/** @memo Binary search of an already sorted array.
@doc Binary search using the comparison function supplied
'compfunc'. The comparison function must return:<br>
<pre>
<0 If node1 is less than node2.
0 If node1 is equivalent to node2.
>0 If node1 is greater than to node2.
</pre>
@return Pointer to the found node within the array,
0 if not found or error.
*/
void * rtp_bsearch (
const void *obj, /** Object that is to be found. */
const void *head, /** Head of array to search. */
unsigned int num, /** Number of nodes in array. */
unsigned int size, /** Size of each node. */
RTP_BSEARCH_COMPARISON_FN compfunc /** Comparison function. */
)
{
long curRightPos = num - 1;
long curLeftPos = 0;
long medianIndex = 0;
int result = 0;
while (curLeftPos <= curRightPos)
{
medianIndex = (curRightPos + curLeftPos) / 2;
result = compfunc ((const void *) (((long)head) + (medianIndex * size)), obj);
if (result < 0)
{
curLeftPos = medianIndex + 1;
}
else if (result > 0)
{
curRightPos = medianIndex - 1;
}
else
{
return ((void *) (((long)head) + (medianIndex * size)));
}
}
return (0);
}
int main(int argc, char *argv[])
{
ptr2func pwr4;
ptr2func pwr6;
ptr2func pwr9;
pwr4 = compfunc(&pwr2, &pwr2);
printf("%8.1f\n", pwr4(2.0));
printf("%8.1f\n", pwr4(3.0));
pwr6 = compfunc(&pwr2, &pwr3);
printf("%8.1f\n", pwr6(2.0));
printf("%8.1f\n", pwr6(3.0));
pwr9 = compfunc(&pwr3, &pwr3);
printf("%8.1f\n", pwr9(2.0));
printf("%8.1f\n", pwr9(3.0));
}