u8-uctomb.c 2.0 KB

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  1. /* Store a character in UTF-8 string.
  2. Copyright (C) 2002, 2005-2006, 2009-2020 Free Software Foundation, Inc.
  3. Written by Bruno Haible <bruno@clisp.org>, 2002.
  4. This program is free software: you can redistribute it and/or modify it
  5. under the terms of the GNU General Public License as published
  6. by the Free Software Foundation; either version 3 of the License, or
  7. (at your option) any later version.
  8. This program is distributed in the hope that it will be useful,
  9. but WITHOUT ANY WARRANTY; without even the implied warranty of
  10. MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  11. General Public License for more details.
  12. You should have received a copy of the GNU General Public License
  13. along with this program. If not, see <https://www.gnu.org/licenses/>. */
  14. #include <config.h>
  15. #if defined IN_LIBUNISTRING
  16. /* Tell unistr.h to declare u8_uctomb as 'extern', not 'static inline'. */
  17. # error #include "unistring-notinline.h"
  18. #endif
  19. /* Specification. */
  20. #include "unistr.h"
  21. #include "attribute.h"
  22. #if !HAVE_INLINE
  23. int
  24. u8_uctomb (uint8_t *s, ucs4_t uc, ptrdiff_t n)
  25. {
  26. if (uc < 0x80)
  27. {
  28. if (n > 0)
  29. {
  30. s[0] = uc;
  31. return 1;
  32. }
  33. /* else return -2, below. */
  34. }
  35. else
  36. {
  37. int count;
  38. if (uc < 0x800)
  39. count = 2;
  40. else if (uc < 0x10000)
  41. {
  42. if (uc < 0xd800 || uc >= 0xe000)
  43. count = 3;
  44. else
  45. return -1;
  46. }
  47. else if (uc < 0x110000)
  48. count = 4;
  49. else
  50. return -1;
  51. if (n >= count)
  52. {
  53. switch (count) /* note: code falls through cases! */
  54. {
  55. case 4: s[3] = 0x80 | (uc & 0x3f); uc = uc >> 6; uc |= 0x10000;
  56. FALLTHROUGH;
  57. case 3: s[2] = 0x80 | (uc & 0x3f); uc = uc >> 6; uc |= 0x800;
  58. FALLTHROUGH;
  59. case 2: s[1] = 0x80 | (uc & 0x3f); uc = uc >> 6; uc |= 0xc0;
  60. /*case 1:*/ s[0] = uc;
  61. }
  62. return count;
  63. }
  64. }
  65. return -2;
  66. }
  67. #endif