qsort: Using array

1. The realloc operation can be expensive if the the operation is carried out for a large number of times AND/OR if the memory is already fragmented.

2. A malloc operation could be considered but it would require a flag to indicate the first instance of executing the function

if ( FLAG == TRUE)
   Memory already allocated. Don't allocate any memory
else  { /* Flag = FALSE */
   Allocate Memory
   Set Flag = TRUE
}


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#define ARRAY_SIZE 10

typedef struct adi_data_t_ {
    unsigned int number;
} adi_data_t;

typedef struct adi_delete_list_t_ {
    adi_data_t ** first;
    unsigned int count;
} adi_delete_list_t;

int adi_compare_data (const void * a, const void *b)
{
   const adi_data_t ** one = (const adi_data_t **) a;
   const adi_data_t ** two = (const adi_data_t **) b;

   printf("Number one : [%d] Number two : [%d]  ret [%d]\n", (*one)->number, (*two)->number, (*one)->number - (*two)->number);
   //return (*one)->number - (*two)->number ;
    return (*two)->number - (*one)->number ;

}

int adi_delete_walker(adi_delete_list_t * delete, adi_data_t * data)
{
    static adi_data_t* array[ARRAY_SIZE];
    void *temp = NULL;

    delete->first = array;
    memcpy(&array[delete->count], &data, sizeof(adi_data_t *));
    delete->count++;


}

int main (int argc, char* argv[])
{
    adi_delete_list_t delete;
    adi_data_t data_array[ARRAY_SIZE];
    unsigned int i = 0;

    memset(&delete, 0, sizeof(adi_delete_list_t));

    /* Fill the array and pass it to the delete function */
    for (i=0; i < ARRAY_SIZE ; i++) {
        data_array[i].number = rand()/1000000;
        printf(" Data Array filled with %d \n", data_array[i].number);
        adi_delete_walker(&delete, &data_array[i]);
    }

    printf("qsort parameters: first [%p] count [%d]", delete.first, delete.count);
    /* qsort the array */
    qsort(delete.first, delete.count, sizeof(adi_data_t *), adi_compare_data);

     for (i=0; i < ARRAY_SIZE ; i++) {
        printf(" POST SORT: Data Array filled with %d \n", (*(delete.first)[i]).number);
     }
 }