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1: /* gnu/regexp/CharIndexed.java 2: Copyright (C) 1998-2001, 2004, 2006 Free Software Foundation, Inc. 3: 4: This file is part of GNU Classpath. 5: 6: GNU Classpath is free software; you can redistribute it and/or modify 7: it under the terms of the GNU General Public License as published by 8: the Free Software Foundation; either version 2, or (at your option) 9: any later version. 10: 11: GNU Classpath is distributed in the hope that it will be useful, but 12: WITHOUT ANY WARRANTY; without even the implied warranty of 13: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 14: General Public License for more details. 15: 16: You should have received a copy of the GNU General Public License 17: along with GNU Classpath; see the file COPYING. If not, write to the 18: Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 19: 02110-1301 USA. 20: 21: Linking this library statically or dynamically with other modules is 22: making a combined work based on this library. Thus, the terms and 23: conditions of the GNU General Public License cover the whole 24: combination. 25: 26: As a special exception, the copyright holders of this library give you 27: permission to link this library with independent modules to produce an 28: executable, regardless of the license terms of these independent 29: modules, and to copy and distribute the resulting executable under 30: terms of your choice, provided that you also meet, for each linked 31: independent module, the terms and conditions of the license of that 32: module. An independent module is a module which is not derived from 33: or based on this library. If you modify this library, you may extend 34: this exception to your version of the library, but you are not 35: obligated to do so. If you do not wish to do so, delete this 36: exception statement from your version. */ 37: 38: package gnu.java.util.regex; 39: 40: /** 41: * Defines the interface used internally so that different types of source 42: * text can be accessed in the same way. Built-in concrete classes provide 43: * support for String, StringBuffer, InputStream and char[] types. 44: * A class that is CharIndexed supports the notion of a cursor within a 45: * block of text. The cursor must be able to be advanced via the move() 46: * method. The charAt() method returns the character at the cursor position 47: * plus a given offset. 48: * 49: * @author <A HREF="mailto:wes@cacas.org">Wes Biggs</A> 50: */ 51: public interface CharIndexed { 52: /** 53: * Defines a constant (0xFFFF was somewhat arbitrarily chosen) 54: * that can be returned by the charAt() function indicating that 55: * the specified index is out of range. 56: */ 57: char OUT_OF_BOUNDS = '\uFFFF'; 58: 59: /** 60: * Returns the character at the given offset past the current cursor 61: * position in the input. The index of the current position is zero. 62: * It is possible for this method to be called with a negative index. 63: * This happens when using the '^' operator in multiline matching mode 64: * or the '\b' or '\<' word boundary operators. In any case, the lower 65: * bound is currently fixed at -2 (for '^' with a two-character newline). 66: * 67: * @param index the offset position in the character field to examine 68: * @return the character at the specified index, or the OUT_OF_BOUNDS 69: * character defined by this interface. 70: */ 71: char charAt(int index); 72: 73: /** 74: * Shifts the input buffer by a given number of positions. Returns 75: * true if the new cursor position is valid. 76: */ 77: boolean move(int index); 78: 79: /** 80: * Returns true if the most recent move() operation placed the cursor 81: * position at a valid position in the input. 82: */ 83: boolean isValid(); 84: 85: /** 86: * Returns another CharIndexed containing length characters to the left 87: * of the given index. The given length is an expected maximum and 88: * the returned CharIndexed may not necessarily contain so many characters. 89: */ 90: CharIndexed lookBehind(int index, int length); 91: 92: /** 93: * Returns the effective length of this CharIndexed 94: */ 95: int length(); 96: 97: /** 98: * Sets the REMatch last found on this input. 99: */ 100: void setLastMatch(REMatch match); 101: 102: /** 103: * Returns the REMatch last found on this input. 104: */ 105: REMatch getLastMatch(); 106: 107: /** 108: * Returns the anchor. 109: */ 110: int getAnchor(); 111: 112: /** 113: * Sets the anchor. 114: */ 115: void setAnchor(int anchor); 116: }