var/external/bufr/crbmg.c

   1 /*$$$  SUBPROGRAM DOCUMENTATION BLOCK
   2 C
   3 C SUBPROGRAM:    CRBMG
   4 C   PRGMMR: ATOR             ORG: NP12       DATE: 2005-11-29
   5 C
   6 C ABSTRACT:  THIS ROUTINE READS THE NEXT BUFR MESSAGE FROM THE SYSTEM
   7 C   FILE MOST RECENTLY OPENED FOR READING/INPUT VIA BUFR ARCHIVE LIBRARY
   8 C   ROUTINE COBFL.  ANY BUFR EDITION 0 OR EDITION 1 MESSAGES THAT ARE
   9 C   READ ARE AUTOMATICALLY CONVERTED TO BUFR EDITION 2.
  10 C
  11 C PROGRAM HISTORY LOG:
  12 C 2005-11-29  J. ATOR    -- ORIGINAL AUTHOR
  13 C
  14 C USAGE:    CALL CRBMG( BMG, MXMB, NMB, IRET )
  15 C   INPUT ARGUMENT LIST:
  16 C     MXMB     - INTEGER: DIMENSIONED SIZE (IN BYTES) OF BMG; USED
  17 C                BY THE ROUTINE TO ENSURE THAT IT DOES NOT OVERFLOW
  18 C                THE BMG ARRAY
  19 C
  20 C   OUTPUT ARGUMENT LIST:
  21 C     BMG      - CHARACTER*1: ARRAY CONTAINING BUFR MESSAGE
  22 C     NMB      - INTEGER: SIZE (IN BYTES) OF BUFR MESSAGE IN BMG
  23 C     IRET     - INTEGER: RETURN CODE:
  24 C                  0 = normal return
  25 C                  1 = overflow of BMG array
  26 C                  2 = "7777" indicator not found in expected location
  27 C                 -1 = end-of-file encountered while reading
  28 C                 -2 = I/O error encountered while reading
  29 C
  30 C REMARKS:
  31 C    THIS ROUTINE CALLS:        BORT     GETS1LOC ICHKSTR  IPKM
  32 C                               IUPBS01  IUPM     RBYTES
  33 C    THIS ROUTINE IS CALLED BY: None
  34 C                               Normally called only by application
  35 C                               programs.
  36 C
  37 C ATTRIBUTES:
  38 C   LANGUAGE: C
  39 C   MACHINE:  PORTABLE TO ALL PLATFORMS
  40 C
  41 C$$$*/
  42
  43 #include "bufrlib.h"
  44
  45 void crbmg( char *bmg, f77int *mxmb, f77int *nmb, f77int *iret )
  46 {
  47     f77int i1 = 1, i2 = 2, i3 = 3, i4 = 4, i24 = 24;
  48     f77int wkint[2];
  49     f77int iben, isbyt, iwid;
  50
  51     char errstr[129];
  52
  53     unsigned short i, nsecs;
  54     unsigned int lsec;
  55 /*
  56 **  Make sure that a file is open for reading.
  57 */
  58     if ( pbf[0] == NULL ) {
  59         sprintf( errstr, "BUFRLIB: CRBMG - NO FILE IS OPEN FOR READING" );
  60         bort( errstr, ( f77int ) strlen( errstr ) );
  61     }
  62 /*
  63 **  Initialize the first 4 characters of the output array to blanks.
  64 */
  65     if ( *mxmb < 4 ) {
  66         *iret = 1;
  67         return;
  68     }
  69     strncpy( bmg, "    ", 4);
  70 /*
  71 **  Look for the start of the next BUFR message.
  72 */
  73     while ( ichkstr( "BUFR", bmg, &i4, 4, 4 ) != 0 ) {
  74         memmove( bmg, &bmg[1], 3 );
  75         if ( ( *iret = rbytes( bmg, mxmb, 3, 1 ) ) != 0 ) return;
  76     }
  77 /*
  78 **  Read the next 4 bytes and determine the BUFR edition number that was used
  79 **  to encode the message.
  80 */
  81     if ( ( *iret = rbytes( bmg, mxmb, 4, 4 ) ) != 0 ) return;
  82     memcpy( wkint, bmg, 8 );
  83     iben = iupbs01( wkint, "BEN", 3 );
  84
  85     if ( iben >= 2 ) {
  86 /*
  87 **      Get the length of the BUFR message.
  88 */
  89         *nmb = iupbs01( wkint, "LENM", 4 );
  90 /*
  91 **      Read the remainder of the BUFR message.
  92 */
  93         if ( ( *iret = rbytes( bmg, mxmb, 8, *nmb-8 ) ) != 0 ) return;
  94     }
  95     else {
  96 /*
  97 **      Read the remainder of the BUFR message and then convert it to BUFR
  98 **      edition 2.  The message length isn't encoded in Section 0, so we need
  99 **      to compute it by unpacking and summing the lengths of the individual
 100 **      sections.
 101 */
 102         lsec = 4;   /* length of Section 0 */
 103 /*
 104 **      Get the length of Section 1 and add it to the total.
 105 */
 106         gets1loc( "LEN1", &iben, &isbyt, &iwid, &wkint[0], 4 );
 107         *nmb = lsec + iupm( &bmg[lsec+isbyt-1], &iwid, 3 );
 108 /*
 109 **      Read up through the end of Section 1.
 110 */
 111         if ( ( *iret = rbytes( bmg, mxmb, 8, *nmb-8 ) ) != 0 ) return;
 112 /*
 113 **      Is there a Section 2?
 114 */
 115         gets1loc( "ISC2", &iben, &isbyt, &iwid, &wkint[0], 4 );
 116         nsecs = iupm( &bmg[lsec+isbyt-1], &iwid, 1 ) + 2;
 117 /*
 118 **      Read up through the end of Section 4.
 119 */
 120         for ( i = 1; i <= nsecs; i++ ) {
 121             if ( ( *iret = rbytes( bmg, mxmb, *nmb, 3 ) ) != 0 ) return;
 122             lsec = iupm( &bmg[*nmb], &i24, 3 );
 123             if ( ( *iret = rbytes( bmg, mxmb, *nmb+3, lsec-3 ) ) != 0 ) return;
 124             *nmb += lsec;
 125         }
 126 /*
 127 **      Read Section 5.
 128 */
 129         if ( ( *iret = rbytes( bmg, mxmb, *nmb, 4 ) ) != 0 ) return;
 130         *nmb += 4;
 131 /*
 132 **      Expand Section 0 from 4 bytes to 8 bytes, then encode the message length
 133 **      and new edition number (i.e. 2) into the new (expanded) Section 0.
 134 */
 135         if ( *nmb + 4 > *mxmb ) {
 136             *iret = 1;
 137             return;
 138         }
 139         memmove( &bmg[8], &bmg[4], *nmb-4 );
 140         *nmb += 4;
 141         ipkm( &bmg[4], &i3, nmb, 3 );
 142         ipkm( &bmg[7], &i1, &i2, 1 );
 143     }
 144 /*
 145 **  Check that the "7777" is in the expected location.
 146 */
 147     *iret = ( ( ichkstr( "7777", &bmg[*nmb-4], &i4, 4, 4 ) == 0 ) ? 0 : 2 );
 148
 149     return;
 150 }