Procedure

     SHIFTL ( Shift left )

     SUBROUTINE SHIFTL ( IN, NSHIFT, FILLC, OUT )

Abstract

     Shift the contents of a character string to the left.
     Characters moved past the beginning of the input string are
     lost. Vacant spaces are filled with a specified character.

Required_Reading

     None.

Keywords

     CHARACTER
     UTILITY

Declarations

     IMPLICIT NONE

     CHARACTER*(*)      IN
     INTEGER            NSHIFT
     CHARACTER*1        FILLC
     CHARACTER*(*)      OUT

Brief_I/O

     VARIABLE  I/O  DESCRIPTION
     --------  ---  --------------------------------------------------
     IN         I   Input string.
     NSHIFT     I   Number of times to shift.
     FILLC      I   Character to fill spaces left vacant.
     OUT        O   Shifted string.

Detailed_Input

     IN       is the input character string.

     NSHIFT   is the number of times the string is to be
              shifted. If NSHIFT is negative, OUT will be
              identical to IN.

     FILLC    is the character with which spaces left vacant by
              the shift are to be filled.

Detailed_Output

     OUT      is the output string. This is the input string,
              shifted N times, filled with FILLC.

              OUT may overwrite IN.

Parameters

     None.

Exceptions

     Error free.

Files

     None.

Particulars

     As a string is shifted left or right, the leftmost or
     rightmost characters of the string disappear (as if pushed
     off the end of the string). This is .TRUE. regardless of
     the length of the output string.

     The remaining characters are shifted simultaneously, and
     the spaces vacated by those characters are filled with a
     replacement character.

Examples

     If FILLC = ' '

        'abcde'   shifted left twice becomes     'cde  '
        'abcde'   shifted right once becomes     ' abcd'

     If FILLC = '.'

        '12345 '  shifted right once becomes     '.12345'
        'Apple '  shifted left ten times becomes '......'

     Given the declarations

        CHARACTER*3         SHORT
        CHARACTER*10        LONG

     The calls

        CALL SHIFTR ( 'abcde ', 2, '-', SHORT )
        CALL SHIFTR ( 'abcde ', 2, '-', LONG  )

     yield the strings

        SHORT = '--a'
        LONG  = '--abcd    '

     while the calls

        CALL SHIFTL ( 'abcde ', 2, '-', SHORT )
        CALL SHIFTL ( 'abcde ', 2, '-', LONG  )

     yield the strings

        SHORT = 'cde'
        LONG  = 'cde ..     '

Restrictions

     None.

Literature_References

     None.

Author_and_Institution

     J. Diaz del Rio    (ODC Space)
     M.J. Spencer       (JPL)
     W.L. Taber         (JPL)
     I.M. Underwood     (JPL)
     E.D. Wright        (JPL)

Version

    SPICELIB Version 2.1.0, 12-AUG-2021 (JDR)

        Added IMPLICIT NONE statement.

        Edited the header to comply with NAIF standard.

    SPICELIB Version 2.0.1, 22-AUG-2001 (EDW)

        Corrected ENDDO to END DO.

    SPICELIB Version 2.0.0, 01-SEP-1994 (MJS)

        This version correctly handles negative shifts.

    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, 31-JAN-1990 (IMU)