This file is indexed.

/usr/share/common-lisp/source/kmrcl/strings.lisp is in cl-kmrcl 1.106-1.

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
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
;;;; -*- Mode: Lisp; Syntax: ANSI-Common-Lisp; Base: 10 -*-
;;;; *************************************************************************
;;;; FILE IDENTIFICATION
;;;;
;;;; Name:          strings.lisp
;;;; Purpose:       Strings utility functions for KMRCL package
;;;; Programmer:    Kevin M. Rosenberg
;;;; Date Started:  Apr 2000
;;;;
;;;; This file, part of KMRCL, is Copyright (c) 2002-2006 by Kevin M. Rosenberg
;;;;
;;;; KMRCL users are granted the rights to distribute and use this software
;;;; as governed by the terms of the Lisp Lesser GNU Public License
;;;; (http://opensource.franz.com/preamble.html), also known as the LLGPL.
;;;; *************************************************************************


(in-package #:kmrcl)

;;; Strings

(defmacro string-append (outputstr &rest args)
  `(setq ,outputstr (concatenate 'string ,outputstr ,@args)))

(defun list-to-string (lst)
  "Converts a list to a string, doesn't include any delimiters between elements"
  (format nil "~{~A~}" lst))

(defun count-string-words (str)
  (declare (simple-string str)
           (optimize (speed 3) (safety 0) (space 0)))
  (let ((n-words 0)
        (in-word nil))
    (declare (fixnum n-words))
    (do* ((len (length str))
          (i 0 (1+ i)))
        ((= i len) n-words)
      (declare (fixnum i))
      (if (alphanumericp (schar str i))
          (unless in-word
            (incf n-words)
            (setq in-word t))
        (setq in-word nil)))))

(defun position-char (char string start max)
  (declare (optimize (speed 3) (safety 0) (space 0))
           (fixnum start max) (simple-string string))
  (do* ((i start (1+ i)))
       ((= i max) nil)
    (declare (fixnum i))
    (when (char= char (schar string i)) (return i))))

(defun position-not-char (char string start max)
  (declare (optimize (speed 3) (safety 0) (space 0))
           (fixnum start max) (simple-string string))
  (do* ((i start (1+ i)))
       ((= i max) nil)
    (declare (fixnum i))
    (when (char/= char (schar string i)) (return i))))

(defun delimited-string-to-list (string &optional (separator #\space)
                                                  skip-terminal)
  "split a string with delimiter"
  (declare (optimize (speed 3) (safety 0) (space 0) (compilation-speed 0))
           (type string string)
           (type character separator))
  (do* ((len (length string))
        (output '())
        (pos 0)
        (end (position-char separator string pos len)
             (position-char separator string pos len)))
       ((null end)
        (if (< pos len)
            (push (subseq string pos) output)
            (when (or (not skip-terminal) (zerop len))
              (push "" output)))
        (nreverse output))
    (declare (type fixnum pos len)
             (type (or null fixnum) end))
    (push (subseq string pos end) output)
    (setq pos (1+ end))))


(defun list-to-delimited-string (list &optional (separator " "))
  (format nil (concatenate 'string "~{~A~^" (string separator) "~}") list))

(defun string-invert (str)
  "Invert case of a string"
  (declare (optimize (speed 3) (compilation-speed 0) (debug 0) (safety 0))
           (simple-string str))
  (let ((up nil) (down nil))
    (block skip
      (loop for char of-type character across str do
            (cond ((upper-case-p char)
                   (if down (return-from skip str) (setf up t)))
                  ((lower-case-p char)
                   (if up   (return-from skip str) (setf down t)))))
      (if up (string-downcase str) (string-upcase str)))))

(defun add-sql-quotes (s)
  (substitute-string-for-char s #\' "''"))

(defun escape-backslashes (s)
  (substitute-string-for-char s #\\ "\\\\"))

(defun substitute-string-for-char (procstr match-char subst-str)
  "Substitutes a string for a single matching character of a string"
  (substitute-chars-strings procstr (list (cons match-char subst-str))))

(defun string-substitute (string substring replacement-string)
  "String substitute by Larry Hunter. Obtained from Google"
  (let ((substring-length (length substring))
        (last-end 0)
        (new-string ""))
    (do ((next-start
          (search substring string)
          (search substring string :start2 last-end)))
        ((null next-start)
         (concatenate 'string new-string (subseq string last-end)))
      (setq new-string
        (concatenate 'string
          new-string
          (subseq string last-end next-start)
          replacement-string))
      (setq last-end (+ next-start substring-length)))))

(defun string-trim-last-character (s)
  "Return the string less the last character"
  (let ((len (length s)))
    (if (plusp len)
        (subseq s 0 (1- len))
        s)))

(defun nstring-trim-last-character (s)
  "Return the string less the last character"
  (let ((len (length s)))
    (if (plusp len)
        (nsubseq s 0 (1- len))
        s)))

(defun string-hash (str &optional (bitmask 65535))
  (let ((hash 0))
    (declare (fixnum hash)
             (simple-string str))
    (dotimes (i (length str))
      (declare (fixnum i))
      (setq hash (+ hash (char-code (char str i)))))
    (logand hash bitmask)))

(defun is-string-empty (str)
  (zerop (length str)))

(defvar *whitespace-chars* '(#\space #\tab #\return #\linefeed
                             #+allegro #\%space
                             #+lispworks #\No-Break-Space))

(defun is-char-whitespace (c)
  (declare (character c) (optimize (speed 3) (safety 0)))
  (or (char= c #\Space) (char= c #\Tab) (char= c #\Return)
      (char= c #\Linefeed)
      #+allegro (char= c #\%space)
      #+lispworks (char= c #\No-Break-Space)))

(defun is-string-whitespace (str)
  "Return t if string is all whitespace"
  (every #'is-char-whitespace str))

(defun string-right-trim-whitespace (str)
  (string-right-trim *whitespace-chars* str))

(defun string-left-trim-whitespace (str)
  (string-left-trim *whitespace-chars* str))

(defun string-trim-whitespace (str)
  (string-trim *whitespace-chars* str))

(defun replaced-string-length (str repl-alist)
  (declare (simple-string str)
           (optimize (speed 3) (safety 0) (space 0)))
    (do* ((i 0 (1+ i))
          (orig-len (length str))
          (new-len orig-len))
         ((= i orig-len) new-len)
      (declare (fixnum i orig-len new-len))
      (let* ((c (char str i))
             (match (assoc c repl-alist :test #'char=)))
        (declare (character c))
        (when match
          (incf new-len (1- (length
                             (the simple-string (cdr match)))))))))

(defun substitute-chars-strings (str repl-alist)
  "Replace all instances of a chars with a string. repl-alist is an assoc
list of characters and replacement strings."
  (declare (simple-string str)
           (optimize (speed 3) (safety 0) (space 0)))
  (do* ((orig-len (length str))
        (new-string (make-string (replaced-string-length str repl-alist)))
        (spos 0 (1+ spos))
        (dpos 0))
      ((>= spos orig-len)
       new-string)
    (declare (fixnum spos dpos) (simple-string new-string))
    (let* ((c (char str spos))
           (match (assoc c repl-alist :test #'char=)))
      (declare (character c))
      (if match
          (let* ((subst (cdr match))
                 (len (length subst)))
            (declare (fixnum len)
                     (simple-string subst))
            (dotimes (j len)
              (declare (fixnum j))
              (setf (char new-string dpos) (char subst j))
              (incf dpos)))
        (progn
          (setf (char new-string dpos) c)
          (incf dpos))))))

(defun escape-xml-string (string)
  "Escape invalid XML characters"
  (substitute-chars-strings string '((#\& . "&amp;") (#\< . "&lt;"))))

(defun make-usb8-array (len)
  (make-array len :element-type '(unsigned-byte 8)))

(defun usb8-array-to-string (vec &key (start 0) end)
  (declare (type (simple-array (unsigned-byte 8) (*)) vec)
           (fixnum start))
  (unless end
    (setq end (length vec)))
  (let* ((len (- end start))
         (str (make-string len)))
    (declare (fixnum len)
             (simple-string str)
             (optimize (speed 3) (safety 0)))
    (do ((i 0 (1+ i)))
        ((= i len) str)
      (declare (fixnum i))
      (setf (schar str i) (code-char (aref vec (the fixnum (+ i start))))))))

(defun string-to-usb8-array (str)
  (declare (simple-string str))
  (let* ((len (length str))
         (vec (make-usb8-array len)))
    (declare (fixnum len)
             (type (simple-array (unsigned-byte 8) (*)) vec)
             (optimize (speed 3)))
    (do ((i 0 (1+ i)))
        ((= i len) vec)
      (declare (fixnum i))
      (setf (aref vec i) (char-code (schar str i))))))

(defun concat-separated-strings (separator &rest lists)
  (format nil (concatenate 'string "~{~A~^" (string separator) "~}")
          (append-sublists lists)))

(defun only-null-list-elements-p (lst)
  (or (null lst) (every #'null lst)))

(defun print-separated-strings (strm separator &rest lists)
  (declare (optimize (speed 3) (safety 0) (space 0) (debug 0)
                     (compilation-speed 0)))
  (do* ((rest-lists lists (cdr rest-lists))
        (list (car rest-lists) (car rest-lists))
        (last-list (only-null-list-elements-p (cdr rest-lists))
                   (only-null-list-elements-p (cdr rest-lists))))
       ((null rest-lists) strm)
    (do* ((lst list (cdr lst))
          (elem (car lst) (car lst))
          (last-elem (null (cdr lst)) (null (cdr lst))))
         ((null lst))
      (write-string elem strm)
      (unless (and last-elem last-list)
        (write-string separator strm)))))

(eval-when (:compile-toplevel :load-toplevel :execute)
  (defmacro def-prefixed-number-string (fn-name type &optional doc)
    `(defun ,fn-name (num pchar len)
       ,@(when (stringp doc) (list doc))
       (declare (optimize (speed 3) (safety 0) (space 0))
                (fixnum len)
                (,type num))
       (when pchar
         (incf len))
       (do* ((zero-code (char-code #\0))
           (result (make-string len :initial-element #\0))
           (minus? (minusp num))
           (val (if minus? (- num) num)
                (nth-value 0 (floor val 10)))
           (pos (1- len) (1- pos))
           (mod (mod val 10) (mod val 10)))
         ((or (zerop val) (minusp pos))
          (when pchar
            (setf (schar result 0) pchar))
          (when minus? (setf (schar result (if pchar 1 0)) #\-))
          result)
       (declare (,type val)
                (fixnum mod zero-code pos)
                (boolean minus?)
                (simple-string result))
       (setf (schar result pos) (code-char (the fixnum (+ zero-code mod))))))))

(def-prefixed-number-string prefixed-fixnum-string fixnum
 "Outputs a string of LEN digit with an optional initial character PCHAR.
Leading zeros are present. LEN must be a fixnum.")

(def-prefixed-number-string prefixed-integer-string integer
 "Outputs a string of LEN digit with an optional initial character PCHAR.
Leading zeros are present. LEN must be an integer.")

(defun integer-string (num len)
  "Outputs a string of LEN digit with an optional initial character PCHAR.
Leading zeros are present."
  (declare (optimize (speed 3) (safety 0) (space 0))
           (type fixnum len)
           (type integer num))
  (do* ((zero-code (char-code #\0))
        (result (make-string len :initial-element #\0))
        (minus? (minusp num))
        (val (if minus? (- 0 num) num)
             (nth-value 0 (floor val 10)))
        (pos (1- len) (1- pos))
        (mod (mod val 10) (mod val 10)))
      ((or (zerop val) (minusp pos))
       (when minus? (setf (schar result 0) #\-))
       result)
    (declare (fixnum mod zero-code pos) (simple-string result) (integer val))
    (setf (schar result pos) (code-char (+ zero-code mod)))))

(defun fast-string-search (substr str substr-length startpos endpos)
  "Optimized search for a substring in a simple-string"
  (declare (simple-string substr str)
           (fixnum substr-length startpos endpos)
           (optimize (speed 3) (space 0) (safety 0)))
  (do* ((pos startpos (1+ pos))
        (lastpos (- endpos substr-length)))
       ((> pos lastpos) nil)
    (declare (fixnum pos lastpos))
    (do ((i 0 (1+ i)))
        ((= i substr-length)
         (return-from fast-string-search pos))
      (declare (fixnum i))
      (unless (char= (schar str (+ i pos)) (schar substr i))
        (return nil)))))

(defun string-delimited-string-to-list (str substr)
  "splits a string delimited by substr into a list of strings"
  (declare (simple-string str substr)
           (optimize (speed 3) (safety 0) (space 0) (compilation-speed 0)
                     (debug 0)))
  (do* ((substr-len (length substr))
        (strlen (length str))
        (output '())
        (pos 0)
        (end (fast-string-search substr str substr-len pos strlen)
             (fast-string-search substr str substr-len pos strlen)))
       ((null end)
        (when (< pos strlen)
          (push (subseq str pos) output))
        (nreverse output))
    (declare (fixnum strlen substr-len pos)
             (type (or fixnum null) end))
    (push (subseq str pos end) output)
    (setq pos (+ end substr-len))))

(defun string-to-list-skip-delimiter (str &optional (delim #\space))
  "Return a list of strings, delimited by spaces, skipping spaces."
  (declare (simple-string str)
           (optimize (speed 0) (space 0) (safety 0)))
  (do* ((results '())
        (end (length str))
        (i (position-not-char delim str 0 end)
           (position-not-char delim str j end))
        (j (when i (position-char delim str i end))
           (when i (position-char delim str i end))))
       ((or (null i) (null j))
        (when (and i (< i end))
          (push (subseq str i end) results))
        (nreverse results))
    (declare (fixnum end)
             (type (or fixnum null) i j))
    (push (subseq str i j) results)))

(defun string-starts-with (start str)
  (and (>= (length str) (length start))
       (string-equal start str :end2 (length start))))

(defun count-string-char (s c)
  "Return a count of the number of times a character appears in a string"
  (declare (simple-string s)
           (character c)
           (optimize (speed 3) (safety 0)))
  (do ((len (length s))
       (i 0 (1+ i))
       (count 0))
      ((= i len) count)
    (declare (fixnum i len count))
    (when (char= (schar s i) c)
      (incf count))))

(defun count-string-char-if (pred s)
  "Return a count of the number of times a predicate is true
for characters in a string"
  (declare (simple-string s)
           (type (or function symbol) pred)
           (optimize (speed 3) (safety 0) (space 0)))
  (do ((len (length s))
       (i 0 (1+ i))
       (count 0))
      ((= i len) count)
    (declare (fixnum i len count))
    (when (funcall pred (schar s i))
      (incf count))))


;;; URL Encoding

(defun non-alphanumericp (ch)
  (not (alphanumericp ch)))

(defvar +hex-chars+ "0123456789ABCDEF")
(declaim (type simple-string +hex-chars+))

(defun hexchar (n)
  (declare (type (integer 0 15) n))
  (schar +hex-chars+ n))

(defconstant* +char-code-lower-a+ (char-code #\a))
(defconstant* +char-code-upper-a+ (char-code #\A))
(defconstant* +char-code-0+ (char-code #\0))
(declaim (type fixnum +char-code-0+ +char-code-upper-a+
               +char-code-0))

(defun charhex (ch)
  "convert hex character to decimal"
  (let ((code (char-code (char-upcase ch))))
    (declare (fixnum ch))
    (if (>= code +char-code-upper-a+)
        (+ 10 (- code +char-code-upper-a+))
        (- code +char-code-0+))))

(defun binary-sequence-to-hex-string (seq)
  (let ((list (etypecase seq
                (list seq)
                (sequence (map 'list #'identity seq)))))
    (string-downcase (format nil "~{~2,'0X~}" list))))

(defun encode-uri-string (query)
  "Escape non-alphanumeric characters for URI fields"
  (declare (simple-string query)
           (optimize (speed 3) (safety 0) (space 0)))
  (do* ((count (count-string-char-if #'non-alphanumericp query))
        (len (length query))
        (new-len (+ len (* 2 count)))
        (str (make-string new-len))
        (spos 0 (1+ spos))
        (dpos 0 (1+ dpos)))
      ((= spos len) str)
    (declare (fixnum count len new-len spos dpos)
             (simple-string str))
    (let ((ch (schar query spos)))
      (if (non-alphanumericp ch)
          (let ((c (char-code ch)))
            (setf (schar str dpos) #\%)
            (incf dpos)
            (setf (schar str dpos) (hexchar (logand (ash c -4) 15)))
            (incf dpos)
            (setf (schar str dpos) (hexchar (logand c 15))))
        (setf (schar str dpos) ch)))))

(defun decode-uri-string (query)
  "Unescape non-alphanumeric characters for URI fields"
  (declare (simple-string query)
           (optimize (speed 3) (safety 0) (space 0)))
  (do* ((count (count-string-char query #\%))
        (len (length query))
        (new-len (- len (* 2 count)))
        (str (make-string new-len))
        (spos 0 (1+ spos))
        (dpos 0 (1+ dpos)))
      ((= spos len) str)
    (declare (fixnum count len new-len spos dpos)
             (simple-string str))
    (let ((ch (schar query spos)))
      (if (char= #\% ch)
          (let ((c1 (charhex (schar query (1+ spos))))
                (c2 (charhex (schar query (+ spos 2)))))
            (declare (fixnum c1 c2))
            (setf (schar str dpos)
                  (code-char (logior c2 (ash c1 4))))
            (incf spos 2))
        (setf (schar str dpos) ch)))))


(defun uri-query-to-alist (query)
  "Converts non-decoded URI query to an alist of settings"
  (mapcar (lambda (set)
            (let ((lst (kmrcl:delimited-string-to-list set #\=)))
              (cons (first lst) (second lst))))
          (kmrcl:delimited-string-to-list
           (kmrcl:decode-uri-string query) #\&)))

(eval-when (:compile-toplevel :load-toplevel :execute)
  (defvar +unambiguous-charset+
    "abcdefghjkmnpqrstuvwxyz123456789ABCDEFGHJKLMNPQSRTUVWXYZ")
  (defconstant* +unambiguous-length+ (length +unambiguous-charset+)))

(defun random-char (&optional (set :lower-alpha))
  (ecase set
    (:lower-alpha
     (code-char (+ +char-code-lower-a+ (random 26))))
    (:lower-alphanumeric
     (let ((n (random 36)))
       (if (>= n 26)
           (code-char (+ +char-code-0+ (- n 26)))
         (code-char (+ +char-code-lower-a+ n)))))
    (:upper-alpha
     (code-char (+ +char-code-upper-a+ (random 26))))
    (:unambiguous
     (schar +unambiguous-charset+ (random +unambiguous-length+)))
    (:upper-lower-alpha
     (let ((n (random 52)))
       (if (>= n 26)
           (code-char (+ +char-code-upper-a+ (- n 26)))
         (code-char (+ +char-code-lower-a+ n)))))))


(defun random-string (&key (length 10) (set :lower-alpha))
  "Returns a random lower-case string."
  (declare (optimize (speed 3)))
  (let ((s (make-string length)))
    (declare (simple-string s))
    (dotimes (i length s)
      (setf (schar s i) (random-char set)))))


(defun first-char (s)
  (declare (simple-string s))
  (when (and (stringp s) (plusp (length s)))
    (schar s 0)))

(defun last-char (s)
  (declare (simple-string s))
  (when (stringp s)
    (let ((len (length s)))
      (when (plusp len))
      (schar s (1- len)))))

(defun ensure-string (v)
  (typecase v
    (string v)
    (character (string v))
    (symbol (symbol-name v))
    (otherwise (write-to-string v))))

(defun string-right-trim-one-char (char str)
  (declare (simple-string str))
  (let* ((len (length str))
         (last (1- len)))
    (declare (fixnum len last))
    (if (char= char (schar str last))
        (subseq str 0 last)
      str)))


(defun remove-char-string (char str)
  (declare (character char)
           (string str))
  (do* ((len (length str))
        (out (make-string len))
        (pos 0 (1+ pos))
        (opos 0))
       ((= pos len) (subseq out 0 opos))
    (declare (fixnum pos opos len)
             (simple-string out))
    (let ((c (char str pos)))
      (declare (character c))
      (when (char/= c char)
        (setf (schar out opos) c)
        (incf opos)))))


(defun string-strip-ending (str endings)
  (if (stringp endings)
      (setq endings (list endings)))
  (let ((len (length str)))
    (dolist (ending endings str)
      (when (and (>= len (length ending))
                 (string-equal ending
                               (subseq str (- len
                                              (length ending)))))
        (return-from string-strip-ending
          (subseq str 0 (- len (length ending))))))))


(defun string-maybe-shorten (str maxlen)
  (string-elide str maxlen :end))

(defun string-elide (str maxlen position)
  (declare (fixnum maxlen))
  (let ((len (length str)))
    (declare (fixnum len))
    (cond
     ((<= len maxlen)
      str)
     ((<= maxlen 3)
      "...")
     ((eq position :middle)
      (multiple-value-bind (mid remain) (truncate maxlen 2)
        (let ((end1 (- mid 1))
              (start2 (- len (- mid 2) remain)))
          (concatenate 'string (subseq str 0 end1) "..." (subseq str start2)))))
     ((or (eq position :end) t)
      (concatenate 'string (subseq str 0 (- maxlen 3)) "...")))))

(defun shrink-vector (str size)
  #+allegro
  (excl::.primcall 'sys::shrink-svector str size)
  #+cmu
  (lisp::shrink-vector str size)
  #+lispworks
  (system::shrink-vector$vector str size)
  #+sbcl
  (sb-kernel:shrink-vector str size)
  #+scl
  (common-lisp::shrink-vector str size)
  #-(or allegro cmu lispworks sbcl scl)
  (setq str (subseq str 0 size))
  str)

(defun lex-string (string &key (whitespace '(#\space #\newline)))
  "Separates a string at whitespace and returns a list of strings"
  (flet ((is-sep (char) (member char whitespace :test #'char=)))
    (let ((tokens nil))
      (do* ((token-start
             (position-if-not #'is-sep string)
             (when token-end
               (position-if-not #'is-sep string :start (1+ token-end))))
            (token-end
             (when token-start
               (position-if #'is-sep string :start token-start))
             (when token-start
               (position-if #'is-sep string :start token-start))))
           ((null token-start) (nreverse tokens))
        (push (subseq string token-start token-end) tokens)))))

(defun split-alphanumeric-string (string)
  "Separates a string at any non-alphanumeric chararacter"
  (declare (simple-string string)
           (optimize (speed 3) (safety 0)))
  (flet ((is-sep (char)
           (declare (character char))
           (and (non-alphanumericp char)
                (not (char= #\_ char)))))
    (let ((tokens nil))
      (do* ((token-start
             (position-if-not #'is-sep string)
             (when token-end
               (position-if-not #'is-sep string :start (1+ token-end))))
            (token-end
             (when token-start
               (position-if #'is-sep string :start token-start))
             (when token-start
               (position-if #'is-sep string :start token-start))))
           ((null token-start) (nreverse tokens))
        (push (subseq string token-start token-end) tokens)))))


(defun trim-non-alphanumeric (word)
  "Strip non-alphanumeric characters from beginning and end of a word."
  (declare (simple-string word)
           (optimize (speed 3) (safety 0) (space 0)))
  (let* ((start 0)
         (len (length word))
         (end len))
    (declare (fixnum start end len))
    (do ((done nil))
        ((or done (= start end)))
      (if (alphanumericp (schar word start))
          (setq done t)
        (incf start)))
    (when (> end start)
      (do ((done nil))
          ((or done (= start end)))
        (if (alphanumericp (schar word (1- end)))
            (setq done t)
          (decf end))))
    (if (or (plusp start) (/= len end))
        (subseq word start end)
      word)))


(defun collapse-whitespace (s)
  "Convert multiple whitespace characters to a single space character."
  (declare (simple-string s)
           (optimize (speed 3) (safety 0)))
  (with-output-to-string (stream)
    (do ((pos 0 (1+ pos))
         (in-white nil)
         (len (length s)))
        ((= pos len))
      (declare (fixnum pos len))
      (let ((c (schar s pos)))
        (declare (character c))
        (cond
         ((kl:is-char-whitespace c)
          (unless in-white
            (write-char #\space stream))
          (setq in-white t))
         (t
          (setq in-white nil)
          (write-char c stream)))))))

(defun string->list (string)
  (let ((eof (list nil)))
    (with-input-from-string (stream string)
      (do ((x (read stream nil eof) (read stream nil eof))
           (l nil (cons x l)))
          ((eq x eof) (nreverse l))))))

(defun safely-read-from-string (str &rest read-from-string-args)
  "Read an expression from the string STR, with *READ-EVAL* set
to NIL. Any unsafe expressions will be replaced by NIL in the
resulting S-Expression."
  (let ((*read-eval* nil))
    (ignore-errors (apply 'read-from-string str read-from-string-args))))

(defun parse-float (f)
  (let ((*read-default-float-format* 'double-float))
    (coerce (safely-read-from-string f) 'double-float)))