strsep.c 1.8 KB

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  1. /* Copyright (C) 1992, 93, 96, 97, 98, 99, 2004 Free Software Foundation, Inc.
  2. This file is part of the GNU C Library.
  3. The GNU C Library is free software; you can redistribute it and/or
  4. modify it under the terms of the GNU Lesser General Public
  5. License as published by the Free Software Foundation; either
  6. version 2.1 of the License, or (at your option) any later version.
  7. The GNU C Library is distributed in the hope that it will be useful,
  8. but WITHOUT ANY WARRANTY; without even the implied warranty of
  9. MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  10. Lesser General Public License for more details.
  11. You should have received a copy of the GNU Lesser General Public
  12. License along with the GNU C Library; if not, write to the Free
  13. Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  14. 02111-1307 USA. */
  15. #include <string.h>
  16. #undef strsep
  17. char *strsep (char **stringp, const char *delim)
  18. {
  19. char *begin, *end;
  20. begin = *stringp;
  21. if (begin == NULL)
  22. return NULL;
  23. /* A frequent case is when the delimiter string contains only one
  24. character. Here we don't need to call the expensive `strpbrk'
  25. function and instead work using `strchr'. */
  26. if (delim[0] == '\0' || delim[1] == '\0')
  27. {
  28. char ch = delim[0];
  29. if (ch == '\0')
  30. end = NULL;
  31. else
  32. {
  33. if (*begin == ch)
  34. end = begin;
  35. else if (*begin == '\0')
  36. end = NULL;
  37. else
  38. end = strchr (begin + 1, ch);
  39. }
  40. }
  41. else
  42. /* Find the end of the token. */
  43. end = strpbrk (begin, delim);
  44. if (end)
  45. {
  46. /* Terminate the token and set *STRINGP past NUL character. */
  47. *end++ = '\0';
  48. *stringp = end;
  49. }
  50. else
  51. /* No more delimiters; this is the last token. */
  52. *stringp = NULL;
  53. return begin;
  54. }