//Copyright (c) 2006, Adobe Systems Incorporated
//All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
// 1. Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// 2. Redistributions in binary form must reproduce the above copyright
// notice, this list of conditions and the following disclaimer in the
// documentation and/or other materials provided with the distribution.
// 3. All advertising materials mentioning features or use of this software
// must display the following acknowledgement:
// This product includes software developed by the Adobe Systems Incorporated.
// 4. Neither the name of the Adobe Systems Incorporated nor the
// names of its contributors may be used to endorse or promote products
// derived from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY ADOBE SYSTEMS INCORPORATED ''AS IS'' AND ANY
// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
// WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
// DISCLAIMED. IN NO EVENT SHALL ADOBE SYSTEMS INCORPORATED BE LIABLE FOR ANY
// DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
// (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
// LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
// ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
// SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
//
// http://www.adobe.com/devnet/xmp/library/eula-xmp-library-java.html
package com.itextpdf.xmp.impl;
import java.io.IOException;
import java.io.PushbackReader;
import java.io.Reader;
/**
* @since 22.08.2006
*/
public class FixASCIIControlsReader extends PushbackReader
{
/** */
private static final int STATE_START = 0;
/** */
private static final int STATE_AMP = 1;
/** */
private static final int STATE_HASH = 2;
/** */
private static final int STATE_HEX = 3;
/** */
private static final int STATE_DIG1 = 4;
/** */
private static final int STATE_ERROR = 5;
/** */
private static final int BUFFER_SIZE = 8;
/** the state of the automaton */
private int state = STATE_START;
/** the result of the escaping sequence */
private int control = 0;
/** count the digits of the sequence */
private int digits = 0;
/**
* The look-ahead size is 6 at maximum («)
* @see PushbackReader#PushbackReader(Reader, int)
* @param in a Reader
*/
public FixASCIIControlsReader(Reader in)
{
super(in, BUFFER_SIZE);
}
/**
* @see Reader#read(char[], int, int)
*/
public int read(char[] cbuf, int off, int len) throws IOException
{
int readAhead = 0;
int read = 0;
int pos = off;
char[] readAheadBuffer = new char[BUFFER_SIZE];
boolean available = true;
while (available && read < len)
{
available = super.read(readAheadBuffer, readAhead, 1) == 1;
if (available)
{
char c = processChar(readAheadBuffer[readAhead]);
if (state == STATE_START)
{
// replace control chars with space
if (Utils.isControlChar(c))
{
c = ' ';
}
cbuf[pos++] = c;
readAhead = 0;
read++;
}
else if (state == STATE_ERROR)
{
unread(readAheadBuffer, 0, readAhead + 1);
readAhead = 0;
}
else
{
readAhead++;
}
}
else if (readAhead > 0)
{
// handles case when file ends within excaped sequence
unread(readAheadBuffer, 0, readAhead);
state = STATE_ERROR;
readAhead = 0;
available = true;
}
}
return read > 0 || available ? read : -1;
}
/**
* Processes numeric escaped chars to find out if they are a control character.
* @param ch a char
* @return Returns the char directly or as replacement for the escaped sequence.
*/
private char processChar(char ch)
{
switch (state)
{
case STATE_START:
if (ch == '&')
{
state = STATE_AMP;
}
return ch;
case STATE_AMP:
if (ch == '#')
{
state = STATE_HASH;
}
else
{
state = STATE_ERROR;
}
return ch;
case STATE_HASH:
if (ch == 'x')
{
control = 0;
digits = 0;
state = STATE_HEX;
}
else if ('0' <= ch && ch <= '9')
{
control = Character.digit(ch, 10);
digits = 1;
state = STATE_DIG1;
}
else
{
state = STATE_ERROR;
}
return ch;
case STATE_DIG1:
if ('0' <= ch && ch <= '9')
{
control = control * 10 + Character.digit(ch, 10);
digits++;
if (digits <= 5)
{
state = STATE_DIG1;
}
else
{
state = STATE_ERROR; // sequence too long
}
}
else if (ch == ';' && Utils.isControlChar((char) control))
{
state = STATE_START;
return (char) control;
}
else
{
state = STATE_ERROR;
}
return ch;
case STATE_HEX:
if (('0' <= ch && ch <= '9') ||
('a' <= ch && ch <= 'f') ||
('A' <= ch && ch <= 'F'))
{
control = control * 16 + Character.digit(ch, 16);
digits++;
if (digits <= 4)
{
state = STATE_HEX;
}
else
{
state = STATE_ERROR; // sequence too long
}
}
else if (ch == ';' && Utils.isControlChar((char) control))
{
state = STATE_START;
return (char) control;
}
else
{
state = STATE_ERROR;
}
return ch;
case STATE_ERROR:
state = STATE_START;
return ch;
default:
// not reachable
return ch;
}
}
}