/* Last edited on 2008-07-19 21:11:04 by stolfi */

/* Tests whether 5 decimals are enough for 16-bit pixels. */

#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
#include <math.h>
#include <values.h>

int main(int argc, char **argv)
  {
    char *fmt = "%8.5f";
    
    FILE *wr = fopen("/tmp/foo.bar", "w");
    int N = (1<<16);
    int i;
    for (i = 0; i < N; i++)
      { double v = ((double)i)/((double)N);
        fprintf(wr, "%d ", i);
        fprintf(wr, fmt, v);
        fprintf(wr, "\n");
      }
    fclose(wr);
    FILE *rd = fopen("/tmp/foo.bar", "r");
    int nbugs = 0;
    for (i = 0; i < N; i++)
      { double v = ((double)i)/((double)N);
        double v_read;
        int i_read;
        fscanf(rd, "%d %lf", &i_read, &v_read);
        assert(i_read == i);
        int i_conv = (int)floor(v_read*N + 0.5);
        if (i_conv != i) 
          { fprintf(stderr, "%d/%d --> %20.16f --> %20.16f --> %d/%d\n", i, N, v, v_read, i_conv, N);
            nbugs++;
          }
      }
    fclose(rd);
    if (nbugs > 0) 
      { fprintf(stderr, "** Format «%s» IS NOT precise enough for 16-bit samples!\n", fmt); exit(1); }
    else 
      { fprintf(stderr, "Yea! Format «%s» is OK for 16 bit samples!\n", fmt); exit(1); }
    return 0;
  }