89 lines
		
	
	
		
			2.3 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
			
		
		
	
	
			89 lines
		
	
	
		
			2.3 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
/*
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 * Copyright (C) 2008 The Android Open Source Project
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 *
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 * Licensed under the Apache License, Version 2.0 (the "License");
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 * you may not use this file except in compliance with the License.
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 * You may obtain a copy of the License at
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 *
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 *      http://www.apache.org/licenses/LICENSE-2.0
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 *
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 * Unless required by applicable law or agreed to in writing, software
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 * distributed under the License is distributed on an "AS IS" BASIS,
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 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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 * See the License for the specific language governing permissions and
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 * limitations under the License.
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 */
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#include <stdint.h>
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#include <errno.h>
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#include <unistd.h>
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#include <poll.h>
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#include <sys/cdefs.h>
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#include <sys/types.h>
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#include <linux/input.h>
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#include <cutils/log.h>
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#include "InputEventReader.h"
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/*****************************************************************************/
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struct input_event;
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InputEventCircularReader::InputEventCircularReader(size_t numEvents)
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    : mBuffer(new input_event[numEvents * 2]),
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      mBufferEnd(mBuffer + numEvents),
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      mHead(mBuffer),
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      mCurr(mBuffer),
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      mFreeSpace(numEvents)
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{
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}
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InputEventCircularReader::~InputEventCircularReader()
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{
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    delete [] mBuffer;
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}
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ssize_t InputEventCircularReader::fill(int fd)
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{
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    size_t numEventsRead = 0;
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    if (mFreeSpace) {
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        const ssize_t nread = read(fd, mHead, mFreeSpace * sizeof(input_event));
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        if (nread<0 || nread % sizeof(input_event)) {
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            // we got a partial event!!
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            return nread<0 ? -errno : -EINVAL;
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        }
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        numEventsRead = nread / sizeof(input_event);
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        if (numEventsRead) {
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            mHead += numEventsRead;
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            mFreeSpace -= numEventsRead;
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            if (mHead > mBufferEnd) {
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                size_t s = mHead - mBufferEnd;
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                memcpy(mBuffer, mBufferEnd, s * sizeof(input_event));
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                mHead = mBuffer + s;
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            }
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        }
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    }
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    return numEventsRead;
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}
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ssize_t InputEventCircularReader::readEvent(input_event const** events)
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{
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    *events = mCurr;
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    ssize_t available = (mBufferEnd - mBuffer) - mFreeSpace;
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    return available ? 1 : 0;
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}
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void InputEventCircularReader::next()
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{
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    mCurr++;
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    mFreeSpace++;
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    if (mCurr >= mBufferEnd) {
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        mCurr = mBuffer;
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    }
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}
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