cn.hutool.core.io.LimitedInputStream Maven / Gradle / Ivy
package cn.hutool.core.io;
import java.io.FilterInputStream;
import java.io.IOException;
import java.io.InputStream;
/**
* 限制读取最大长度的{@link FilterInputStream} 实现
* 来自：https://github.com/skylot/jadx/blob/master/jadx-plugins/jadx-plugins-api/src/main/java/jadx/api/plugins/utils/LimitedInputStream.java
*
* @author jadx
*/
public class LimitedInputStream extends FilterInputStream {
private final long maxSize;
private long currentPos;
/**
* 构造
* @param in {@link InputStream}
* @param maxSize 限制最大读取量，单位byte
*/
public LimitedInputStream(InputStream in, long maxSize) {
super(in);
this.maxSize = maxSize;
}
@Override
public int read() throws IOException {
final int data = super.read();
if (data != -1) {
currentPos++;
checkPos();
}
return data;
}
@Override
public int read(byte[] b, int off, int len) throws IOException {
final int count = super.read(b, off, len);
if (count > 0) {
currentPos += count;
checkPos();
}
return count;
}
@Override
public long skip(long n) throws IOException {
final long skipped = super.skip(n);
if (skipped != 0) {
currentPos += skipped;
checkPos();
}
return skipped;
}
private void checkPos() {
if (currentPos > maxSize) {
throw new IllegalStateException("Read limit exceeded");
}
}
}