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/*
 * $Id: WildcardHelper.java 54929 2004-10-16 16:38:42Z germuska $ 
 *
 * Copyright 2003-2004 The Apache Software Foundation.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
 
package org.apache.struts.util;

import java.util.Map;

/**
 * This class is an utility class that perform wilcard-patterns matching and
 * isolation taken from Apache Cocoon.
 *
 * @since Struts 1.2
 * @version $Rev: 54929 $ $Date: 2004-10-16 17:38:42 +0100 (Sat, 16 Oct 2004) $
 */
public class WildcardHelper {

    /** The int representing '*' in the pattern int []. */
    protected static final int MATCH_FILE = -1;
    
    /** The int representing '**' in the pattern int []. */
    protected static final int MATCH_PATH = -2;
    
    /** The int representing begin in the pattern int []. */
    protected static final int MATCH_BEGIN = -4;
    
    /** The int representing end in pattern int []. */
    protected static final int MATCH_THEEND = -5;
    
    /** The int value that terminates the pattern int []. */
    protected static final int MATCH_END = -3;


    /**
     * Translate the given String into a int []
     * representing the pattern matchable by this class.
     * 
* This function translates a String into an int array * converting the special '*' and '\' characters. *
* Here is how the conversion algorithm works: *
    *
  • The '*' character is converted to MATCH_FILE, meaning that zero * or more characters (excluding the path separator '/') are to * be matched.
  • *
  • The '**' sequence is converted to MATCH_PATH, meaning that zero * or more characters (including the path separator '/') are to * be matched.
  • *
  • The '\' character is used as an escape sequence ('\*' is * translated in '*', not in MATCH_FILE). If an exact '\' character * is to be matched the source string must contain a '\\'. * sequence.
  • *
* When more than two '*' characters, not separated by another character, * are found their value is considered as '**' (MATCH_PATH). *
* The array is always terminated by a special value (MATCH_END). *
* All MATCH* values are less than zero, while normal characters are equal * or greater. * * @param data The string to translate. * @return The encoded string as an int array, terminated by the MATCH_END * value (don't consider the array length). * @exception NullPointerException If data is null. */ public int[] compilePattern(String data) { // Prepare the arrays int expr[] = new int[data.length() + 2]; char buff[] = data.toCharArray(); // Prepare variables for the translation loop int y = 0; boolean slash = false; // Must start from beginning expr[y++] = MATCH_BEGIN; if (buff.length > 0) { if (buff[0] == '\\') { slash = true; } else if (buff[0] == '*') { expr[y++] = MATCH_FILE; } else { expr[y++] = buff[0]; } // Main translation loop for (int x = 1; x < buff.length; x++) { // If the previous char was '\' simply copy this char. if (slash) { expr[y++] = buff[x]; slash = false; // If the previous char was not '\' we have to do a bunch of // checks } else { // If this char is '\' declare that and continue if (buff[x] == '\\') { slash = true; // If this char is '*' check the previous one } else if (buff[x] == '*') { // If the previous character als was '*' match a path if (expr[y - 1] <= MATCH_FILE) { expr[y - 1] = MATCH_PATH; } else { expr[y++] = MATCH_FILE; } } else { expr[y++] = buff[x]; } } } } // Must match end at the end expr[y] = MATCH_THEEND; return expr; } /** * Match a pattern agains a string and isolates wildcard replacement into a * Stack. * * @param map The map to store matched values * @param data The string to match * @param expr The compiled wildcard expression * @return True if a match * @throws NullPointerException If any parameters are null */ public boolean match(Map map, String data, int[] expr) { if (map == null) { throw new NullPointerException ("No map provided"); } if (data == null) { throw new NullPointerException ("No data provided"); } if (expr == null) { throw new NullPointerException ("No pattern expression provided"); } char buff[] = data.toCharArray(); // Allocate the result buffer char rslt[] = new char[expr.length + buff.length]; // The previous and current position of the expression character // (MATCH_*) int charpos = 0; // The position in the expression, input, translation and result arrays int exprpos = 0; int buffpos = 0; int rsltpos = 0; int offset = -1; // The matching count int mcount = 0; // We want the complete data be in {0} map.put(Integer.toString(mcount), data); // First check for MATCH_BEGIN boolean matchBegin = false; if (expr[charpos] == MATCH_BEGIN) { matchBegin = true; exprpos = ++charpos; } // Search the fist expression character (except MATCH_BEGIN - already // skipped) while (expr[charpos] >= 0) { charpos++; } // The expression charater (MATCH_*) int exprchr = expr[charpos]; while (true) { // Check if the data in the expression array before the current // expression character matches the data in the input buffer if (matchBegin) { if (!matchArray(expr, exprpos, charpos, buff, buffpos)) { return (false); } matchBegin = false; } else { offset = indexOfArray (expr, exprpos, charpos, buff, buffpos); if (offset < 0) { return (false); } } // Check for MATCH_BEGIN if (matchBegin) { if (offset != 0) { return (false); } matchBegin = false; } // Advance buffpos buffpos += (charpos - exprpos); // Check for END's if (exprchr == MATCH_END) { if (rsltpos > 0) { map.put(Integer.toString(++mcount), new String(rslt, 0, rsltpos)); } // Don't care about rest of input buffer return (true); } else if (exprchr == MATCH_THEEND) { if (rsltpos > 0) { map.put(Integer.toString(++mcount), new String(rslt, 0, rsltpos)); } // Check that we reach buffer's end return (buffpos == buff.length); } // Search the next expression character exprpos = ++charpos; while (expr[charpos] >= 0) { charpos++; } int prevchr = exprchr; exprchr = expr[charpos]; // We have here prevchr == * or **. offset = (prevchr == MATCH_FILE) ? indexOfArray (expr, exprpos, charpos, buff, buffpos) : lastIndexOfArray (expr, exprpos, charpos, buff, buffpos); if (offset < 0) { return (false); } // Copy the data from the source buffer into the result buffer // to substitute the expression character if (prevchr == MATCH_PATH) { while (buffpos < offset) { rslt[rsltpos++] = buff[buffpos++]; } } else { // Matching file, don't copy '/' while (buffpos < offset) { if (buff[buffpos] == '/') { return (false); } rslt[rsltpos++] = buff[buffpos++]; } } map.put(Integer.toString(++mcount), new String (rslt, 0, rsltpos)); rsltpos = 0; } } /** * Get the offset of a part of an int array within a char array. *
* This method return the index in d of the first occurrence after dpos of * that part of array specified by r, starting at rpos and terminating at * rend. * * @param r The array containing the data that need to be matched in d. * @param rpos The index of the first character in r to look for. * @param rend The index of the last character in r to look for plus 1. * @param d The array of char that should contain a part of r. * @param dpos The starting offset in d for the matching. * @return The offset in d of the part of r matched in d or -1 if that was * not found. */ protected int indexOfArray (int r[], int rpos, int rend, char d[], int dpos) { // Check if pos and len are legal if (rend < rpos) { throw new IllegalArgumentException ("rend < rpos"); } // If we need to match a zero length string return current dpos if (rend == rpos) { return (d.length); //?? dpos? } // If we need to match a 1 char length string do it simply if ((rend - rpos) == 1) { // Search for the specified character for (int x = dpos; x < d.length; x++) { if (r[rpos] == d[x]) { return (x); } } } // Main string matching loop. It gets executed if the characters to // match are less then the characters left in the d buffer while ((dpos + rend - rpos) <= d.length) { // Set current startpoint in d int y = dpos; // Check every character in d for equity. If the string is matched // return dpos for (int x = rpos; x <= rend; x++) { if (x == rend) { return (dpos); } if (r[x] != d[y++]) { break; } } // Increase dpos to search for the same string at next offset dpos++; } // The remaining chars in d buffer were not enough or the string // wasn't matched return (-1); } /** * Get the offset of a last occurance of an int array within a char array. *
* This method return the index in d of the last occurrence after dpos of * that part of array specified by r, starting at rpos and terminating at * rend. * * @param r The array containing the data that need to be matched in d. * @param rpos The index of the first character in r to look for. * @param rend The index of the last character in r to look for plus 1. * @param d The array of char that should contain a part of r. * @param dpos The starting offset in d for the matching. * @return The offset in d of the last part of r matched in d or -1 if * that was not found. */ protected int lastIndexOfArray (int r[], int rpos, int rend, char d[], int dpos) { // Check if pos and len are legal if (rend < rpos) { throw new IllegalArgumentException ("rend < rpos"); } // If we need to match a zero length string return current dpos if (rend == rpos) { return (d.length); //?? dpos? } // If we need to match a 1 char length string do it simply if ((rend - rpos) == 1) { // Search for the specified character for (int x = d.length - 1; x > dpos; x--) { if (r[rpos] == d[x]) { return (x); } } } // Main string matching loop. It gets executed if the characters to // match are less then the characters left in the d buffer int l = d.length - (rend - rpos); while (l >= dpos) { // Set current startpoint in d int y = l; // Check every character in d for equity. If the string is matched // return dpos for (int x = rpos; x <= rend; x++) { if (x == rend) { return (l); } if (r[x] != d[y++]) { break; } } // Decrease l to search for the same string at next offset l--; } // The remaining chars in d buffer were not enough or the string // wasn't matched return (-1); } /** * Matches elements of array r from rpos to rend with array d, starting * from dpos. *
* This method return true if elements of array r from rpos to rend * equals elements of array d starting from dpos to dpos+(rend-rpos). * * @param r The array containing the data that need to be matched in d. * @param rpos The index of the first character in r to look for. * @param rend The index of the last character in r to look for. * @param d The array of char that should start from a part of r. * @param dpos The starting offset in d for the matching. * @return true if array d starts from portion of array r. */ protected boolean matchArray (int r[], int rpos, int rend, char d[], int dpos) { if (d.length - dpos < rend - rpos) { return (false); } for (int i = rpos; i < rend; i++) { if (r[i] != d[dpos++]) { return (false); } } return (true); } }




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