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slalib/dbjin.f

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+      SUBROUTINE sla_DBJIN (STRING, NSTRT, DRESLT, J1, J2)
+*+
+*     - - - - - -
+*      D B J I N
+*     - - - - - -
+*
+*  Convert free-format input into double precision floating point,
+*  using DFLTIN but with special syntax extensions.
+*
+*  The purpose of the syntax extensions is to help cope with mixed
+*  FK4 and FK5 data.  In addition to the syntax accepted by DFLTIN,
+*  the following two extensions are recognized by DBJIN:
+*
+*     1)  A valid non-null field preceded by the character 'B'
+*         (or 'b') is accepted.
+*
+*     2)  A valid non-null field preceded by the character 'J'
+*         (or 'j') is accepted.
+*
+*  The calling program is notified of the incidence of either of these
+*  extensions through an supplementary status argument.  The rest of
+*  the arguments are as for DFLTIN.
+*
+*  Given:
+*     STRING      char       string containing field to be decoded
+*     NSTRT       int        pointer to 1st character of field in string
+*
+*  Returned:
+*     NSTRT       int        incremented
+*     DRESLT      double     result
+*     J1          int        DFLTIN status: -1 = -OK
+*                                            0 = +OK
+*                                           +1 = null field
+*                                           +2 = error
+*     J2          int        syntax flag:  0 = normal DFLTIN syntax
+*                                         +1 = 'B' or 'b'
+*                                         +2 = 'J' or 'j'
+*
+*  Called:  sla_DFLTIN
+*
+*  For details of the basic syntax, see sla_DFLTIN.
+*
+*  P.T.Wallace   Starlink   23 November 1995
+*
+*  Copyright (C) 1995 Rutherford Appleton Laboratory
+*
+*  License:
+*    This program is free software; you can redistribute it and/or modify
+*    it under the terms of the GNU General Public License as published by
+*    the Free Software Foundation; either version 2 of the License, or
+*    (at your option) any later version.
+*
+*    This program is distributed in the hope that it will be useful,
+*    but WITHOUT ANY WARRANTY; without even the implied warranty of
+*    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+*    GNU General Public License for more details.
+*
+*    You should have received a copy of the GNU General Public License
+*    along with this program (see SLA_CONDITIONS); if not, write to the 
+*    Free Software Foundation, Inc., 59 Temple Place, Suite 330, 
+*    Boston, MA  02111-1307  USA
+*
+*-
+
+      IMPLICIT NONE
+
+      CHARACTER*(*) STRING
+      INTEGER NSTRT
+      DOUBLE PRECISION DRESLT
+      INTEGER J1,J2
+
+      INTEGER J2A,LENSTR,NA,J1A,NB,J1B
+      CHARACTER C
+
+
+
+*   Preset syntax flag
+      J2A=0
+
+*   Length of string
+      LENSTR=LEN(STRING)
+
+*   Pointer to current character
+      NA=NSTRT
+
+*   Attempt normal decode
+      CALL sla_DFLTIN(STRING,NA,DRESLT,J1A)
+
+*   Proceed only if pointer still within string
+      IF (NA.GE.1.AND.NA.LE.LENSTR) THEN
+
+*      See if DFLTIN reported a null field
+         IF (J1A.EQ.1) THEN
+
+*         It did: examine character it stuck on
+            C=STRING(NA:NA)
+            IF (C.EQ.'B'.OR.C.EQ.'b') THEN
+*            'B' - provisionally note
+               J2A=1
+            ELSE IF (C.EQ.'J'.OR.C.EQ.'j') THEN
+*            'J' - provisionally note
+               J2A=2
+            END IF
+
+*         Following B or J, attempt to decode a number
+            IF (J2A.EQ.1.OR.J2A.EQ.2) THEN
+               NB=NA+1
+               CALL sla_DFLTIN(STRING,NB,DRESLT,J1B)
+
+*            If successful, copy pointer and status
+               IF (J1B.LE.0) THEN
+                  NA=NB
+                  J1A=J1B
+*            If not, forget about the B or J
+               ELSE
+                  J2A=0
+               END IF
+
+            END IF
+
+         END IF
+
+      END IF
+
+*   Return argument values and exit
+      NSTRT=NA
+      J1=J1A
+      J2=J2A
+
+      END