wcstombs_r.c

Newlib 嵌入式 C库 标准实现代码

#include <stdlib.h>
#include <wchar.h>

size_t
_DEFUN (_wcstombs_r, (reent, s, pwcs, n, state),
        struct _reent *r    _AND         
        char          *s    _AND
        const wchar_t *pwcs _AND
        size_t         n    _AND
        mbstate_t     *state)
{
  char *ptr = s;
  size_t max = n;
  char buff[8];
  int i, num_to_copy;

  if (s == NULL)
    {
      size_t num_bytes = 0;
      while (*pwcs != 0)
         num_bytes += _wctomb_r (r, buff, *pwcs++, state);
      return num_bytes;
    }
  else
    {
      while (n > 0)
        {
          int bytes = _wctomb_r (r, buff, *pwcs, state);
          if (bytes == -1)
            return -1;
          num_to_copy = (n > bytes ? bytes : (int)n);
          for (i = 0; i < num_to_copy; ++i)
            *ptr++ = buff[i];
          
          if (*pwcs == 0x00)
            return ptr - s - (n >= bytes);
          ++pwcs;
          n -= num_to_copy;
        }
      return max;
    }
}