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/*
* 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.tomcat.util.bcel.classfile;
import java.io.BufferedInputStream;
import java.io.DataInput;
import java.io.DataInputStream;
import java.io.EOFException;
import java.io.IOException;
import java.io.InputStream;
/**
* A "FastDataInputStream" that get the numbers from buffer and from the target
* directly instead of "DataInputStream".
*/
class FastDataInputStream extends BufferedInputStream implements DataInput {
private final byte readBuffer[] = new byte[8];
public FastDataInputStream(InputStream in, int size) {
super(in, size);
}
@Override
public final int read(byte b[]) throws IOException {
return this.read(b, 0, b.length);
}
@Override
public final void readFully(byte b[]) throws IOException {
readFully(b, 0, b.length);
}
@Override
public final void readFully(byte b[], int off, int len) throws IOException {
if (len < 0)
throw new IndexOutOfBoundsException();
// Total read
int sum = 0;
// Current read
int cur = 0;
for(; sum < len; sum += cur){
cur = read(b, off + sum, len - sum);
if(cur < 0)
throw new EOFException();
sum += cur;
}
}
@Override
public boolean readBoolean() throws IOException {
if (pos >= count) {
fillNew();
if (pos >= count)
throw new EOFException();
}
int ch = this.buf[pos++] & 0xff;
return (ch != 0);
}
@Override
public final byte readByte() throws IOException {
if (pos >= count) {
fillNew();
if (pos >= count)
throw new EOFException();
}
return this.buf[pos++];
}
@Override
public int readUnsignedByte() throws IOException {
if (pos >= count) {
fillNew();
if (pos >= count)
throw new EOFException();
}
int ch = this.buf[pos++] & 0xff;
return ch;
}
@Override
public final short readShort() throws IOException {
if(pos + 1 >= count){
fillNew();
if(pos + 1 >= count) throw new EOFException();
}
int ch1 = this.buf[pos++] & 0xff;
int ch2 = this.buf[pos++] & 0xff;
return (short)((ch1 << 8) + ch2);
}
@Override
public int readUnsignedShort() throws IOException{
if(pos + 1 >= count) {
fillNew();
if(pos + 1 >= count) throw new EOFException();
}
int ch1 = this.buf[pos++] & 0xff;
int ch2 = this.buf[pos++] & 0xff;
return (ch1 << 8) + ch2;
}
@Override
public final char readChar() throws IOException {
if(pos + 1 >= count) {
fillNew();
if(pos + 1 >= count) throw new EOFException();
}
int ch1 = this.buf[pos++] & 0xff;
int ch2 = this.buf[pos++] & 0xff;
return (char)((ch1 << 8) + ch2);
}
@Override
public final int readInt() throws IOException {
if(pos + 3 >= count){
fillNew();
if(pos + 3 >= count) throw new EOFException();
}
int ch1 = this.buf[pos++] & 0xff;
int ch2 = this.buf[pos++] & 0xff;
int ch3 = this.buf[pos++] & 0xff;
int ch4 = this.buf[pos++] & 0xff;
return ((ch1 << 24) + (ch2 << 16) + (ch3 << 8) + ch4);
}
@Override
public final long readLong() throws IOException {
readFully(readBuffer, 0, 8);
return (((long)readBuffer[0] << 56) +
((long)(readBuffer[1] & 255) << 48) +
((long)(readBuffer[2] & 255) << 40) +
((long)(readBuffer[3] & 255) << 32) +
((long)(readBuffer[4] & 255) << 24) +
((readBuffer[5] & 255) << 16) +
((readBuffer[6] & 255) << 8) +
(readBuffer[7] & 255));
}
@Override
public final float readFloat() throws IOException {
return Float.intBitsToFloat(readInt());
}
@Override
public double readDouble() throws IOException {
return Double.longBitsToDouble(readLong());
}
@Override
public final String readUTF() throws IOException {
return DataInputStream.readUTF(this);
}
private void fillNew() throws IOException {
int remain = 0;
if(pos < count){
remain = count - pos;
System.arraycopy(buf, pos, buf, 0, remain);
}
pos = 0;
int n = this.in.read(buf, remain, buf.length - remain);
count = pos + n + remain;
}
@Override
public int skipBytes(int n) throws IOException {
int avail = count - pos;
// Total Skipped
int sum = 0;
// Current skipped
int cur = 0;
if (avail <= 0) {
// buffer is exhausted, read via stream directly
while (sum < n && (cur = (int) in.skip(n - sum)) > 0) {
sum += cur;
}
return sum;
}
// Data in the buffer is not enough
if(n > avail){
// Skip the data in buffer
pos += avail;
sum += avail;
// Read via stream
while (sum < n && (cur = (int) in.skip(n - sum)) > 0) {
sum += cur;
}
return sum;
}
pos += n;
return n;
}
@Override
public String readLine() throws IOException {
// Unimplemented
throw new UnsupportedOperationException();
}
}
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