k-9/src/com/android/email/PeekableInputStream.java

65 lines
1.6 KiB
Java
Raw Normal View History

package com.android.email;
import java.io.IOException;
import java.io.InputStream;
/**
* A filtering InputStream that allows single byte "peeks" without consuming the byte. The
* client of this stream can call peek() to see the next available byte in the stream
* and a subsequent read will still return the peeked byte.
*/
public class PeekableInputStream extends InputStream {
private InputStream mIn;
private boolean mPeeked;
private int mPeekedByte;
public PeekableInputStream(InputStream in) {
this.mIn = in;
}
@Override
public int read() throws IOException {
if (!mPeeked) {
return mIn.read();
} else {
mPeeked = false;
return mPeekedByte;
}
}
public int peek() throws IOException {
if (!mPeeked) {
mPeekedByte = read();
mPeeked = true;
}
return mPeekedByte;
}
@Override
public int read(byte[] b, int offset, int length) throws IOException {
if (!mPeeked) {
return mIn.read(b, offset, length);
} else {
b[0] = (byte)mPeekedByte;
mPeeked = false;
int r = mIn.read(b, offset + 1, length - 1);
if (r == -1) {
return 1;
} else {
return r + 1;
}
}
}
@Override
public int read(byte[] b) throws IOException {
return read(b, 0, b.length);
}
public String toString() {
return String.format("PeekableInputStream(in=%s, peeked=%b, peekedByte=%d)",
mIn.toString(), mPeeked, mPeekedByte);
}
}