1 /* 2 * Copyright (C) 2008-2014 The Android Open Source Project 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 #include <errno.h> 18 #include <poll.h> 19 #include <stdint.h> 20 #include <sys/cdefs.h> 21 #include <sys/types.h> 22 #include <unistd.h> 23 24 #include <cutils/log.h> 25 26 #include "InputEventReader.h" 27 28 /*****************************************************************************/ 29 30 struct cw_event; 31 32 InputEventCircularReader::InputEventCircularReader(size_t numEvents) 33 : mBuffer(new cw_event[numEvents * 2]) 34 , mBufferEnd(mBuffer + numEvents) 35 , mHead(mBuffer) 36 , mCurr(mBuffer) 37 , mFreeSpace(numEvents) 38 { 39 } 40 41 InputEventCircularReader::~InputEventCircularReader() 42 { 43 delete [] mBuffer; 44 } 45 46 ssize_t InputEventCircularReader::fill(int fd) 47 { 48 size_t numEventsRead = 0; 49 if (mFreeSpace) { 50 const ssize_t nread = read(fd, mHead, mFreeSpace * sizeof(cw_event)); 51 if (nread<0 || nread % sizeof(cw_event)) { 52 // we got a partial event!! 53 return nread<0 ? -errno : -EINVAL; 54 } 55 56 numEventsRead = nread / sizeof(cw_event); 57 if (numEventsRead) { 58 mHead += numEventsRead; 59 mFreeSpace -= numEventsRead; 60 if (mHead > mBufferEnd) { 61 size_t s = mHead - mBufferEnd; 62 memcpy(mBuffer, mBufferEnd, s * sizeof(cw_event)); 63 mHead = mBuffer + s; 64 } 65 } 66 } 67 68 return numEventsRead; 69 } 70 71 ssize_t InputEventCircularReader::readEvent(cw_event const** events) 72 { 73 *events = mCurr; 74 ssize_t available = (mBufferEnd - mBuffer) - mFreeSpace; 75 return available ? 1 : 0; 76 } 77 78 void InputEventCircularReader::next() 79 { 80 mCurr++; 81 mFreeSpace++; 82 if (mCurr >= mBufferEnd) { 83 mCurr = mBuffer; 84 } 85 } 86