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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 #include "local_log_def.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 }
     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     LOGV_IF(INPUT_EVENT_DEBUG,
     57             "DEBUG:%s enter, fd=%d\n", __PRETTY_FUNCTION__, fd);
     58     if (mFreeSpace) {
     59         const ssize_t nread = read(fd, mHead, mFreeSpace * sizeof(input_event));
     60         if (nread < 0 || nread % sizeof(input_event)) {
     61             //LOGE("Partial event received nread=%d, required=%d",
     62             //     nread, sizeof(input_event));
     63             //LOGE("FD trying to read is: %d");
     64             // we got a partial event!!
     65             if (INPUT_EVENT_DEBUG) {
     66                 LOGV_IF(nread < 0, "DEBUG:%s exit nread < 0\n",
     67                         __PRETTY_FUNCTION__);
     68                 LOGV_IF(nread % sizeof(input_event),
     69                         "DEBUG:%s exit nread %% sizeof(input_event)\n",
     70                         __PRETTY_FUNCTION__);
     71             }
     72             return (nread < 0 ? -errno : -EINVAL);
     73         }
     74 
     75         numEventsRead = nread / sizeof(input_event);
     76         if (numEventsRead) {
     77             mHead += numEventsRead;
     78             mFreeSpace -= numEventsRead;
     79             if (mHead > mBufferEnd) {
     80                 size_t s = mHead - mBufferEnd;
     81                 memcpy(mBuffer, mBufferEnd, s * sizeof(input_event));
     82                 mHead = mBuffer + s;
     83             }
     84         }
     85     }
     86 
     87     LOGV_IF(INPUT_EVENT_DEBUG, "DEBUG:%s exit\n", __PRETTY_FUNCTION__);
     88     return numEventsRead;
     89 }
     90 
     91 ssize_t InputEventCircularReader::readEvent(input_event const** events)
     92 {
     93     *events = mCurr;
     94     ssize_t available = (mBufferEnd - mBuffer) - mFreeSpace;
     95     return available ? 1 : 0;
     96 }
     97 
     98 void InputEventCircularReader::next()
     99 {
    100     mCurr++;
    101     mFreeSpace++;
    102     if (mCurr >= mBufferEnd) {
    103         mCurr = mBuffer;
    104     }
    105 }
    106