/*
* $Id: WildcardHelper.java 471754 2006-11-06 14:55:09Z husted $
*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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.
*
* @version $Rev: 471754 $ $Date: 2005-05-07 12:11:38 -0400 (Sat, 07 May 2005)
* $
* @since Struts 1.2
*/
public class WildcardHelper {
/**
* The int representing '*' in the pattern <code>int []</code>.
*/
protected static final int MATCH_FILE = -1;
/**
* The int representing '**' in the pattern <code>int []</code>.
*/
protected static final int MATCH_PATH = -2;
/**
* The int representing begin in the pattern <code>int []</code>.
*/
protected static final int MATCH_BEGIN = -4;
/**
* The int representing end in pattern <code>int []</code>.
*/
protected static final int MATCH_THEEND = -5;
/**
* The int value that terminates the pattern <code>int []</code>.
*/
protected static final int MATCH_END = -3;
/**
* <p> Translate the given <code>String</code> into a <code>int []</code>
* representing the pattern matchable by this class. <br> This function
* translates a <code>String</code> into an int array converting the
* special '*' and '\' characters. <br> Here is how the conversion
* algorithm works:</p>
*
* <ul>
*
* <li>The '*' character is converted to MATCH_FILE, meaning that zero or
* more characters (excluding the path separator '/') are to be
* matched.</li>
*
* <li>The '**' sequence is converted to MATCH_PATH, meaning that zero or
* more characters (including the path separator '/') are to be
* matched.</li>
*
* <li>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.</li>
*
* </ul>
*
* <p>When more than two '*' characters, not separated by another
* character, are found their value is considered as '**' (MATCH_PATH).
* <br> The array is always terminated by a special value (MATCH_END).
* <br> All MATCH* values are less than zero, while normal characters are
* equal or greater.</p>
*
* @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).
* @throws 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 <code>Stack</code>.
*
* @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. <br> 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.
* <br> 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. <br> 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);
}
}