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 } 65