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fd26d811 FT |
1 | ;;;; CHAR-CODE -- Conversions between characters and byte |
2 | ;;;; representations thereof | |
3 | ||
4 | (defpackage :charcode | |
5 | (:use :cl #+sbcl :sb-gray #-sbcl :gray) | |
6 | (:export "MAKE-ENCODER" "MAKE-DECODER" "ENCODE-STRING" "DECODE-STRING" | |
7 | "CODING-ERROR" | |
ebf1ccf7 | 8 | "MAKE-CODEC-CHARACTER-STREAM" |
fd26d811 FT |
9 | "LATIN-1" "LATIN1" "UTF-8" "UTF8")) |
10 | (in-package :charcode) | |
11 | ||
12 | ;;; General stuff | |
13 | ||
14 | (define-condition coding-error (error) | |
15 | ((input :initarg :input) | |
16 | (position :initarg :position) | |
17 | (result :initarg :result))) | |
18 | ||
19 | (define-condition simple-coding-error (coding-error simple-error) ()) | |
20 | ||
21 | (defun coding-error (input position result format &rest format-args) | |
22 | (error 'simple-coding-error | |
23 | :input input :position position :result result | |
24 | :format-control format :format-arguments format-args)) | |
25 | ||
26 | (deftype decoder-fun () `(function ((array (unsigned-byte 8)) | |
27 | (array character) | |
28 | &key (start fixnum) (end fixnum)) | |
29 | (member t nil))) | |
30 | (deftype encoder-fun () `(function ((array character) | |
31 | (array (unsigned-byte 8)) | |
32 | &key (start fixnum) (end fixnum)) | |
33 | (member t nil))) | |
34 | ||
35 | (defmacro define-encoder ((name) &body make-encoder) | |
36 | `(setf (get ',name 'make-encoder) #'(lambda () ,@make-encoder))) | |
37 | ||
38 | (defmacro define-decoder ((name) &body make-decoder) | |
39 | `(setf (get ',name 'make-decoder) #'(lambda () ,@make-decoder))) | |
40 | ||
41 | (defmacro define-codec-synonyms (name &rest synonyms) | |
42 | `(eval-when (:load-toplevel :execute) | |
43 | ,@(mapcar #'(lambda (sym) | |
44 | `(setf (get ',sym 'make-encoder) (get ',name 'make-encoder) | |
45 | (get ',sym 'make-decoder) (get ',name 'make-decoder))) | |
46 | synonyms))) | |
47 | ||
48 | (defun make-encoder (name) | |
49 | (the encoder-fun (values (funcall (get name 'make-encoder))))) | |
50 | ||
51 | (defun make-decoder (name) | |
52 | (the decoder-fun (values (funcall (get name 'make-decoder))))) | |
53 | ||
54 | (defun encode-string (string coding) | |
55 | (declare (type string string)) | |
56 | (let ((encoder (make-encoder coding)) | |
57 | (buf (make-array (list (length string)) :element-type '(unsigned-byte 8) :adjustable t :fill-pointer 0))) | |
58 | (unless (funcall encoder string buf) | |
59 | (coding-error string (length string) buf "Encoding of string in ~A ended prematurely." coding)) | |
60 | buf)) | |
61 | ||
62 | (defun decode-string (buffer coding) | |
63 | (declare (type (array (unsigned-byte 8)) buffer)) | |
64 | (let ((decoder (make-decoder coding)) | |
65 | (buf (make-array (list (length buffer)) :element-type 'character :adjustable t :fill-pointer 0))) | |
66 | (unless (funcall decoder buffer buf) | |
67 | (coding-error buffer (length buffer) buf "~A byte sequence ended prematurely." coding)) | |
68 | buf)) | |
69 | ||
70 | ;;; Gray stream implementation | |
71 | ||
72 | (defclass codec-character-stream (fundamental-character-input-stream fundamental-character-output-stream) | |
73 | ((decoder :initarg :decoder) | |
74 | (encoder :initarg :encoder) | |
75 | (back :initarg :back) | |
76 | (read-pos :initform 0) | |
77 | (buffer :initform (make-array '(64) :element-type 'character :adjustable t :fill-pointer 0)))) | |
78 | ||
ebf1ccf7 FT |
79 | (defun make-codec-character-stream (real-stream charset) |
80 | (declare (type stream real-stream)) | |
81 | (make-instance 'codec-character-stream :decoder (make-decoder charset) :encoder (make-encoder charset) :back real-stream)) | |
82 | ||
fd26d811 FT |
83 | (defmethod close ((stream codec-character-stream) &key abort) |
84 | (with-slots (back) stream | |
85 | (close back :abort abort)) | |
86 | (call-next-method)) | |
87 | ||
88 | (defmethod open-stream-p ((stream codec-character-stream)) | |
89 | (with-slots (back) stream | |
90 | (open-stream-p stream))) | |
91 | ||
92 | (defun ccs-ensure-buffer (stream len) | |
93 | (declare (type codec-character-stream stream) | |
94 | (type integer len)) | |
95 | (with-slots (decoder back buffer read-pos) stream | |
96 | (let ((readbuf (make-array (list len) :element-type '(unsigned-byte 8)))) | |
97 | (loop (unless (< (- (length buffer) read-pos) len) (return t)) | |
98 | (let ((readlen (read-sequence readbuf back))) | |
99 | (when (= readlen 0) | |
100 | (return-from ccs-ensure-buffer nil)) | |
101 | (funcall decoder readbuf buffer :end readlen)))))) | |
102 | ||
103 | (defun ccs-clear-buffer (stream) | |
104 | (declare (type codec-character-stream stream)) | |
105 | (with-slots (read-pos buffer) stream | |
106 | (replace buffer buffer :start2 read-pos) | |
107 | (setf (fill-pointer buffer) (- (fill-pointer buffer) read-pos) | |
108 | read-pos 0))) | |
109 | ||
110 | (defmethod stream-read-char ((stream codec-character-stream)) | |
111 | (unless (ccs-ensure-buffer stream 1) | |
112 | (return-from stream-read-char :eof)) | |
113 | (with-slots (read-pos buffer) stream | |
114 | (prog1 (aref buffer read-pos) | |
115 | (when (>= (incf read-pos) 16) | |
116 | (ccs-clear-buffer stream))))) | |
117 | ||
118 | (defmethod stream-unread-char ((stream codec-character-stream) char) | |
119 | (with-slots (read-pos buffer) stream | |
120 | (when (= read-pos 0) | |
121 | (let ((len (length buffer))) | |
122 | (when (< (array-dimension buffer 0) (+ len 16)) | |
123 | (adjust-array buffer (list (setf (fill-pointer buffer) | |
124 | (+ len 16))))) | |
125 | (replace buffer buffer :start1 16 :end2 len))) | |
126 | (setf (aref buffer read-pos) char) | |
127 | (decf read-pos) | |
128 | nil)) | |
129 | ||
130 | (defun ccs-wont-hang-p (stream) | |
131 | (declare (type codec-character-stream stream)) | |
132 | (with-slots (read-pos back buffer) stream | |
133 | (or (and (< read-pos (length buffer)) (aref buffer read-pos)) | |
134 | (listen back)))) | |
135 | ||
136 | (defmethod stream-read-char-no-hang ((stream codec-character-stream)) | |
137 | (if (ccs-wont-hang-p stream) | |
138 | (stream-read-char stream) | |
139 | nil)) | |
140 | ||
141 | (defmethod stream-peek-char ((stream codec-character-stream)) | |
142 | (unless (ccs-ensure-buffer stream 1) | |
143 | (return-from stream-peek-char :eof)) | |
144 | (with-slots (read-pos buffer) stream | |
145 | (aref buffer read-pos))) | |
146 | ||
147 | (defmethod stream-listen ((stream codec-character-stream)) | |
148 | (if (ccs-wont-hang-p stream) | |
149 | (let ((peek (stream-peek-char stream))) | |
150 | (if (eq peek :eof) | |
151 | nil | |
152 | peek)) | |
153 | nil)) | |
154 | ||
155 | (defmethod stream-write-char ((stream codec-character-stream) char) | |
156 | (with-slots (encoder back) stream | |
157 | (let ((seq (make-array '(1) :element-type 'character :initial-element char)) | |
158 | (outbuf (make-array '(16) :element-type '(unsigned-byte 8) :adjustable t :fill-pointer 0))) | |
159 | (funcall encoder seq outbuf) | |
160 | (write-sequence outbuf back)))) | |
161 | ||
162 | (defmethod stream-finish-output ((stream codec-character-stream)) | |
163 | (finish-output (slot-value stream 'back))) | |
164 | ||
165 | (defmethod stream-force-output ((stream codec-character-stream)) | |
166 | (force-output (slot-value stream 'back))) | |
167 | ||
168 | (defmethod stream-read-sequence ((stream codec-character-stream) seq &optional (start 0) (end (length seq))) | |
169 | (ccs-ensure-buffer stream (- end start)) | |
170 | (with-slots (read-pos buffer) stream | |
171 | (replace seq buffer :start1 start :end1 end :start2 read-pos :end2 (length buffer)) | |
172 | (let ((len (min (- end start) (- (length buffer) read-pos)))) | |
173 | (when (>= (incf read-pos len) 128) | |
174 | (ccs-clear-buffer stream))))) | |
175 | ||
176 | (defmethod stream-write-sequence ((stream codec-character-stream) seq &optional (start 0) (end (length seq))) | |
177 | (with-slots (encoder back) stream | |
178 | (let ((outbuf (make-array (list (- end start)) :element-type '(unsigned-byte 8) :adjustable t :fill-pointer 0))) | |
179 | (funcall encoder seq outbuf) | |
180 | (write-sequence outbuf back)))) | |
181 | ||
182 | ;;; Implementation-specific functions | |
183 | ||
184 | #+(or (and clisp unicode) sbcl) | |
185 | (defun unicode->char (unicode) | |
186 | (declare (type (unsigned-byte 24) unicode)) | |
187 | (code-char unicode)) | |
188 | ||
189 | #+(or (and clisp unicode) sbcl) | |
190 | (defun char->unicode (char) | |
191 | (declare (type character char)) | |
192 | (char-code char)) | |
193 | ||
194 | ;;; Latin-1 | |
195 | ||
196 | (defun decode-latin-1 (byteseq charseq &key (start 0) (end (length byteseq))) | |
197 | (declare (type (array (unsigned-byte 8)) byteseq) | |
198 | (type (array character) charseq) | |
199 | (type fixnum start end)) | |
200 | (do ((i start (1+ i))) | |
201 | ((>= i end)) | |
202 | (vector-push-extend (unicode->char (aref byteseq i)) charseq)) | |
203 | t) | |
204 | ||
205 | (defun encode-latin-1 (charseq byteseq &key (start 0) (end (length charseq))) | |
206 | (declare (type (array (unsigned-byte 8)) byteseq) | |
207 | (type (array character) charseq) | |
208 | (type fixnum start end)) | |
209 | (loop | |
210 | (restart-case | |
211 | (loop | |
212 | (unless (< start end) (return-from encode-latin-1 t)) | |
213 | (vector-push-extend (let ((cp (char->unicode (aref charseq (prog1 start (incf start)))))) | |
214 | (unless (< cp 256) | |
215 | (coding-error charseq start byteseq "ISO-8859-1 cannot encode code-points higher than 256.")) | |
216 | cp) | |
217 | byteseq)) | |
218 | (:replace-char (&optional (replacement #\?)) | |
219 | :report "Replace this character with another." | |
220 | (vector-push-extend (char->unicode replacement) byteseq)) | |
221 | (:skip-char () | |
222 | :report "Ignore this character." | |
223 | nil)))) | |
224 | ||
225 | (define-decoder (latin-1) | |
226 | #'decode-latin-1) | |
227 | ||
228 | (define-encoder (latin-1) | |
229 | #'encode-latin-1) | |
230 | ||
231 | (define-codec-synonyms latin-1 latin1 iso-8859-1) | |
232 | ||
233 | ;;; UTF-8 | |
234 | ||
235 | (defun encode-utf-8 (charseq byteseq &key (start 0) (end (length charseq))) | |
236 | (declare (type (array (unsigned-byte 8)) byteseq) | |
237 | (type (array character) charseq) | |
238 | (type fixnum start end)) | |
239 | (do ((i start (1+ i))) | |
240 | ((>= i end)) | |
241 | (let ((cp (char->unicode (aref charseq i)))) | |
242 | (if (< cp 128) | |
243 | (vector-push-extend cp byteseq) | |
244 | (let ((nbytes 0) | |
245 | (bytes '())) | |
246 | (loop | |
247 | (push (logior (ldb (byte 6 0) cp) #x80) bytes) | |
248 | (setf cp (truncate cp 64)) | |
249 | (incf nbytes) | |
250 | (when (< cp (expt 2 (- 6 nbytes))) | |
251 | (push (logior (logand #xff (lognot (1- (expt 2 (- 7 nbytes))))) | |
252 | cp) | |
253 | bytes) | |
254 | (return))) | |
255 | (dolist (byte bytes) | |
256 | (vector-push-extend byte byteseq)))))) | |
257 | t) | |
258 | ||
259 | (define-encoder (utf-8) | |
260 | #'encode-utf-8) | |
261 | ||
262 | (define-decoder (utf-8) | |
263 | (let ((mbuf 0) | |
264 | (mlen 0)) | |
265 | (flet ((decode (byteseq charseq &key (start 0) (end (length byteseq))) | |
266 | (declare (type (array (unsigned-byte 8)) byteseq) | |
267 | (type (array character) charseq) | |
268 | (type fixnum start end)) | |
269 | (let ((i start)) | |
270 | (flet ((failure (format &rest args) | |
271 | (error 'simple-coding-error | |
272 | :input byteseq :position i :result charseq | |
273 | :format-control format :format-arguments args))) | |
274 | (loop | |
275 | (restart-case | |
276 | (progn | |
277 | (loop | |
278 | (unless (< i end) (return)) | |
279 | (let ((byte (aref byteseq (prog1 i (incf i))))) | |
280 | (if (= mlen 0) | |
281 | (if (< byte 128) | |
282 | (vector-push-extend (unicode->char byte) charseq) | |
283 | (setf mlen (block zero | |
284 | (dotimes (i 7) | |
285 | (when (= (ldb (byte 1 (- 7 i)) byte) 0) | |
286 | (when (< i 2) | |
287 | (failure "UTF-8 sequence started with continuation byte: ~D" byte)) | |
288 | (return-from zero (1- i)))) | |
289 | (failure "Invalid UTF-8 sequence start byte: ~D" byte)) | |
290 | mbuf (ldb (byte (- 6 mlen) 0) byte))) | |
291 | (progn (when (not (= (ldb (byte 2 6) byte) 2)) | |
292 | (failure "Invalid UTF-8 continuation byte: ~D" byte)) | |
293 | (setf mbuf (+ (* mbuf 64) (ldb (byte 6 0) byte))) | |
294 | (when (= (decf mlen) 0) | |
295 | (when (< mbuf 128) | |
296 | (with-simple-restart (:accept "Accept anyway.") | |
297 | (failure "UTF-8 multibyte sequence denoted an ASCII character ~S (either an encoding error or an attempt at breaking security)." (unicode->char mbuf)))) | |
298 | (vector-push-extend (unicode->char mbuf) charseq)))))) | |
299 | (return-from decode (= mlen 0))) | |
300 | (:replace-char (&optional (replacement (unicode->char #xfffd))) | |
301 | :report "Replace the invalid bytes with a character." | |
302 | (vector-push-extend replacement charseq) | |
303 | (loop (unless (and (< i end) (= (ldb (byte 2 6) (aref byteseq i)) 2)) | |
304 | (return)) | |
305 | (incf i)) | |
306 | (setf mlen 0)) | |
307 | (:skip-char () | |
308 | :report "Ignore the invalid byte sequence." | |
309 | (loop (unless (and (< i end) (= (ldb (byte 2 6) (aref byteseq i)) 2)) | |
310 | (return)) | |
311 | (incf i)) | |
312 | (setf mlen 0)))))))) | |
313 | #'decode))) | |
314 | ||
315 | (define-codec-synonyms utf-8 utf8) |