Question

让我们看一看这样的法典:

  my $str =  some text ;
  my $result = my_subroutine($str);

和my_subroutine(>>,应作为《标准指示》加以实施。例如,它可以退还(统一编码)扼杀物的tes。

In the XS code, how to process a string (a) char by char, as a general method, and (b) byte by byte, if the string is composed of ASCII codes subset (a built-in function to convert from the native data srtucture of a string to char[]) ?

Answer 1

在XS层面,你穿透或UTF-8型护卫。在一般情况下,你的代码可能包含一个char *,以标明其行文中的下一个项目。用于XS的一套有用的UTF-8支助职能,改为 section of

http://cpansearch.perl.org/src/PEVANS/Tickit-0.15/lib/Tickit/Utils.xs”rel=“nofollow” http://cpansearch.perl.org/src/PEVANS/Tickit-0.15/lib/Tickit/Utils.xs。

int textwidth(str)
    SV *str
  INIT:
    STRLEN len;
    const char *s, *e;

  CODE:
    RETVAL = 0;

    if(!SvUTF8(str)) {
      str = sv_mortalcopy(str);
      sv_utf8_upgrade(str);
    }

    s = SvPV_const(str, len);
    e = s + len;

    while(s < e) {
      UV ord = utf8n_to_uvchr(s, e-s, &len, (UTF8_DISALLOW_SURROGATE
                                               |UTF8_WARN_SURROGATE
                                               |UTF8_DISALLOW_FE_FF
                                               |UTF8_WARN_FE_FF
                                               |UTF8_WARN_NONCHAR));
      int width = wcwidth(ord);
      if(width == -1)
        XSRETURN_UNDEF;

      s += len;
      RETVAL += width;
    }

  OUTPUT:
    RETVAL

简言之,这项职能在一段时间内使一个统法协会的编码特性发生重叠,从而累积了<代码>wcwidth()所规定的宽度。

Answer 2

如果你重新期望:

STRLEN len;
char* buf = SvPVbyte(sv, len);

while (len--) {
   char byte = *(buf++);

   ... do something with byte ...
}

If you re expecting text or any non-byte characters:

STRLEN len;
U8* buf = SvPVutf8(sv, len);

while (len) {
   STRLEN ch_len;
   UV ch = utf8n_to_uvchr(buf, len, &ch_len, 0);
   buf += ch_len;
   len -= ch_len;

   ... do something with ch ...
}

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