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Contains deprecated classes that will disappear in the next major release.
/*
* 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.axiom.attachments.utils;
/**
* Various byte array searching utilities. This includes a "skip search", which is an optimized
* search for finding a byte pattern in a large byte array.
*
* @deprecated This class was part of the MIME parser in Axiom versions before 1.2.13 and is no
* longer used. It will be removed in Axiom 1.3. Please note that the code in this class
* is known to have issues; see AXIOM-449 and AXIOM-450 for more
* information.
*/
public class ByteSearch {
/**
* Search a byte sequence for a given pattern. The method uses the
* skip search algorithm. The search can be performed in forward
* or backward direction, i.e. beginning from the start or end of the
* byte sequence.
*
* @param pattern byte[]
* @param direction true if forward, false if backward
* @param buffer byte[] to search
* @param start index to start search
* @param end index to end search (end index is not within the search)
* @param skip short[256] A skipArray generated from a call to
* generateSkipArray.
* @return index or -1 if not found
*/
public static int skipSearch(byte[] pattern,
boolean direction,
byte[] buffer,
int start,
int end,
short[] skip) {
int patternLength = pattern.length;
// If patternLength is larger than buffer,
// return not found
if (patternLength > (end - start)) {
return -1;
}
if (direction) {
int k = 0;
for (k = start + patternLength - 1;
k < end; // end is exclusive
k += skip[buffer[k] & (0xff)]) // SKIP NOTE below
{
try {
// k is the location in the buffer
// that may match the last byte in the pattern.
if (isEqual(pattern, buffer, (k-patternLength)+1, end)) {
return (k-patternLength)+1;
}
// SKIP NOTE: The next k index is calculated from
// the skip array. Basically if the k byte is not
// within the pattern, we skip ahead the length of the
// pattern. Otherwise we skip ahead a distance less
// than the length.
} catch (ArrayIndexOutOfBoundsException e) {
throw e;
}
}
} else {
for (int k = end - patternLength;
k <= start;
k -= skip[buffer[k] & (0xff)])
{
try {
// k is the location in the buffer
// that may match the first byte in the pattern.
if (isEqual(pattern, buffer, k, end)) {
return k;
}
} catch (ArrayIndexOutOfBoundsException e) {
throw e;
}
}
}
return -1;
}
/**
* skipArray
* Builds a skip array for this pattern and direction.
* The skipArray is used in the optimized skipSearch
* @param pattern
* @param direction
* @return short[256]
*/
public static short[] getSkipArray(byte[] pattern,
boolean direction) {
// The index key is a byte.
// The short[key] is the number of bytes that can
// be skipped that won't match the pattern
short[] skip = new short[256];
// If a byte is not within pattern, then we can
// skip ahead the entire length of the pattern.
// So fill the skip array with the pattern length
java.util.Arrays.fill(skip, (short) pattern.length);
if (direction) {
// If the byte is found in the pattern,
// this affects how far we can skip.
// The skip distance is the distance of the
// character from the end of the pattern.
// The last character in the pattern is excluded.
for (int k = 0; k < pattern.length -1; k++) {
skip[pattern[k] & (0xff)] = (short)(pattern.length - k - 1);
}
} else {
for (int k = pattern.length-2; k >= 0; k--) {
skip[pattern[k] &(0xff)] = (short)(pattern.length - k - 1);
}
}
return skip;
}
/**
*
* isEqual
* @param pattern
* @param buffer
* @param start index
* @param end index
* @return true if the bytes in buffer[start] equal pattern
*
*/
public static boolean isEqual(byte[] pattern, byte[] buffer, int start, int end) {
// if (pattern.length >= end-start) {
if (pattern.length > end-start) {
return false;
}
for (int j=0; j= end) {
found = false;
} else {
found = (bytes[i+i2] == search[i2]);
}
}
// If found match, set return idx
if (found) {
idx = i;
}
}
}
} else {
for (int i=end-1; idx < 0 && i>=start; i--) {
if (bytes[i] == search[0]) {
// Potential match..check remaining bytes
boolean found = true; // assume found
for (int i2=1; found && i2= end) {
found = false;
} else {
found = (bytes[i+i2] == search[i2]);
}
}
// If found match, set return idx
if (found) {
idx = i;
}
}
}
}
return idx;
}
}
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