source: mainline/uspace/lib/posix/string.c@ 4f4b4e7

lfn serial ticket/834-toolchain-update topic/msim-upgrade topic/simplify-dev-export
Last change on this file since 4f4b4e7 was 4f4b4e7, checked in by Petr Koupy <petr.koupy@…>, 14 years ago

Coding style and file structure unified.
_exit moved to unistd.h.
  • Property mode set to 100644
File size: 9.7 KB
Line 
1/*
2 * Copyright (c) 2011 Petr Koupy
3 * Copyright (c) 2011 Jiri Zarevucky
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 *
10 * - Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * - Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * - The name of the author may not be used to endorse or promote products
16 * derived from this software without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
19 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
20 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
21 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
22 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
23 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
24 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
25 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
27 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 */
29
30/** @addtogroup libposix
31 * @{
32 */
33/** @file
34 */
35
36#define LIBPOSIX_INTERNAL
37
38#include "string.h"
39
40#include <assert.h>
41#include <str_error.h>
42#include <stdlib.h>
43#include <errno.h>
44
45/**
46 * Defined for convenience. Returns pointer to the terminating nul character.
47 *
48 * @param s
49 * @return
50 */
51static char *strzero(const char *s)
52{
53 while (*s != '\0') {
54 s++;
55 }
56
57 return (char *) s;
58}
59
60/**
61 * Returns true if s2 is a prefix of s1.
62 *
63 * @param s1
64 * @param s2
65 * @return
66 */
67static bool begins_with(const char *s1, const char *s2)
68{
69 while (*s1 == *s2 && *s2 != '\0') {
70 s1++;
71 s2++;
72 }
73
74 /* true if the end was reached */
75 return *s2 == '\0';
76}
77
78/**
79 * The same as strpbrk, except it returns pointer to the nul terminator
80 * if no occurence is found.
81 *
82 * @param s1
83 * @param s2
84 * @return
85 */
86static char *strpbrk_null(const char *s1, const char *s2)
87{
88 while (!posix_strchr(s2, *s1)) {
89 ++s1;
90 }
91
92 return (char *) s1;
93}
94
95/**
96 *
97 * @param dest
98 * @param src
99 * @return
100 */
101char *posix_strcpy(char *dest, const char *src)
102{
103 posix_stpcpy(dest, src);
104 return dest;
105}
106
107/**
108 *
109 * @param dest
110 * @param src
111 * @param n
112 * @return
113 */
114char *posix_strncpy(char *dest, const char *src, size_t n)
115{
116 posix_stpncpy(dest, src, n);
117 return dest;
118}
119
120/**
121 *
122 * @param dest
123 * @param src
124 * @return Pointer to the nul character in the dest string
125 */
126char *posix_stpcpy(char *restrict dest, const char *restrict src)
127{
128 assert(dest != NULL);
129 assert(src != NULL);
130
131 for (size_t i = 0; ; ++i) {
132 dest[i] = src[i];
133
134 if (src[i] == '\0') {
135 /* pointer to the terminating nul character */
136 return &dest[i];
137 }
138 }
139
140 /* unreachable */
141 return NULL;
142}
143
144/**
145 *
146 * @param dest
147 * @param src
148 * @param n
149 * @return Pointer to the first written nul character or &dest[n]
150 */
151char *posix_stpncpy(char *restrict dest, const char *restrict src, size_t n)
152{
153 assert(dest != NULL);
154 assert(src != NULL);
155
156 for (size_t i = 0; i < n; ++i) {
157 dest[i] = src[i];
158
159 /* the standard requires that nul characters
160 * are appended to the length of n, in case src is shorter
161 */
162 if (src[i] == '\0') {
163 char *result = &dest[i];
164 for (++i; i < n; ++i) {
165 dest[i] = '\0';
166 }
167 return result;
168 }
169 }
170
171 return &dest[n];
172}
173
174/**
175 *
176 * @param dest
177 * @param src
178 * @return
179 */
180char *posix_strcat(char *dest, const char *src)
181{
182 assert(dest != NULL);
183 assert(src != NULL);
184
185 posix_strcpy(strzero(dest), src);
186 return dest;
187}
188
189/**
190 *
191 * @param dest
192 * @param src
193 * @param n
194 * @return
195 */
196char *posix_strncat(char *dest, const char *src, size_t n)
197{
198 assert(dest != NULL);
199 assert(src != NULL);
200
201 char *zeroptr = posix_strncpy(strzero(dest), src, n);
202 /* strncpy doesn't append the nul terminator, so we do it here */
203 zeroptr[n] = '\0';
204 return dest;
205}
206
207/**
208 *
209 * @param dest
210 * @param src
211 * @param c
212 * @param n
213 * @return Pointer to the first byte after c in dest if found, NULL otherwise.
214 */
215void *posix_memccpy(void *dest, const void *src, int c, size_t n)
216{
217 assert(dest != NULL);
218 assert(src != NULL);
219
220 unsigned char* bdest = dest;
221 const unsigned char* bsrc = src;
222
223 for (size_t i = 0; i < n; ++i) {
224 bdest[i] = bsrc[i];
225
226 if (bsrc[i] == (unsigned char) c) {
227 /* pointer to the next byte */
228 return &bdest[i + 1];
229 }
230 }
231
232 return NULL;
233}
234
235/**
236 *
237 * @param s
238 * @return Newly allocated string
239 */
240char *posix_strdup(const char *s)
241{
242 // FIXME: SIZE_MAX doesn't work
243 return posix_strndup(s, STR_NO_LIMIT);
244}
245
246/**
247 *
248 * @param s
249 * @param n
250 * @return Newly allocated string of length at most n
251 */
252char *posix_strndup(const char *s, size_t n)
253{
254 assert(s != NULL);
255
256 size_t len = posix_strnlen(s, n);
257 char *dup = malloc(len + 1);
258 if (dup == NULL) {
259 return NULL;
260 }
261
262 memcpy(dup, s, len);
263 dup[len] = '\0';
264
265 return dup;
266}
267
268/**
269 *
270 * @param mem1
271 * @param mem2
272 * @param n
273 * @return Difference of the first pair of inequal bytes,
274 * or 0 if areas have the same content
275 */
276int posix_memcmp(const void *mem1, const void *mem2, size_t n)
277{
278 assert(mem1 != NULL);
279 assert(mem2 != NULL);
280
281 const unsigned char *s1 = mem1;
282 const unsigned char *s2 = mem2;
283
284 for (size_t i = 0; i < n; ++i) {
285 if (s1[i] != s2[i]) {
286 return s2[i] - s1[i];
287 }
288 }
289
290 return 0;
291}
292
293/**
294 *
295 * @param s1
296 * @param s2
297 * @return
298 */
299int posix_strcmp(const char *s1, const char *s2)
300{
301 assert(s1 != NULL);
302 assert(s2 != NULL);
303
304 return posix_strncmp(s1, s2, STR_NO_LIMIT);
305}
306
307/**
308 *
309 * @param s1
310 * @param s2
311 * @param n
312 * @return
313 */
314int posix_strncmp(const char *s1, const char *s2, size_t n)
315{
316 assert(s1 != NULL);
317 assert(s2 != NULL);
318
319 for (size_t i = 0; i < n; ++i) {
320 if (s1[i] != s2[i]) {
321 return s2[i] - s1[i];
322 }
323 if (s1[i] == '\0') {
324 break;
325 }
326 }
327
328 return 0;
329}
330
331/**
332 *
333 * @param mem
334 * @param c
335 * @param n
336 * @return
337 */
338void *posix_memchr(const void *mem, int c, size_t n)
339{
340 assert(mem != NULL);
341
342 const unsigned char *s = mem;
343
344 for (size_t i = 0; i < n; ++i) {
345 if (s[i] == (unsigned char) c) {
346 return (void *) &s[i];
347 }
348 }
349 return NULL;
350}
351
352/**
353 *
354 * @param s
355 * @param c
356 * @return
357 */
358char *posix_strchr(const char *s, int c)
359{
360 assert(s != NULL);
361
362 /* special handling for the case that zero is searched for */
363 if (c == '\0') {
364 return strzero(s);
365 }
366
367 /* otherwise just loop through the string until found */
368 while (*s != (char) c) {
369 if (*s == '\0') {
370 return NULL;
371 }
372
373 s++;
374 }
375
376 return (char *) s;
377}
378
379/**
380 *
381 * @param s
382 * @param c
383 * @return
384 */
385char *posix_strrchr(const char *s, int c)
386{
387 assert(s != NULL);
388
389 const char *ptr = strzero(s);
390
391 /* the same as in strchr, except it loops in reverse direction */
392 while (*ptr != (char) c) {
393 if (ptr == s) {
394 return NULL;
395 }
396
397 ptr++;
398 }
399
400 return (char *) ptr;
401}
402
403/**
404 *
405 * @param s1
406 * @param s2
407 * @return
408 */
409char *posix_strpbrk(const char *s1, const char *s2)
410{
411 assert(s1 != NULL);
412 assert(s2 != NULL);
413
414 char *ptr = strpbrk_null(s1, s2);
415 return (*ptr == '\0') ? NULL : ptr;
416}
417
418/**
419 *
420 * @param s1
421 * @param s2
422 * @return
423 */
424size_t posix_strcspn(const char *s1, const char *s2)
425{
426 assert(s1 != NULL);
427 assert(s2 != NULL);
428
429 char *ptr = strpbrk_null(s1, s2);
430 return (size_t) (ptr - s1);
431}
432
433/**
434 *
435 * @param s1
436 * @param s2
437 * @return
438 */
439size_t posix_strspn(const char *s1, const char *s2)
440{
441 assert(s1 != NULL);
442 assert(s2 != NULL);
443
444 const char *ptr;
445 for (ptr = s1; *ptr != '\0'; ++ptr) {
446 if (!posix_strchr(s2, *ptr)) {
447 break;
448 }
449 }
450 return ptr - s1;
451}
452
453/**
454 *
455 * @param s1
456 * @param s2
457 * @return
458 */
459char *posix_strstr(const char *s1, const char *s2)
460{
461 assert(s1 != NULL);
462 assert(s2 != NULL);
463
464 /* special case - needle is an empty string */
465 if (*s2 == '\0') {
466 return (char *) s1;
467 }
468
469 // TODO: use faster algorithm
470 /* check for prefix from every position - quadratic complexity */
471 while (*s1 != '\0') {
472 if (begins_with(s1, s2)) {
473 return (char *) s1;
474 }
475
476 s1++;
477 }
478
479 return NULL;
480}
481
482/**
483 * Currently ignores locale and just calls strcmp.
484 *
485 * @param s1
486 * @param s2
487 * @return
488 */
489int posix_strcoll(const char *s1, const char *s2)
490{
491 assert(s1 != NULL);
492 assert(s2 != NULL);
493
494 return posix_strcmp(s1, s2);
495}
496
497/**
498 * strcoll is equal to strcmp here, so this just makes a copy.
499 *
500 * @param s1
501 * @param s2
502 * @param n
503 * @return
504 */
505size_t posix_strxfrm(char *s1, const char *s2, size_t n)
506{
507 assert(s1 != NULL || n == 0);
508 assert(s2 != NULL);
509
510 size_t len = posix_strlen(s2);
511
512 if (n > len) {
513 posix_strcpy(s1, s2);
514 }
515
516 return len;
517}
518
519/**
520 *
521 * @param errnum
522 * @return
523 */
524char *posix_strerror(int errnum)
525{
526 /* uses function from libc, we just have to negate errno
527 * (POSIX uses positive errorcodes, HelenOS has negative)
528 */
529 return (char *) str_error(-errnum);
530}
531
532/**
533 *
534 * @param errnum Error code
535 * @param buf Buffer to store a human readable string to
536 * @param bufsz Size of buffer pointed to by buf
537 * @return
538 */
539int posix_strerror_r(int errnum, char *buf, size_t bufsz)
540{
541 assert(buf != NULL);
542
543 char *errstr = posix_strerror(errnum);
544 /* HelenOS str_error can't fail */
545
546 if (posix_strlen(errstr) + 1 > bufsz) {
547 return -ERANGE;
548 } else {
549 posix_strcpy(buf, errstr);
550 }
551
552 return 0;
553}
554
555/**
556 *
557 * @param s
558 * @return
559 */
560size_t posix_strlen(const char *s)
561{
562 assert(s != NULL);
563
564 return (size_t) (strzero(s) - s);
565}
566
567/**
568 *
569 * @param s
570 * @param n
571 * @return
572 */
573size_t posix_strnlen(const char *s, size_t n)
574{
575 assert(s != NULL);
576
577 for (size_t sz = 0; sz < n; ++sz) {
578
579 if (s[sz] == '\0') {
580 return sz;
581 }
582 }
583
584 return n;
585}
586
587/** @}
588 */
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