program main

!*****************************************************************************80
!
!! MAIN is the main program for DSP_TO_ST.
!
!  Discussion:
!
!    DSP_TO_ST converts a DSP sparse matrix file to ST format.
!
!    Each line of the DSP file has the form I, J, A(I,J).
!    The ST file uses the same format, but ST files use 0-based
!    indexing rather than 1-based indexing.
!
!  Usage:
!
!    dsp_to_st file.dsp
!
!  Licensing:
!
!    This code is distributed under the GNU LGPL license.
!
!  Modified:
!
!    03 August 2006
!
!  Author:
!
!    John Burkardt
!
  implicit none

  real ( kind = 8 ) a
  integer ( kind = 4 ) arg_num
  integer ( kind = 4 ) i
  integer ( kind = 4 ) iarg
  integer ( kind = 4 ) iargc
  character ( len = 255 ) input_filename
  integer ( kind = 4 ) input_unit
  integer ( kind = 4 ) ios
  integer ( kind = 4 ) j
  integer ( kind = 4 ) line_num
  character ( len = 255 ) output_filename
  integer ( kind = 4 ) output_unit

  call timestamp ( )

  write ( *, '(a)' ) ' '
  write ( *, '(a)' ) 'DSP_TO_ST'
  write ( *, '(a)' ) '  FORTRAN90 version'
  write ( *, '(a)' ) '  Read a DSP sparse matrix file,'
  write ( *, '(a)' ) '  write the corresponding ST sparse matrix file.'
!
!  Get the number of command line arguments.
!
  arg_num = iargc ( )
!
!  If at least one command line argument, it's the input file name.
!
  if ( 1 <= arg_num ) then

    iarg = 1
    call getarg ( iarg, input_filename )

  else

    write ( *, '(a)' ) ' '
    write ( *, '(a)' ) 'DSP_TO_ST:'
    write ( *, '(a)' ) '  Please enter the name of the input file.'

    read ( *, '(a)' ) input_filename

  end if
!
!  Need to create the output file name from the input filename.
!
  output_filename = input_filename
  call file_name_ext_swap ( output_filename, 'st' )
!
!  Read a line, write a line.
!
  call get_unit ( input_unit )
  open ( unit = input_unit, file = input_filename, status = 'old', &
    iostat = ios )

  if ( ios /= 0 ) then
    write ( *, '(a)' ) ' '
    write ( *, '(a)' ) 'DSP_TO_ST - Fatal error!'
    write ( *, '(a)' ) '  Could not open the input file "' &
      // trim ( input_filename ) // '".'
    stop
  end if

  call get_unit ( output_unit )
  open ( unit = output_unit, file = output_filename, status = 'replace' )

  line_num = 0

  do

    read ( input_unit, *, iostat = ios ) i, j, a

    if ( ios /= 0 ) then
      exit
    end if

    write ( output_unit, * ) i-1, j-1, a

    line_num = line_num + 1

  end do

  close ( unit = input_unit )
  close ( unit = output_unit )

  write ( *, '(a)' ) ' '
  write ( *, '(a)' ) 'DSP_TO_ST:'
  write ( *, '(a,i8)' ) '  Number of records read was ', line_num
  write ( *, '(a)' ) '  Created output ST file: "' &
    // trim ( output_filename ) // '".'
!
!  Terminate.
!
  write ( *, '(a)' ) ' '
  write ( *, '(a)' ) 'DSP_TO_ST:'
  write ( *, '(a)' ) '  Normal end of execution.'

  write ( *, '(a)' ) ' '
  call timestamp ( )

  stop
end
subroutine file_name_ext_get ( file_name, i, j )

!*****************************************************************************80
!
!! FILE_NAME_EXT_GET determines the "extension" of a file name.
!
!  Discussion:
!
!    The "extension" of a filename is the string of characters
!    that appears after the LAST period in the name.  A file
!    with no period, or with a period as the last character
!    in the name, has a "null" extension.
!
!    Blanks are unusual in filenames.  This routine ignores all
!    trailing blanks, but will treat initial or internal blanks
!    as regular characters acceptable in a file name.
!
!  Example:
!
!    FILE_NAME   I  J
!
!    bob.for     4  7
!    N.B.C.D     6  7
!    Naomi.      6  6
!    Arthur     -1 -1
!    .com        1  1
!
!  Licensing:
!
!    This code is distributed under the GNU LGPL license.
!
!  Modified:
!
!    17 July 1998
!
!  Author:
!
!    John Burkardt
!
!  Parameters:
!
!    Input, character ( len = * ) FILE_NAME, a file name to be examined.
!
!    Output, integer ( kind = 4 ) I, J, the indices of the first and last
!    characters in the file extension.
!
!    If no period occurs in FILE_NAME, then
!      I = J = -1;
!    Otherwise,
!      I is the position of the LAST period in FILE_NAME, and J is the
!      position of the last nonblank character following the period.
!
  implicit none

  character ( len = * ) file_name
  integer ( kind = 4 ) i
  integer ( kind = 4 ) j
  integer ( kind = 4 ) s_index_last_c

  i = s_index_last_c ( file_name, '.' )

  if ( i == -1 ) then

    j = -1

  else

    j = len_trim ( file_name )

  end if

  return
end
subroutine file_name_ext_swap ( file_name, ext )

!*****************************************************************************80
!
!! FILE_NAME_EXT_SWAP replaces the current "extension" of a file name.
!
!  Discussion:
!
!    The "extension" of a filename is the string of characters
!    that appears after the LAST period in the name.  A file
!    with no period, or with a period as the last character
!    in the name, has a "null" extension.
!
!  Example:
!
!          Input           Output
!    ================     =========
!    FILE_NAME    EXT     FILE_NAME
!
!    bob.for      obj     bob.obj
!    bob.bob.bob  txt     bob.bob.txt
!    bob          yak     bob.yak
!
!  Licensing:
!
!    This code is distributed under the GNU LGPL license.
!
!  Modified:
!
!    09 August 1999
!
!  Author:
!
!    John Burkardt
!
!  Parameters:
!
!    Input/output, character ( len = * ) FILE_NAME, a file name.
!    On output, the extension of the file has been changed.
!
!    Input, character ( len = * ) EXT, the extension to be used on the output
!    copy of FILE_NAME, replacing the current extension if any.
!
  implicit none

  character ( len = * ) ext
  character ( len = * ) file_name
  integer ( kind = 4 ) i
  integer ( kind = 4 ) j
  integer ( kind = 4 ) len_max
  integer ( kind = 4 ) len_name

  len_max = len ( file_name )
  len_name = len_trim ( file_name )

  call file_name_ext_get ( file_name, i, j )

  if ( i == -1 ) then

    if ( len_max < len_name + 1 ) then
      return
    end if

    len_name = len_name + 1
    file_name(len_name:len_name) = '.'
    i = len_name + 1

  else

    i = i + 1
    file_name(i:j) = ' '

  end if

  file_name(i:) = ext

  return
end
subroutine get_unit ( iunit )

!*****************************************************************************80
!
!! GET_UNIT returns a free FORTRAN unit number.
!
!  Discussion:
!
!    A "free" FORTRAN unit number is a value between 1 and 99 which
!    is not currently associated with an I/O device.  A free FORTRAN unit
!    number is needed in order to open a file with the OPEN command.
!
!    If IUNIT = 0, then no free FORTRAN unit could be found, although
!    all 99 units were checked (except for units 5, 6 and 9, which
!    are commonly reserved for console I/O).
!
!    Otherwise, IUNIT is a value between 1 and 99, representing a
!    free FORTRAN unit.  Note that GET_UNIT assumes that units 5 and 6
!    are special, and will never return those values.
!
!  Licensing:
!
!    This code is distributed under the GNU LGPL license.
!
!  Modified:
!
!    18 September 2005
!
!  Author:
!
!    John Burkardt
!
!  Parameters:
!
!    Output, integer ( kind = 4 ) IUNIT, the free unit number.
!
  implicit none

  integer ( kind = 4 ) i
  integer ( kind = 4 ) ios
  integer ( kind = 4 ) iunit
  logical lopen

  iunit = 0

  do i = 1, 99

    if ( i /= 5 .and. i /= 6 .and. i /= 9 ) then

      inquire ( unit = i, opened = lopen, iostat = ios )

      if ( ios == 0 ) then
        if ( .not. lopen ) then
          iunit = i
          return
        end if
      end if

    end if

  end do

  return
end
function s_index_last_c ( s, c )

!*****************************************************************************80
!
!! S_INDEX_LAST_C finds the LAST occurrence of a given character.
!
!  Licensing:
!
!    This code is distributed under the GNU LGPL license.
!
!  Modified:
!
!    06 December 2003
!
!  Author:
!
!    John Burkardt
!
!  Parameters:
!
!    Input, character ( len = * ) S, the string to be searched.
!
!    Input, character C, the character to search for.
!
!    Output, integer ( kind = 4 ) S_INDEX_LAST_C, the index in S where C occurs
!    last, or -1 if it does not occur.
!
  implicit none

  character c
  integer ( kind = 4 ) i
  character ( len = * ) s
  integer ( kind = 4 ) s_len
  integer ( kind = 4 ) s_index_last_c

  if ( c == ' ' ) then
    s_len = len ( s )
  else
    s_len = len_trim ( s )
  end if

  do i = s_len, 1, -1

    if ( s(i:i) == c ) then
      s_index_last_c = i
      return
    end if

  end do

  s_index_last_c = -1

  return
end
subroutine timestamp ( )

!*****************************************************************************80
!
!! TIMESTAMP prints the current YMDHMS date as a time stamp.
!
!  Example:
!
!    31 May 2001   9:45:54.872 AM
!
!  Licensing:
!
!    This code is distributed under the GNU LGPL license.
!
!  Modified:
!
!    18 May 2013
!
!  Author:
!
!    John Burkardt
!
!  Parameters:
!
!    None
!
  implicit none

  character ( len = 8 ) ampm
  integer ( kind = 4 ) d
  integer ( kind = 4 ) h
  integer ( kind = 4 ) m
  integer ( kind = 4 ) mm
  character ( len = 9 ), parameter, dimension(12) :: month = (/ &
    'January  ', 'February ', 'March    ', 'April    ', &
    'May      ', 'June     ', 'July     ', 'August   ', &
    'September', 'October  ', 'November ', 'December ' /)
  integer ( kind = 4 ) n
  integer ( kind = 4 ) s
  integer ( kind = 4 ) values(8)
  integer ( kind = 4 ) y

  call date_and_time ( values = values )

  y = values(1)
  m = values(2)
  d = values(3)
  h = values(5)
  n = values(6)
  s = values(7)
  mm = values(8)

  if ( h < 12 ) then
    ampm = 'AM'
  else if ( h == 12 ) then
    if ( n == 0 .and. s == 0 ) then
      ampm = 'Noon'
    else
      ampm = 'PM'
    end if
  else
    h = h - 12
    if ( h < 12 ) then
      ampm = 'PM'
    else if ( h == 12 ) then
      if ( n == 0 .and. s == 0 ) then
        ampm = 'Midnight'
      else
        ampm = 'AM'
      end if
    end if
  end if

  write ( *, '(i2,1x,a,1x,i4,2x,i2,a1,i2.2,a1,i2.2,a1,i3.3,1x,a)' ) &
    d, trim ( month(m) ), y, h, ':', n, ':', s, '.', mm, trim ( ampm )

  return
end