1 | /* Copyright (C) 1995-2020 Free Software Foundation, Inc. |
---|---|

2 | This file is part of the GNU C Library. |

3 | Contributed by Ulrich Drepper <drepper@gnu.ai.mit.edu>, 1995. |

4 | |

5 | The GNU C Library is free software; you can redistribute it and/or |

6 | modify it under the terms of the GNU Lesser General Public |

7 | License as published by the Free Software Foundation; either |

8 | version 2.1 of the License, or (at your option) any later version. |

9 | |

10 | The GNU C Library is distributed in the hope that it will be useful, |

11 | but WITHOUT ANY WARRANTY; without even the implied warranty of |

12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |

13 | Lesser General Public License for more details. |

14 | |

15 | You should have received a copy of the GNU Lesser General Public |

16 | License along with the GNU C Library; if not, see |

17 | <https://www.gnu.org/licenses/>. */ |

18 | |

19 | #include <wchar.h> |

20 | |

21 | |

22 | /* Append no more than N wide-character of SRC onto DEST. */ |

23 | wchar_t * |

24 | __wcsncat_chk (wchar_t *dest, const wchar_t *src, size_t n, size_t destlen) |

25 | { |

26 | wchar_t c; |

27 | wchar_t * const s = dest; |

28 | |

29 | /* Find the end of DEST. */ |

30 | do |

31 | { |

32 | if (__glibc_unlikely (destlen-- == 0)) |

33 | __chk_fail (); |

34 | c = *dest++; |

35 | } |

36 | while (c != L'\0'); |

37 | |

38 | /* Make DEST point before next character, so we can increment |

39 | it while memory is read (wins on pipelined cpus). */ |

40 | ++destlen; |

41 | dest -= 2; |

42 | |

43 | if (n >= 4) |

44 | { |

45 | size_t n4 = n >> 2; |

46 | do |

47 | { |

48 | if (__glibc_unlikely (destlen-- == 0)) |

49 | __chk_fail (); |

50 | c = *src++; |

51 | *++dest = c; |

52 | if (c == L'\0') |

53 | return s; |

54 | if (__glibc_unlikely (destlen-- == 0)) |

55 | __chk_fail (); |

56 | c = *src++; |

57 | *++dest = c; |

58 | if (c == L'\0') |

59 | return s; |

60 | if (__glibc_unlikely (destlen-- == 0)) |

61 | __chk_fail (); |

62 | c = *src++; |

63 | *++dest = c; |

64 | if (c == L'\0') |

65 | return s; |

66 | if (__glibc_unlikely (destlen-- == 0)) |

67 | __chk_fail (); |

68 | c = *src++; |

69 | *++dest = c; |

70 | if (c == L'\0') |

71 | return s; |

72 | } while (--n4 > 0); |

73 | n &= 3; |

74 | } |

75 | |

76 | while (n > 0) |

77 | { |

78 | if (__glibc_unlikely (destlen-- == 0)) |

79 | __chk_fail (); |

80 | c = *src++; |

81 | *++dest = c; |

82 | if (c == L'\0') |

83 | return s; |

84 | n--; |

85 | } |

86 | |

87 | if (c != L'\0') |

88 | { |

89 | if (__glibc_unlikely (destlen-- == 0)) |

90 | __chk_fail (); |

91 | *++dest = L'\0'; |

92 | } |

93 | |

94 | return s; |

95 | } |

96 |