com.adobe.internal.io.CountingInputStream Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of aem-sdk-api Show documentation

The Adobe Experience Manager SDK

There is a newer version: 2024.11.18751.20241128T090041Z-241100

/**
 * 
 */
package com.adobe.internal.io;

import java.io.FilterInputStream;
import java.io.IOException;
import java.io.InputStream;

/**
 * A FilterInputStream wrapper that counts the number of bytes read from the stream or skipped over 
 * since the creation of this wrapper.
 *
 */
public class CountingInputStream extends FilterInputStream
{
	private long offset;

	/**
	 * @param is
	 */
	public CountingInputStream(InputStream is) 
	{
		super(is);
	}

	/**
	 * Reads the next byte of data from this input stream. The value byte is returned as an 
	 * int in the range 0 to 255. If no byte is available because the end of the stream has 
	 * been reached, the value -1 is returned. This method blocks until input data is available, 
	 * the end of the stream is detected, or an exception is thrown.
	 * @return the next byte of data or -1 if the end of stream is reached
	 * @throws IOException if an I/O error occurs 
	 */
	public int read() throws IOException 
	{
		int b = super.read();
		if (b != -1)
		{
			offset++;
		}
		return b;
	}

	/**
	 * Reads up to len bytes of data from this input stream into an array of bytes. This method 
	 * blocks until some input is available.
	 * @param b the buffer into which the data is read
	 * @param off the start offset in the buffer to write the data
	 * @param len the maximum number of bytes to read
	 * @return the total number of bytes read into the buffer, or -1 if there
	 * is no more data because the end of the stream has been reached.
	 * @exception IOException if an I/O error occurs 
	 */
	public int read(byte[] b, int off, int len) throws IOException 
	{
		int bytesRead = super.read(b, off, len);
		if (bytesRead > 0)
		{
			offset += bytesRead;
		}
		return bytesRead;
	}

	/**
	 * Reads up to byte.length bytes of data from this input stream into an array of bytes. 
	 * This method blocks until some input is available.
	 * @return the total number of bytes read into the buffer, or -1 if there
	 * is no more data because the end of the stream has been reached.
	 * @exception IOException if an I/O error occurs 
	 */
	public int read(byte[] b) throws IOException 
	{
		int bytesRead =  super.read(b);
		if (bytesRead > 0)
		{
			offset += bytesRead;
		}
		return bytesRead;
	}

	/**
	 * Skips over and discards n bytes of data from the input stream. The skip method may, for a 
	 * variety of reasons, end up skipping over some smaller number of bytes, possibly 0. The 
	 * actual number of bytes skipped is returned.
	 * @param n the number of bytes to be skipped
	 * @return the actual number of bytes skipped
	 * @exception IOException if an I/O error occurs 
	 */
	public long skip(long n) throws IOException 
	{
		long bytesSkipped = super.skip(n);
		if (bytesSkipped > 0)
		{
			offset += bytesSkipped;
		}
		return bytesSkipped;
	}

	/**
	 * Get the offset in the wrapped stream since the creation of this wrapper.
	 * @return the offset in bytes
	 */
	public long getOffset()
	{
		return this.offset;
	}
}