proplib/prop_expand.c

   1 #include <err.h>
   2 #include <stdio.h>
   3 #include <stdlib.h>
   4 #include <prop/proplib.h>
   5
   6 #define INIT_CAPACITY 10
   7 #define NUM_STRINGS 32
   8 #define PRINT_STEP 5    /* Print stats every 5 steps */
   9
  10 /* Function prototypes */
  11 void print_array_stats(const prop_array_t pa);
  12
  13 int
  14 main(int argc, char *argv[])
  15 {
  16     prop_array_t pa;
  17     prop_string_t ps;
  18     unsigned int i;
  19
  20     /*
  21      * Create array object with initial capacity set to
  22      * ``INIT_CAPACITY''. The array will expand on demand
  23      * if its count exceeds its capacity.
  24      * This happens in prop_array_add() with ``EXPAND_STEP''
  25      * step, as defined in libprop/prop_array.c file.
  26      */
  27     pa = prop_array_create_with_capacity(INIT_CAPACITY);
  28     if (pa == NULL)
  29         errx(EXIT_FAILURE, "prop_array_create_with_capacity()");
  30
  31     /* Create prop_string_t object */
  32     ps = prop_string_create_cstring("foo");
  33     if (ps == NULL) {
  34         prop_object_release(pa);
  35         errx(EXIT_FAILURE, "prop_string_create_cstring()");
  36     }
  37
  38     /*
  39      * Add up to ``NUM_STRINGS'' references of prop_string_t
  40      * object to array and watch if/how the latter expands on demand.
  41      */
  42     for (i = 0; i < NUM_STRINGS; i++) {
  43         /* Print statistics every ``PRINT_STEP'' step */
  44         if (i % PRINT_STEP == 0)
  45             print_array_stats(pa);
  46
  47         /* Add object reference in array */
  48         if (prop_array_add(pa, ps) == FALSE) {
  49             prop_object_release(pa);
  50             prop_object_release(ps);
  51             errx(EXIT_FAILURE, "prop_array_add()");
  52         }
  53     }
  54
  55     /*
  56      * Remove references from array and note that
  57      * if an expansion has happened before, array's
  58      * capacity won't reduce to its initial value,
  59      * i.e. ``INIT_CAPACITY''
  60      */
  61     for (i = 0; i < NUM_STRINGS; i++) {
  62         /* Print statistics every ``PRINT_STEP'' step */
  63         if (i % PRINT_STEP == 0)
  64             print_array_stats(pa);
  65
  66         prop_array_remove(pa, NUM_STRINGS - i - 1);
  67     }
  68
  69     /* Release objects */
  70     prop_object_release(pa);
  71     prop_object_release(ps);
  72
  73     print_array_stats(pa);
  74
  75     return EXIT_SUCCESS;
  76 }
  77
  78 void print_array_stats(const prop_array_t pa)
  79 {
  80     printf("count = %u\tcapacity = %u\n",
  81            prop_array_count(pa),
  82            prop_array_capacity(pa));
  83 }