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Commit 389ddbad authored by Dan Austin's avatar Dan Austin
Browse files

Enable multiple benign overflow conditions. 

In VelocityTracker.cpp, there are multiple loops in which loop
termination occurs when the value becomes zero. These termination
conditions are all written value-- > 0, which, since value is
unsigned, result in an integer overflow condition when value is 0.
These loop were refactored to eliminate these conditions.

Bug: 24171356
Change-Id: Ie44940cfef8a122ee1aff59c021274ba39a368bf
parent 251c8b3f

libs/input/VelocityTracker.cpp

+6 −3
Original line number Diff line number Diff line
@@ -46,7 +46,8 @@ static const nsecs_t ASSUME_POINTER_STOPPED_TIME = 40 * NANOS_PER_MS; 


static float vectorDot(const float* a, const float* b, uint32_t m) {

    float r = 0;

    while (m--) {

    while (m) {

        m--;

        r += *(a++) * *(b++);

    }

    return r;
@@ -54,7 +55,8 @@ static float vectorDot(const float* a, const float* b, uint32_t m) { 


static float vectorNorm(const float* a, uint32_t m) {

    float r = 0;

    while (m--) {

    while (m) {

        m--;

        float t = *(a++);

        r += t * t;

    }
@@ -511,7 +513,8 @@ static bool solveLeastSquares(const float* x, const float* y, 
    for (uint32_t h = 0; h < m; h++) {

        wy[h] = y[h] * w[h];

    }

    for (uint32_t i = n; i-- != 0; ) {

    for (uint32_t i = n; i != 0; ) {

        i--;

        outB[i] = vectorDot(&q[i][0], wy, m);

        for (uint32_t j = n - 1; j > i; j--) {

            outB[i] -= r[i][j] * outB[j];