/****************************************************************
* 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.james.mime4j.io;
import org.apache.james.mime4j.util.ByteArrayBuffer;
import java.io.IOException;
import java.io.InputStream;
/**
* Input buffer that can be used to search for patterns using Quick Search
* algorithm in data read from an {@link InputStream}.
*/
public class BufferedLineReaderInputStream extends LineReaderInputStream {
private boolean truncated;
private byte[] buffer;
private int bufpos;
private int buflen;
private final int maxLineLen;
public BufferedLineReaderInputStream(
final InputStream instream,
int buffersize,
int maxLineLen) {
super(instream);
if (instream == null) {
throw new IllegalArgumentException("Input stream may not be null");
}
if (buffersize <= 0) {
throw new IllegalArgumentException("Buffer size may not be negative or zero");
}
this.buffer = new byte[buffersize];
this.bufpos = 0;
this.buflen = 0;
this.maxLineLen = maxLineLen;
this.truncated = false;
}
public BufferedLineReaderInputStream(
final InputStream instream,
int buffersize) {
this(instream, buffersize, -1);
}
private void expand(int newlen) {
byte newbuffer[] = new byte[newlen];
int len = this.buflen - this.bufpos;
if (len > 0) {
System.arraycopy(this.buffer, this.bufpos, newbuffer, this.bufpos, len);
}
this.buffer = newbuffer;
}
public void ensureCapacity(int len) {
if (len > this.buffer.length) {
expand(len);
}
}
public int fillBuffer() throws IOException {
// compact the buffer if necessary
if (this.bufpos > 0) {
int len = this.buflen - this.bufpos;
if (len > 0) {
System.arraycopy(this.buffer, this.bufpos, this.buffer, 0, len);
}
this.bufpos = 0;
this.buflen = len;
}
int l;
int off = this.buflen;
int len = this.buffer.length - off;
l = in.read(this.buffer, off, len);
if (l == -1) {
return -1;
} else {
this.buflen = off + l;
return l;
}
}
public boolean hasBufferedData() {
return this.bufpos < this.buflen;
}
public void truncate() {
clear();
this.truncated = true;
}
@Override
public int read() throws IOException {
if (this.truncated) {
return -1;
}
int noRead = 0;
while (!hasBufferedData()) {
noRead = fillBuffer();
if (noRead == -1) {
return -1;
}
}
return this.buffer[this.bufpos++] & 0xff;
}
@Override
public int read(final byte[] b, int off, int len) throws IOException {
if (this.truncated) {
return -1;
}
if (b == null) {
return 0;
}
int noRead = 0;
while (!hasBufferedData()) {
noRead = fillBuffer();
if (noRead == -1) {
return -1;
}
}
int chunk = this.buflen - this.bufpos;
if (chunk > len) {
chunk = len;
}
System.arraycopy(this.buffer, this.bufpos, b, off, chunk);
this.bufpos += chunk;
return chunk;
}
@Override
public int read(final byte[] b) throws IOException {
if (this.truncated) {
return -1;
}
if (b == null) {
return 0;
}
return read(b, 0, b.length);
}
@Override
public boolean markSupported() {
return false;
}
@Override
public int readLine(final ByteArrayBuffer dst) throws IOException {
if (dst == null) {
throw new IllegalArgumentException("Buffer may not be null");
}
if (this.truncated) {
return -1;
}
int total = 0;
boolean found = false;
int bytesRead = 0;
while (!found) {
if (!hasBufferedData()) {
bytesRead = fillBuffer();
if (bytesRead == -1) {
break;
}
}
int i = indexOf((byte)'\n');
int chunk;
if (i != -1) {
found = true;
chunk = i + 1 - pos();
} else {
chunk = length();
}
if (chunk > 0) {
dst.append(buf(), pos(), chunk);
skip(chunk);
total += chunk;
}
if (this.maxLineLen > 0 && dst.length() >= this.maxLineLen) {
throw new MaxLineLimitException("Maximum line length limit exceeded");
}
}
if (total == 0 && bytesRead == -1) {
return -1;
} else {
return total;
}
}
/**
* Implements quick search algorithm as published by
* <p>
* SUNDAY D.M., 1990,
* A very fast substring search algorithm,
* Communications of the ACM . 33(8):132-142.
* </p>
*/
public int indexOf(final byte[] pattern, int off, int len) {
if (pattern == null) {
throw new IllegalArgumentException("Pattern may not be null");
}
if (off < this.bufpos || len < 0 || off + len > this.buflen) {
throw new IndexOutOfBoundsException();
}
if (len < pattern.length) {
return -1;
}
int[] shiftTable = new int[256];
for (int i = 0; i < shiftTable.length; i++) {
shiftTable[i] = pattern.length + 1;
}
for (int i = 0; i < pattern.length; i++) {
int x = pattern[i] & 0xff;
shiftTable[x] = pattern.length - i;
}
int j = 0;
while (j <= len - pattern.length) {
int cur = off + j;
boolean match = true;
for (int i = 0; i < pattern.length; i++) {
if (this.buffer[cur + i] != pattern[i]) {
match = false;
break;
}
}
if (match) {
return cur;
}
int pos = cur + pattern.length;
if (pos >= this.buffer.length) {
break;
}
int x = this.buffer[pos] & 0xff;
j += shiftTable[x];
}
return -1;
}
/**
* Implements quick search algorithm as published by
* <p>
* SUNDAY D.M., 1990,
* A very fast substring search algorithm,
* Communications of the ACM . 33(8):132-142.
* </p>
*/
public int indexOf(final byte[] pattern) {
return indexOf(pattern, this.bufpos, this.buflen - this.bufpos);
}
public int indexOf(byte b, int off, int len) {
if (off < this.bufpos || len < 0 || off + len > this.buflen) {
throw new IndexOutOfBoundsException();
}
for (int i = off; i < off + len; i++) {
if (this.buffer[i] == b) {
return i;
}
}
return -1;
}
public int indexOf(byte b) {
return indexOf(b, this.bufpos, this.buflen - this.bufpos);
}
public byte charAt(int pos) {
if (pos < this.bufpos || pos > this.buflen) {
throw new IndexOutOfBoundsException();
}
return this.buffer[pos];
}
public byte[] buf() {
return this.buffer;
}
public int pos() {
return this.bufpos;
}
public int limit() {
return this.buflen;
}
public int length() {
return this.buflen - this.bufpos;
}
public int capacity() {
return this.buffer.length;
}
public int skip(int n) {
int chunk = Math.min(n, this.buflen - this.bufpos);
this.bufpos += chunk;
return chunk;
}
public void clear() {
this.bufpos = 0;
this.buflen = 0;
}
@Override
public String toString() {
StringBuilder buffer = new StringBuilder();
buffer.append("[pos: ");
buffer.append(this.bufpos);
buffer.append("]");
buffer.append("[limit: ");
buffer.append(this.buflen);
buffer.append("]");
buffer.append("[");
for (int i = this.bufpos; i < this.buflen; i++) {
buffer.append((char) this.buffer[i]);
}
buffer.append("]");
return buffer.toString();
}
}