/usr/share/common-lisp/source/trivial-utf-8/trivial-utf-8.lisp is in cl-trivial-utf-8 20111001-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 | ;;; Minimal utf-8 decoding and encoding library.
;;;
;;; See http://common-lisp.net/project/trivial-utf-8/
(defpackage :trivial-utf-8
(:use :common-lisp)
(:export #:utf-8-byte-length
#:string-to-utf-8-bytes
#:write-utf-8-bytes
#:utf-8-group-size
#:utf-8-bytes-to-string
#:read-utf-8-string
#:utf-8-decoding-error))
(in-package :trivial-utf-8)
(eval-when (:compile-toplevel :load-toplevel :execute)
(defparameter *optimize*
'(optimize (speed 3) (safety 0) (space 0) (debug 1)
(compilation-speed 0))))
(defun utf-8-byte-length (string)
"Calculate the amount of bytes needed to encode a string."
(declare (type string string)
#'*optimize*)
(let ((length (length string))
(string (coerce string 'simple-string)))
(loop :for char :across string
:do (let ((code (char-code char)))
(when (> code 127)
(incf length
(cond ((< code 2048) 1)
((< code 65536) 2)
(t 3))))))
length))
(defmacro as-utf-8-bytes (char writer)
"Given a character, calls the writer function for every byte in the
encoded form of that character."
(let ((char-code (gensym)))
`(let ((,char-code (char-code ,char)))
(declare (type fixnum ,char-code))
(cond ((< ,char-code 128)
(,writer ,char-code))
((< ,char-code 2048)
(,writer (logior #b11000000 (ldb (byte 5 6) ,char-code)))
(,writer (logior #b10000000 (ldb (byte 6 0) ,char-code))))
((< ,char-code 65536)
(,writer (logior #b11100000 (ldb (byte 4 12) ,char-code)))
(,writer (logior #b10000000 (ldb (byte 6 6) ,char-code)))
(,writer (logior #b10000000 (ldb (byte 6 0) ,char-code))))
(t
(,writer (logior #b11110000 (ldb (byte 3 18) ,char-code)))
(,writer (logior #b10000000 (ldb (byte 6 12) ,char-code)))
(,writer (logior #b10000000 (ldb (byte 6 6) ,char-code)))
(,writer (logior #b10000000 (ldb (byte 6 0) ,char-code))))))))
(defun string-to-utf-8-bytes (string &key null-terminate)
"Convert a string into an array of unsigned bytes containing its
utf-8 representation."
(declare (type string string)
#.*optimize*)
(let ((buffer (make-array (+ (the fixnum (utf-8-byte-length string))
(if null-terminate 1 0))
:element-type '(unsigned-byte 8)))
(position 0)
(string (coerce string 'simple-string)))
(declare (type (array (unsigned-byte 8)) buffer)
(type fixnum position))
(macrolet ((add-byte (byte)
`(progn (setf (aref buffer position) ,byte)
(incf position))))
(loop :for char :across string
:do (as-utf-8-bytes char add-byte)))
(when null-terminate
(setf (elt buffer (1- (length buffer))) 0))
buffer))
(defun write-utf-8-bytes (string output &key null-terminate)
"Write a string to a byte-stream, encoding it as utf-8."
(declare (type string string)
(type stream output)
#.*optimize*)
(macrolet ((byte-out (byte)
`(write-byte ,byte output)))
(let ((string (coerce string 'simple-string)))
(loop :for char :across string
:do (as-utf-8-bytes char byte-out))))
(when null-terminate
(write-byte 0 output)))
(define-condition utf-8-decoding-error (simple-error)
((message :initarg :message)
(byte :initarg :byte :initform nil))
(:report (lambda (err stream)
(format stream (slot-value err 'message)
(slot-value err 'byte)))))
(declaim (inline utf-8-group-size))
(defun utf-8-group-size (byte)
"Determine the amount of bytes that are part of the character
starting with a given byte."
(declare (type fixnum byte)
#.*optimize*)
(cond ((zerop (logand byte #b10000000)) 1)
((= (logand byte #b11100000) #b11000000) 2)
((= (logand byte #b11110000) #b11100000) 3)
((= (logand byte #b11111000) #b11110000) 4)
(t (error 'utf-8-decoding-error :byte byte
:message "Invalid byte at start of character: 0x~X"))))
(defun utf-8-string-length (bytes &key (start 0) (end (length bytes)))
"Calculate the length of the string encoded by the given bytes."
(declare (type (simple-array (unsigned-byte 8) (*)) bytes)
(type fixnum start end)
#.*optimize*)
(loop :with i :of-type fixnum = start
:with string-length = 0
:while (< i end)
:do (progn
(incf (the fixnum string-length) 1)
(incf i (utf-8-group-size (elt bytes i))))
:finally (return string-length)))
(defun get-utf-8-character (bytes group-size &optional (start 0))
"Given an array of bytes and the amount of bytes to use,
extract the character starting at the given start position."
(declare (type (simple-array (unsigned-byte 8) (*)) bytes)
(type fixnum group-size start)
#.*optimize*)
(macrolet ((next-byte ()
'(prog1 (elt bytes start)
(incf start)))
(six-bits (byte)
(let ((b (gensym)))
`(let ((,b ,byte))
(unless (= (logand ,b #b11000000) #b10000000)
(error 'utf-8-decoding-error :byte ,b
:message "Invalid byte 0x~X inside a character."))
(ldb (byte 6 0) ,b))))
(test-overlong (byte min-size)
(let ((b (gensym)))
`(let ((,b ,byte))
(unless (>= ,b ,min-size)
(error 'utf-8-decoding-error :byte ,b
:message "Overlong byte sequence found."))
,b))))
(case group-size
(1 (next-byte))
(2 (test-overlong (logior (ash (ldb (byte 5 0) (next-byte)) 6)
(six-bits (next-byte))) 128))
(3 (test-overlong (logior (ash (ldb (byte 4 0) (next-byte)) 12)
(ash (six-bits (next-byte)) 6)
(six-bits (next-byte))) 2048))
(4 (test-overlong (logior (ash (ldb (byte 3 0) (next-byte)) 18)
(ash (six-bits (next-byte)) 12)
(ash (six-bits (next-byte)) 6)
(six-bits (next-byte))) 65536)))))
(defun utf-8-bytes-to-string (bytes-in &key (start 0) (end (length bytes-in)))
"Convert a byte array containing utf-8 encoded characters into
the string it encodes."
(declare (type vector bytes-in)
(type fixnum start end)
#.*optimize*)
(loop :with bytes = (coerce bytes-in '(simple-array (unsigned-byte 8) (*)))
:with buffer = (make-string (utf-8-string-length bytes :start start :end end) :element-type 'character)
:with array-position :of-type fixnum = start
:with string-position :of-type fixnum = 0
:while (< array-position end)
:do (let* ((char (elt bytes array-position))
(current-group (utf-8-group-size char)))
(when (> (+ current-group array-position) end)
(error 'utf-8-decoding-error
:message "Unfinished character at end of byte array."))
(setf (char buffer string-position)
(code-char (get-utf-8-character bytes current-group
array-position)))
(incf string-position 1)
(incf array-position current-group))
:finally (return buffer)))
(defun read-utf-8-string (input &key null-terminated stop-at-eof
(char-length -1) (byte-length -1))
"Read utf-8 encoded data from a byte stream and construct a
string with the characters found. When null-terminated is given
it will stop reading at a null character, stop-at-eof tells it to
stop at the end of file without raising an error, and the
char-length and byte-length parameters can be used to specify the
max amount of characters or bytes to read."
(declare (type stream input)
(type fixnum byte-length char-length)
#.*optimize*)
(let ((buffer (make-array 4 :element-type '(unsigned-byte 8)))
(bytes-read 0)
(string (make-array 64 :element-type 'character
:adjustable t :fill-pointer 0)))
(declare (type fixnum bytes-read))
(loop
(when (or (and (/= -1 byte-length) (>= bytes-read byte-length))
(and (/= -1 char-length) (= char-length (length string))))
(return))
(let ((next-char (read-byte input (not stop-at-eof) :eof)))
(when (or (eq next-char :eof)
(and null-terminated (eq next-char 0)))
(return))
(let ((current-group (utf-8-group-size next-char)))
(incf bytes-read current-group)
(cond ((= current-group 1)
(vector-push-extend (code-char next-char) string))
(t
(setf (elt buffer 0) next-char)
(loop :for i :from 1 :below current-group
:for next-char = (read-byte input nil :eof)
:do (when (eq next-char :eof)
(error 'utf-8-decoding-error
:message "Unfinished character at end of input."))
:do (setf (elt buffer i) next-char))
(vector-push-extend (code-char (get-utf-8-character
buffer current-group))
string))))))
string))
;;; Copyright (c) Marijn Haverbeke
;;;
;;; This software is provided 'as-is', without any express or implied
;;; warranty. In no event will the authors be held liable for any
;;; damages arising from the use of this software.
;;;
;;; Permission is granted to anyone to use this software for any
;;; purpose, including commercial applications, and to alter it and
;;; redistribute it freely, subject to the following restrictions:
;;;
;;; 1. The origin of this software must not be misrepresented; you must
;;; not claim that you wrote the original software. If you use this
;;; software in a product, an acknowledgment in the product
;;; documentation would be appreciated but is not required.
;;;
;;; 2. Altered source versions must be plainly marked as such, and must
;;; not be misrepresented as being the original software.
;;;
;;; 3. This notice may not be removed or altered from any source
;;; distribution.
|