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 struct input_event; 34 35 InputEventCircularReader::InputEventCircularReader(size_t numEvents) 36 : mBuffer(new input_event[numEvents * 2]), 37 mBufferEnd(mBuffer + numEvents), 38 mHead(mBuffer), 39 mCurr(mBuffer), 40 mFreeSpace(numEvents) 41 { 42 } 43 44 InputEventCircularReader::~InputEventCircularReader() 45 { 46 delete [] mBuffer; 47 } 48 49 ssize_t InputEventCircularReader::fill(int fd) 50 { 51 size_t numEventsRead = 0; 52 if (mFreeSpace) { 53 const ssize_t nread = read(fd, mHead, mFreeSpace * sizeof(input_event)); 54 if (nread<0 || nread % sizeof(input_event)) { 55 // we got a partial event!! 56 return nread<0 ? -errno : -EINVAL; 57 } 58 59 numEventsRead = nread / sizeof(input_event); 60 if (numEventsRead) { 61 mHead += numEventsRead; 62 mFreeSpace -= numEventsRead; 63 if (mHead > mBufferEnd) { 64 size_t s = mHead - mBufferEnd; 65 memcpy(mBuffer, mBufferEnd, s * sizeof(input_event)); 66 mHead = mBuffer + s; 67 } 68 } 69 } 70 71 return numEventsRead; 72 } 73 74 ssize_t InputEventCircularReader::readEvent(input_event const** events) 75 { 76 *events = mCurr; 77 ssize_t available = (mBufferEnd - mBuffer) - mFreeSpace; 78 return available ? 1 : 0; 79 } 80 81 void InputEventCircularReader::next() 82 { 83 mCurr++; 84 mFreeSpace++; 85 if (mCurr >= mBufferEnd) { 86 mCurr = mBuffer; 87 } 88 } 89
