runestrstr.c 1.2 KB

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  1. /*
  2. * The authors of this software are Rob Pike and Ken Thompson.
  3. * Copyright (c) 2002 by Lucent Technologies.
  4. * Permission to use, copy, modify, and distribute this software for any
  5. * purpose without fee is hereby granted, provided that this entire notice
  6. * is included in all copies of any software which is or includes a copy
  7. * or modification of this software and in all copies of the supporting
  8. * documentation for such software.
  9. * THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR IMPLIED
  10. * WARRANTY. IN PARTICULAR, NEITHER THE AUTHORS NOR LUCENT TECHNOLOGIES MAKE ANY
  11. * REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE MERCHANTABILITY
  12. * OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR PURPOSE.
  13. */
  14. #include <stdarg.h>
  15. #include <string.h>
  16. #include "third_party/utf/utf.h"
  17. #include "third_party/utf/utfdef.h"
  18. /*
  19. * Return pointer to first occurrence of s2 in s1,
  20. * 0 if none
  21. */
  22. const
  23. Rune*
  24. runestrstr(const Rune *s1, const Rune *s2)
  25. {
  26. const Rune *p, *pa, *pb;
  27. int c0, c;
  28. c0 = *s2;
  29. if(c0 == 0)
  30. return s1;
  31. s2++;
  32. for(p=runestrchr(s1, c0); p; p=runestrchr(p+1, c0)) {
  33. pa = p;
  34. for(pb=s2;; pb++) {
  35. c = *pb;
  36. if(c == 0)
  37. return p;
  38. if(c != *++pa)
  39. break;
  40. }
  41. }
  42. return 0;
  43. }