Range Binary Search in C

range_binary_search.c

void range_binary_search(int *array, int len, int val, int *res) {
    int right = 0;
    int left = 0;
    int middle;

    // not found
    if(val < array[0] || val > array[len - 1]){
        right = 0;
        left = -1;
    }

    // found
    else{
        while(right < len){
            middle = (right + len) / 2;
            if(val < array[middle])
                len = middle;
            else
                right = middle + 1;
        }
        len = right - 1;
        while(left < len){
            middle = (left + len) / 2;
            if(val > array[middle])
                left = middle + 1;
            else
                len = middle;
        }
    }
    res[0] = left;
    res[1] = right - 1;
}