libs/ui/InputReader.cpp

//
// Copyright 2010 The Android Open Source Project
//
// The input reader.
//
#define LOG_TAG "InputReader"

//#define LOG_NDEBUG 0

// Log debug messages for each raw event received from the EventHub.
#define DEBUG_RAW_EVENTS 0

// Log debug messages about touch screen filtering hacks.
#define DEBUG_HACKS 1

// Log debug messages about virtual key processing.
#define DEBUG_VIRTUAL_KEYS 1

// Log debug messages about pointers.
#define DEBUG_POINTERS 1

// Log debug messages about pointer assignment calculations.
#define DEBUG_POINTER_ASSIGNMENT 0

#include <cutils/log.h>
#include <ui/InputReader.h>

#include <stddef.h>
#include <unistd.h>
#include <errno.h>
#include <limits.h>

/** Amount that trackball needs to move in order to generate a key event. */
#define TRACKBALL_MOVEMENT_THRESHOLD 6

/* Slop distance for jumpy pointer detection.
 * The vertical range of the screen divided by this is our epsilon value. */
#define JUMPY_EPSILON_DIVISOR 212

/* Number of jumpy points to drop for touchscreens that need it. */
#define JUMPY_TRANSITION_DROPS 3
#define JUMPY_DROP_LIMIT 3

/* Maximum squared distance for averaging.
 * If moving farther than this, turn of averaging to avoid lag in response. */
#define AVERAGING_DISTANCE_LIMIT (75 * 75)


namespace android {

// --- Static Functions ---

template<typename T>
inline static T abs(const T& value) {
    return value < 0 ? - value : value;
}

template<typename T>
inline static T min(const T& a, const T& b) {
    return a < b ? a : b;
}

template<typename T>
inline static void swap(T& a, T& b) {
    T temp = a;
    a = b;
    b = temp;
}


int32_t updateMetaState(int32_t keyCode, bool down, int32_t oldMetaState) {
    int32_t mask;
    switch (keyCode) {
    case KEYCODE_ALT_LEFT:
        mask = META_ALT_LEFT_ON;
        break;
    case KEYCODE_ALT_RIGHT:
        mask = META_ALT_RIGHT_ON;
        break;
    case KEYCODE_SHIFT_LEFT:
        mask = META_SHIFT_LEFT_ON;
        break;
    case KEYCODE_SHIFT_RIGHT:
        mask = META_SHIFT_RIGHT_ON;
        break;
    case KEYCODE_SYM:
        mask = META_SYM_ON;
        break;
    default:
        return oldMetaState;
    }

    int32_t newMetaState = down ? oldMetaState | mask : oldMetaState & ~ mask
            & ~ (META_ALT_ON | META_SHIFT_ON);

    if (newMetaState & (META_ALT_LEFT_ON | META_ALT_RIGHT_ON)) {
        newMetaState |= META_ALT_ON;
    }

    if (newMetaState & (META_SHIFT_LEFT_ON | META_SHIFT_RIGHT_ON)) {
        newMetaState |= META_SHIFT_ON;
    }

    return newMetaState;
}

static const int32_t keyCodeRotationMap[][4] = {
        // key codes enumerated counter-clockwise with the original (unrotated) key first
        // no rotation,        90 degree rotation,  180 degree rotation, 270 degree rotation
        { KEYCODE_DPAD_DOWN,   KEYCODE_DPAD_RIGHT,  KEYCODE_DPAD_UP,     KEYCODE_DPAD_LEFT },
        { KEYCODE_DPAD_RIGHT,  KEYCODE_DPAD_UP,     KEYCODE_DPAD_LEFT,   KEYCODE_DPAD_DOWN },
        { KEYCODE_DPAD_UP,     KEYCODE_DPAD_LEFT,   KEYCODE_DPAD_DOWN,   KEYCODE_DPAD_RIGHT },
        { KEYCODE_DPAD_LEFT,   KEYCODE_DPAD_DOWN,   KEYCODE_DPAD_RIGHT,  KEYCODE_DPAD_UP },
};
static const int keyCodeRotationMapSize =
        sizeof(keyCodeRotationMap) / sizeof(keyCodeRotationMap[0]);

int32_t rotateKeyCode(int32_t keyCode, int32_t orientation) {
    if (orientation != InputReaderPolicyInterface::ROTATION_0) {
        for (int i = 0; i < keyCodeRotationMapSize; i++) {
            if (keyCode == keyCodeRotationMap[i][0]) {
                return keyCodeRotationMap[i][orientation];
            }
        }
    }
    return keyCode;
}


// --- InputDevice ---

InputDevice::InputDevice(int32_t id, uint32_t classes, String8 name) :
    id(id), classes(classes), name(name), ignored(false) {
}

void InputDevice::reset() {
    if (isKeyboard()) {
        keyboard.reset();
    }

    if (isTrackball()) {
        trackball.reset();
    }

    if (isMultiTouchScreen()) {
        multiTouchScreen.reset();
    } else if (isSingleTouchScreen()) {
        singleTouchScreen.reset();
    }

    if (isTouchScreen()) {
        touchScreen.reset();
    }
}


// --- InputDevice::TouchData ---

void InputDevice::TouchData::copyFrom(const TouchData& other) {
    pointerCount = other.pointerCount;
    idBits = other.idBits;

    for (uint32_t i = 0; i < pointerCount; i++) {
        pointers[i] = other.pointers[i];
        idToIndex[i] = other.idToIndex[i];
    }
}


// --- InputDevice::KeyboardState ---

void InputDevice::KeyboardState::reset() {
    current.metaState = META_NONE;
    current.downTime = 0;
}


// --- InputDevice::TrackballState ---

void InputDevice::TrackballState::reset() {
    accumulator.clear();
    current.down = false;
    current.downTime = 0;
}


// --- InputDevice::TouchScreenState ---

void InputDevice::TouchScreenState::reset() {
    lastTouch.clear();
    downTime = 0;
    currentVirtualKey.down = false;

    for (uint32_t i = 0; i < MAX_POINTERS; i++) {
        averagingTouchFilter.historyStart[i] = 0;
        averagingTouchFilter.historyEnd[i] = 0;
    }

    jumpyTouchFilter.jumpyPointsDropped = 0;
}

struct PointerDistanceHeapElement {
    uint32_t currentPointerIndex : 8;
    uint32_t lastPointerIndex : 8;
    uint64_t distance : 48; // squared distance
};

void InputDevice::TouchScreenState::calculatePointerIds() {
    uint32_t currentPointerCount = currentTouch.pointerCount;
    uint32_t lastPointerCount = lastTouch.pointerCount;

    if (currentPointerCount == 0) {
        // No pointers to assign.
        currentTouch.idBits.clear();
    } else if (lastPointerCount == 0) {
        // All pointers are new.
        currentTouch.idBits.clear();
        for (uint32_t i = 0; i < currentPointerCount; i++) {
            currentTouch.pointers[i].id = i;
            currentTouch.idToIndex[i] = i;
            currentTouch.idBits.markBit(i);
        }
    } else if (currentPointerCount == 1 && lastPointerCount == 1) {
        // Only one pointer and no change in count so it must have the same id as before.
        uint32_t id = lastTouch.pointers[0].id;
        currentTouch.pointers[0].id = id;
        currentTouch.idToIndex[id] = 0;
        currentTouch.idBits.value = BitSet32::valueForBit(id);
    } else {
        // General case.
        // We build a heap of squared euclidean distances between current and last pointers
        // associated with the current and last pointer indices.  Then, we find the best
        // match (by distance) for each current pointer.
        PointerDistanceHeapElement heap[MAX_POINTERS * MAX_POINTERS];

        uint32_t heapSize = 0;
        for (uint32_t currentPointerIndex = 0; currentPointerIndex < currentPointerCount;
                currentPointerIndex++) {
            for (uint32_t lastPointerIndex = 0; lastPointerIndex < lastPointerCount;
                    lastPointerIndex++) {
                int64_t deltaX = currentTouch.pointers[currentPointerIndex].x
                        - lastTouch.pointers[lastPointerIndex].x;
                int64_t deltaY = currentTouch.pointers[currentPointerIndex].y
                        - lastTouch.pointers[lastPointerIndex].y;

                uint64_t distance = uint64_t(deltaX * deltaX + deltaY * deltaY);

                // Insert new element into the heap (sift up).
                heap[heapSize].currentPointerIndex = currentPointerIndex;
                heap[heapSize].lastPointerIndex = lastPointerIndex;
                heap[heapSize].distance = distance;
                heapSize += 1;
            }
        }

        // Heapify
        for (uint32_t startIndex = heapSize / 2; startIndex != 0; ) {
            startIndex -= 1;
            for (uint32_t parentIndex = startIndex; ;) {
                uint32_t childIndex = parentIndex * 2 + 1;
                if (childIndex >= heapSize) {
                    break;
                }

                if (childIndex + 1 < heapSize
                        && heap[childIndex + 1].distance < heap[childIndex].distance) {
                    childIndex += 1;
                }

                if (heap[parentIndex].distance <= heap[childIndex].distance) {
                    break;
                }

                swap(heap[parentIndex], heap[childIndex]);
                parentIndex = childIndex;
            }
        }

#if DEBUG_POINTER_ASSIGNMENT
        LOGD("calculatePointerIds - initial distance min-heap: size=%d", heapSize);
        for (size_t i = 0; i < heapSize; i++) {
            LOGD("  heap[%d]: cur=%d, last=%d, distance=%lld",
                    i, heap[i].currentPointerIndex, heap[i].lastPointerIndex,
                    heap[i].distance);
        }
#endif

        // Pull matches out by increasing order of distance.
        // To avoid reassigning pointers that have already been matched, the loop keeps track
        // of which last and current pointers have been matched using the matchedXXXBits variables.
        // It also tracks the used pointer id bits.
        BitSet32 matchedLastBits(0);
        BitSet32 matchedCurrentBits(0);
        BitSet32 usedIdBits(0);
        bool first = true;
        for (uint32_t i = min(currentPointerCount, lastPointerCount); i > 0; i--) {
            for (;;) {
                if (first) {
                    // The first time through the loop, we just consume the root element of
                    // the heap (the one with smallest distance).
                    first = false;
                } else {
                    // Previous iterations consumed the root element of the heap.
                    // Pop root element off of the heap (sift down).
                    heapSize -= 1;
                    assert(heapSize > 0);

                    // Sift down.
                    heap[0] = heap[heapSize];
                    for (uint32_t parentIndex = 0; ;) {
                        uint32_t childIndex = parentIndex * 2 + 1;
                        if (childIndex >= heapSize) {
                            break;
                        }

                        if (childIndex + 1 < heapSize
                                && heap[childIndex + 1].distance < heap[childIndex].distance) {
                            childIndex += 1;
                        }

                        if (heap[parentIndex].distance <= heap[childIndex].distance) {
                            break;
                        }

                        swap(heap[parentIndex], heap[childIndex]);
                        parentIndex = childIndex;
                    }

#if DEBUG_POINTER_ASSIGNMENT
                    LOGD("calculatePointerIds - reduced distance min-heap: size=%d", heapSize);
                    for (size_t i = 0; i < heapSize; i++) {
                        LOGD("  heap[%d]: cur=%d, last=%d, distance=%lld",
                                i, heap[i].currentPointerIndex, heap[i].lastPointerIndex,
                                heap[i].distance);
                    }
#endif
                }

                uint32_t currentPointerIndex = heap[0].currentPointerIndex;
                if (matchedCurrentBits.hasBit(currentPointerIndex)) continue; // already matched

                uint32_t lastPointerIndex = heap[0].lastPointerIndex;
                if (matchedLastBits.hasBit(lastPointerIndex)) continue; // already matched

                matchedCurrentBits.markBit(currentPointerIndex);
                matchedLastBits.markBit(lastPointerIndex);

                uint32_t id = lastTouch.pointers[lastPointerIndex].id;
                currentTouch.pointers[currentPointerIndex].id = id;
                currentTouch.idToIndex[id] = currentPointerIndex;
                usedIdBits.markBit(id);

#if DEBUG_POINTER_ASSIGNMENT
                LOGD("calculatePointerIds - matched: cur=%d, last=%d, id=%d, distance=%lld",
                        lastPointerIndex, currentPointerIndex, id, heap[0].distance);
#endif
                break;
            }
        }

        // Assign fresh ids to new pointers.
        if (currentPointerCount > lastPointerCount) {
            for (uint32_t i = currentPointerCount - lastPointerCount; ;) {
                uint32_t currentPointerIndex = matchedCurrentBits.firstUnmarkedBit();
                uint32_t id = usedIdBits.firstUnmarkedBit();

                currentTouch.pointers[currentPointerIndex].id = id;
                currentTouch.idToIndex[id] = currentPointerIndex;
                usedIdBits.markBit(id);

#if DEBUG_POINTER_ASSIGNMENT
                LOGD("calculatePointerIds - assigned: cur=%d, id=%d",
                        currentPointerIndex, id);
#endif

                if (--i == 0) break; // done
                matchedCurrentBits.markBit(currentPointerIndex);
            }
        }

        // Fix id bits.
        currentTouch.idBits = usedIdBits;
    }
}

/* Special hack for devices that have bad screen data: if one of the
 * points has moved more than a screen height from the last position,
 * then drop it. */
bool InputDevice::TouchScreenState::applyBadTouchFilter() {
    uint32_t pointerCount = currentTouch.pointerCount;

    // Nothing to do if there are no points.
    if (pointerCount == 0) {
        return false;
    }

    // Don't do anything if a finger is going down or up.  We run
    // here before assigning pointer IDs, so there isn't a good
    // way to do per-finger matching.
    if (pointerCount != lastTouch.pointerCount) {
        return false;
    }

    // We consider a single movement across more than a 7/16 of
    // the long size of the screen to be bad.  This was a magic value
    // determined by looking at the maximum distance it is feasible
    // to actually move in one sample.
    int32_t maxDeltaY = parameters.yAxis.range * 7 / 16;

    // XXX The original code in InputDevice.java included commented out
    //     code for testing the X axis.  Note that when we drop a point
    //     we don't actually restore the old X either.  Strange.
    //     The old code also tries to track when bad points were previously
    //     detected but it turns out that due to the placement of a "break"
    //     at the end of the loop, we never set mDroppedBadPoint to true
    //     so it is effectively dead code.
    // Need to figure out if the old code is busted or just overcomplicated
    // but working as intended.

    // Look through all new points and see if any are farther than
    // acceptable from all previous points.
    for (uint32_t i = pointerCount; i-- > 0; ) {
        int32_t y = currentTouch.pointers[i].y;
        int32_t closestY = INT_MAX;
        int32_t closestDeltaY = 0;

#if DEBUG_HACKS
        LOGD("BadTouchFilter: Looking at next point #%d: y=%d", i, y);
#endif

        for (uint32_t j = pointerCount; j-- > 0; ) {
            int32_t lastY = lastTouch.pointers[j].y;
            int32_t deltaY = abs(y - lastY);

#if DEBUG_HACKS
            LOGD("BadTouchFilter: Comparing with last point #%d: y=%d deltaY=%d",
                    j, lastY, deltaY);
#endif

            if (deltaY < maxDeltaY) {
                goto SkipSufficientlyClosePoint;
            }
            if (deltaY < closestDeltaY) {
                closestDeltaY = deltaY;
                closestY = lastY;
            }
        }

        // Must not have found a close enough match.
#if DEBUG_HACKS
        LOGD("BadTouchFilter: Dropping bad point #%d: newY=%d oldY=%d deltaY=%d maxDeltaY=%d",
                i, y, closestY, closestDeltaY, maxDeltaY);
#endif

        currentTouch.pointers[i].y = closestY;
        return true; // XXX original code only corrects one point

    SkipSufficientlyClosePoint: ;
    }

    // No change.
    return false;
}

/* Special hack for devices that have bad screen data: drop points where
 * the coordinate value for one axis has jumped to the other pointer's location.
 */
bool InputDevice::TouchScreenState::applyJumpyTouchFilter() {
    uint32_t pointerCount = currentTouch.pointerCount;
    if (lastTouch.pointerCount != pointerCount) {
#if DEBUG_HACKS
        LOGD("JumpyTouchFilter: Different pointer count %d -> %d",
                lastTouch.pointerCount, pointerCount);
        for (uint32_t i = 0; i < pointerCount; i++) {
            LOGD("  Pointer %d (%d, %d)", i,
                    currentTouch.pointers[i].x, currentTouch.pointers[i].y);
        }
#endif

        if (jumpyTouchFilter.jumpyPointsDropped < JUMPY_TRANSITION_DROPS) {
            if (lastTouch.pointerCount == 1 && pointerCount == 2) {
                // Just drop the first few events going from 1 to 2 pointers.
                // They're bad often enough that they're not worth considering.
                currentTouch.pointerCount = 1;
                jumpyTouchFilter.jumpyPointsDropped += 1;

#if DEBUG_HACKS
                LOGD("JumpyTouchFilter: Pointer 2 dropped");
#endif
                return true;
            } else if (lastTouch.pointerCount == 2 && pointerCount == 1) {
                // The event when we go from 2 -> 1 tends to be messed up too
                currentTouch.pointerCount = 2;
                currentTouch.pointers[0] = lastTouch.pointers[0];
                currentTouch.pointers[1] = lastTouch.pointers[1];
                jumpyTouchFilter.jumpyPointsDropped += 1;

#if DEBUG_HACKS
                for (int32_t i = 0; i < 2; i++) {
                    LOGD("JumpyTouchFilter: Pointer %d replaced (%d, %d)", i,
                            currentTouch.pointers[i].x, currentTouch.pointers[i].y);
                }
#endif
                return true;
            }
        }
        // Reset jumpy points dropped on other transitions or if limit exceeded.
        jumpyTouchFilter.jumpyPointsDropped = 0;

#if DEBUG_HACKS
        LOGD("JumpyTouchFilter: Transition - drop limit reset");
#endif
        return false;
    }

    // We have the same number of pointers as last time.
    // A 'jumpy' point is one where the coordinate value for one axis
    // has jumped to the other pointer's location. No need to do anything
    // else if we only have one pointer.
    if (pointerCount < 2) {
        return false;
    }

    if (jumpyTouchFilter.jumpyPointsDropped < JUMPY_DROP_LIMIT) {
        int jumpyEpsilon = parameters.yAxis.range / JUMPY_EPSILON_DIVISOR;

        // We only replace the single worst jumpy point as characterized by pointer distance
        // in a single axis.
        int32_t badPointerIndex = -1;
        int32_t badPointerReplacementIndex = -1;
        int32_t badPointerDistance = INT_MIN; // distance to be corrected

        for (uint32_t i = pointerCount; i-- > 0; ) {
            int32_t x = currentTouch.pointers[i].x;
            int32_t y = currentTouch.pointers[i].y;

#if DEBUG_HACKS
            LOGD("JumpyTouchFilter: Point %d (%d, %d)", i, x, y);
#endif

            // Check if a touch point is too close to another's coordinates
            bool dropX = false, dropY = false;
            for (uint32_t j = 0; j < pointerCount; j++) {
                if (i == j) {
                    continue;
                }

                if (abs(x - currentTouch.pointers[j].x) <= jumpyEpsilon) {
                    dropX = true;
                    break;
                }

                if (abs(y - currentTouch.pointers[j].y) <= jumpyEpsilon) {
                    dropY = true;
                    break;
                }
            }
            if (! dropX && ! dropY) {
                continue; // not jumpy
            }

            // Find a replacement candidate by comparing with older points on the
            // complementary (non-jumpy) axis.
            int32_t distance = INT_MIN; // distance to be corrected
            int32_t replacementIndex = -1;

            if (dropX) {
                // X looks too close.  Find an older replacement point with a close Y.
                int32_t smallestDeltaY = INT_MAX;
                for (uint32_t j = 0; j < pointerCount; j++) {
                    int32_t deltaY = abs(y - lastTouch.pointers[j].y);
                    if (deltaY < smallestDeltaY) {
                        smallestDeltaY = deltaY;
                        replacementIndex = j;
                    }
                }
                distance = abs(x - lastTouch.pointers[replacementIndex].x);
            } else {
                // Y looks too close.  Find an older replacement point with a close X.
                int32_t smallestDeltaX = INT_MAX;
                for (uint32_t j = 0; j < pointerCount; j++) {
                    int32_t deltaX = abs(x - lastTouch.pointers[j].x);
                    if (deltaX < smallestDeltaX) {
                        smallestDeltaX = deltaX;
                        replacementIndex = j;
                    }
                }
                distance = abs(y - lastTouch.pointers[replacementIndex].y);
            }

            // If replacing this pointer would correct a worse error than the previous ones
            // considered, then use this replacement instead.
            if (distance > badPointerDistance) {
                badPointerIndex = i;
                badPointerReplacementIndex = replacementIndex;
                badPointerDistance = distance;
            }
        }

        // Correct the jumpy pointer if one was found.
        if (badPointerIndex >= 0) {
#if DEBUG_HACKS
            LOGD("JumpyTouchFilter: Replacing bad pointer %d with (%d, %d)",
                    badPointerIndex,
                    lastTouch.pointers[badPointerReplacementIndex].x,
                    lastTouch.pointers[badPointerReplacementIndex].y);
#endif

            currentTouch.pointers[badPointerIndex].x =
                    lastTouch.pointers[badPointerReplacementIndex].x;
            currentTouch.pointers[badPointerIndex].y =
                    lastTouch.pointers[badPointerReplacementIndex].y;
            jumpyTouchFilter.jumpyPointsDropped += 1;
            return true;
        }
    }

    jumpyTouchFilter.jumpyPointsDropped = 0;
    return false;
}

/* Special hack for devices that have bad screen data: aggregate and
 * compute averages of the coordinate data, to reduce the amount of
 * jitter seen by applications. */
void InputDevice::TouchScreenState::applyAveragingTouchFilter() {
    for (uint32_t currentIndex = 0; currentIndex < currentTouch.pointerCount; currentIndex++) {
        uint32_t id = currentTouch.pointers[currentIndex].id;
        int32_t x = currentTouch.pointers[currentIndex].x;
        int32_t y = currentTouch.pointers[currentIndex].y;
        int32_t pressure = currentTouch.pointers[currentIndex].pressure;

        if (lastTouch.idBits.hasBit(id)) {
            // Pointer still down compute average.
            uint32_t start = averagingTouchFilter.historyStart[id];
            uint32_t end = averagingTouchFilter.historyEnd[id];

            int64_t deltaX = x - averagingTouchFilter.historyData[end].pointers[id].x;
            int64_t deltaY = y - averagingTouchFilter.historyData[end].pointers[id].y;
            uint64_t distance = uint64_t(deltaX * deltaX + deltaY * deltaY);

#if DEBUG_HACKS
            LOGD("AveragingTouchFilter: Pointer id %d - Distance from last sample: %lld",
                    id, distance);
#endif

            if (distance < AVERAGING_DISTANCE_LIMIT) {
                end += 1;
                if (end > AVERAGING_HISTORY_SIZE) {
                    end = 0;
                }

                if (end == start) {
                    start += 1;
                    if (start > AVERAGING_HISTORY_SIZE) {
                        start = 0;
                    }
                }

                averagingTouchFilter.historyStart[id] = start;
                averagingTouchFilter.historyEnd[id] = end;
                averagingTouchFilter.historyData[end].pointers[id].x = x;
                averagingTouchFilter.historyData[end].pointers[id].y = y;
                averagingTouchFilter.historyData[end].pointers[id].pressure = pressure;

                int32_t averagedX = 0;
                int32_t averagedY = 0;
                int32_t totalPressure = 0;
                for (;;) {
                    int32_t historicalX = averagingTouchFilter.historyData[start].pointers[id].x;
                    int32_t historicalY = averagingTouchFilter.historyData[start].pointers[id].x;
                    int32_t historicalPressure = averagingTouchFilter.historyData[start]
                            .pointers[id].pressure;

                    averagedX += historicalX;
                    averagedY += historicalY;
                    totalPressure += historicalPressure;

                    if (start == end) {
                        break;
                    }

                    start += 1;
                    if (start > AVERAGING_HISTORY_SIZE) {
                        start = 0;
                    }
                }

                averagedX /= totalPressure;
                averagedY /= totalPressure;

#if DEBUG_HACKS
                LOGD("AveragingTouchFilter: Pointer id %d - "
                        "totalPressure=%d, averagedX=%d, averagedY=%d", id, totalPressure,
                        averagedX, averagedY);
#endif

                currentTouch.pointers[currentIndex].x = averagedX;
                currentTouch.pointers[currentIndex].y = averagedY;
            } else {
#if DEBUG_HACKS
                LOGD("AveragingTouchFilter: Pointer id %d - Exceeded max distance", id);
#endif
            }
        } else {
#if DEBUG_HACKS
            LOGD("AveragingTouchFilter: Pointer id %d - Pointer went up", id);
#endif
        }

        // Reset pointer history.
        averagingTouchFilter.historyStart[id] = 0;
        averagingTouchFilter.historyEnd[id] = 0;
        averagingTouchFilter.historyData[0].pointers[id].x = x;
        averagingTouchFilter.historyData[0].pointers[id].y = y;
        averagingTouchFilter.historyData[0].pointers[id].pressure = pressure;
    }
}

bool InputDevice::TouchScreenState::isPointInsideDisplay(int32_t x, int32_t y) const {
    return x >= parameters.xAxis.minValue
        && x <= parameters.xAxis.maxValue
        && y >= parameters.yAxis.minValue
        && y <= parameters.yAxis.maxValue;
}


// --- InputDevice::SingleTouchScreenState ---

void InputDevice::SingleTouchScreenState::reset() {
    accumulator.clear();
    current.down = false;
    current.x = 0;
    current.y = 0;
    current.pressure = 0;
    current.size = 0;
}


// --- InputDevice::MultiTouchScreenState ---

void InputDevice::MultiTouchScreenState::reset() {
    accumulator.clear();
}


// --- InputReader ---

InputReader::InputReader(const sp<EventHubInterface>& eventHub,
        const sp<InputReaderPolicyInterface>& policy,
        const sp<InputDispatcherInterface>& dispatcher) :
        mEventHub(eventHub), mPolicy(policy), mDispatcher(dispatcher) {
    configureExcludedDevices();
    resetGlobalMetaState();
    resetDisplayProperties();
    updateExportedVirtualKeyState();
}

InputReader::~InputReader() {
    for (size_t i = 0; i < mDevices.size(); i++) {
        delete mDevices.valueAt(i);
    }
}

void InputReader::loopOnce() {
    RawEvent rawEvent;
    mEventHub->getEvent(& rawEvent.deviceId, & rawEvent.type, & rawEvent.scanCode,
            & rawEvent.keyCode, & rawEvent.flags, & rawEvent.value, & rawEvent.when);

    // Replace the event timestamp so it is in same timebase as java.lang.System.nanoTime()
    // and android.os.SystemClock.uptimeMillis() as expected by the rest of the system.
    rawEvent.when = systemTime(SYSTEM_TIME_MONOTONIC);

#if DEBUG_RAW_EVENTS
    LOGD("Input event: device=0x%x type=0x%x scancode=%d keycode=%d value=%d",
            rawEvent.deviceId, rawEvent.type, rawEvent.scanCode, rawEvent.keyCode,
            rawEvent.value);
#endif

    process(& rawEvent);
}

void InputReader::process(const RawEvent* rawEvent) {
    switch (rawEvent->type) {
    case EventHubInterface::DEVICE_ADDED:
        handleDeviceAdded(rawEvent);
        break;

    case EventHubInterface::DEVICE_REMOVED:
        handleDeviceRemoved(rawEvent);
        break;

    case EV_SYN:
        handleSync(rawEvent);
        break;

    case EV_KEY:
        handleKey(rawEvent);
        break;

    case EV_REL:
        handleRelativeMotion(rawEvent);
        break;

    case EV_ABS:
        handleAbsoluteMotion(rawEvent);
        break;

    case EV_SW:
        handleSwitch(rawEvent);
        break;
    }
}

void InputReader::handleDeviceAdded(const RawEvent* rawEvent) {
    InputDevice* device = getDevice(rawEvent->deviceId);
    if (device) {
        LOGW("Ignoring spurious device added event for deviceId %d.", rawEvent->deviceId);
        return;
    }

    addDevice(rawEvent->when, rawEvent->deviceId);
}

void InputReader::handleDeviceRemoved(const RawEvent* rawEvent) {
    InputDevice* device = getDevice(rawEvent->deviceId);
    if (! device) {
        LOGW("Ignoring spurious device removed event for deviceId %d.", rawEvent->deviceId);
        return;
    }

    removeDevice(rawEvent->when, device);
}

void InputReader::handleSync(const RawEvent* rawEvent) {
    InputDevice* device = getNonIgnoredDevice(rawEvent->deviceId);
    if (! device) return;

    if (rawEvent->scanCode == SYN_MT_REPORT) {
        // MultiTouch Sync: The driver has returned all data for *one* of the pointers.
        // We drop pointers with pressure <= 0 since that indicates they are not down.
        if (device->isMultiTouchScreen()) {
            uint32_t pointerIndex = device->multiTouchScreen.accumulator.pointerCount;

            if (device->multiTouchScreen.accumulator.pointers[pointerIndex].fields) {
                if (pointerIndex == MAX_POINTERS) {
                    LOGW("MultiTouch device driver returned more than maximum of %d pointers.",
                            MAX_POINTERS);
                } else {
                    pointerIndex += 1;
                    device->multiTouchScreen.accumulator.pointerCount = pointerIndex;
                }
            }

            device->multiTouchScreen.accumulator.pointers[pointerIndex].clear();
        }
    } else if (rawEvent->scanCode == SYN_REPORT) {
        // General Sync: The driver has returned all data for the current event update.
        if (device->isMultiTouchScreen()) {
            if (device->multiTouchScreen.accumulator.isDirty()) {
                onMultiTouchScreenStateChanged(rawEvent->when, device);
                device->multiTouchScreen.accumulator.clear();
            }
        } else if (device->isSingleTouchScreen()) {
            if (device->singleTouchScreen.accumulator.isDirty()) {
                onSingleTouchScreenStateChanged(rawEvent->when, device);
                device->singleTouchScreen.accumulator.clear();
            }
        }

        if (device->trackball.accumulator.isDirty()) {
            onTrackballStateChanged(rawEvent->when, device);
            device->trackball.accumulator.clear();
        }
    }
}

void InputReader::handleKey(const RawEvent* rawEvent) {
    InputDevice* device = getNonIgnoredDevice(rawEvent->deviceId);
    if (! device) return;

    bool down = rawEvent->value != 0;
    int32_t scanCode = rawEvent->scanCode;

    if (device->isKeyboard() && (scanCode < BTN_FIRST || scanCode > BTN_LAST)) {
        int32_t keyCode = rawEvent->keyCode;
        onKey(rawEvent->when, device, down, keyCode, scanCode, rawEvent->flags);
    } else if (device->isSingleTouchScreen()) {
        switch (rawEvent->scanCode) {
        case BTN_TOUCH:
            device->singleTouchScreen.accumulator.fields |=
                    InputDevice::SingleTouchScreenState::Accumulator::FIELD_BTN_TOUCH;
            device->singleTouchScreen.accumulator.btnTouch = down;
            break;
        }
    } else if (device->isTrackball()) {
        switch (rawEvent->scanCode) {
        case BTN_MOUSE:
            device->trackball.accumulator.fields |=
                    InputDevice::TrackballState::Accumulator::FIELD_BTN_MOUSE;
            device->trackball.accumulator.btnMouse = down;

            // send the down immediately
            // XXX this emulates the old behavior of KeyInputQueue, unclear whether it is
            //     necessary or if we can wait until the next sync
            onTrackballStateChanged(rawEvent->when, device);
            device->trackball.accumulator.clear();
            break;
        }
    }
}

void InputReader::handleRelativeMotion(const RawEvent* rawEvent) {
    InputDevice* device = getNonIgnoredDevice(rawEvent->deviceId);
    if (! device) return;

    if (device->isTrackball()) {
        switch (rawEvent->scanCode) {
        case REL_X:
            device->trackball.accumulator.fields |=
                    InputDevice::TrackballState::Accumulator::FIELD_REL_X;
            device->trackball.accumulator.relX = rawEvent->value;
            break;
        case REL_Y:
            device->trackball.accumulator.fields |=
                    InputDevice::TrackballState::Accumulator::FIELD_REL_Y;
            device->trackball.accumulator.relY = rawEvent->value;
            break;
        }
    }
}

void InputReader::handleAbsoluteMotion(const RawEvent* rawEvent) {
    InputDevice* device = getNonIgnoredDevice(rawEvent->deviceId);
    if (! device) return;

    if (device->isMultiTouchScreen()) {
        uint32_t pointerIndex = device->multiTouchScreen.accumulator.pointerCount;
        InputDevice::MultiTouchScreenState::Accumulator::Pointer* pointer =
                & device->multiTouchScreen.accumulator.pointers[pointerIndex];

        switch (rawEvent->scanCode) {
        case ABS_MT_POSITION_X:
            pointer->fields |=
                    InputDevice::MultiTouchScreenState::Accumulator::FIELD_ABS_MT_POSITION_X;
            pointer->absMTPositionX = rawEvent->value;
            break;
        case ABS_MT_POSITION_Y:
            pointer->fields |=
                    InputDevice::MultiTouchScreenState::Accumulator::FIELD_ABS_MT_POSITION_Y;
            pointer->absMTPositionY = rawEvent->value;
            break;
        case ABS_MT_TOUCH_MAJOR:
            pointer->fields |=
                    InputDevice::MultiTouchScreenState::Accumulator::FIELD_ABS_MT_TOUCH_MAJOR;
            pointer->absMTTouchMajor = rawEvent->value;
            break;
        case ABS_MT_WIDTH_MAJOR:
            pointer->fields |=
                    InputDevice::MultiTouchScreenState::Accumulator::FIELD_ABS_MT_WIDTH_MAJOR;
            pointer->absMTWidthMajor = rawEvent->value;
            break;
        case ABS_MT_TRACKING_ID:
            pointer->fields |=
                    InputDevice::MultiTouchScreenState::Accumulator::FIELD_ABS_MT_TRACKING_ID;
            pointer->absMTTrackingId = rawEvent->value;
            break;
        }
    } else if (device->isSingleTouchScreen()) {
        switch (rawEvent->scanCode) {
        case ABS_X:
            device->singleTouchScreen.accumulator.fields |=
                    InputDevice::SingleTouchScreenState::Accumulator::FIELD_ABS_X;
            device->singleTouchScreen.accumulator.absX = rawEvent->value;
            break;
        case ABS_Y:
            device->singleTouchScreen.accumulator.fields |=
                    InputDevice::SingleTouchScreenState::Accumulator::FIELD_ABS_Y;
            device->singleTouchScreen.accumulator.absY = rawEvent->value;
            break;
        case ABS_PRESSURE:
            device->singleTouchScreen.accumulator.fields |=
                    InputDevice::SingleTouchScreenState::Accumulator::FIELD_ABS_PRESSURE;
            device->singleTouchScreen.accumulator.absPressure = rawEvent->value;
            break;
        case ABS_TOOL_WIDTH:
            device->singleTouchScreen.accumulator.fields |=
                    InputDevice::SingleTouchScreenState::Accumulator::FIELD_ABS_TOOL_WIDTH;
            device->singleTouchScreen.accumulator.absToolWidth = rawEvent->value;
            break;
        }
    }
}

void InputReader::handleSwitch(const RawEvent* rawEvent) {
    InputDevice* device = getNonIgnoredDevice(rawEvent->deviceId);
    if (! device) return;

    onSwitch(rawEvent->when, device, rawEvent->scanCode, rawEvent->value);
}

void InputReader::onKey(nsecs_t when, InputDevice* device,
        bool down, int32_t keyCode, int32_t scanCode, uint32_t policyFlags) {
    /* Refresh display properties so we can rotate key codes according to display orientation */

    if (! refreshDisplayProperties()) {
        return;
    }

    /* Update device state */

    int32_t oldMetaState = device->keyboard.current.metaState;
    int32_t newMetaState = updateMetaState(keyCode, down, oldMetaState);
    if (oldMetaState != newMetaState) {
        device->keyboard.current.metaState = newMetaState;
        resetGlobalMetaState();
    }

    // FIXME if we send a down event about a rotated key press we should ensure that we send
    //       a corresponding up event about the rotated key press even if the orientation
    //       has changed in the meantime
    keyCode = rotateKeyCode(keyCode, mDisplayOrientation);

    if (down) {
        device->keyboard.current.downTime = when;
    }

    /* Apply policy */

    int32_t policyActions = mPolicy->interceptKey(when, device->id,
            down, keyCode, scanCode, policyFlags);

    if (! applyStandardInputDispatchPolicyActions(when, policyActions, & policyFlags)) {
        return; // event dropped
    }

    /* Enqueue key event for dispatch */

    int32_t keyEventAction;
    if (down) {
        device->keyboard.current.downTime = when;
        keyEventAction = KEY_EVENT_ACTION_DOWN;
    } else {
        keyEventAction = KEY_EVENT_ACTION_UP;
    }

    int32_t keyEventFlags = KEY_EVENT_FLAG_FROM_SYSTEM;
    if (policyActions & InputReaderPolicyInterface::ACTION_WOKE_HERE) {
        keyEventFlags = keyEventFlags | KEY_EVENT_FLAG_WOKE_HERE;
    }

    mDispatcher->notifyKey(when, device->id, INPUT_EVENT_NATURE_KEY, policyFlags,
            keyEventAction, keyEventFlags, keyCode, scanCode,
            device->keyboard.current.metaState,
            device->keyboard.current.downTime);
}

void InputReader::onSwitch(nsecs_t when, InputDevice* device, int32_t switchCode,
        int32_t switchValue) {
    int32_t policyActions = mPolicy->interceptSwitch(when, switchCode, switchValue);

    uint32_t policyFlags = 0;
    applyStandardInputDispatchPolicyActions(when, policyActions, & policyFlags);
}

void InputReader::onMultiTouchScreenStateChanged(nsecs_t when,
        InputDevice* device) {
    static const uint32_t REQUIRED_FIELDS =
            InputDevice::MultiTouchScreenState::Accumulator::FIELD_ABS_MT_POSITION_X
            | InputDevice::MultiTouchScreenState::Accumulator::FIELD_ABS_MT_POSITION_Y
            | InputDevice::MultiTouchScreenState::Accumulator::FIELD_ABS_MT_TOUCH_MAJOR
            | InputDevice::MultiTouchScreenState::Accumulator::FIELD_ABS_MT_WIDTH_MAJOR;

    /* Refresh display properties so we can map touch screen coords into display coords */

    if (! refreshDisplayProperties()) {
        return;
    }

    /* Update device state */

    InputDevice::MultiTouchScreenState* in = & device->multiTouchScreen;
    InputDevice::TouchData* out = & device->touchScreen.currentTouch;

    uint32_t inCount = in->accumulator.pointerCount;
    uint32_t outCount = 0;
    bool havePointerIds = true;

    out->clear();

    for (uint32_t inIndex = 0; inIndex < inCount; inIndex++) {
        uint32_t fields = in->accumulator.pointers[inIndex].fields;

        if ((fields & REQUIRED_FIELDS) != REQUIRED_FIELDS) {
#if DEBUG_POINTERS
            LOGD("Pointers: Missing required multitouch pointer fields: index=%d, fields=%d",
                    inIndex, fields);
            continue;
#endif
        }

        if (in->accumulator.pointers[inIndex].absMTTouchMajor <= 0) {
            // Pointer is not down.  Drop it.
            continue;
        }

        // FIXME assignment of pressure may be incorrect, probably better to let
        // pressure = touch / width.  Later on we pass width to MotionEvent as a size, which
        // isn't quite right either.  Should be using touch for that.
        out->pointers[outCount].x = in->accumulator.pointers[inIndex].absMTPositionX;
        out->pointers[outCount].y = in->accumulator.pointers[inIndex].absMTPositionY;
        out->pointers[outCount].pressure = in->accumulator.pointers[inIndex].absMTTouchMajor;
        out->pointers[outCount].size = in->accumulator.pointers[inIndex].absMTWidthMajor;

        if (havePointerIds) {
            if (fields & InputDevice::MultiTouchScreenState::Accumulator::
                    FIELD_ABS_MT_TRACKING_ID) {
                uint32_t id = uint32_t(in->accumulator.pointers[inIndex].absMTTrackingId);

                if (id > MAX_POINTER_ID) {
#if DEBUG_POINTERS
                    LOGD("Pointers: Ignoring driver provided pointer id %d because "
                            "it is larger than max supported id %d for optimizations",
                            id, MAX_POINTER_ID);
#endif
                    havePointerIds = false;
                }
                else {
                    out->pointers[outCount].id = id;
                    out->idToIndex[id] = outCount;
                    out->idBits.markBit(id);
                }
            } else {
                havePointerIds = false;
            }
        }

        outCount += 1;
    }

    out->pointerCount = outCount;

    onTouchScreenChanged(when, device, havePointerIds);
}

void InputReader::onSingleTouchScreenStateChanged(nsecs_t when,
        InputDevice* device) {
    static const uint32_t POSITION_FIELDS =
            InputDevice::SingleTouchScreenState::Accumulator::FIELD_ABS_X
            | InputDevice::SingleTouchScreenState::Accumulator::FIELD_ABS_Y
            | InputDevice::SingleTouchScreenState::Accumulator::FIELD_ABS_PRESSURE
            | InputDevice::SingleTouchScreenState::Accumulator::FIELD_ABS_TOOL_WIDTH;

    /* Refresh display properties so we can map touch screen coords into display coords */

    if (! refreshDisplayProperties()) {
        return;
    }

    /* Update device state */

    InputDevice::SingleTouchScreenState* in = & device->singleTouchScreen;
    InputDevice::TouchData* out = & device->touchScreen.currentTouch;

    uint32_t fields = in->accumulator.fields;

    if (fields & InputDevice::SingleTouchScreenState::Accumulator::FIELD_BTN_TOUCH) {
        in->current.down = in->accumulator.btnTouch;
    }

    if ((fields & POSITION_FIELDS) == POSITION_FIELDS) {
        in->current.x = in->accumulator.absX;
        in->current.y = in->accumulator.absY;
        in->current.pressure = in->accumulator.absPressure;
        in->current.size = in->accumulator.absToolWidth;
    }

    out->clear();

    if (in->current.down) {
        out->pointerCount = 1;
        out->pointers[0].id = 0;
        out->pointers[0].x = in->current.x;
        out->pointers[0].y = in->current.y;
        out->pointers[0].pressure = in->current.pressure;
        out->pointers[0].size = in->current.size;
        out->idToIndex[0] = 0;
        out->idBits.markBit(0);
    }

    onTouchScreenChanged(when, device, true);
}

void InputReader::onTouchScreenChanged(nsecs_t when,
        InputDevice* device, bool havePointerIds) {
    /* Apply policy */

    int32_t policyActions = mPolicy->interceptTouch(when);

    uint32_t policyFlags = 0;
    if (! applyStandardInputDispatchPolicyActions(when, policyActions, & policyFlags)) {
        device->touchScreen.lastTouch.clear();
        return; // event dropped
    }

    /* Preprocess pointer data */

    if (device->touchScreen.parameters.useBadTouchFilter) {
        if (device->touchScreen.applyBadTouchFilter()) {
            havePointerIds = false;
        }
    }

    if (device->touchScreen.parameters.useJumpyTouchFilter) {
        if (device->touchScreen.applyJumpyTouchFilter()) {
            havePointerIds = false;
        }
    }

    if (! havePointerIds) {
        device->touchScreen.calculatePointerIds();
    }

    InputDevice::TouchData temp;
    InputDevice::TouchData* savedTouch;
    if (device->touchScreen.parameters.useAveragingTouchFilter) {
        temp.copyFrom(device->touchScreen.currentTouch);
        savedTouch = & temp;

        device->touchScreen.applyAveragingTouchFilter();
    } else {
        savedTouch = & device->touchScreen.currentTouch;
    }

    /* Process virtual keys or touches */

    if (! consumeVirtualKeyTouches(when, device, policyFlags)) {
        dispatchTouches(when, device, policyFlags);
    }

    // Copy current touch to last touch in preparation for the next cycle.
    device->touchScreen.lastTouch.copyFrom(*savedTouch);
}

bool InputReader::consumeVirtualKeyTouches(nsecs_t when,
        InputDevice* device, uint32_t policyFlags) {
    if (device->touchScreen.currentVirtualKey.down) {
        if (device->touchScreen.currentTouch.pointerCount == 0) {
            // Pointer went up while virtual key was down.  Send key up event.
            device->touchScreen.currentVirtualKey.down = false;

#if DEBUG_VIRTUAL_KEYS
            LOGD("VirtualKeys: Generating key up: keyCode=%d, scanCode=%d",
                    device->touchScreen.currentVirtualKey.keyCode,
                    device->touchScreen.currentVirtualKey.scanCode);
#endif

            dispatchVirtualKey(when, device, policyFlags, KEY_EVENT_ACTION_UP,
                    KEY_EVENT_FLAG_FROM_SYSTEM | KEY_EVENT_FLAG_VIRTUAL_HARD_KEY);
            return true; // consumed
        }

        int32_t x = device->touchScreen.currentTouch.pointers[0].x;
        int32_t y = device->touchScreen.currentTouch.pointers[0].y;
        if (device->touchScreen.isPointInsideDisplay(x, y)
                || device->touchScreen.currentTouch.pointerCount != 1) {
            // Pointer moved inside the display area or another pointer also went down.
            // Send key cancellation.
            device->touchScreen.currentVirtualKey.down = false;

#if DEBUG_VIRTUAL_KEYS
            LOGD("VirtualKeys: Canceling key: keyCode=%d, scanCode=%d",
                    device->touchScreen.currentVirtualKey.keyCode,
                    device->touchScreen.currentVirtualKey.scanCode);
#endif

            dispatchVirtualKey(when, device, policyFlags, KEY_EVENT_ACTION_UP,
                    KEY_EVENT_FLAG_FROM_SYSTEM | KEY_EVENT_FLAG_VIRTUAL_HARD_KEY
                            | KEY_EVENT_FLAG_CANCELED);

            // Clear the last touch data so we will consider the pointer as having just been
            // pressed down when generating subsequent motion events.
            device->touchScreen.lastTouch.clear();
            return false; // not consumed
        }
    } else if (device->touchScreen.currentTouch.pointerCount == 1
            && device->touchScreen.lastTouch.pointerCount == 0) {
        int32_t x = device->touchScreen.currentTouch.pointers[0].x;
        int32_t y = device->touchScreen.currentTouch.pointers[0].y;
        for (size_t i = 0; i < device->touchScreen.virtualKeys.size(); i++) {
            const InputDevice::VirtualKey& virtualKey = device->touchScreen.virtualKeys[i];

#if DEBUG_VIRTUAL_KEYS
            LOGD("VirtualKeys: Hit test (%d, %d): keyCode=%d, scanCode=%d, "
                    "left=%d, top=%d, right=%d, bottom=%d",
                    x, y,
                    virtualKey.keyCode, virtualKey.scanCode,
                    virtualKey.hitLeft, virtualKey.hitTop,
                    virtualKey.hitRight, virtualKey.hitBottom);
#endif

            if (virtualKey.isHit(x, y)) {
                device->touchScreen.currentVirtualKey.down = true;
                device->touchScreen.currentVirtualKey.downTime = when;
                device->touchScreen.currentVirtualKey.keyCode = virtualKey.keyCode;
                device->touchScreen.currentVirtualKey.scanCode = virtualKey.scanCode;

#if DEBUG_VIRTUAL_KEYS
                    LOGD("VirtualKeys: Generating key down: keyCode=%d, scanCode=%d",
                            device->touchScreen.currentVirtualKey.keyCode,
                            device->touchScreen.currentVirtualKey.scanCode);
#endif

                dispatchVirtualKey(when, device, policyFlags, KEY_EVENT_ACTION_DOWN,
                        KEY_EVENT_FLAG_FROM_SYSTEM | KEY_EVENT_FLAG_VIRTUAL_HARD_KEY);
                return true; // consumed
            }
        }
    }

    return false; // not consumed
}

void InputReader::dispatchVirtualKey(nsecs_t when,
        InputDevice* device, uint32_t policyFlags,
        int32_t keyEventAction, int32_t keyEventFlags) {
    int32_t keyCode = device->touchScreen.currentVirtualKey.keyCode;
    int32_t scanCode = device->touchScreen.currentVirtualKey.scanCode;
    nsecs_t downTime = device->touchScreen.currentVirtualKey.downTime;
    int32_t metaState = globalMetaState();

    updateExportedVirtualKeyState();

    mPolicy->virtualKeyFeedback(when, device->id, keyEventAction, keyEventFlags,
            keyCode, scanCode, metaState, downTime);

    mDispatcher->notifyKey(when, device->id, INPUT_EVENT_NATURE_KEY, policyFlags,
            keyEventAction, keyEventFlags, keyCode, scanCode, metaState, downTime);
}

void InputReader::dispatchTouches(nsecs_t when,
        InputDevice* device, uint32_t policyFlags) {
    uint32_t currentPointerCount = device->touchScreen.currentTouch.pointerCount;
    uint32_t lastPointerCount = device->touchScreen.lastTouch.pointerCount;
    if (currentPointerCount == 0 && lastPointerCount == 0) {
        return; // nothing to do!
    }

    BitSet32 currentIdBits = device->touchScreen.currentTouch.idBits;
    BitSet32 lastIdBits = device->touchScreen.lastTouch.idBits;

    if (currentIdBits == lastIdBits) {
        // No pointer id changes so this is a move event.
        // The dispatcher takes care of batching moves so we don't have to deal with that here.
        int32_t motionEventAction = MOTION_EVENT_ACTION_MOVE;
        dispatchTouch(when, device, policyFlags, & device->touchScreen.currentTouch,
                currentIdBits, motionEventAction);
    } else {
        // There may be pointers going up and pointers going down at the same time when pointer
        // ids are reported by the device driver.
        BitSet32 upIdBits(lastIdBits.value & ~ currentIdBits.value);
        BitSet32 downIdBits(currentIdBits.value & ~ lastIdBits.value);
        BitSet32 activeIdBits(lastIdBits.value);

        while (! upIdBits.isEmpty()) {
            uint32_t upId = upIdBits.firstMarkedBit();
            upIdBits.clearBit(upId);
            BitSet32 oldActiveIdBits = activeIdBits;
            activeIdBits.clearBit(upId);

            int32_t motionEventAction;
            if (activeIdBits.isEmpty()) {
                motionEventAction = MOTION_EVENT_ACTION_UP;
            } else {
                motionEventAction = MOTION_EVENT_ACTION_POINTER_UP
                        | (upId << MOTION_EVENT_ACTION_POINTER_INDEX_SHIFT);
            }

            dispatchTouch(when, device, policyFlags, & device->touchScreen.lastTouch,
                    oldActiveIdBits, motionEventAction);
        }

        while (! downIdBits.isEmpty()) {
            uint32_t downId = downIdBits.firstMarkedBit();
            downIdBits.clearBit(downId);
            BitSet32 oldActiveIdBits = activeIdBits;
            activeIdBits.markBit(downId);

            int32_t motionEventAction;
            if (oldActiveIdBits.isEmpty()) {
                motionEventAction = MOTION_EVENT_ACTION_DOWN;
                device->touchScreen.downTime = when;
            } else {
                motionEventAction = MOTION_EVENT_ACTION_POINTER_DOWN
                        | (downId << MOTION_EVENT_ACTION_POINTER_INDEX_SHIFT);
            }

            dispatchTouch(when, device, policyFlags, & device->touchScreen.currentTouch,
                    activeIdBits, motionEventAction);
        }
    }
}

void InputReader::dispatchTouch(nsecs_t when, InputDevice* device, uint32_t policyFlags,
        InputDevice::TouchData* touch, BitSet32 idBits,
        int32_t motionEventAction) {
    int32_t orientedWidth, orientedHeight;
    switch (mDisplayOrientation) {
    case InputReaderPolicyInterface::ROTATION_90:
    case InputReaderPolicyInterface::ROTATION_270:
        orientedWidth = mDisplayHeight;
        orientedHeight = mDisplayWidth;
        break;
    default:
        orientedWidth = mDisplayWidth;
        orientedHeight = mDisplayHeight;
        break;
    }

    uint32_t pointerCount = 0;
    int32_t pointerIds[MAX_POINTERS];
    PointerCoords pointerCoords[MAX_POINTERS];

    // Walk through the the active pointers and map touch screen coordinates (TouchData) into
    // display coordinates (PointerCoords) and adjust for display orientation.
    while (! idBits.isEmpty()) {
        uint32_t id = idBits.firstMarkedBit();
        idBits.clearBit(id);
        uint32_t index = touch->idToIndex[id];

        float x = (float(touch->pointers[index].x)
                        - device->touchScreen.parameters.xAxis.minValue)
                * device->touchScreen.precalculated.xScale;
        float y = (float(touch->pointers[index].y)
                        - device->touchScreen.parameters.yAxis.minValue)
                * device->touchScreen.precalculated.yScale;
        float pressure = (float(touch->pointers[index].pressure)
                        - device->touchScreen.parameters.pressureAxis.minValue)
                * device->touchScreen.precalculated.pressureScale;
        float size = (float(touch->pointers[index].size)
                        - device->touchScreen.parameters.sizeAxis.minValue)
                * device->touchScreen.precalculated.sizeScale;

        switch (mDisplayOrientation) {
        case InputReaderPolicyInterface::ROTATION_90: {
            float xTemp = x;
            x = y;
            y = mDisplayHeight - xTemp;
            break;
        }
        case InputReaderPolicyInterface::ROTATION_180: {
            x = mDisplayWidth - x;
            y = mDisplayHeight - y;
            break;
        }
        case InputReaderPolicyInterface::ROTATION_270: {
            float xTemp = x;
            x = mDisplayWidth - y;
            y = xTemp;
            break;
        }
        }

        pointerIds[pointerCount] = int32_t(id);

        pointerCoords[pointerCount].x = x;
        pointerCoords[pointerCount].y = y;
        pointerCoords[pointerCount].pressure = pressure;
        pointerCoords[pointerCount].size = size;

        pointerCount += 1;
    }

    // Check edge flags by looking only at the first pointer since the flags are
    // global to the event.
    // XXX Maybe we should revise the edge flags API to work on a per-pointer basis.
    int32_t motionEventEdgeFlags = 0;
    if (motionEventAction == MOTION_EVENT_ACTION_DOWN) {
        if (pointerCoords[0].x <= 0) {
            motionEventEdgeFlags |= MOTION_EVENT_EDGE_FLAG_LEFT;
        } else if (pointerCoords[0].x >= orientedWidth) {
            motionEventEdgeFlags |= MOTION_EVENT_EDGE_FLAG_RIGHT;
        }
        if (pointerCoords[0].y <= 0) {
            motionEventEdgeFlags |= MOTION_EVENT_EDGE_FLAG_TOP;
        } else if (pointerCoords[0].y >= orientedHeight) {
            motionEventEdgeFlags |= MOTION_EVENT_EDGE_FLAG_BOTTOM;
        }
    }

    nsecs_t downTime = device->touchScreen.downTime;
    mDispatcher->notifyMotion(when, device->id, INPUT_EVENT_NATURE_TOUCH, policyFlags,
            motionEventAction, globalMetaState(), motionEventEdgeFlags,
            pointerCount, pointerIds, pointerCoords,
            0, 0, downTime);
}

void InputReader::onTrackballStateChanged(nsecs_t when,
        InputDevice* device) {
    static const uint32_t DELTA_FIELDS =
            InputDevice::TrackballState::Accumulator::FIELD_REL_X
            | InputDevice::TrackballState::Accumulator::FIELD_REL_Y;

    /* Refresh display properties so we can trackball moves according to display orientation */

    if (! refreshDisplayProperties()) {
        return;
    }

    /* Update device state */

    uint32_t fields = device->trackball.accumulator.fields;
    bool downChanged = fields & InputDevice::TrackballState::Accumulator::FIELD_BTN_MOUSE;
    bool deltaChanged = (fields & DELTA_FIELDS) == DELTA_FIELDS;

    bool down;
    if (downChanged) {
        if (device->trackball.accumulator.btnMouse) {
            device->trackball.current.down = true;
            device->trackball.current.downTime = when;
            down = true;
        } else {
            device->trackball.current.down = false;
            down = false;
        }
    } else {
        down = device->trackball.current.down;
    }

    /* Apply policy */

    int32_t policyActions = mPolicy->interceptTrackball(when, downChanged, down, deltaChanged);

    uint32_t policyFlags = 0;
    if (! applyStandardInputDispatchPolicyActions(when, policyActions, & policyFlags)) {
        return; // event dropped
    }

    /* Enqueue motion event for dispatch */

    int32_t motionEventAction;
    if (downChanged) {
        motionEventAction = down ? MOTION_EVENT_ACTION_DOWN : MOTION_EVENT_ACTION_UP;
    } else {
        motionEventAction = MOTION_EVENT_ACTION_MOVE;
    }

    int32_t pointerId = 0;
    PointerCoords pointerCoords;
    pointerCoords.x = device->trackball.accumulator.relX
            * device->trackball.precalculated.xScale;
    pointerCoords.y = device->trackball.accumulator.relY
            * device->trackball.precalculated.yScale;
    pointerCoords.pressure = 1.0f; // XXX Consider making this 1.0f if down, 0 otherwise.
    pointerCoords.size = 0;

    float temp;
    switch (mDisplayOrientation) {
    case InputReaderPolicyInterface::ROTATION_90:
        temp = pointerCoords.x;
        pointerCoords.x = pointerCoords.y;
        pointerCoords.y = - temp;
        break;

    case InputReaderPolicyInterface::ROTATION_180:
        pointerCoords.x = - pointerCoords.x;
        pointerCoords.y = - pointerCoords.y;
        break;

    case InputReaderPolicyInterface::ROTATION_270:
        temp = pointerCoords.x;
        pointerCoords.x = - pointerCoords.y;
        pointerCoords.y = temp;
        break;
    }

    mDispatcher->notifyMotion(when, device->id, INPUT_EVENT_NATURE_TRACKBALL, policyFlags,
            motionEventAction, globalMetaState(), MOTION_EVENT_EDGE_FLAG_NONE,
            1, & pointerId, & pointerCoords,
            device->trackball.precalculated.xPrecision,
            device->trackball.precalculated.yPrecision,
            device->trackball.current.downTime);
}

void InputReader::onConfigurationChanged(nsecs_t when) {
    // Reset global meta state because it depends on the list of all configured devices.
    resetGlobalMetaState();

    // Reset virtual keys, just in case.
    updateExportedVirtualKeyState();

    // Update input configuration.
    updateExportedInputConfiguration();

    // Enqueue configuration changed.
    mDispatcher->notifyConfigurationChanged(when);
}

bool InputReader::applyStandardInputDispatchPolicyActions(nsecs_t when,
        int32_t policyActions, uint32_t* policyFlags) {
    if (policyActions & InputReaderPolicyInterface::ACTION_APP_SWITCH_COMING) {
        mDispatcher->notifyAppSwitchComing(when);
    }

    if (policyActions & InputReaderPolicyInterface::ACTION_WOKE_HERE) {
        *policyFlags |= POLICY_FLAG_WOKE_HERE;
    }

    if (policyActions & InputReaderPolicyInterface::ACTION_BRIGHT_HERE) {
        *policyFlags |= POLICY_FLAG_BRIGHT_HERE;
    }

    return policyActions & InputReaderPolicyInterface::ACTION_DISPATCH;
}

void InputReader::resetDisplayProperties() {
    mDisplayWidth = mDisplayHeight = -1;
    mDisplayOrientation = -1;
}

bool InputReader::refreshDisplayProperties() {
    int32_t newWidth, newHeight, newOrientation;
    if (mPolicy->getDisplayInfo(0, & newWidth, & newHeight, & newOrientation)) {
        if (newWidth != mDisplayWidth || newHeight != mDisplayHeight) {
            LOGD("Display size changed from %dx%d to %dx%d, updating device configuration",
                    mDisplayWidth, mDisplayHeight, newWidth, newHeight);

            mDisplayWidth = newWidth;
            mDisplayHeight = newHeight;

            for (size_t i = 0; i < mDevices.size(); i++) {
                configureDeviceForCurrentDisplaySize(mDevices.valueAt(i));
            }
        }

        mDisplayOrientation = newOrientation;
        return true;
    } else {
        resetDisplayProperties();
        return false;
    }
}

InputDevice* InputReader::getDevice(int32_t deviceId) {
    ssize_t index = mDevices.indexOfKey(deviceId);
    return index >= 0 ? mDevices.valueAt((size_t) index) : NULL;
}

InputDevice* InputReader::getNonIgnoredDevice(int32_t deviceId) {
    InputDevice* device = getDevice(deviceId);
    return device && ! device->ignored ? device : NULL;
}

void InputReader::addDevice(nsecs_t when, int32_t deviceId) {
    uint32_t classes = mEventHub->getDeviceClasses(deviceId);
    String8 name = mEventHub->getDeviceName(deviceId);
    InputDevice* device = new InputDevice(deviceId, classes, name);

    if (classes != 0) {
        LOGI("Device added: id=0x%x, name=%s, classes=%02x", device->id,
                device->name.string(), device->classes);

        configureDevice(device);
    } else {
        LOGI("Device added: id=0x%x, name=%s (ignored non-input device)", device->id,
                device->name.string());

        device->ignored = true;
    }

    device->reset();

    mDevices.add(deviceId, device);

    if (! device->ignored) {
        onConfigurationChanged(when);
    }
}

void InputReader::removeDevice(nsecs_t when, InputDevice* device) {
    mDevices.removeItem(device->id);

    if (! device->ignored) {
        LOGI("Device removed: id=0x%x, name=%s, classes=%02x", device->id,
                device->name.string(), device->classes);

        onConfigurationChanged(when);
    } else {
        LOGI("Device removed: id=0x%x, name=%s (ignored non-input device)", device->id,
                device->name.string());
    }

    delete device;
}

void InputReader::configureDevice(InputDevice* device) {
    if (device->isMultiTouchScreen()) {
        configureAbsoluteAxisInfo(device, ABS_MT_POSITION_X, "X",
                & device->touchScreen.parameters.xAxis);
        configureAbsoluteAxisInfo(device, ABS_MT_POSITION_Y, "Y",
                & device->touchScreen.parameters.yAxis);
        configureAbsoluteAxisInfo(device, ABS_MT_TOUCH_MAJOR, "Pressure",
                & device->touchScreen.parameters.pressureAxis);
        configureAbsoluteAxisInfo(device, ABS_MT_WIDTH_MAJOR, "Size",
                & device->touchScreen.parameters.sizeAxis);
    } else if (device->isSingleTouchScreen()) {
        configureAbsoluteAxisInfo(device, ABS_X, "X",
                & device->touchScreen.parameters.xAxis);
        configureAbsoluteAxisInfo(device, ABS_Y, "Y",
                & device->touchScreen.parameters.yAxis);
        configureAbsoluteAxisInfo(device, ABS_PRESSURE, "Pressure",
                & device->touchScreen.parameters.pressureAxis);
        configureAbsoluteAxisInfo(device, ABS_TOOL_WIDTH, "Size",
                & device->touchScreen.parameters.sizeAxis);
    }

    if (device->isTouchScreen()) {
        device->touchScreen.parameters.useBadTouchFilter =
                mPolicy->filterTouchEvents();
        device->touchScreen.parameters.useAveragingTouchFilter =
                mPolicy->filterTouchEvents();
        device->touchScreen.parameters.useJumpyTouchFilter =
                mPolicy->filterJumpyTouchEvents();

        device->touchScreen.precalculated.pressureScale =
                1.0f / device->touchScreen.parameters.pressureAxis.range;
        device->touchScreen.precalculated.sizeScale =
                1.0f / device->touchScreen.parameters.sizeAxis.range;
    }

    if (device->isTrackball()) {
        device->trackball.precalculated.xPrecision = TRACKBALL_MOVEMENT_THRESHOLD;
        device->trackball.precalculated.yPrecision = TRACKBALL_MOVEMENT_THRESHOLD;
        device->trackball.precalculated.xScale = 1.0f / TRACKBALL_MOVEMENT_THRESHOLD;
        device->trackball.precalculated.yScale = 1.0f / TRACKBALL_MOVEMENT_THRESHOLD;
    }

    configureDeviceForCurrentDisplaySize(device);
}

void InputReader::configureDeviceForCurrentDisplaySize(InputDevice* device) {
    if (device->isTouchScreen()) {
        if (mDisplayWidth < 0) {
            LOGD("Skipping part of touch screen configuration since display size is unknown.");
        } else {
            LOGI("Device configured: id=0x%x, name=%s (display size was changed)", device->id,
                    device->name.string());
            configureVirtualKeys(device);

            device->touchScreen.precalculated.xScale =
                    float(mDisplayWidth) / device->touchScreen.parameters.xAxis.range;
            device->touchScreen.precalculated.yScale =
                    float(mDisplayHeight) / device->touchScreen.parameters.yAxis.range;
        }
    }
}

void InputReader::configureVirtualKeys(InputDevice* device) {
    device->touchScreen.virtualKeys.clear();

    Vector<InputReaderPolicyInterface::VirtualKeyDefinition> virtualKeyDefinitions;
    mPolicy->getVirtualKeyDefinitions(device->name, virtualKeyDefinitions);
    if (virtualKeyDefinitions.size() == 0) {
        return;
    }

    device->touchScreen.virtualKeys.setCapacity(virtualKeyDefinitions.size());

    int32_t touchScreenLeft = device->touchScreen.parameters.xAxis.minValue;
    int32_t touchScreenTop = device->touchScreen.parameters.yAxis.minValue;
    int32_t touchScreenWidth = device->touchScreen.parameters.xAxis.range;
    int32_t touchScreenHeight = device->touchScreen.parameters.yAxis.range;

    for (size_t i = 0; i < virtualKeyDefinitions.size(); i++) {
        const InputReaderPolicyInterface::VirtualKeyDefinition& virtualKeyDefinition =
                virtualKeyDefinitions[i];

        device->touchScreen.virtualKeys.add();
        InputDevice::VirtualKey& virtualKey =
                device->touchScreen.virtualKeys.editTop();

        virtualKey.scanCode = virtualKeyDefinition.scanCode;
        int32_t keyCode;
        uint32_t flags;
        if (mEventHub->scancodeToKeycode(device->id, virtualKey.scanCode,
                & keyCode, & flags)) {
            LOGI("  VirtualKey %d: could not obtain key code, ignoring", virtualKey.scanCode);
            device->touchScreen.virtualKeys.pop(); // drop the key
            continue;
        }

        virtualKey.keyCode = keyCode;
        virtualKey.flags = flags;

        // convert the key definition's display coordinates into touch coordinates for a hit box
        int32_t halfWidth = virtualKeyDefinition.width / 2;
        int32_t halfHeight = virtualKeyDefinition.height / 2;

        virtualKey.hitLeft = (virtualKeyDefinition.centerX - halfWidth)
                * touchScreenWidth / mDisplayWidth + touchScreenLeft;
        virtualKey.hitRight= (virtualKeyDefinition.centerX + halfWidth)
                * touchScreenWidth / mDisplayWidth + touchScreenLeft;
        virtualKey.hitTop = (virtualKeyDefinition.centerY - halfHeight)
                * touchScreenHeight / mDisplayHeight + touchScreenTop;
        virtualKey.hitBottom = (virtualKeyDefinition.centerY + halfHeight)
                * touchScreenHeight / mDisplayHeight + touchScreenTop;

        LOGI("  VirtualKey %d: keyCode=%d hitLeft=%d hitRight=%d hitTop=%d hitBottom=%d",
                virtualKey.scanCode, virtualKey.keyCode,
                virtualKey.hitLeft, virtualKey.hitRight, virtualKey.hitTop, virtualKey.hitBottom);
    }
}

void InputReader::configureAbsoluteAxisInfo(InputDevice* device,
        int axis, const char* name, InputDevice::AbsoluteAxisInfo* out) {
    if (! mEventHub->getAbsoluteInfo(device->id, axis,
            & out->minValue, & out->maxValue, & out->flat, &out->fuzz)) {
        out->range = out->maxValue - out->minValue;
        if (out->range != 0) {
            LOGI("  %s: min=%d max=%d flat=%d fuzz=%d",
                    name, out->minValue, out->maxValue, out->flat, out->fuzz);
            return;
        }
    }

    out->minValue = 0;
    out->maxValue = 0;
    out->flat = 0;
    out->fuzz = 0;
    out->range = 0;
    LOGI("  %s: unknown axis values, setting to zero", name);
}

void InputReader::configureExcludedDevices() {
    Vector<String8> excludedDeviceNames;
    mPolicy->getExcludedDeviceNames(excludedDeviceNames);

    for (size_t i = 0; i < excludedDeviceNames.size(); i++) {
        mEventHub->addExcludedDevice(excludedDeviceNames[i]);
    }
}

void InputReader::resetGlobalMetaState() {
    mGlobalMetaState = -1;
}

int32_t InputReader::globalMetaState() {
    if (mGlobalMetaState == -1) {
        mGlobalMetaState = 0;
        for (size_t i = 0; i < mDevices.size(); i++) {
            InputDevice* device = mDevices.valueAt(i);
            if (device->isKeyboard()) {
                mGlobalMetaState |= device->keyboard.current.metaState;
            }
        }
    }
    return mGlobalMetaState;
}

void InputReader::updateExportedVirtualKeyState() {
    int32_t keyCode = -1, scanCode = -1;

    for (size_t i = 0; i < mDevices.size(); i++) {
        InputDevice* device = mDevices.valueAt(i);
        if (device->isTouchScreen()) {
            if (device->touchScreen.currentVirtualKey.down) {
                keyCode = device->touchScreen.currentVirtualKey.keyCode;
                scanCode = device->touchScreen.currentVirtualKey.scanCode;
            }
        }
    }

    { // acquire exported state lock
        AutoMutex _l(mExportedStateLock);

        mExportedVirtualKeyCode = keyCode;
        mExportedVirtualScanCode = scanCode;
    } // release exported state lock
}

bool InputReader::getCurrentVirtualKey(int32_t* outKeyCode, int32_t* outScanCode) const {
    { // acquire exported state lock
        AutoMutex _l(mExportedStateLock);

        *outKeyCode = mExportedVirtualKeyCode;
        *outScanCode = mExportedVirtualScanCode;
        return mExportedVirtualKeyCode != -1;
    } // release exported state lock
}

void InputReader::updateExportedInputConfiguration() {
    int32_t touchScreenConfig = InputConfiguration::TOUCHSCREEN_NOTOUCH;
    int32_t keyboardConfig = InputConfiguration::KEYBOARD_NOKEYS;
    int32_t navigationConfig = InputConfiguration::NAVIGATION_NONAV;

    for (size_t i = 0; i < mDevices.size(); i++) {
        InputDevice* device = mDevices.valueAt(i);
        int32_t deviceClasses = device->classes;

        if (deviceClasses & INPUT_DEVICE_CLASS_TOUCHSCREEN) {
            touchScreenConfig = InputConfiguration::TOUCHSCREEN_FINGER;
        }
        if (deviceClasses & INPUT_DEVICE_CLASS_ALPHAKEY) {
            keyboardConfig = InputConfiguration::KEYBOARD_QWERTY;
        }
        if (deviceClasses & INPUT_DEVICE_CLASS_TRACKBALL) {
            navigationConfig = InputConfiguration::NAVIGATION_TRACKBALL;
        } else if (deviceClasses & INPUT_DEVICE_CLASS_DPAD) {
            navigationConfig = InputConfiguration::NAVIGATION_DPAD;
        }
    }

    { // acquire exported state lock
        AutoMutex _l(mExportedStateLock);

        mExportedInputConfiguration.touchScreen = touchScreenConfig;
        mExportedInputConfiguration.keyboard = keyboardConfig;
        mExportedInputConfiguration.navigation = navigationConfig;
    } // release exported state lock
}

void InputReader::getCurrentInputConfiguration(InputConfiguration* outConfiguration) const {
    { // acquire exported state lock
        AutoMutex _l(mExportedStateLock);

        *outConfiguration = mExportedInputConfiguration;
    } // release exported state lock
}

int32_t InputReader::getCurrentScanCodeState(int32_t deviceId, int32_t deviceClasses,
        int32_t scanCode) const {
    { // acquire exported state lock
        AutoMutex _l(mExportedStateLock);

        if (mExportedVirtualScanCode == scanCode) {
            return KEY_STATE_VIRTUAL;
        }
    } // release exported state lock

    return mEventHub->getScanCodeState(deviceId, deviceClasses, scanCode);
}

int32_t InputReader::getCurrentKeyCodeState(int32_t deviceId, int32_t deviceClasses,
        int32_t keyCode) const {
    { // acquire exported state lock
        AutoMutex _l(mExportedStateLock);

        if (mExportedVirtualKeyCode == keyCode) {
            return KEY_STATE_VIRTUAL;
        }
    } // release exported state lock

    return mEventHub->getKeyCodeState(deviceId, deviceClasses, keyCode);
}

int32_t InputReader::getCurrentSwitchState(int32_t deviceId, int32_t deviceClasses,
        int32_t sw) const {
    return mEventHub->getSwitchState(deviceId, deviceClasses, sw);
}

bool InputReader::hasKeys(size_t numCodes, const int32_t* keyCodes, uint8_t* outFlags) const {
    return mEventHub->hasKeys(numCodes, keyCodes, outFlags);
}


// --- InputReaderThread ---

InputReaderThread::InputReaderThread(const sp<InputReaderInterface>& reader) :
        Thread(/*canCallJava*/ true), mReader(reader) {
}

InputReaderThread::~InputReaderThread() {
}

bool InputReaderThread::threadLoop() {
    mReader->loopOnce();
    return true;
}

} // namespace android