curl_memrchr.c 1.8 KB

12345678910111213141516171819202122232425262728293031323334353637383940414243444546474849505152535455565758596061626364
  1. /***************************************************************************
  2. * _ _ ____ _
  3. * Project ___| | | | _ \| |
  4. * / __| | | | |_) | |
  5. * | (__| |_| | _ <| |___
  6. * \___|\___/|_| \_\_____|
  7. *
  8. * Copyright (C) 1998 - 2022, Daniel Stenberg, <daniel@haxx.se>, et al.
  9. *
  10. * This software is licensed as described in the file COPYING, which
  11. * you should have received as part of this distribution. The terms
  12. * are also available at https://curl.se/docs/copyright.html.
  13. *
  14. * You may opt to use, copy, modify, merge, publish, distribute and/or sell
  15. * copies of the Software, and permit persons to whom the Software is
  16. * furnished to do so, under the terms of the COPYING file.
  17. *
  18. * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
  19. * KIND, either express or implied.
  20. *
  21. * SPDX-License-Identifier: curl
  22. *
  23. ***************************************************************************/
  24. #include "curl_setup.h"
  25. #include <curl/curl.h>
  26. #include "curl_memrchr.h"
  27. #include "curl_memory.h"
  28. /* The last #include file should be: */
  29. #include "memdebug.h"
  30. #ifndef HAVE_MEMRCHR
  31. /*
  32. * Curl_memrchr()
  33. *
  34. * Our memrchr() function clone for systems which lack this function. The
  35. * memrchr() function is like the memchr() function, except that it searches
  36. * backwards from the end of the n bytes pointed to by s instead of forward
  37. * from the beginning.
  38. */
  39. void *
  40. Curl_memrchr(const void *s, int c, size_t n)
  41. {
  42. if(n > 0) {
  43. const unsigned char *p = s;
  44. const unsigned char *q = s;
  45. p += n - 1;
  46. while(p >= q) {
  47. if(*p == (unsigned char)c)
  48. return (void *)p;
  49. p--;
  50. }
  51. }
  52. return NULL;
  53. }
  54. #endif /* HAVE_MEMRCHR */