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///////////////////////////////////////////////////////////////////////////////
//
/// \file tuklib_mbstr_width.c
/// \brief Calculate width of a multibyte string
//
// Author: Lasse Collin
//
///////////////////////////////////////////////////////////////////////////////
#include "tuklib_mbstr.h"
#include <string.h>
#if defined(HAVE_MBRTOWC) && defined(HAVE_WCWIDTH)
# include <wchar.h>
#endif
extern size_t
tuklib_mbstr_width(const char *str, size_t *bytes)
{
const size_t len = strlen(str);
if (bytes != NULL)
*bytes = len;
#if !(defined(HAVE_MBRTOWC) && defined(HAVE_WCWIDTH))
// In single-byte mode, the width of the string is the same
// as its length.
return len;
#else
mbstate_t state;
memset(&state, 0, sizeof(state));
size_t width = 0;
size_t i = 0;
// Convert one multibyte character at a time to wchar_t
// and get its width using wcwidth().
while (i < len) {
wchar_t wc;
const size_t ret = mbrtowc(&wc, str + i, len - i, &state);
if (ret < 1 || ret > len)
return (size_t)-1;
i += ret;
const int wc_width = wcwidth(wc);
if (wc_width < 0)
return (size_t)-1;
width += (size_t)wc_width;
}
// Require that the string ends in the initial shift state.
// This way the caller can be combine the string with other
// strings without needing to worry about the shift states.
if (!mbsinit(&state))
return (size_t)-1;
return width;
#endif
}
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