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program testit
! example showing use of NOTABS(3f). Creates a small filter
! that removes tabs and trailing white space from input
! on files up to 255 characters wide. For example
! notabs < infile >outfile
!
character(len=255) :: in,out
integer :: ios ! error flag from read
integer :: iout
do
read(*,"(a)",iostat=ios)in
if(ios /= 0)then
stop
endif
call notabs(in,out,iout)
if(iout == 0)then
write(*,"(a)")
else
write(*,"(a)")out(1:iout)
endif
enddo
end program testit
!===================================================================================================================================
subroutine notabs(INSTR,OUTSTR,ILEN)
! @(#) convert tabs in input to spaces in output while maintaining columns, assuming a tab is set every 8 characters
!
! USES:
! It is often useful to expand tabs in input files to simplify further processing such as tokenizing an input line.
! Some FORTRAN compilers hate tabs in input files; some printers; some editors will have problems with tabs
! AUTHOR:
! John S. Urban
!
! SEE ALSO:
! GNU/Unix commands expand(1) and unexpand(1)
!
use ISO_FORTRAN_ENV, only : ERROR_UNIT ! get unit for standard error. if not supported yet, define ERROR_UNIT for your system (typically 0)
character(len=*),intent(in) :: INSTR ! input line to scan for tab characters
character(len=*),intent(out) :: OUTSTR ! tab-expanded version of INSTR produced
integer,intent(out) :: ILEN ! column position of last character put into output string
integer,parameter :: TABSIZE=8 ! assume a tab stop is set every 8th column
character(len=1) :: c ! character read from stdin
integer :: ipos ! position in OUTSTR to put next character of INSTR
integer :: lenin ! length of input string trimmed of trailing spaces
integer :: lenout ! number of characters output string can hold
integer :: i10 ! counter that advances thru input string INSTR one character at a time
!===================================================================================================================================
IPOS=1 ! where to put next character in output string OUTSTR
lenin=len(INSTR) ! length of character variable INSTR
lenin=len_trim(INSTR(1:lenin)) ! length of INSTR trimmed of trailing spaces
lenout=len(OUTSTR) ! number of characters output string OUTSTR can hold
OUTSTR=" " ! this SHOULD blank-fill string, a buggy machine required a loop to set all characters
!===================================================================================================================================
do i10=1,lenin ! look through input string one character at a time
c=INSTR(i10:i10)
if(ichar(c) == 9)then ! test if character is a tab (ADE (ASCII Decimal Equivalent) of tab character is 9)
IPOS = IPOS + (TABSIZE - (mod(IPOS-1,TABSIZE)))
else ! c is anything else other than a tab insert it in output string
if(IPOS > lenout)then
write(ERROR_UNIT,*)"*notabs* output string overflow"
exit
else
OUTSTR(IPOS:IPOS)=c
IPOS=IPOS+1
endif
endif
enddo
!===================================================================================================================================
ILEN=len_trim(OUTSTR(:IPOS)) ! trim trailing spaces
return
!===================================================================================================================================
end subroutine notabs
!===================================================================================================================================