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| 1 /////////////////////////////////////////////////////////////////////////////// |
| 2 // |
| 3 /// \file tuklib_mstr_width.c |
| 4 /// \brief Calculate width of a multibyte string |
| 5 // |
| 6 // Author: Lasse Collin |
| 7 // |
| 8 // This file has been put into the public domain. |
| 9 // You can do whatever you want with this file. |
| 10 // |
| 11 /////////////////////////////////////////////////////////////////////////////// |
| 12 |
| 13 #include "tuklib_mbstr.h" |
| 14 |
| 15 #if defined(HAVE_MBRTOWC) && defined(HAVE_WCWIDTH) |
| 16 # include <wchar.h> |
| 17 #endif |
| 18 |
| 19 |
| 20 extern size_t |
| 21 tuklib_mbstr_width(const char *str, size_t *bytes) |
| 22 { |
| 23 const size_t len = strlen(str); |
| 24 if (bytes != NULL) |
| 25 *bytes = len; |
| 26 |
| 27 #if !(defined(HAVE_MBRTOWC) && defined(HAVE_WCWIDTH)) |
| 28 // In single-byte mode, the width of the string is the same |
| 29 // as its length. |
| 30 return len; |
| 31 |
| 32 #else |
| 33 mbstate_t state; |
| 34 memset(&state, 0, sizeof(state)); |
| 35 |
| 36 size_t width = 0; |
| 37 size_t i = 0; |
| 38 |
| 39 // Convert one multibyte character at a time to wchar_t |
| 40 // and get its width using wcwidth(). |
| 41 while (i < len) { |
| 42 wchar_t wc; |
| 43 const size_t ret = mbrtowc(&wc, str + i, len - i, &state); |
| 44 if (ret < 1 || ret > len) |
| 45 return (size_t)-1; |
| 46 |
| 47 i += ret; |
| 48 |
| 49 const int wc_width = wcwidth(wc); |
| 50 if (wc_width < 0) |
| 51 return (size_t)-1; |
| 52 |
| 53 width += wc_width; |
| 54 } |
| 55 |
| 56 // Require that the string ends in the initial shift state. |
| 57 // This way the caller can be combine the string with other |
| 58 // strings without needing to worry about the shift states. |
| 59 if (!mbsinit(&state)) |
| 60 return (size_t)-1; |
| 61 |
| 62 return width; |
| 63 #endif |
| 64 } |
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