Procedure

     LTRIM ( Left trim )

     INTEGER FUNCTION LTRIM ( STRING )

Abstract

     Return the maximum of 1 and the location of the first non-blank
     character in the string.

Required_Reading

     None.

Keywords

     CHARACTER
     STRING

Declarations

     IMPLICIT NONE

     CHARACTER*(*)         STRING

Brief_I/O

     VARIABLE  I/O  DESCRIPTION
     --------  ---  --------------------------------------------------

     STRING     I   String to be trimmed.

     The function returns the maximum of 1 and the location of the
     first non-blank character in STRING.

Detailed_Input

     STRING   is a string to be trimmed: the location of the
              first non-blank character is desired.

Detailed_Output

     The function returns the maximum of 1 and the location of the
     first non-blank character in STRING.

     In particular, when STRING is blank, the function returns the
     value 1.

Parameters

     None.

Exceptions

     Error free.

Files

     None.

Particulars

     When writing a character string to a file, we may wish to omit
     leading blanks. We'd like to use FRSTNB as a lower substring
     bound, but we have to handle the case where FRSTNB returns 0,
     so we write:


        WRITE ( UNIT, '(A)' ),  STRING ( MAX (1, FRSTNB (STRING)) : )


     This can be simplified using LTRIM:


        WRITE ( UNIT, '(A)' ),  STRING ( LTRIM (STRING) : )


     This routine has a counterpart, RTRIM, which finds the maximum of
     1 and the position of the last non-blank character of a string.

Examples

     1)  Write the non-blank portion of each element of a character
         cell to file SPUD.DAT:

            DO I = 1,  CARDC (CELL)

               CALL WRLINE ( 'SPUD.DAT',
           .                  CELL(I) ( LTRIM (CELL) : RTRIM (CELL) ) )

            END DO

         When CELL(I) is blank, the string ' ' will be written.

Restrictions

     None.

Literature_References

     None.

Author_and_Institution

     N.J. Bachman       (JPL)
     J. Diaz del Rio    (ODC Space)
     W.L. Taber         (JPL)

Version

    SPICELIB Version 1.1.0, 12-AUG-2021 (JDR)

        Added IMPLICIT NONE statement.

        Edited the header to comply with NAIF standard.

    SPICELIB Version 1.0.1, 10-MAR-1992 (WLT)

        Comment section for permuted index source lines was added
        following the header.

    SPICELIB Version 1.0.0, 02-MAY-1990 (NJB)