src/core/string.c

   1 /*
   2  *  Copyright (C) 1991, 1992  Linus Torvalds
   3  *  Copyright (C) 2004 Tobias Lorenz
   4  *
   5  *  string handling functions
   6  *  based on linux/lib/string.c
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 as
  10  * published by the Free Software Foundation.
  11  */
  12
  13 FILE_LICENCE ( GPL2_ONLY );
  14
  15 /*
  16  * stupid library routines.. The optimized versions should generally be found
  17  * as inline code in <asm-xx/string.h>
  18  *
  19  * These are buggy as well..
  20  *
  21  * * Fri Jun 25 1999, Ingo Oeser <ioe@informatik.tu-chemnitz.de>
  22  * -  Added strsep() which will replace strtok() soon (because strsep() is
  23  *    reentrant and should be faster). Use only strsep() in new code, please.
  24  */
  25
  26 #include <stdint.h>
  27 #include <stdlib.h>
  28 #include <string.h>
  29 #include <ctype.h>
  30
  31 /* *** FROM string.c *** */
  32
  33 #ifndef __HAVE_ARCH_STRCPY
  34 /**
  35  * strcpy - Copy a %NUL terminated string
  36  * @dest: Where to copy the string to
  37  * @src: Where to copy the string from
  38  */
  39 char * strcpy(char * dest,const char *src)
  40 {
  41         char *tmp = dest;
  42
  43         while ((*dest++ = *src++) != '\0')
  44                 /* nothing */;
  45         return tmp;
  46 }
  47 #endif
  48
  49 #ifndef __HAVE_ARCH_STRNCPY
  50 /**
  51  * strncpy - Copy a length-limited, %NUL-terminated string
  52  * @dest: Where to copy the string to
  53  * @src: Where to copy the string from
  54  * @count: The maximum number of bytes to copy
  55  *
  56  * Note that unlike userspace strncpy, this does not %NUL-pad the buffer.
  57  * However, the result is not %NUL-terminated if the source exceeds
  58  * @count bytes.
  59  */
  60 char * strncpy(char * dest,const char *src,size_t count)
  61 {
  62         char *tmp = dest;
  63
  64         while (count-- && (*dest++ = *src++) != '\0')
  65                 /* nothing */;
  66
  67         return tmp;
  68 }
  69 #endif
  70
  71 #ifndef __HAVE_ARCH_STRCAT
  72 /**
  73  * strcat - Append one %NUL-terminated string to another
  74  * @dest: The string to be appended to
  75  * @src: The string to append to it
  76  */
  77 char * strcat(char * dest, const char * src)
  78 {
  79         char *tmp = dest;
  80
  81         while (*dest)
  82                 dest++;
  83         while ((*dest++ = *src++) != '\0')
  84                 ;
  85
  86         return tmp;
  87 }
  88 #endif
  89
  90 #ifndef __HAVE_ARCH_STRCMP
  91 /**
  92  * strcmp - Compare two strings
  93  * @cs: One string
  94  * @ct: Another string
  95  */
  96 int strcmp(const char * cs,const char * ct)
  97 {
  98         register signed char __res;
  99
 100         while (1) {
 101                 if ((__res = *cs - *ct++) != 0 || !*cs++)
 102                         break;
 103         }
 104
 105         return __res;
 106 }
 107 #endif
 108
 109 #ifndef __HAVE_ARCH_STRNCMP
 110 /**
 111  * strncmp - Compare two length-limited strings
 112  * @cs: One string
 113  * @ct: Another string
 114  * @count: The maximum number of bytes to compare
 115  */
 116 int strncmp(const char * cs,const char * ct,size_t count)
 117 {
 118         register signed char __res = 0;
 119
 120         while (count) {
 121                 if ((__res = *cs - *ct++) != 0 || !*cs++)
 122                         break;
 123                 count--;
 124         }
 125
 126         return __res;
 127 }
 128 #endif
 129
 130 #ifndef __HAVE_ARCH_STRCASECMP
 131 int strcasecmp(const char *a, const char *b)
 132 {
 133         while (*a && *b && (*a & ~0x20) == (*b & ~0x20)) {a++; b++; }
 134         return((*a & ~0x20) - (*b & ~0x20));
 135 }
 136 #endif
 137
 138 #ifndef __HAVE_ARCH_STRCHR
 139 /**
 140  * strchr - Find the first occurrence of a character in a string
 141  * @s: The string to be searched
 142  * @c: The character to search for
 143  */
 144 char * strchr(const char * s, int c)
 145 {
 146         for(; *s != (char) c; ++s)
 147                 if (*s == '\0')
 148                         return NULL;
 149         return (char *) s;
 150 }
 151 #endif
 152
 153 #ifndef __HAVE_ARCH_STRRCHR
 154 /**
 155  * strrchr - Find the last occurrence of a character in a string
 156  * @s: The string to be searched
 157  * @c: The character to search for
 158  */
 159 char * strrchr(const char * s, int c)
 160 {
 161        const char *p = s + strlen(s);
 162        do {
 163            if (*p == (char)c)
 164                return (char *)p;
 165        } while (--p >= s);
 166        return NULL;
 167 }
 168 #endif
 169
 170 #ifndef __HAVE_ARCH_STRLEN
 171 /**
 172  * strlen - Find the length of a string
 173  * @s: The string to be sized
 174  */
 175 size_t strlen(const char * s)
 176 {
 177         const char *sc;
 178
 179         for (sc = s; *sc != '\0'; ++sc)
 180                 /* nothing */;
 181         return sc - s;
 182 }
 183 #endif
 184
 185 #ifndef __HAVE_ARCH_STRNLEN
 186 /**
 187  * strnlen - Find the length of a length-limited string
 188  * @s: The string to be sized
 189  * @count: The maximum number of bytes to search
 190  */
 191 size_t strnlen(const char * s, size_t count)
 192 {
 193         const char *sc;
 194
 195         for (sc = s; count-- && *sc != '\0'; ++sc)
 196                 /* nothing */;
 197         return sc - s;
 198 }
 199 #endif
 200
 201 #ifndef __HAVE_ARCH_MEMSET
 202 /**
 203  * memset - Fill a region of memory with the given value
 204  * @s: Pointer to the start of the area.
 205  * @c: The byte to fill the area with
 206  * @count: The size of the area.
 207  *
 208  * Do not use memset() to access IO space, use memset_io() instead.
 209  */
 210 void * memset(void * s,int c,size_t count)
 211 {
 212         char *xs = (char *) s;
 213
 214         while (count--)
 215                 *xs++ = c;
 216
 217         return s;
 218 }
 219 #endif
 220
 221 #ifndef __HAVE_ARCH_MEMCPY
 222 /**
 223  * memcpy - Copy one area of memory to another
 224  * @dest: Where to copy to
 225  * @src: Where to copy from
 226  * @count: The size of the area.
 227  *
 228  * You should not use this function to access IO space, use memcpy_toio()
 229  * or memcpy_fromio() instead.
 230  */
 231 void * memcpy(void * dest,const void *src,size_t count)
 232 {
 233         char *tmp = (char *) dest, *s = (char *) src;
 234
 235         while (count--)
 236                 *tmp++ = *s++;
 237
 238         return dest;
 239 }
 240 #endif
 241
 242 #ifndef __HAVE_ARCH_MEMMOVE
 243 /**
 244  * memmove - Copy one area of memory to another
 245  * @dest: Where to copy to
 246  * @src: Where to copy from
 247  * @count: The size of the area.
 248  *
 249  * Unlike memcpy(), memmove() copes with overlapping areas.
 250  */
 251 void * memmove(void * dest,const void *src,size_t count)
 252 {
 253         char *tmp, *s;
 254
 255         if (dest <= src) {
 256                 tmp = (char *) dest;
 257                 s = (char *) src;
 258                 while (count--)
 259                         *tmp++ = *s++;
 260                 }
 261         else {
 262                 tmp = (char *) dest + count;
 263                 s = (char *) src + count;
 264                 while (count--)
 265                         *--tmp = *--s;
 266                 }
 267
 268         return dest;
 269 }
 270 #endif
 271
 272 #ifndef __HAVE_ARCH_MEMCMP
 273 /**
 274  * memcmp - Compare two areas of memory
 275  * @cs: One area of memory
 276  * @ct: Another area of memory
 277  * @count: The size of the area.
 278  */
 279 int memcmp(const void * cs,const void * ct,size_t count)
 280 {
 281         const unsigned char *su1, *su2;
 282         int res = 0;
 283
 284         for( su1 = cs, su2 = ct; 0 < count; ++su1, ++su2, count--)
 285                 if ((res = *su1 - *su2) != 0)
 286                         break;
 287         return res;
 288 }
 289 #endif
 290
 291 #ifndef __HAVE_ARCH_STRSTR
 292 /**
 293  * strstr - Find the first substring in a %NUL terminated string
 294  * @s1: The string to be searched
 295  * @s2: The string to search for
 296  */
 297 char * strstr(const char * s1,const char * s2)
 298 {
 299         int l1, l2;
 300
 301         l2 = strlen(s2);
 302         if (!l2)
 303                 return (char *) s1;
 304         l1 = strlen(s1);
 305         while (l1 >= l2) {
 306                 l1--;
 307                 if (!memcmp(s1,s2,l2))
 308                         return (char *) s1;
 309                 s1++;
 310         }
 311         return NULL;
 312 }
 313 #endif
 314
 315 #ifndef __HAVE_ARCH_MEMCHR
 316 /**
 317  * memchr - Find a character in an area of memory.
 318  * @s: The memory area
 319  * @c: The byte to search for
 320  * @n: The size of the area.
 321  *
 322  * returns the address of the first occurrence of @c, or %NULL
 323  * if @c is not found
 324  */
 325 void * memchr(const void *s, int c, size_t n)
 326 {
 327         const unsigned char *p = s;
 328         while (n-- != 0) {
 329                 if ((unsigned char)c == *p++) {
 330                         return (void *)(p-1);
 331                 }
 332         }
 333         return NULL;
 334 }
 335
 336 #endif
 337
 338 char * strndup(const char *s, size_t n)
 339 {
 340         size_t len = strlen(s);
 341         char *new;
 342
 343         if (len>n)
 344                 len = n;
 345         new = malloc(len+1);
 346         if (new) {
 347                 new[len] = '\0';
 348                 memcpy(new,s,len);
 349         }
 350         return new;
 351 }
 352
 353 char * strdup(const char *s) {
 354         return strndup(s, ~((size_t)0));
 355 }