#| -*-Scheme-*-

$Id: strpad.scm,v 1.11 2003/02/14 18:28:13 cph Exp $

Copyright 1985, 1989-1999 Massachusetts Institute of Technology

This file is part of MIT/GNU Scheme.

MIT/GNU Scheme is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or (at
your option) any later version.

MIT/GNU Scheme is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
General Public License for more details.

You should have received a copy of the GNU General Public License
along with MIT/GNU Scheme; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
USA.

|#

;;;; String Padding Stuff

(declare (usual-integrations))

(define (pad-on-right-to string n)
  (let ((l (string-length string)))
    (if (> n l)
	(let ((result (string-allocate n)))
	  (substring-move-right! string 0 l result 0)
	  (substring-fill! result l n #\space)
	  result)
	string)))

(define (pad-on-left-to string n)
  (let ((l (string-length string)))
    (let ((delta (- n l)))
      (if (positive? delta)
	  (let ((result (string-allocate n)))
	    (substring-fill! result 0 delta #\space)
	    (substring-move-right! string 0 l result delta)
	    result)
	  string))))

(define (write-strings-densely strings #!optional port x-size)
  (let ((port (if (default-object? port) (current-output-port) port))
	(n (reduce max 0 (map string-length strings))))
    (let ((x-size
	   (if (default-object? x-size) (output-port/x-size port) x-size)))
      (let ((n-per-line (max 1 (quotient (+ x-size 1) (+ 2 n)))))
	(if (not (null? strings))
	    (let loop ((strings strings) (i 0))
	      (write-string (pad-on-right-to (car strings) n) port)
	      (let ((strings (cdr strings))
		    (i (+ i 1)))
		(if (not (null? strings))
		    (if (< i n-per-line)
			(begin
			  (write-string "  " port)
			  (loop strings i))
			(begin
			  (newline port)
			  (loop strings 0)))))))))))