hwrf-baseline-20120103-1354/geogrid/src/write_geogrid.c

   1 /* File: write_geogrid.c
   2
   3    Sample subroutine to write an array into the geogrid binary format.
   4
   5    Side effects: Upon completion, a file named 00001-<NX>.00001-<NY> is
   6    created, where <NX> is the argument nx and <NY> is the argument ny,
   7    both in i5.5 format.
   8
   9    Notes: Depending on the compiler and compiler flags, the name of
  10    the write_geogrid() routine may need to be adjusted with respect
  11    to the number of trailing underscores when calling from Fortran.
  12
  13    Michael G. Duda, NCAR/MMM
  14 */
  15
  16 #include <stdlib.h>
  17 #include <stdio.h>
  18 #include <string.h>
  19
  20 #ifdef _UNDERSCORE
  21 #define write_geogrid write_geogrid_
  22 #endif
  23 #ifdef _DOUBLEUNDERSCORE
  24 #define write_geogrid write_geogrid__
  25 #endif
  26
  27 #define BIG_ENDIAN    0
  28 #define LITTLE_ENDIAN 1
  29
  30 int write_geogrid(
  31       float * rarray,          /* The array to be written */
  32       int * nx,                /* x-dimension of the array */
  33       int * ny,                /* y-dimension of the array */
  34       int * nz,                /* z-dimension of the array */
  35       int * isigned,           /* 0=unsigned data, 1=signed data */
  36       int * endian,            /* 0=big endian, 1=little endian */
  37       float * scalefactor,     /* value to divide array elements by before truncation to integers */
  38       int * wordsize )         /* number of bytes to use for each array element */
  39 {
  40    int i, narray;
  41    int A2, B2;
  42    int A3, B3, C3;
  43    int A4, B4, C4, D4;
  44    unsigned int * iarray;
  45    unsigned char * barray;
  46    char fname[24];
  47    FILE * bfile;
  48
  49    narray = (*nx) * (*ny) * (*nz);
  50
  51    iarray = (unsigned int *)malloc(sizeof(int) * narray);
  52    barray = (unsigned char *)malloc(sizeof(unsigned char) * narray * (*wordsize));
  53
  54    /* Scale real-valued array by scalefactor and convert to integers */
  55    for (i=0; i<narray; i++)
  56       iarray[i] = (unsigned int)(rarray[i] / (*scalefactor));
  57
  58    /*
  59       Set up byte offsets for each wordsize depending on byte order.
  60       A, B, C, D give the offsets of the LSB through MSB (i.e., for
  61       word ABCD, A=MSB, D=LSB) in the array from the beginning of a word
  62    */
  63    if (*endian == BIG_ENDIAN) {
  64       A2 = 0; B2 = 1;
  65       A3 = 0; B3 = 1; C3 = 2;
  66       A4 = 0; B4 = 1; C4 = 2; D4 = 3;
  67    }
  68    else {
  69       B2 = 0; A2 = 1;
  70       C3 = 0; B3 = 1; A3 = 2;
  71       D4 = 0; C4 = 1; B4 = 2; A4 = 3;
  72    }
  73
  74    /* Place words into storage byte order */
  75    switch(*wordsize) {
  76       case 1:
  77          for(i=0; i<narray; i++) {
  78             if (iarray[i] < 0 && *isigned) iarray[i] += (1 << 8);
  79             barray[(*wordsize)*i] = (unsigned char)(iarray[i] & 0xff);
  80          }
  81          break;
  82
  83       case 2:
  84          for(i=0; i<narray; i++) {
  85             if (iarray[i] < 0 && *isigned) iarray[i] += (1 << 16);
  86             barray[(*wordsize)*i+A2] = (unsigned char)((iarray[i] >> 8) & 0xff);
  87             barray[(*wordsize)*i+B2] = (unsigned char)( iarray[i]       & 0xff);
  88          }
  89          break;
  90
  91       case 3:
  92          for(i=0; i<narray; i++) {
  93             if (iarray[i] < 0 && *isigned) iarray[i] += (1 << 24);
  94             barray[(*wordsize)*i+A3] = (unsigned char)((iarray[i] >> 16) & 0xff);
  95             barray[(*wordsize)*i+B3] = (unsigned char)((iarray[i] >> 8)  & 0xff);
  96             barray[(*wordsize)*i+C3] = (unsigned char)( iarray[i]        & 0xff);
  97          }
  98          break;
  99
 100       case 4:
 101          for(i=0; i<narray; i++) {
 102             if (iarray[i] < 0 && *isigned) iarray[i] += (1 << 32);
 103             barray[(*wordsize)*i+A4] = (unsigned char)((iarray[i] >> 24) & 0xff);
 104             barray[(*wordsize)*i+B4] = (unsigned char)((iarray[i] >> 16) & 0xff);
 105             barray[(*wordsize)*i+C4] = (unsigned char)((iarray[i] >> 8)  & 0xff);
 106             barray[(*wordsize)*i+D4] = (unsigned char)( iarray[i]        & 0xff);
 107          }
 108          break;
 109    }
 110
 111    sprintf(fname,"%5.5i-%5.5i.%5.5i-%5.5i",1,*nx,1,*ny);
 112
 113    /* Write array to file */
 114    bfile = fopen(fname,"wb");
 115    fwrite(barray,sizeof(unsigned char),narray*(*wordsize),bfile);
 116    fclose(bfile);
 117
 118    free(iarray);
 119    free(barray);
 120
 121    return 0;
 122 }