| 1 | /* |
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| 2 | FUNCTION |
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| 3 | <<wcswidth>>---number of column positions of a wide-character string |
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| 4 | |
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| 5 | INDEX |
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| 6 | wcswidth |
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| 7 | |
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| 8 | SYNOPSIS |
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| 9 | #include <wchar.h> |
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| 10 | int wcswidth(const wchar_t *<[pwcs]>, size_t <[n]>); |
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| 11 | |
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| 12 | DESCRIPTION |
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| 13 | The <<wcswidth>> function shall determine the number of column |
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| 14 | positions required for <[n]> wide-character codes (or fewer than <[n]> |
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| 15 | wide-character codes if a null wide-character code is encountered |
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| 16 | before <[n]> wide-character codes are exhausted) in the string pointed |
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| 17 | to by <[pwcs]>. |
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| 18 | |
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| 19 | RETURNS |
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| 20 | The <<wcswidth>> function either shall return 0 (if <[pwcs]> points to a |
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| 21 | null wide-character code), or return the number of column positions |
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| 22 | to be occupied by the wide-character string pointed to by <[pwcs]>, or |
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| 23 | return -1 (if any of the first <[n]> wide-character codes in the |
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| 24 | wide-character string pointed to by <[pwcs]> is not a printable |
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| 25 | wide-character code). |
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| 26 | |
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| 27 | PORTABILITY |
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| 28 | <<wcswidth>> has been introduced in the Single UNIX Specification Volume 2. |
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| 29 | <<wcswidth>> has been marked as an extension in the Single UNIX Specification Volume 3. |
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| 30 | */ |
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| 31 | |
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| 32 | #include <_ansi.h> |
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| 33 | #include <wchar.h> |
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| 34 | #include "local.h" |
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| 35 | |
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| 36 | int |
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| 37 | wcswidth (const wchar_t *pwcs, |
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| 38 | size_t n) |
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| 39 | |
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| 40 | { |
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| 41 | int w, len = 0; |
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| 42 | if (!pwcs || n == 0) |
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| 43 | return 0; |
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| 44 | do { |
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| 45 | wint_t wi = *pwcs; |
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| 46 | |
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| 47 | #ifdef _MB_CAPABLE |
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| 48 | wi = _jp2uc (wi); |
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| 49 | /* First half of a surrogate pair? */ |
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| 50 | if (sizeof (wchar_t) == 2 && wi >= 0xd800 && wi <= 0xdbff) |
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| 51 | { |
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| 52 | wint_t wi2; |
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| 53 | |
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| 54 | /* Extract second half and check for validity. */ |
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| 55 | if (--n == 0 || (wi2 = _jp2uc (*++pwcs)) < 0xdc00 || wi2 > 0xdfff) |
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| 56 | return -1; |
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| 57 | /* Compute actual unicode value to use in call to __wcwidth. */ |
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| 58 | wi = (((wi & 0x3ff) << 10) | (wi2 & 0x3ff)) + 0x10000; |
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| 59 | } |
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| 60 | #endif /* _MB_CAPABLE */ |
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| 61 | if ((w = __wcwidth (wi)) < 0) |
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| 62 | return -1; |
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| 63 | len += w; |
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| 64 | } while (*pwcs++ && --n > 0); |
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| 65 | return len; |
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| 66 | } |
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