src/stdlib/wcstod.c

   1 #include "shgetc.h"
   2 #include "floatscan.h"
   3 #include "stdio_impl.h"
   4 #include <wchar.h>
   5 #include <wctype.h>
   6
   7 /* This read function heavily cheats. It knows:
   8  *  (1) len will always be 1
   9  *  (2) non-ascii characters don't matter */
  10
  11 static size_t do_read(FILE *f, unsigned char *buf, size_t len)
  12 {
  13         size_t i;
  14         const wchar_t *wcs = f->cookie;
  15
  16         if (!wcs[0]) wcs=L"@";
  17         for (i=0; i<f->buf_size && wcs[i]; i++)
  18                 f->buf[i] = wcs[i] < 128 ? wcs[i] : '@';
  19         f->rpos = f->buf;
  20         f->rend = f->buf + i;
  21         f->cookie = (void *)(wcs+i);
  22
  23         if (i && len) {
  24                 *buf = *f->rpos++;
  25                 return 1;
  26         }
  27         return 0;
  28 }
  29
  30 static long double wcstox(const wchar_t *s, wchar_t **p, int prec)
  31 {
  32         wchar_t *t = (wchar_t *)s;
  33         unsigned char buf[64];
  34         FILE f = {0};
  35         f.flags = 0;
  36         f.rpos = f.rend = f.buf = buf + 4;
  37         f.buf_size = sizeof buf - 4;
  38         f.lock = -1;
  39         f.read = do_read;
  40         while (iswspace(*t)) t++;
  41         f.cookie = (void *)t;
  42         shlim(&f, 0);
  43         long double y = __floatscan(&f, prec, 1);
  44         if (p) {
  45                 size_t cnt = shcnt(&f);
  46                 *p = cnt ? t + cnt : (wchar_t *)s;
  47         }
  48         return y;
  49 }
  50
  51 float wcstof(const wchar_t *restrict s, wchar_t **restrict p)
  52 {
  53         return wcstox(s, p, 0);
  54 }
  55
  56 double wcstod(const wchar_t *restrict s, wchar_t **restrict p)
  57 {
  58         return wcstox(s, p, 1);
  59 }
  60
  61 long double wcstold(const wchar_t *restrict s, wchar_t **restrict p)
  62 {
  63         return wcstox(s, p, 2);
  64 }