external/io_grib1/WGRIB/wrtieee.c

   1 #include <stdio.h>
   2 #include <stdlib.h>
   3 #include <stddef.h>
   4 #include "grib.h"
   5
   6
   7 /* wesley ebisuzaki v1.3
   8  *
   9  * write ieee file -- big endian format
  10  *
  11  * input float *array           data to be written
  12  *       int n                  size of array
  13  *       int header             1 for f77 style header 0 for none
  14  *                              (header is 4 byte header
  15  *       FILE *output           output file
  16  *
  17  * v1.2 7/97 buffered, faster
  18  * v1.3 2/99 fixed (typo) error in wrtieee_header found by
  19  *     Bob Farquhar
  20  */
  21
  22 #define BSIZ 1024*4
  23
  24 int wrtieee(float *array, int n, int header, FILE *output) {
  25
  26         unsigned long int l;
  27         int i, nbuf;
  28         unsigned char buff[BSIZ];
  29         unsigned char h4[4];
  30
  31         nbuf = 0;
  32         if (header) {
  33                 l = n * 4;
  34                 for (i = 0; i < 4; i++) {
  35                         h4[i] = l & 255;
  36                         l >>= 8;
  37                 }
  38                 buff[nbuf++] = h4[3];
  39                 buff[nbuf++] = h4[2];
  40                 buff[nbuf++] = h4[1];
  41                 buff[nbuf++] = h4[0];
  42         }
  43         for (i = 0; i < n; i++) {
  44                 if (nbuf >= BSIZ) {
  45                     fwrite(buff, 1, BSIZ, output);
  46                     nbuf = 0;
  47                 }
  48                 flt2ieee(array[i], buff + nbuf);
  49                 nbuf += 4;
  50         }
  51         if (header) {
  52                 if (nbuf == BSIZ) {
  53                     fwrite(buff, 1, BSIZ, output);
  54                     nbuf = 0;
  55                 }
  56                 buff[nbuf++] = h4[3];
  57                 buff[nbuf++] = h4[2];
  58                 buff[nbuf++] = h4[1];
  59                 buff[nbuf++] = h4[0];
  60         }
  61         if (nbuf) fwrite(buff, 1, nbuf, output);
  62         return 0;
  63 }
  64
  65 /* write a big-endian 4 byte integer .. f77 IEEE  header */
  66
  67 int wrtieee_header(unsigned int n, FILE *output) {
  68         unsigned h4[4];
  69
  70         h4[0] = n & 255;
  71         h4[1] = (n >> 8) & 255;
  72         h4[2] = (n >> 16) & 255;
  73         h4[3] = (n >> 24) & 255;
  74
  75         putc(h4[3],output);
  76         putc(h4[2],output);
  77         putc(h4[1],output);
  78         putc(h4[0],output);
  79
  80         return 0;
  81 }
  82