1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
|
;;; installed-scm-file
;;;; Copyright (C) 1997, 1999, 2000, 2001, 2006, 2010, 2013,
;;;; 2014 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 3 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-string
read-string!
%read-delimited!
%read-line
write-line))
(%init-rdelim-builtins)
(define* (read-line! string #:optional (port current-input-port))
;; corresponds to SCM_LINE_INCREMENTORS in libguile.
(define scm-line-incrementors "\n")
(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 #:optional
(port (current-input-port)) (handle-delim 'trim)
(start 0) (end (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 #:optional (port (current-input-port))
(handle-delim '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))
(new-total (+ total-chars nchars)))
(cond
((not terminator)
;; buffer filled.
(loop (cons (substring buf 0 nchars) substrings)
new-total
(* buf-size 2)))
((and (eof-object? terminator) (zero? new-total))
(if (eq? handle-delim 'split)
(cons terminator terminator)
terminator))
(else
(let ((joined
(string-concatenate-reverse
(cons (substring buf 0 nchars) substrings))))
(case handle-delim
((concat)
(if (eof-object? terminator)
joined
(string-append joined (string terminator))))
((trim peek) joined)
((split) (cons joined terminator))
(else (error "unexpected handle-delim value: "
handle-delim)))))))))
(define-syntax-rule (check-arg exp message arg ...)
(unless exp
(error message arg ...)))
(define (index? n)
(and (integer? n) (exact? n) (>= n 0)))
(define* (read-string! buf #:optional
(port (current-input-port))
(start 0) (end (string-length buf)))
"Read all of the characters out of PORT and write them to BUF.
Returns the number of characters read.
This function only reads out characters from PORT if it will be able to
write them to BUF. That is to say, if BUF is smaller than the number of
available characters, then BUF will be filled, and characters will be
left in the port."
(check-arg (string? buf) "not a string" buf)
(check-arg (index? start) "bad index" start)
(check-arg (index? end) "bad index" end)
(check-arg (<= start end) "start beyond end" start end)
(check-arg (<= end (string-length buf)) "end beyond string length" end)
(let lp ((n start))
(if (< n end)
(let ((c (read-char port)))
(if (eof-object? c)
(- n start)
(begin
(string-set! buf n c)
(lp (1+ n)))))
(- n start))))
(define* read-string
(case-lambda*
"Read all of the characters out of PORT and return them as a string.
If the COUNT argument is present, treat it as a limit to the number of
characters to read. By default, there is no limit."
((#:optional (port (current-input-port)))
;; Fast path.
(let loop ((head (make-string 30)) (pos 0) (tail '()))
(let ((char (read-char port)))
(cond
((eof-object? char)
(let ((head (substring head 0 pos)))
(if (null? tail)
(substring head 0 pos)
(string-concatenate-reverse tail head pos))))
(else
(string-set! head pos char)
(if (< (1+ pos) (string-length head))
(loop head (1+ pos) tail)
(loop (make-string (* (string-length head) 2)) 0
(cons head tail))))))))
((port count)
;; Slower path.
(let loop ((chars '())
(total 0))
(let ((char (read-char port)))
(if (or (eof-object? char) (>= total count))
(list->string (reverse chars))
(loop (cons char chars) (+ 1 total))))))))
;;; 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 #:optional (port (current-input-port))
(handle-delim 'trim))
(let* ((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)))))
|