var/external/bufr/cread.c

   1 /*C$$$  SUBPROGRAM DOCUMENTATION BLOCK
   2 C
   3 C SUBPROGRAM: CREAD
   4 C   PRGMMR: WOOLLEN          ORG: NP20       DATE: 2012-09-15
   5 C
   6 C ABSTRACT: CREAD IS A PACKAGE OF C LANGUAGE I/O ROUTINES WHICH
   7 C           ARE DESIGNED TO OPERATE BUFRLIB INPUT AND OUTPUT
   8 C           FUNCTIONS IN A LESS RESTRICTIVE WAY COMPARED TO
   9 C           THOSE AVAILABLE IN STANDARD FORTRAN IMPLEMENTATIONS.
  10 C           THE PACKAGE CONSISTS OF THREE FILE OPEN ROUTINES,
  11 C           ONE FILE CLOSE ROUTINE, TWO FILE POSITIONING
  12 C           ROUTINES, ONE READ BUFR AND ONE WRITE BUFR ROUTINE.
  13 C           ARRAYS OF FILE CONNECTION DESCRIPTORS AND FILE
  14 C           POSITION POINTERS PROVIDE THE CONNECTION TO THE
  15 C           BUFRLIB INTERNAL FILE STATUS INDICATORS.  THE
  16 C           BUFRLIB FILE CONNECTION INDEX LUN, OBTAINED BY
  17 C           CALLS TO STATUS, IS USED TO REFERENCE THE CREAD
  18 C           DESCRIPTOR AND POINTER ARRAYS.
  19 C
  20 C PROGRAM HISTORY LOG:
  21 C 2012-09-15  J. WOOLLEN -- ORIGINAL AUTHOR
  22 C
  23 C USAGE: CALL openrb(nfile,ufile)        - open ufile for binary reading
  24 C        CALL openwb(nfile,ufile)        - open ufile for binary writing
  25 C        CALL openab(nfile,ufile)        - open ufile for binary appending
  26 C        CALL backbufr(nfile)            - backspace file nfile 1 message
  27 C        CALL cewind(nfile)              - rewind file nfile to beginning
  28 C        CALL closfb(nfile)              - disconnect file nfile from c
  29 C        CALL crdbufr(nfile,bufr,maxbyt) - read next bufr message from file nfile into bufr
  30 C        CALL cwrbufr(nfile,bufr,nwrd)   - write bufr message from bufr into file nfile
  31 C
  32 C   INPUT ARGUMENTS:
  33 c      nfile  - integer bufrlib file connection index
  34 C      ufile  - full file path/filename
  35 c      bufr   - in crdbufr: char array to read a bufr message into
  36 c      maxbyt - in crdbufr: maximum number of bytes allowed to read
  37 c      bufr   - in cwrbufr: integer array to write a bufr message from
  38 c      nwrd   - in cwrbufr: number of words to write for bufr message
  39 C
  40 C   OUTPUT ARGUMENTS:
  41 c      crdbufr - return code from reading
  42 c                -3 - sec0 message length > maxbyt
  43 c                -2 - error reading bufr message
  44 c                -1 - no more more messages in file
  45 c                 0 - read a bufr message
  46 C
  47 C REMARKS:
  48 C    THIS ROUTINE CALLS:           IUPBS01
  49 C
  50 C    THIS ROUTINE IS CALLED BY:
  51 C
  52 C ATTRIBUTES:
  53 C   LANGUAGE: C
  54 C   MACHINE:  PORTABLE TO ALL PLATFORMS
  55 C
  56 C$$$*/
  57
  58 #include "bufrlib.h"
  59
  60 /* The following arrays are dimensioned one larger than NFILES because of the difference in array
  61    indexing between Fortran and C.  In each of the following C functions, the value passed in for
  62    nfile will a be Fortran index ranging from 1 to NFILES, so we need to allow for this same range
  63    of values in C, which would otherwise expect the array indices to range from 0 to NFILES-1. */
  64 FILE *pb[NFILES+1]; fpos_t lstpos[NFILES+1];
  65
  66 void openrb   (nfile,ufile) f77int *nfile; char *ufile; { pb[*nfile] = fopen( ufile , "rb " ); }
  67 void openwb   (nfile,ufile) f77int *nfile; char *ufile; { pb[*nfile] = fopen( ufile , "wb " ); }
  68 void openab   (nfile,ufile) f77int *nfile; char *ufile; { pb[*nfile] = fopen( ufile , "a+b" ); }
  69 void backbufr (nfile      ) f77int *nfile;              { fsetpos(pb[*nfile],&lstpos[*nfile]);}
  70 void cewind   (nfile      ) f77int *nfile;              { rewind(pb[*nfile]); }
  71 void closfb   (nfile      ) f77int *nfile;              { fclose(pb[*nfile]); }
  72
  73 f77int crdbufr (nfile,bufr,mxbyt)
  74 f77int *nfile; f77int *mxbyt; char *bufr;
  75 {  f77int  nbyt; f77int  nb; f77int wkint[2]; fpos_t nxtpos;
  76    fgetpos(pb[*nfile],&lstpos[*nfile]);
  77    nb = sizeof(*bufr); bufr[0]=bufr[1];
  78    while ( strncmp(bufr,"BUFR",4)!=0)
  79    {  memmove(bufr,&bufr[1],3);
  80       if(fread(bufr+3,nb,1,pb[*nfile])!=1) return -1;
  81    }
  82    fgetpos(pb[*nfile],&nxtpos); if(fread(bufr+4,nb,4,pb[*nfile])!=4) return -1;
  83    memcpy(wkint,bufr,8); nbyt=iupbs01(wkint,"LENM",4)-8;
  84    if(nbyt+8>*mxbyt)                           {fsetpos(pb[*nfile],&nxtpos);return -3;};
  85    if(fread(bufr+8,nb,nbyt,pb[*nfile])!=nbyt)  {fsetpos(pb[*nfile],&nxtpos);return -2;};
  86    if(strncmp(bufr+nbyt+4,"7777",4)!=0)        {fsetpos(pb[*nfile],&nxtpos);return -2;};
  87    return 0;
  88 }
  89
  90 void cwrbufr (nfile,bufr,nwrd)
  91 f77int *nfile; f77int *nwrd; f77int  *bufr;
  92 {  f77int  nb; nb = sizeof(*bufr);
  93    fwrite(bufr,nb,*nwrd,pb[*nfile]);
  94 }