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