CTITLEUSCDRI - DECODE AN INTEGER FIELD
C***********************************************************************
C                 COPYRIGHT ATLANTIC RICHFIELD COMPANY 1991            *
C***********************************************************************
C
CA    AUTHOR                 H. W. SWAN
CA    DESIGNER               H. W. SWAN
CA    SYSTEM                 IBM/CRAY
CA    LANGUAGE               VS FORTRAN VERSION 2.2
CA    WRITTEN                12-03-87
C     REVISED      05-23-91  JJC - CHANGED IMPLICIT TO (A-Z).
C     REVISED      12-17-91  JJC - MODIFIED TO MEET SPARC STANDARDS.
CA
CA    CALLING SEQUENCE
CA        CALL USCDRI(STRING,*,FMAT,IVAL)
CA
CA   IN/OUT   ARGUMENT   TYPE   DESCRIPTION
CA   ------   --------   ----   -----------
CA
CA     IN      STRING    C*(*)   THE INPUT STRING TO BE DECODED
CA     IN        *       LABEL   A FORTRAN LABEL TO GAIN CONTROL
CA                               IF 'STRING' IS NOT A VALID INTEGER
CA     IN      FMAT      C*(*)   THE FORMAT STATMENT TO DECODE THE
CA                               INTEGER FIELD
CA     OUT     IVAL       I4     THE DECODED INTEGER
CA
CA
CA
CA   PURPOSE:   SCAN A STRING TO MAKE SURE IT'S A VALID INTEGER, THEN
CA              THEN DECODE IT.
CA
CA
CA THE FOLLOWING TWO GROUPS OF STATEMENTS SHOULD BE EQUIVALENT:
CA
CA 1)       CHARACTER*5 STRING
CA          READ (STRING, 7000, ERR=100) IVAL
CA     7000 FORMAT(I5)
CA
CA 2)       CHARACTER*5 STRING, FMAT
CA          FMAT = '(I5)'
CA          CALL USCDRI(STRING, *100, FMAT, IVAL)
CA
CA UNFORTUNATELY, ALTERNATIVE (1) DOESN'T WORK, WHICH IS WHY 'USCDRI'
CA WAS WRITTEN.
CA
CA
      SUBROUTINE USCDRI(STRING,*,FMAT,IVAL)
C
CJJ   IMPLICIT NONE
      IMPLICIT INTEGER (A-Z)
C
      INTEGER  IVAL, LENGTH, IBND1, IBND2, I, IC
      CHARACTER     C
      CHARACTER*(*) STRING, FMAT

C
C  CHECK TO MAKE SURE THERE ARE NO NON-NUMERIC CHARACTERS IN 'STRING'.
C
      LENGTH = LEN(STRING)
      IBND1  = ICHAR('0')
      IBND2  = ICHAR('9')
      DO 100 I=1,LENGTH
           C  = STRING(I:I)
           IF(C .EQ. ' ' .OR. C .EQ. '+' .OR. C .EQ. '-') GO TO 100
           IC = ICHAR(C)
           IF(IC .LT. IBND1 .OR. IC .GT. IBND2) RETURN 1
 100       CONTINUE
C
C   NOW IT'S SAFE TO DO THE INTERNAL READ.
C
      READ (STRING,FMAT) IVAL
      RETURN
      END