1 /* 2 * Copyright (C) 2008 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 <stdint.h> 18 #include <errno.h> 19 #include <unistd.h> 20 #include <poll.h> 21 22 #include <sys/cdefs.h> 23 #include <sys/types.h> 24 25 #include <linux/input.h> 26 27 #include <cutils/log.h> 28 29 #include "InputEventReader.h" 30 31 /*****************************************************************************/ 32 33 template <typename T> min(T a,T b)34 static inline T min(T a, T b) { 35 return a<b ? a : b; 36 } 37 38 struct input_event; 39 InputEventCircularReader(size_t numEvents)40 InputEventCircularReader::InputEventCircularReader(size_t numEvents) 41 : mBuffer(new input_event[numEvents]), 42 mBufferEnd(mBuffer + numEvents), 43 mHead(mBuffer), 44 mCurr(mBuffer), 45 mEvents(numEvents), 46 mFreeSpace(numEvents) 47 { 48 } 49 ~InputEventCircularReader()50 InputEventCircularReader::~InputEventCircularReader() 51 { 52 delete [] mBuffer; 53 } 54 fill(int fd)55 ssize_t InputEventCircularReader::fill(int fd) 56 { 57 size_t numEventsRead = 0; 58 if (mFreeSpace) { 59 struct iovec iov[2]; 60 61 const size_t numFirst = min(mFreeSpace, (size_t)(mBufferEnd - mHead)); 62 const size_t numSecond = mFreeSpace - numFirst; 63 64 int iovcnt = 1; 65 iov[0].iov_base = mHead; 66 iov[0].iov_len = numFirst * sizeof(input_event); 67 68 if (numSecond > 0) 69 { 70 iovcnt++; 71 iov[1].iov_base = mBuffer; 72 iov[1].iov_len = numSecond * sizeof(input_event); 73 } 74 75 const ssize_t nread = readv(fd, iov, iovcnt); 76 if (nread < 0 || nread % sizeof(input_event)) { 77 // we got a partial event!! 78 return nread < 0 ? -errno : -EINVAL; 79 } 80 81 numEventsRead = nread / sizeof(input_event); 82 if (numEventsRead) { 83 mHead += numEventsRead; 84 mFreeSpace -= numEventsRead; 85 if (mHead >= mBufferEnd) 86 mHead -= mBufferEnd - mBuffer; 87 } 88 } 89 90 return numEventsRead; 91 } 92 readEvent(int fd,input_event const ** events)93 bool InputEventCircularReader::readEvent(int fd, input_event const** events) 94 { 95 if (mFreeSpace >= mEvents) { 96 ssize_t eventCount = fill(fd); 97 if (eventCount <= 0) 98 return false; 99 } 100 *events = mCurr; 101 return true; 102 } 103 next()104 void InputEventCircularReader::next() 105 { 106 mCurr++; 107 mFreeSpace++; 108 if (mCurr >= mBufferEnd) { 109 mCurr = mBuffer; 110 } 111 } 112