/*
* Copyright 2006-2017 ICEsoft Technologies Canada Corp.
*
* 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.icepdf.core.pobjects.filters;
import org.icepdf.core.util.Parser;
import java.io.IOException;
import java.io.InputStream;
/**
* @author Mark Collette
* @since 2.0
*/
public class ASCIIHexDecode extends ChunkingInputStream {
public ASCIIHexDecode(InputStream input) {
super();
setInputStream(input);
setBufferSize(4096);
}
protected int fillInternalBuffer() throws IOException {
int numRead = 0;
for (int i = 0; i < buffer.length; i++) {
byte val = 0;
int hi;
int lo;
do {
hi = in.read();
} while (Parser.isWhitespace((char) hi));
if (hi < 0)
break;
do {
lo = in.read();
} while (Parser.isWhitespace((char) lo));
if (hi >= '0' && hi <= '9') {
hi -= '0';
val |= ((byte) ((hi << 4) & 0xF0));
} else if (hi >= 'a' && hi <= 'z') {
hi = hi - 'a' + 10;
val |= ((byte) ((hi << 4) & 0xF0));
} else if (hi >= 'A' && hi <= 'Z') {
hi = hi - 'A' + 10;
val |= ((byte) ((hi << 4) & 0xF0));
}
if (lo >= 0) {
if (lo >= '0' && lo <= '9') {
lo -= '0';
val |= ((byte) (lo & 0x0F));
} else if (lo >= 'a' && lo <= 'z') {
lo = lo - 'a' + 10;
val |= ((byte) (lo & 0x0F));
} else if (lo >= 'A' && lo <= 'Z') {
lo = lo - 'A' + 10;
val |= ((byte) (lo & 0x0F));
}
}
buffer[numRead++] = val;
}
if (numRead == 0)
return -1;
return numRead;
}
}