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package it.unimi.dsi.util;
/*
* DSI utilities
*
* Copyright (C) 2003-2009 Paolo Boldi and Sebastiano Vigna
*
* This library is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as published by the Free
* Software Foundation; either version 2.1 of the License, or (at your option)
* any later version.
*
* This library is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
* for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
*/
import it.unimi.dsi.bits.Fast;
import it.unimi.dsi.fastutil.chars.CharList;
import it.unimi.dsi.lang.MutableString;
/** QuickSearch matching against a constant string.
*
* The {@linkplain java.util.regex regular expression facilities} of the Java API
* are a powerful tool; however, when searching for a constant pattern
* many algorithms can increase of orders magnitude the speed of a search.
*
*
This class provides constant-pattern text search facilities by
* implementing Sunday's QuickSearch (a simplified but very effective variant
* of the Boyer—Moore search algorithm) using compact
* approximators, a randomised data structure that can accomodate in a
* small space (but in an approximated way) the bad-character shift table of a
* large alphabet such as Unicode.
*
*
Since a large subset of US-ASCII is used in all languages (e.g.,
* whitespace, punctuation, etc.), this class caches separately the shifts for
* the first 128 Unicode characters, resulting in very good performance even on
* text in pure US-ASCII.
*
*
Note that the {@link MutableString#indexOf(MutableString) indexOf}
* methods of {@link MutableString} use a even more simplified variant of
* QuickSearch which is less efficient, but has a smaller setup time and does
* not generate any object. The search facilities provided by this class are
* targeted at searches on very large texts, repeated searches with the same
* pattern, and case-insensitive searches.
*
*
Instances of this class are immutable and thread-safe.
*
*
This class is experimental: APIs could change with the next release.
*
* @author Sebastiano Vigna
* @author Paolo Boldi
* @since 0.6
*/
public class TextPattern implements java.io.Serializable, CharSequence {
private static final long serialVersionUID = 1L;
/** Enables case-insensitive matching.
*
*
By default, case-insensitive matching assumes that only characters in
* the ASCII charset are being matched. Unicode-aware case-insensitive
* matching can be enabled by specifying the UNICODE_CASE flag in
* conjunction with this flag.
*
*
Case-insensitivity involves a performance drop.
*/
public final static int CASE_INSENSITIVE = 1;
/** Enables Unicode-aware case folding.
*
*
When this flag is specified then case-insensitive matching, when enabled
* by the CASE_INSENSITIVE flag, is done in a manner consistent with the
* Unicode Standard. By default, case-insensitive matching assumes that
* only characters in the ASCII charset are being matched.
*
*
Unicode-aware case folding is very expensive (two method calls per
* examined non-ASCII character).
*/
public final static int UNICODE_CASE = 2;
/** The square of the golden ratio multiplied by 232. */
private final static int PHI2 = 1640531525;
/** The pattern backing array. */
protected char[] pattern;
/** The compact approximator containing the bad-character shifts; its lenght is a power of 2. */
private transient int[] badCharShift;
/** The bad-character shift for US-ASCII. */
private transient int[] asciiBadCharShift = new int[ 128 ];
/** A bit mask equal to the length of {@link #badCharShift} minus 1. */
private transient int mask;
/** A cached shift value for computing one of the hashes. It is equal to 16 minus the base 2 logarithm of the length of {@link #badCharShift}. */
private transient int hashShift;
/** Whether this pattern is case sensitive. */
private boolean caseSensitive;
/** Whether this pattern uses optimised ASCII downcasing (as opposed to the correct Unicode downcasing procedure). */
private boolean asciiCase;
/** Creates a new case-sensitive {@link TextPattern} object that can be used to search for the given pattern.
*
* @param pattern the constant pattern to search for.
*/
public TextPattern( final CharSequence pattern ) {
this( pattern, 0 );
}
/** Creates a new {@link TextPattern} object that can be used to search for the given pattern.
*
* @param pattern the constant pattern to search for.
* @param flags a bit mask that may include {@link #CASE_INSENSITIVE} and {@link #UNICODE_CASE}.
*/
public TextPattern( final CharSequence pattern, final int flags ) {
this.pattern = new char[ pattern.length() ];
MutableString.getChars( pattern, 0, this.pattern.length, this.pattern, 0 );
caseSensitive = ( flags & CASE_INSENSITIVE ) == 0;
asciiCase = ( flags & UNICODE_CASE ) == 0;
if ( ! caseSensitive ) {
int i = this.pattern.length;
if ( asciiCase ) while( i-- != 0 ) this.pattern[ i ] = asciiToLowerCase( this.pattern[ i ] );
else while( i-- != 0 ) this.pattern[ i ] = unicodeToLowerCase( this.pattern[ i ] );
}
compile();
}
/** Returns whether this pattern is case insensitive.
*
*/
public boolean caseInsensitive() {
return ! caseSensitive;
}
/** Returns whether this pattern uses Unicode case folding.
*
*/
public boolean unicodeCase() {
return ! asciiCase;
}
/** A fast, optimised method to lower case just ASCII letters.
*
* @param c a character.
* @return the character c, downcased if it lies between A and Z.
*/
private static char asciiToLowerCase( final char c ) {
return c >= 'A' && c <= 'Z' ? (char)( c + 32 ) : c;
}
/** A method to downcase correctly Unicode characters optimised for ASCII letters.
*
* @param c a character.
* @return the character c, downcased.
*/
private static char unicodeToLowerCase( final char c ) {
if ( c < 128 ) return c >= 'A' && c <= 'Z' ? (char)( c + 32 ) : c;
return Character.toLowerCase( Character.toUpperCase( c ) );
}
private static final int MIN_COUNT = 8;
/** Fills the search data structures using the pattern contained in {@link #pattern}. */
private void compile() {
final char[] p = pattern;
final int n = p.length;
int[] s = asciiBadCharShift;
char c;
// We make two passes on the pattern, so to approximate first the number of non-US-ASCII characters.
int h, i, j = 0, k = 0, l;
int[] max = new int[ MIN_COUNT ];
i = s.length;
while( i-- != 0 ) s[ i ] = n;
i = MIN_COUNT;
while( i-- != 0 ) max[ i ] = Integer.MAX_VALUE;
i = n;
while( i-- != 0 ) {
c = p[ j++ ];
if ( c < 128 ) s[ c ] = i;
else {
k++;
/* Bar-Yossef-Jayram-Kumar-Sivakumar-Trevisan's improvement on
Flajolet-Martin's algorithm for approximating the number of
distinct elements in a stream. We map each character with a
hash function on the unit interval, keep track of the smallest
MIN_COUNT elements, and then approximate the number of distinct
characters with MIN_COUNT divided by the largest element we
have (of course, everything is done in fixed point arithmetic
on the interval 0-2^32). If the approximation is less than the
number of characters, we use it. */
h = c * PHI2;
l = MIN_COUNT;
while( l-- != 0 ) if ( h > max[ l ] ) break;
if ( ++l < MIN_COUNT && h != max[ l ] ) {
System.arraycopy( max, l , max, l + 1, MIN_COUNT - l - 1 );
max[ l ] = h;
}
}
}
//System.err.println( k );
//System.err.println( (int)( MIN_COUNT * 0x100000000L / ( 0x80000000L + M[ MIN_COUNT - 1 ] ) ) );
k = Math.min( k, (int)( MIN_COUNT * 0x100000000L / ( 0x80000000L + max[ MIN_COUNT - 1 ] ) ) );
/* We do not use less than 2^7 entries, so to compensate the setup
overhead with a more precise approximator for very small patterns. If,
however, there are no non-US-ASCII characters, we use a single-bucket
approximator (so to avoid special cases in the algorithm). In any case,
we do not use approximators with more than 2^16 entries. */
final int log2m = k == 0 ? 0 : Math.min( Math.max( Fast.mostSignificantBit( k * 3 ) + 1, 7 ), 16 );
final int m = ( 1 << log2m ) - 1;
final int hs = 16 - log2m;
/* For the characters outside Unicode, we build a compact approximator
with two hash functions h_0 and h_1. The approximator stores a function
f from the character set to integers in a table s. The value of the
function on c can be obtained by maximising the values s[h_0(c)] and
s[h_1(c)]. When storing a value, instead, we minimise s[h_0(c)] and
s[h_1(c)] with f(c). As a result, the value stored is smaller than or
equal to the actual value f(c). By tuning the size of s and the number
of hash functions one can get a desired error precision. */
s = new int[ m + 1 ];
i = m + 1;
while( i-- != 0 ) s[ i ] = n;
i = n;
j = 0;
while( i-- != 0 ) {
c = p[ j++ ];
if ( c >= 128 ) {
s[ c * c & m ] = i;
s[ ( c * PHI2 ) >> hs & m ] = i;
}
}
this.badCharShift = s;
this.mask = m;
this.hashShift = hs;
/*
for( i = 0; i <= m; i++ ) System.err.print( "" + s[ i ] + ", " );
System.err.println();
for( c = 'a'; c <= 'z'; c++ ) System.err.print( c + ":" + Math.max( s[ c * c & m ], s[ ( c * PHI2 ) >> hs & m ] ) + ", " );
System.err.println();
for( c = 'A'; c <= 'Z'; c++ ) System.err.print( c + ":" + Math.max( s[ c * c & m ], s[ ( c * PHI2 ) >> hs & m ] ) + ", " );
System.err.println();
MutableString msp = new MutableString( pattern );
for( c = 'a'; c <= 'z'; c++ ) if ( msp.indexOf( c ) == -1 && Math.max( s[ c * c & m ], s[ ( c * PHI2 ) >> hs & m ] ) != n )
System.err.println( c + ":" + Math.max( s[ c * c & m ], s[ ( c * PHI2 ) >> hs & m ] ) + ", " );
for( c = 'A'; c <= 'Z'; c++ ) if ( msp.indexOf( c ) == -1 && Math.max( s[ c * c & m ], s[ ( c * PHI2 ) >> hs & m ] ) != n )
System.err.println( c + ":" + Math.max( s[ c * c & m ], s[ ( c * PHI2 ) >> hs & m ] ) + ", " );
*/
}
public int length() {
return pattern.length;
}
public char charAt( final int i ) {
return pattern[ i ];
}
public CharSequence subSequence( final int from, final int to ) {
return new MutableString( pattern, from, to - from + 1 );
}
/** Returns the index of the first occurrence of this one-character pattern
* in the specified character array, starting at the specified index.
*
*
This method is a fallback for searches on one-character patterns.
*
* @param array the character array to look in.
* @param from the index from which the search must start.
* @param to the index at which the search must end.
* @return the index of the first occurrence of this pattern or
* -1, if this pattern never appears with index greater than
* or equal to from.
*/
private int indexOf( final char[] array, final int from, final int to ) {
final char[] a = array;
final int c = pattern[ 0 ];
int i = from < 0 ? -1 : from - 1;
if ( caseSensitive ) {
while( ++i < to ) if ( a[ i ] == c ) return i;
return -1;
}
else if ( asciiCase ) {
while( ++i < to ) if ( asciiToLowerCase( a[ i ] ) == c ) return i;
return -1;
}
else {
while( ++i < to ) if ( unicodeToLowerCase( a[ i ] ) == c ) return i;
return -1;
}
}
/** Returns the index of the first occurrence of this one-character pattern
* in the specified character sequence, starting at the specified index.
*
*
This method is a fallback for searches on one-character patterns.
*
* @param s the character sequence to look in.
* @param from the index from which the search must start.
* @return the index of the first occurrence of this pattern or
* -1, if the this pattern never appears with index greater than
* or equal to from.
*/
private int indexOf( final CharSequence s, final int from, final int to ) {
final int c = pattern[ 0 ];
int i = from < 0 ? -1 : from - 1;
if ( caseSensitive ) {
while( ++i < to ) if ( s.charAt( i ) == c ) return i;
return -1;
}
else if ( asciiCase ) {
while( ++i < to ) if ( asciiToLowerCase( s.charAt( i ) ) == c ) return i;
return -1;
}
else {
while( ++i < to ) if ( unicodeToLowerCase( s.charAt( i ) ) == c ) return i;
return -1;
}
}
/** Returns the index of the first occurrence of this one-character pattern
* in the specified byte array, seen as an ISO-8859-1 string,
* starting at the specified index.
*
*
This method is a fallback for searches on one-character patterns.
*
* @param array the byte array to look in.
* @param from the index from which the search must start.
* @return the index of the first occurrence of this pattern or
* -1, if this pattern never appears with index greater than
* or equal to from.
*/
private int indexOf( final byte[] array, final int from, final int to ) {
final byte[] a = array;
final int c = pattern[ 0 ];
int i = from < 0 ? -1 : from - 1;
if ( caseSensitive ) {
while( ++i < to ) if ( ( a[ i ] & 0xFF ) == c ) return i;
return -1;
}
else {
while( ++i < to ) if ( asciiToLowerCase( (char)( a[ i ] & 0xFF ) ) == c ) return i;
return -1;
}
}
/** Returns the index of the first occurrence of this pattern in the given character array.
*
* @param array the character array to look in.
* @return the index of the first occurrence of this pattern contained in the
* given array, or -1, if the pattern cannot be found.
*/
public int search( final char[] array ) {
return search( array, 0, array.length );
}
/** Returns the index of the first occurrence of this pattern in the given character array starting from a given index.
*
* @param array the character array to look in.
* @param from the index from which the search must start.
* @return the index of the first occurrence of this pattern contained in the
* subarray starting from from (inclusive), or
* -1, if the pattern cannot be found.
*/
public int search( char[] array, int from ) {
return search( array, from, array.length );
}
/** Returns the index of the first occurrence of this pattern in the given character array between given indices.
*
* @param a the character array to look in.
* @param from the index from which the search must start.
* @param to the index at which the search must end.
* @return the index of the first occurrence of this pattern contained in the
* subarray starting from from (inclusive) up to to
* (exclusive) characters, or -1, if the pattern cannot be found.
*/
public int search( final char[] a, final int from, final int to ) {
final int n = pattern.length;
if ( n == 0 ) return from > to ? to : ( from < 0 ? 0 : from );
if ( n == 1 ) return indexOf( a, from, to );
final char[] p = pattern;
final char last = p[ n - 1 ];
final int m1 = to - 1;
final int[] shift = badCharShift;
final int[] asciiShift = asciiBadCharShift;
final int m = mask;
final int hs = hashShift;
int i = ( from < 0 ? 0 : from ) + n - 1, j, k;
char c;
if ( caseSensitive ) {
while ( i < m1 ) {
if ( a[ i ] == last ) {
j = n - 1;
k = i;
while( j-- != 0 && a[ --k ] == p[ j ] );
if ( j < 0 ) return k;
}
if ( ( c = a[ ++i ] ) < 128 ) i += asciiShift[ c ];
else {
j = shift[ c * c & m ];
k = shift[ ( c * PHI2 ) >> hs & m ];
i += j > k ? j : k;
}
}
if ( i == m1 ) {
j = n;
while( j-- != 0 && a[ i-- ] == p[ j ] );
if ( j < 0 ) return i + 1;
}
return -1;
}
else if ( asciiCase ) {
while ( i < m1 ) {
if ( asciiToLowerCase( a[ i ] ) == last ) {
j = n - 1;
k = i;
while( j-- != 0 && asciiToLowerCase( a[ --k ] ) == p[ j ] );
if ( j < 0 ) return k;
}
if ( ( c = asciiToLowerCase( a[ ++i ] ) ) < 128 ) i += asciiShift[ c ];
else {
j = shift[ c * c & m ];
k = shift[ ( c * PHI2 ) >> hs & m ];
i += j > k ? j : k;
}
}
if ( i == m1 ) {
j = n;
while( j-- != 0 && asciiToLowerCase( a[ i-- ] ) == p[ j ] );
if ( j < 0 ) return i + 1;
}
return -1;
}
else {
while ( i < m1 ) {
if ( unicodeToLowerCase( a[ i ] ) == last ) {
j = n - 1;
k = i;
while( j-- != 0 && unicodeToLowerCase( a[ --k ] ) == p[ j ] );
if ( j < 0 ) return k;
}
if ( ( c = unicodeToLowerCase( a[ ++i ] ) ) < 128 ) i += asciiShift[ c ];
else {
j = shift[ c * c & m ];
k = shift[ ( c * PHI2 ) >> hs & m ];
i += j > k ? j : k;
}
}
if ( i == m1 ) {
j = n;
while( j-- != 0 && unicodeToLowerCase( a[ i-- ] ) == p[ j ] );
if ( j < 0 ) return i + 1;
}
return -1;
}
}
/** Returns the index of the first occurrence of this pattern in the given character sequence.
*
* @param s the character sequence to look in.
* @return the index of the first occurrence of this pattern contained in the
* given character sequence, or -1, if the pattern cannot be found.
*/
public int search( final CharSequence s ) {
return search( s, 0, s.length() );
}
/** Returns the index of the first occurrence of this pattern in the given character sequence starting from a given index.
*
* @param s the character array to look in.
* @param from the index from which the search must start.
* @return the index of the first occurrence of this pattern contained in the
* subsequence starting from from (inclusive), or
* -1, if the pattern cannot be found.
*/
public int search( final CharSequence s, final int from ) {
return search( s, from, s.length() );
}
/** Returns the index of the first occurrence of this pattern in the given character sequence between given indices.
*
* @param s the character array to look in.
* @param from the index from which the search must start.
* @param to the index at which the search must end.
* @return the index of the first occurrence of this pattern contained in the
* subsequence starting from from (inclusive) up to to
* (exclusive) characters, or -1, if the pattern cannot be found.
*/
public int search( final CharSequence s, final int from, final int to ) {
final int n = pattern.length;
if ( n == 0 ) return from > to ? to : ( from < 0 ? 0 : from );
if ( n == 1 ) return indexOf( s, from, to );
final char[] p = pattern;
final char last = p[ n - 1 ];
final int m1 = to - 1;
final int[] shift = badCharShift;
final int[] asciiShift = asciiBadCharShift;
final int m = mask;
final int hs = hashShift;
int i = ( from < 0 ? 0 : from ) + n - 1, j, k;
char c;
if ( caseSensitive ) {
while ( i < m1 ) {
if ( s.charAt( i ) == last ) {
j = n - 1;
k = i;
while( j-- != 0 && s.charAt( --k ) == p[ j ] );
if ( j < 0 ) return k;
}
if ( ( c = s.charAt( ++i ) ) < 128 ) i += asciiShift[ c ];
else {
j = shift[ c * c & m ];
k = shift[ ( c * PHI2 ) >> hs & m ];
i += j > k ? j : k;
}
}
if ( i == m1 ) {
j = n;
while( j-- != 0 && s.charAt( i-- ) == p[ j ] );
if ( j < 0 ) return i + 1;
}
return -1;
}
else if ( asciiCase ) {
while ( i < m1 ) {
if ( asciiToLowerCase( s.charAt( i ) ) == last ) {
j = n - 1;
k = i;
while( j-- != 0 && asciiToLowerCase( s.charAt( --k ) ) == p[ j ] );
if ( j < 0 ) return k;
}
if ( ( c = asciiToLowerCase( s.charAt( ++i ) ) ) < 128 ) i += asciiShift[ c ];
else {
j = shift[ c * c & m ];
k = shift[ ( c * PHI2 ) >> hs & m ];
i += j > k ? j : k;
}
}
if ( i == m1 ) {
j = n;
while( j-- != 0 && asciiToLowerCase( s.charAt( i-- ) ) == p[ j ] );
if ( j < 0 ) return i + 1;
}
return -1;
}
else {
while ( i < m1 ) {
if ( unicodeToLowerCase( s.charAt( i ) ) == last ) {
j = n - 1;
k = i;
while( j-- != 0 && unicodeToLowerCase( s.charAt( --k ) ) == p[ j ] );
if ( j < 0 ) return k;
}
if ( ( c = unicodeToLowerCase( s.charAt( ++i ) ) ) < 128 ) i += asciiShift[ c ];
else {
j = shift[ c * c & m ];
k = shift[ ( c * PHI2 ) >> hs & m ];
i += j > k ? j : k;
}
}
if ( i == m1 ) {
j = n;
while( j-- != 0 && unicodeToLowerCase( s.charAt( i-- ) ) == p[ j ] );
if ( j < 0 ) return i + 1;
}
return -1;
}
}
/** Returns the index of the first occurrence of this pattern in the given byte array.
*
* @param a the byte array to look in.
* @return the index of the first occurrence of this pattern contained in the
* given byte array, or -1, if the pattern cannot be found.
*/
public int search( final byte[] a ) {
return search( a, 0, a.length );
}
/** Returns the index of the first occurrence of this pattern in the given byte array starting from a given index.
*
* @param a the byte array to look in.
* @param from the index from which the search must start.
* @return the index of the first occurrence of this pattern contained in the
* array fragment starting from from (inclusive), or
* -1, if the pattern cannot be found.
*/
public int search( final byte[] a, final int from ) {
return search( a, from, a.length );
}
/** Returns the index of the first occurrence of this pattern in the given byte array between given indices.
*
* @param a the byte array to look in.
* @param from the index from which the search must start.
* @param to the index at which the search must end.
* @return the index of the first occurrence of this pattern contained in the
* array fragment starting from from (inclusive) up to to
* (exclusive) characters, or -1, if the pattern cannot be found.
* TODO: this must be tested
*/
public int search( final byte[] a, final int from, final int to ) {
final int n = pattern.length;
if ( n == 0 ) return from > to ? to : ( from < 0 ? 0 : from );
if ( n == 1 ) return indexOf( a, from, to );
final char[] p = pattern;
final char last = p[ n - 1 ];
final int m1 = to - 1;
final int[] shift = badCharShift;
final int[] asciiShift = asciiBadCharShift;
final int m = mask;
final int hs = hashShift;
int i = ( from < 0 ? 0 : from ) + n - 1, j, k;
char c;
if ( caseSensitive ) {
while ( i < m1 ) {
if ( ( a[ i ] & 0xFF ) == last ) {
j = n - 1;
k = i;
while( j-- != 0 && ( a[ --k ] & 0xFF )== p[ j ] );
if ( j < 0 ) return k;
}
if ( ( c = (char)( a[ ++i ] & 0xFF ) ) < 128 ) i += asciiShift[ c ];
else {
j = shift[ c * c & m ];
k = shift[ ( c * PHI2 ) >> hs & m ];
i += j > k ? j : k;
}
}
if ( i == m1 ) {
j = n;
while( j-- != 0 && ( a[ i-- ] & 0xFF ) == p[ j ] );
if ( j < 0 ) return i + 1;
}
return -1;
}
else if ( asciiCase ) {
while ( i < m1 ) {
if ( asciiToLowerCase( (char)( a[ i ] & 0xFF ) ) == last ) {
j = n - 1;
k = i;
while( j-- != 0 && asciiToLowerCase( (char)( a[ --k ] & 0xFF ) ) == p[ j ] );
if ( j < 0 ) return k;
}
if ( ( c = asciiToLowerCase( (char)( a[ ++i ] & 0xFF ) ) ) < 128 ) i += asciiShift[ c ];
else {
j = shift[ c * c & m ];
k = shift[ ( c * PHI2 ) >> hs & m ];
i += j > k ? j : k;
}
}
if ( i == m1 ) {
j = n;
while( j-- != 0 && asciiToLowerCase( (char)( a[ i-- ] & 0xFF ) ) == p[ j ] );
if ( j < 0 ) return i + 1;
}
return -1;
}
else {
while ( i < m1 ) {
if ( unicodeToLowerCase( (char)( a[ i ] & 0xFF ) ) == last ) {
j = n - 1;
k = i;
while( j-- != 0 && unicodeToLowerCase( (char)( a[ --k ] & 0xFF ) ) == p[ j ] );
if ( j < 0 ) return k;
}
if ( ( c = unicodeToLowerCase( (char)( a[ ++i ] & 0xFF ) ) ) < 128 ) i += asciiShift[ c ];
else {
j = shift[ c * c & m ];
k = shift[ ( c * PHI2 ) >> hs & m ];
i += j > k ? j : k;
}
}
if ( i == m1 ) {
j = n;
while( j-- != 0 && unicodeToLowerCase( (char)( a[ i-- ] & 0xFF ) ) == p[ j ] );
if ( j < 0 ) return i + 1;
}
return -1;
}
}
/** Returns the index of the first occurrence of this pattern in the given character list.
*
* @param list the character list to look in.
* @return the index of the first occurrence of this pattern contained in the
* given list, or -1, if the pattern cannot be found.
*/
public int search( final CharList list ) {
return search( list, 0, list.size() );
}
/** Returns the index of the first occurrence of this pattern in the given character list starting from a given index.
*
* @param list the character list to look in.
* @param from the index from which the search must start.
* @return the index of the first occurrence of this pattern contained in the
* sublist starting from from (inclusive), or
* -1, if the pattern cannot be found.
*/
public int search( final CharList list, int from ) {
return search( list, from, list.size() );
}
/** Returns the index of the first occurrence of this pattern in the given character list between given indices.
*
* @param list the character list to look in.
* @param from the index from which the search must start.
* @param to the index at which the search must end.
* @return the index of the first occurrence of this pattern contained in the
* sublist starting from from (inclusive) up to to
* (exclusive) characters, or -1, if the pattern cannot be found.
*/
public int search( final CharList list, final int from, final int to ) {
final int n = pattern.length;
if ( n == 0 ) return from > to ? to : ( from < 0 ? 0 : from );
if ( n == 1 ) return list.subList( from, to ).indexOf( pattern[ 0 ] );
final char[] p = pattern;
final char last = p[ n - 1 ];
final int m1 = to - 1;
final int[] shift = badCharShift;
final int[] asciiShift = asciiBadCharShift;
final int m = mask;
final int hs = hashShift;
int i = ( from < 0 ? 0 : from ) + n - 1, j, k;
char c;
if ( caseSensitive ) {
while ( i < m1 ) {
if ( list.getChar( i ) == last ) {
j = n - 1;
k = i;
while( j-- != 0 && list.getChar( --k ) == p[ j ] );
if ( j < 0 ) return k;
}
if ( ( c = list.getChar( ++i ) ) < 128 ) i += asciiShift[ c ];
else {
j = shift[ c * c & m ];
k = shift[ ( c * PHI2 ) >> hs & m ];
i += j > k ? j : k;
}
}
if ( i == m1 ) {
j = n;
while( j-- != 0 && list.getChar( i-- ) == p[ j ] );
if ( j < 0 ) return i + 1;
}
return -1;
}
else if ( asciiCase ) {
while ( i < m1 ) {
if ( asciiToLowerCase( list.getChar( i ) ) == last ) {
j = n - 1;
k = i;
while( j-- != 0 && asciiToLowerCase( list.getChar( --k ) ) == p[ j ] );
if ( j < 0 ) return k;
}
if ( ( c = asciiToLowerCase( list.getChar( ++i ) ) ) < 128 ) i += asciiShift[ c ];
else {
j = shift[ c * c & m ];
k = shift[ ( c * PHI2 ) >> hs & m ];
i += j > k ? j : k;
}
}
if ( i == m1 ) {
j = n;
while( j-- != 0 && asciiToLowerCase( list.getChar( i-- ) ) == p[ j ] );
if ( j < 0 ) return i + 1;
}
return -1;
}
else {
while ( i < m1 ) {
if ( unicodeToLowerCase( list.getChar( i ) ) == last ) {
j = n - 1;
k = i;
while( j-- != 0 && unicodeToLowerCase( list.getChar( --k ) ) == p[ j ] );
if ( j < 0 ) return k;
}
if ( ( c = unicodeToLowerCase( list.getChar( ++i ) ) ) < 128 ) i += asciiShift[ c ];
else {
j = shift[ c * c & m ];
k = shift[ ( c * PHI2 ) >> hs & m ];
i += j > k ? j : k;
}
}
if ( i == m1 ) {
j = n;
while( j-- != 0 && unicodeToLowerCase( list.getChar( i-- ) ) == p[ j ] );
if ( j < 0 ) return i + 1;
}
return -1;
}
}
/** Compares this text pattern to another object.
*
*
This method will return true iff its argument
* is a TextPattern containing the same constant pattern with the same flags set.
*
* @param o an object.
* @return true if the argument is a TextPatterns that contains the same constant pattern of this text pattern
* and has the same flags set.
*/
final public boolean equals( final Object o ) {
if ( o instanceof TextPattern ) {
TextPattern p = (TextPattern)o;
return caseSensitive == p.caseSensitive && asciiCase == p.asciiCase && java.util.Arrays.equals( p.pattern, pattern );
}
return false;
}
/** Returns a hash code for this text pattern.
*
*
The hash code of a text pattern is the same as that of a
* String with the same content (suitably lower cased, if the pattern is case insensitive).
*
* @return a hash code array for this object.
* @see java.lang.String#hashCode()
*/
final public int hashCode() {
final char[] a = pattern;
final int l = a.length;
int h;
for ( int i = h = 0; i < l; i++ ) h = 31 * h + a[ i ];
return h;
}
final public String toString() {
return new String( pattern );
}
}