latester/histogram.h

   1 #ifndef HISTOGRAM_H
   2 #define HISTOGRAM_H
   3
   4 struct histogram {
   5         unsigned *data;
   6         unsigned allocated;
   7         unsigned resolution;
   8 };
   9
  10 int histogram_init(struct histogram *h,
  11                    unsigned max_value,
  12                    unsigned resolution)
  13 {
  14         size_t mem;
  15         h->allocated = max_value/resolution + 1;
  16         h->resolution = resolution;
  17         mem = h->allocated*sizeof(*h->data);
  18         h->data = malloc(mem);
  19         if (h->data) {
  20                 memset(h->data, 0, mem);
  21                 return 0;
  22         } else
  23                 return -1;
  24 }
  25
  26 void histogram_add(struct histogram *h, int value)
  27 {
  28         if (value < 0) value = 0;
  29         unsigned index = value / h->resolution;
  30         if (index >= h->allocated)
  31                 index = h->allocated - 1;
  32         h->data[index]++;
  33 }
  34
  35 void histogram_fprint(struct histogram *h, FILE *f)
  36 {
  37         unsigned long long sum = 0, cum;
  38         unsigned i;
  39         for (i = 0; i < h->allocated; i++)
  40                 sum += h->data[i];
  41         cum = sum;
  42         for (i = 0; i < h->allocated; i++) {
  43                 if (h->data[i] != 0) {
  44                         fprintf(f, "%g %lld\n", 1e-3*(i*h->resolution), cum);
  45                 }
  46                 cum -= h->data[i];
  47         }
  48 }
  49
  50
  51
  52 #endif