toolchain/gcc/newlib/libc/string/wcswidth.c

   1 /*
   2 FUNCTION
   3         <<wcswidth>>---number of column positions of a wide-character string
   4
   5 INDEX
   6         wcswidth
   7
   8 ANSI_SYNOPSIS
   9         #include <wchar.h>
  10         int wcswidth(const wchar_t *<[pwcs]>, size_t <[n]>);
  11
  12 TRAD_SYNOPSIS
  13         #include <wchar.h>
  14         int wcswidth(<[pwcs]>, <[n]>)
  15         wchar_t *<[wc]>;
  16         size_t <[n]>;
  17
  18 DESCRIPTION
  19         The <<wcswidth>> function shall determine the number of column
  20         positions required for n wide-character codes (or fewer than n
  21         wide-character codes if a null wide-character code is encountered
  22         before n wide-character codes are exhausted) in the string pointed
  23         to by pwcs.
  24
  25 RETURNS
  26         The <<wcswidth>> function either shall return 0 (if pwcs points to a
  27         null wide-character code), or return the number of column positions
  28         to be occupied by the wide-character string pointed to by pwcs, or
  29         return -1 (if any of the first n wide-character codes in the
  30         wide-character string pointed to by pwcs is not a printable
  31         wide-character code).
  32
  33 PORTABILITY
  34 <<wcswidth>> has been introduced in the Single UNIX Specification Volume 2
  35 <<wcswidth>> has been marked as extension in Single UNIX Specification Volume 3
  36 */
  37
  38 #include <_ansi.h>
  39 #include <wchar.h>
  40
  41 int
  42 _DEFUN (wcswidth, (pwcs, n),
  43         _CONST wchar_t *pwcs _AND
  44         size_t n)
  45
  46 {
  47   int w, len = 0;
  48   if (!pwcs || n == 0)
  49     return 0;
  50   do {
  51     if ((w = wcwidth (*pwcs)) < 0)
  52       return -1;
  53     len += w;
  54   } while (*pwcs++ && --n > 0);
  55   return len;
  56 }