external/io_grib1/WGRIB/missing.c

   1 #include <stdio.h>
   2 #include <stdlib.h>
   3 #include "grib.h"
   4
   5 /*
   6  *  number of missing data points w. ebisuzaki
   7  *
   8  *  v1.1: just faster my dear
   9  *  v1.2: just faster my dear
  10  *
  11  */
  12
  13 static int bitsum[256] = {
  14     8, 7, 7, 6, 7, 6, 6, 5, 7, 6, 6, 5, 6, 5, 5, 4,
  15     7, 6, 6, 5, 6, 5, 5, 4, 6, 5, 5, 4, 5, 4, 4, 3,
  16     7, 6, 6, 5, 6, 5, 5, 4, 6, 5, 5, 4, 5, 4, 4, 3,
  17     6, 5, 5, 4, 5, 4, 4, 3, 5, 4, 4, 3, 4, 3, 3, 2,
  18     7, 6, 6, 5, 6, 5, 5, 4, 6, 5, 5, 4, 5, 4, 4, 3,
  19     6, 5, 5, 4, 5, 4, 4, 3, 5, 4, 4, 3, 4, 3, 3, 2,
  20     6, 5, 5, 4, 5, 4, 4, 3, 5, 4, 4, 3, 4, 3, 3, 2,
  21     5, 4, 4, 3, 4, 3, 3, 2, 4, 3, 3, 2, 3, 2, 2, 1,
  22     7, 6, 6, 5, 6, 5, 5, 4, 6, 5, 5, 4, 5, 4, 4, 3,
  23     6, 5, 5, 4, 5, 4, 4, 3, 5, 4, 4, 3, 4, 3, 3, 2,
  24     6, 5, 5, 4, 5, 4, 4, 3, 5, 4, 4, 3, 4, 3, 3, 2,
  25     5, 4, 4, 3, 4, 3, 3, 2, 4, 3, 3, 2, 3, 2, 2, 1,
  26     6, 5, 5, 4, 5, 4, 4, 3, 5, 4, 4, 3, 4, 3, 3, 2,
  27     5, 4, 4, 3, 4, 3, 3, 2, 4, 3, 3, 2, 3, 2, 2, 1,
  28     5, 4, 4, 3, 4, 3, 3, 2, 4, 3, 3, 2, 3, 2, 2, 1,
  29     4, 3, 3, 2, 3, 2, 2, 1, 3, 2, 2, 1, 2, 1, 1, 0};
  30
  31
  32 int missing_points(unsigned char *bitmap, int n) {
  33
  34     int count;
  35     unsigned int tmp;
  36     if (bitmap == NULL) return 0;
  37
  38     count = 0;
  39     while (n >= 8) {
  40         tmp = *bitmap++;
  41         n -= 8;
  42         count += bitsum[tmp];
  43     }
  44     tmp = *bitmap | ((1 << (8 - n)) - 1);
  45     count += bitsum[tmp];
  46
  47     return count;
  48 }