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      1 /*
      2 * Copyright (C) 2012 Invensense, Inc.
      3 *
      4 * Licensed under the Apache License, Version 2.0 (the "License");
      5 * you may not use this file except in compliance with the License.
      6 * You may obtain a copy of the License at
      7 *
      8 *      http://www.apache.org/licenses/LICENSE-2.0
      9 *
     10 * Unless required by applicable law or agreed to in writing, software
     11 * distributed under the License is distributed on an "AS IS" BASIS,
     12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13 * See the License for the specific language governing permissions and
     14 * limitations under the License.
     15 */
     16 
     17 #define LOG_NDEBUG 0
     18 
     19 #include <stdint.h>
     20 #include <errno.h>
     21 #include <unistd.h>
     22 #include <poll.h>
     23 
     24 #include <sys/cdefs.h>
     25 #include <sys/types.h>
     26 
     27 #include <linux/input.h>
     28 
     29 #include <cutils/log.h>
     30 
     31 #include "InputEventReader.h"
     32 
     33 /*****************************************************************************/
     34 
     35 struct input_event;
     36 
     37 InputEventCircularReader::InputEventCircularReader(size_t numEvents)
     38     : mBuffer(new input_event[numEvents * 2]),
     39       mBufferEnd(mBuffer + numEvents),
     40       mHead(mBuffer),
     41       mCurr(mBuffer),
     42       mFreeSpace(numEvents)
     43 {
     44     mLastFd = -1;
     45 }
     46 
     47 InputEventCircularReader::~InputEventCircularReader()
     48 {
     49     delete [] mBuffer;
     50 }
     51 
     52 #define INPUT_EVENT_DEBUG (0)
     53 ssize_t InputEventCircularReader::fill(int fd)
     54 {
     55     size_t numEventsRead = 0;
     56     mLastFd = fd;
     57 
     58     LOGV_IF(INPUT_EVENT_DEBUG,
     59             "DEBUG:%s enter, fd=%d\n", __PRETTY_FUNCTION__, fd);
     60     if (mFreeSpace) {
     61         const ssize_t nread = read(fd, mHead, mFreeSpace * sizeof(input_event));
     62         if (nread < 0 || nread % sizeof(input_event)) {
     63             //LOGE("Partial event received nread=%d, required=%d",
     64             //     nread, sizeof(input_event));
     65             //LOGE("FD trying to read is: %d");
     66             // we got a partial event!!
     67             if (INPUT_EVENT_DEBUG) {
     68                 LOGV_IF(nread < 0, "DEBUG:%s exit nread < 0\n",
     69                         __PRETTY_FUNCTION__);
     70                 LOGV_IF(nread % sizeof(input_event),
     71                         "DEBUG:%s exit nread %% sizeof(input_event)\n",
     72                         __PRETTY_FUNCTION__);
     73             }
     74             return (nread < 0 ? -errno : -EINVAL);
     75         }
     76 
     77         numEventsRead = nread / sizeof(input_event);
     78         if (numEventsRead) {
     79             mHead += numEventsRead;
     80             mFreeSpace -= numEventsRead;
     81             if (mHead > mBufferEnd) {
     82                 size_t s = mHead - mBufferEnd;
     83                 memcpy(mBuffer, mBufferEnd, s * sizeof(input_event));
     84                 mHead = mBuffer + s;
     85             }
     86         }
     87     }
     88 
     89     LOGV_IF(INPUT_EVENT_DEBUG, "DEBUG:%s exit, numEventsRead:%d\n",
     90             __PRETTY_FUNCTION__, numEventsRead);
     91     return numEventsRead;
     92 }
     93 
     94 ssize_t InputEventCircularReader::readEvent(input_event const** events)
     95 {
     96     *events = mCurr;
     97     ssize_t available = (mBufferEnd - mBuffer) - mFreeSpace;
     98     LOGV_IF(INPUT_EVENT_DEBUG, "DEBUG:%s fd:%d, available:%d\n",
     99             __PRETTY_FUNCTION__, mLastFd, (int)available);
    100     return (available ? 1 : 0);
    101 }
    102 
    103 void InputEventCircularReader::next()
    104 {
    105     mCurr++;
    106     mFreeSpace++;
    107     if (mCurr >= mBufferEnd) {
    108         mCurr = mBuffer;
    109     }
    110     ssize_t available = (mBufferEnd - mBuffer) - mFreeSpace;
    111     LOGV_IF(INPUT_EVENT_DEBUG, "DEBUG:%s fd:%d, still available:%d\n",
    112             __PRETTY_FUNCTION__, mLastFd, (int)available);
    113 }
    114 
    115