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;;; installed-scm-file
;;;; Copyright (C) 1997, 1999, 2000, 2001, 2006 Free Software Foundation, Inc.
;;;;
;;;; This library is free software; you can redistribute it and/or
;;;; modify it under the terms of the GNU Lesser General Public
;;;; License as published by the Free Software Foundation; either
;;;; version 2.1 of the License, or (at your option) any later version.
;;;;
;;;; This library 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
;;;; Lesser General Public License for more details.
;;;;
;;;; You should have received a copy of the GNU Lesser General Public
;;;; License along with this library; if not, write to the Free Software
;;;; Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
;;;;
;;; This is the Scheme part of the module for delimited I/O. It's
;;; similar to (scsh rdelim) but somewhat incompatible.
(define-module (ice-9 rdelim)
:export (read-line read-line! read-delimited read-delimited!
%read-delimited! %read-line write-line) ; C
)
(%init-rdelim-builtins)
(define (read-line! string . maybe-port)
;; corresponds to SCM_LINE_INCREMENTORS in libguile.
(define scm-line-incrementors "\n")
(let* ((port (if (pair? maybe-port)
(car maybe-port)
(current-input-port))))
(let* ((rv (%read-delimited! scm-line-incrementors
string
#t
port))
(terminator (car rv))
(nchars (cdr rv)))
(cond ((and (= nchars 0)
(eof-object? terminator))
terminator)
((not terminator) #f)
(else nchars)))))
(define (read-delimited! delims buf . args)
(let* ((num-args (length args))
(port (if (> num-args 0)
(car args)
(current-input-port)))
(handle-delim (if (> num-args 1)
(cadr args)
'trim))
(start (if (> num-args 2)
(caddr args)
0))
(end (if (> num-args 3)
(cadddr args)
(string-length buf))))
(let* ((rv (%read-delimited! delims
buf
(not (eq? handle-delim 'peek))
port
start
end))
(terminator (car rv))
(nchars (cdr rv)))
(cond ((or (not terminator) ; buffer filled
(eof-object? terminator))
(if (zero? nchars)
(if (eq? handle-delim 'split)
(cons terminator terminator)
terminator)
(if (eq? handle-delim 'split)
(cons nchars terminator)
nchars)))
(else
(case handle-delim
((trim peek) nchars)
((concat) (string-set! buf (+ nchars start) terminator)
(+ nchars 1))
((split) (cons nchars terminator))
(else (error "unexpected handle-delim value: "
handle-delim))))))))
(define (read-delimited delims . args)
(let* ((port (if (pair? args)
(let ((pt (car args)))
(set! args (cdr args))
pt)
(current-input-port)))
(handle-delim (if (pair? args)
(car args)
'trim)))
(let loop ((substrings '())
(total-chars 0)
(buf-size 100)) ; doubled each time through.
(let* ((buf (make-string buf-size))
(rv (%read-delimited! delims
buf
(not (eq? handle-delim 'peek))
port))
(terminator (car rv))
(nchars (cdr rv))
(join-substrings
(lambda ()
(apply string-append
(reverse
(cons (if (and (eq? handle-delim 'concat)
(not (eof-object? terminator)))
(string terminator)
"")
(cons (substring buf 0 nchars)
substrings))))))
(new-total (+ total-chars nchars)))
(cond ((not terminator)
;; buffer filled.
(loop (cons (substring buf 0 nchars) substrings)
new-total
(* buf-size 2)))
((eof-object? terminator)
(if (zero? new-total)
(if (eq? handle-delim 'split)
(cons terminator terminator)
terminator)
(if (eq? handle-delim 'split)
(cons (join-substrings) terminator)
(join-substrings))))
(else
(case handle-delim
((trim peek concat) (join-substrings))
((split) (cons (join-substrings) terminator))
(else (error "unexpected handle-delim value: "
handle-delim)))))))))
;;; read-line [PORT [HANDLE-DELIM]] reads a newline-terminated string
;;; from PORT. The return value depends on the value of HANDLE-DELIM,
;;; which may be one of the symbols `trim', `concat', `peek' and
;;; `split'. If it is `trim' (the default), the trailing newline is
;;; removed and the string is returned. If `concat', the string is
;;; returned with the trailing newline intact. If `peek', the newline
;;; is left in the input port buffer and the string is returned. If
;;; `split', the newline is split from the string and read-line
;;; returns a pair consisting of the truncated string and the newline.
(define (read-line . args)
(let* ((port (if (null? args)
(current-input-port)
(car args)))
(handle-delim (if (> (length args) 1)
(cadr args)
'trim))
(line/delim (%read-line port))
(line (car line/delim))
(delim (cdr line/delim)))
(case handle-delim
((trim) line)
((split) line/delim)
((concat) (if (and (string? line) (char? delim))
(string-append line (string delim))
line))
((peek) (if (char? delim)
(unread-char delim port))
line)
(else
(error "unexpected handle-delim value: " handle-delim)))))
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