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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 #include <string.h>
     24 
     25 #include <sys/cdefs.h>
     26 #include <sys/types.h>
     27 
     28 #include <linux/input.h>
     29 
     30 #include <cutils/log.h>
     31 
     32 #include "InputEventReader.h"
     33 
     34 /*****************************************************************************/
     35 
     36 struct input_event;
     37 
     38 InputEventCircularReader::InputEventCircularReader(size_t numEvents)
     39     : mBuffer(new input_event[numEvents * 2]),
     40       mBufferEnd(mBuffer + numEvents),
     41       mHead(mBuffer),
     42       mCurr(mBuffer),
     43       mFreeSpace(numEvents)
     44 {
     45     mLastFd = -1;
     46 }
     47 
     48 InputEventCircularReader::~InputEventCircularReader()
     49 {
     50     delete [] mBuffer;
     51 }
     52 
     53 #define INPUT_EVENT_DEBUG (0)
     54 ssize_t InputEventCircularReader::fill(int fd)
     55 {
     56     size_t numEventsRead = 0;
     57     mLastFd = fd;
     58 
     59     LOGV_IF(INPUT_EVENT_DEBUG,
     60             "DEBUG:%s enter, fd=%d\n", __PRETTY_FUNCTION__, fd);
     61     if (mFreeSpace) {
     62         const ssize_t nread = read(fd, mHead, mFreeSpace * sizeof(input_event));
     63         if (nread < 0 || nread % sizeof(input_event)) {
     64             //LOGE("Partial event received nread=%d, required=%d",
     65             //     nread, sizeof(input_event));
     66             //LOGE("FD trying to read is: %d");
     67             // we got a partial event!!
     68             if (INPUT_EVENT_DEBUG) {
     69                 LOGV_IF(nread < 0, "DEBUG:%s exit nread < 0\n",
     70                         __PRETTY_FUNCTION__);
     71                 LOGV_IF(nread % sizeof(input_event),
     72                         "DEBUG:%s exit nread %% sizeof(input_event)\n",
     73                         __PRETTY_FUNCTION__);
     74             }
     75             return (nread < 0 ? -errno : -EINVAL);
     76         }
     77 
     78         numEventsRead = nread / sizeof(input_event);
     79         if (numEventsRead) {
     80             mHead += numEventsRead;
     81             mFreeSpace -= numEventsRead;
     82             if (mHead > mBufferEnd) {
     83                 size_t s = mHead - mBufferEnd;
     84                 memcpy(mBuffer, mBufferEnd, s * sizeof(input_event));
     85                 mHead = mBuffer + s;
     86             }
     87         }
     88     }
     89 
     90     LOGV_IF(INPUT_EVENT_DEBUG, "DEBUG:%s exit, numEventsRead:%d\n",
     91             __PRETTY_FUNCTION__, numEventsRead);
     92     return numEventsRead;
     93 }
     94 
     95 ssize_t InputEventCircularReader::readEvent(input_event const** events)
     96 {
     97     *events = mCurr;
     98     ssize_t available = (mBufferEnd - mBuffer) - mFreeSpace;
     99     LOGV_IF(INPUT_EVENT_DEBUG, "DEBUG:%s fd:%d, available:%d\n",
    100             __PRETTY_FUNCTION__, mLastFd, (int)available);
    101     return (available ? 1 : 0);
    102 }
    103 
    104 void InputEventCircularReader::next()
    105 {
    106     mCurr++;
    107     mFreeSpace++;
    108     if (mCurr >= mBufferEnd) {
    109         mCurr = mBuffer;
    110     }
    111     ssize_t available = (mBufferEnd - mBuffer) - mFreeSpace;
    112     LOGV_IF(INPUT_EVENT_DEBUG, "DEBUG:%s fd:%d, still available:%d\n",
    113             __PRETTY_FUNCTION__, mLastFd, (int)available);
    114 }
    115 
    116