteBuffer, or 0 for no match

startsWith

public int startsWith(byte[] data,
 int offset,
 int length,
 int matched)

Search for a possibly partial match of the pattern at the start of the data.

Parameters:

data - The data in which to search for. The data may be arbitrary binary data, but the pattern will always be StandardCharsets.US_ASCII encoded.

offset - The offset within the data to start the search

length - The length of the data to search

matched - The length of the partial pattern already matched

Returns:

the length of the partial pattern matched and 0 for no match.

startsWith

public int startsWith(ByteBuffer buffer,
 int matched)

Searches for a partial match of the pattern at the beginning of the ByteBuffer.

The ByteBuffer may contain arbitrary binary data, but the pattern will always be StandardCharsets.US_ASCII encoded.

The position and limit of the ByteBuffer are not changed.

Parameters:

buffer - the ByteBuffer to search into

matched - how many bytes of the pattern were already matched

Returns:

how many bytes of the pattern were matched (including those already matched) at the beginning of the ByteBuffer, or 0 for no match

getLength

public int getLength()

Returns:

The length of the pattern in bytes.