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

   1 /*
   2 FUNCTION
   3         <<wcwidth>>---number of column positions of a wide-character code
   4
   5 INDEX
   6         wcwidth
   7
   8 ANSI_SYNOPSIS
   9         #include <wchar.h>
  10         int wcwidth(const wchar_t <[wc]>);
  11
  12 TRAD_SYNOPSIS
  13         #include <wchar.h>
  14         int wcwidth(<[wc]>)
  15         wchar_t *<[wc]>;
  16
  17 DESCRIPTION
  18         The <<wcwidth>> function shall determine the number of column
  19         positions required for the wide character wc. The application
  20         shall ensure that the value of wc is a character representable
  21         as a wchar_t, and is a wide-character code corresponding to a
  22         valid character in the current locale.
  23
  24 RETURNS
  25         The <<wcwidth>> function shall either return 0 (if wc is a null
  26         wide-character code), or return the number of column positions to
  27         be occupied by the wide-character code wc, or return -1 (if wc
  28         does not correspond to a printable wide-character code).
  29
  30         The current implementation of <<wcwidth>> simply sets the width
  31         of all printable characters to 1 since newlib has no character
  32         tables around.
  33
  34 PORTABILITY
  35 <<wcwidth>> has been introduced in the Single UNIX Specification Volume 2
  36 <<wcwidth>> has been marked as extension in Single UNIX Specification Volume 3
  37 */
  38
  39 #include <_ansi.h>
  40 #include <wchar.h>
  41 #include <wctype.h>
  42
  43 int
  44 _DEFUN (wcwidth, (wc),
  45         _CONST wchar_t wc)
  46
  47 {
  48   if (iswprint (wc))
  49     return 1;
  50   if (iswcntrl (wc) || wc == L'\0')
  51     return 0;
  52   return -1;
  53 }