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/*
* libjingle
* Copyright 2013, Google Inc.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
* EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package org.appspot.apprtc;
import org.webrtc.VideoRenderer.I420Frame;
import java.util.HashMap;
import java.util.LinkedList;
/**
* This class acts as an allocation pool meant to minimize GC churn caused by
* frame allocation & disposal. The public API comprises of just two methods:
* copyFrame(), which allocates as necessary and copies, and
* returnFrame(), which returns frame ownership to the pool for use by a later
* call to copyFrame().
*
* This class is thread-safe; calls to copyFrame() and returnFrame() are allowed
* to happen on any thread.
*/
class FramePool {
// Maps each summary code (see summarizeFrameDimensions()) to a list of frames
// of that description.
private final HashMap<Long, LinkedList<I420Frame>> availableFrames =
new HashMap<Long, LinkedList<I420Frame>>();
// Every dimension (e.g. width, height, stride) of a frame must be less than
// this value.
private static final long MAX_DIMENSION = 4096;
public I420Frame takeFrame(I420Frame source) {
long desc = summarizeFrameDimensions(source);
I420Frame dst = null;
synchronized (availableFrames) {
LinkedList<I420Frame> frames = availableFrames.get(desc);
if (frames == null) {
frames = new LinkedList<I420Frame>();
availableFrames.put(desc, frames);
}
if (!frames.isEmpty()) {
dst = frames.pop();
} else {
dst = new I420Frame(
source.width, source.height, source.yuvStrides, null);
}
}
return dst;
}
public void returnFrame(I420Frame frame) {
long desc = summarizeFrameDimensions(frame);
synchronized (availableFrames) {
LinkedList<I420Frame> frames = availableFrames.get(desc);
if (frames == null) {
throw new IllegalArgumentException("Unexpected frame dimensions");
}
frames.add(frame);
}
}
/** Validate that |frame| can be managed by the pool. */
public static boolean validateDimensions(I420Frame frame) {
return frame.width < MAX_DIMENSION && frame.height < MAX_DIMENSION &&
frame.yuvStrides[0] < MAX_DIMENSION &&
frame.yuvStrides[1] < MAX_DIMENSION &&
frame.yuvStrides[2] < MAX_DIMENSION;
}
// Return a code summarizing the dimensions of |frame|. Two frames that
// return the same summary are guaranteed to be able to store each others'
// contents. Used like Object.hashCode(), but we need all the bits of a long
// to do a good job, and hashCode() returns int, so we do this.
private static long summarizeFrameDimensions(I420Frame frame) {
long ret = frame.width;
ret = ret * MAX_DIMENSION + frame.height;
ret = ret * MAX_DIMENSION + frame.yuvStrides[0];
ret = ret * MAX_DIMENSION + frame.yuvStrides[1];
ret = ret * MAX_DIMENSION + frame.yuvStrides[2];
return ret;
}
}
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