src/lib/string/compat_string.c

   1 /* Copyright (c) 2003-2004, Roger Dingledine
   2  * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
   3  * Copyright (c) 2007-2021, The Tor Project, Inc. */
   4 /* See LICENSE for licensing information */
   5
   6 /**
   7  * \file compat_string.c
   8  * \brief Useful string-processing functions that some platforms don't
   9  * provide.
  10  **/
  11
  12 #include "lib/string/compat_string.h"
  13 #include "lib/err/torerr.h"
  14
  15 /* Inline the strl functions if the platform doesn't have them. */
  16 #ifndef HAVE_STRLCPY
  17 #include "ext/strlcpy.c"
  18 #endif
  19 #ifndef HAVE_STRLCAT
  20 #include "ext/strlcat.c"
  21 #endif
  22
  23 #include <stdlib.h>
  24 #include <string.h>
  25
  26 /** Helper for tor_strtok_r_impl: Advances cp past all characters in
  27  * <b>sep</b>, and returns its new value. */
  28 static char *
  29 strtok_helper(char *cp, const char *sep)
  30 {
  31   if (sep[1]) {
  32     while (*cp && strchr(sep, *cp))
  33       ++cp;
  34   } else {
  35     while (*cp && *cp == *sep)
  36       ++cp;
  37   }
  38   return cp;
  39 }
  40
  41 /** Implementation of strtok_r for platforms whose coders haven't figured out
  42  * how to write one.  Hey, retrograde libc developers!  You can use this code
  43  * here for free! */
  44 char *
  45 tor_strtok_r_impl(char *str, const char *sep, char **lasts)
  46 {
  47   char *cp, *start;
  48   raw_assert(*sep);
  49   if (str) {
  50     str = strtok_helper(str, sep);
  51     if (!*str)
  52       return NULL;
  53     start = cp = *lasts = str;
  54   } else if (!*lasts || !**lasts) {
  55     return NULL;
  56   } else {
  57     start = cp = *lasts;
  58   }
  59
  60   if (sep[1]) {
  61     while (*cp && !strchr(sep, *cp))
  62       ++cp;
  63   } else {
  64     cp = strchr(cp, *sep);
  65   }
  66
  67   if (!cp || !*cp) {
  68     *lasts = NULL;
  69   } else {
  70     *cp++ = '\0';
  71     *lasts = strtok_helper(cp, sep);
  72   }
  73   return start;
  74 }