vfscanf.c

Newlib 嵌入式 C库 标准实现代码

		    if (__srefill (fp))
#endif
		      goto input_failure;
		}
	    }

 	}
      else /* save to counter-act changes made to flags when processing */
	orig_flags = flags;

      /*
       * Do the conversion.
       */
      switch (type)
	{

	case CT_CHAR:
	  /* scan arbitrary characters (sets NOSKIP) */
	  if (width == 0)
	    width = 1;
	  if (flags & SUPPRESS)
	    {
	      size_t sum = 0;

	      for (;;)
		{
		  if ((n = fp->_r) < (int)width)
		    {
		      sum += n;
		      width -= n;
		      fp->_p += n;
#ifndef CYGNUS_NEC
		      if (__srefill (fp))
			{
#endif
			  if (sum == 0)
			    goto input_failure;
			  break;
#ifndef CYGNUS_NEC
			}
#endif
		    }
		  else
		    {
		      sum += width;
		      fp->_r -= width;
		      fp->_p += width;
		      break;
		    }
		}
	      nread += sum;
	    }
	  else
	    {
	      int n = width;
	      if (!looped)
		{
		  if (flags & VECTOR)
		    ch_dest = vec_buf.c;
		  else
		    ch_dest = va_arg (ap, char *);
		}
#ifdef CYGNUS_NEC
	      /* Kludge city for the moment */
	      if (fp->_r == 0)
		goto input_failure;

	      while (n && fp->_r)
		{
		  *ch_dest++ = *(fp->_p++);
		  n--;
		  fp->_r--;
		  nread++;
		}
#else
	      size_t r = fread (ch_dest, 1, width, fp);

	      if (r == 0)
		goto input_failure;
	      nread += r;
	      ch_dest += r;
#endif
	      if (!(flags & VECTOR))
		nassigned++;
	    }
	  break;

	case CT_CCL:
	  /* scan a (nonempty) character class (sets NOSKIP) */
	  if (width == 0)
	    width = ~0;		/* `infinity' */
	  /* take only those things in the class */
	  if (flags & SUPPRESS)
	    {
	      n = 0;
	      while (ccltab[*fp->_p])
		{
		  n++, fp->_r--, fp->_p++;
		  if (--width == 0)
		    break;
		  if (BufferEmpty)
		    {
		      if (n == 0)
			goto input_failure;
		      break;
		    }
		}
	      if (n == 0)
		goto match_failure;
	    }
	  else
	    {
	      p0 = p = va_arg (ap, char *);
	      while (ccltab[*fp->_p])
		{
		  fp->_r--;
		  *p++ = *fp->_p++;
		  if (--width == 0)
		    break;
		  if (BufferEmpty)
		    {
		      if (p == p0)
			goto input_failure;
		      break;
		    }
		}
	      n = p - p0;
	      if (n == 0)
		goto match_failure;
	      *p = 0;
	      nassigned++;
	    }
	  nread += n;
	  break;

	case CT_STRING:
	  /* like CCL, but zero-length string OK, & no NOSKIP */
	  if (width == 0)
	    width = ~0;
	  if (flags & SUPPRESS)
	    {
	      n = 0;
	      while (!isspace (*fp->_p))
		{
		  n++, fp->_r--, fp->_p++;
		  if (--width == 0)
		    break;
		  if (BufferEmpty)
		    break;
		}
	      nread += n;
	    }
	  else
	    {
	      p0 = p = va_arg (ap, char *);
	      while (!isspace (*fp->_p))
		{
		  fp->_r--;
		  *p++ = *fp->_p++;
		  if (--width == 0)
		    break;
		  if (BufferEmpty)
		    break;
		}
	      *p = 0;
	      nread += p - p0;
	      nassigned++;
	    }
	  continue;

	case CT_INT:
	  {
	  unsigned int_width_left = 0;
	  int skips = 0;
	  int_width = width;
#ifdef hardway
	  if (int_width == 0 || int_width > sizeof (buf) - 1)
#else
	  /* size_t is unsigned, hence this optimisation */
	  if (int_width - 1 > sizeof (buf) - 2)
#endif
	    {
	      int_width_left = width - (sizeof (buf) - 1);
	      int_width = sizeof (buf) - 1;
	    }
	  flags |= SIGNOK | NDIGITS | NZDIGITS | NNZDIGITS;
	  for (p = buf; int_width; int_width--)
	    {
	      c = *fp->_p;
	      /*
	       * Switch on the character; `goto ok' if we
	       * accept it as a part of number.
	       */
	      switch (c)
		{
		  /*
		   * The digit 0 is always legal, but is special.
		   * For %i conversions, if no digits (zero or nonzero)
		   * have been scanned (only signs), we will have base==0.
		   * In that case, we should set it to 8 and enable 0x
		   * prefixing. Also, if we have not scanned zero digits
		   * before this, do not turn off prefixing (someone else
		   * will turn it off if we have scanned any nonzero digits).
		   */
		case '0':
		  if (! (flags & NNZDIGITS))
		    goto ok;
		  if (base == 0)
		    {
		      base = 8;
		      flags |= PFXOK;
		    }
		  if (flags & NZDIGITS)
		    {
		      flags &= ~(SIGNOK | NZDIGITS | NDIGITS);
		      goto ok;
		    }
		  flags &= ~(SIGNOK | PFXOK | NDIGITS);
		  if (int_width_left)
		    {
		      int_width_left--;
		      int_width++;
		    }
		  ++skips;
		  goto skip;

		  /* 1 through 7 always legal */
		case '1':
		case '2':
		case '3':
		case '4':
		case '5':
		case '6':
		case '7':
		  base = basefix[base];
		  flags &= ~(SIGNOK | PFXOK | NDIGITS | NNZDIGITS);
		  goto ok;

		  /* digits 8 and 9 ok iff decimal or hex */
		case '8':
		case '9':
		  base = basefix[base];
		  if (base <= 8)
		    break;	/* not legal here */
		  flags &= ~(SIGNOK | PFXOK | NDIGITS | NNZDIGITS);
		  goto ok;

		  /* letters ok iff hex */
		case 'A':
		case 'B':
		case 'C':
		case 'D':
		case 'E':
		case 'F':
		case 'a':
		case 'b':
		case 'c':
		case 'd':
		case 'e':
		case 'f':
		  /* no need to fix base here */
		  if (base <= 10)
		    break;	/* not legal here */
		  flags &= ~(SIGNOK | PFXOK | NDIGITS | NNZDIGITS);
		  goto ok;

		  /* sign ok only as first character */
		case '+':
		case '-':
		  if (flags & SIGNOK)
		    {
		      flags &= ~SIGNOK;
		      goto ok;
		    }
		  break;

		  /* x ok iff flag still set & 2nd char */
		case 'x':
		case 'X':
		  if (flags & PFXOK && p == buf + 1)
		    {
		      base = 16;/* if %i */
		      flags &= ~PFXOK;
		      /* We must reset the NZDIGITS and NDIGITS
		         flags that would have been unset by seeing
		         the zero that preceded the X or x.  */
		      flags |= NZDIGITS | NDIGITS;
		      goto ok;
		    }
		  break;
		}

	      /*
	       * If we got here, c is not a legal character
	       * for a number.  Stop accumulating digits.
	       */
	      break;
	    ok:
	      /*
	       * c is legal: store it and look at the next.
	       */
	      *p++ = c;
	    skip:
	      if (--fp->_r > 0)
		fp->_p++;
	      else
#ifndef CYGNUS_NEC
	      if (__srefill (fp))
#endif
		break;		/* EOF */
	    }
	  /*
	   * If we had only a sign, it is no good; push back the sign.
	   * If the number ends in `x', it was [sign] '0' 'x', so push back
	   * the x and treat it as [sign] '0'.
	   */
	  if (flags & NDIGITS)
	    {
	      if (p > buf)
		_CAST_VOID ungetc (*(u_char *)-- p, fp);
	      goto match_failure;
	    }
	  c = ((u_char *) p)[-1];
	  if (c == 'x' || c == 'X')
	    {
	      --p;
	      /*(void)*/ ungetc (c, fp);
	    }
	  if ((flags & SUPPRESS) == 0)
	    {
	      u_long res;

	      *p = 0;
	      res = (*ccfn) (rptr, buf, (char **) NULL, base);
	      if ((flags & POINTER) && !(flags & VECTOR))
		*(va_arg (ap, _PTR *)) = (_PTR) (unsigned _POINTER_INT) res;
	      else if (flags & SHORT)
		{
		  if (!(flags & VECTOR))
		    sp = va_arg (ap, short *);
		  else if (!looped)
		    sp = vec_buf.h;
		  *sp++ = res;
		}
	      else if (flags & LONG)
		{
		  if (!(flags & VECTOR))
		    lp = va_arg (ap, long *);
		  else if (!looped)
		    lp = vec_buf.l;
		  *lp++ = res;
		}
#ifndef _NO_LONGLONG
	      else if (flags & LONGDBL)
		{
		  u_long_long resll;
		  if (ccfn == _strtoul_r)
		    resll = _strtoull_r (rptr, buf, (char **) NULL, base);
		  else
		    resll = _strtoll_r (rptr, buf, (char **) NULL, base);
		  llp = va_arg (ap, long long*);
		  *llp = resll;
		}
#endif
	      else
		{
		  if (!(flags & VECTOR))
		    {
		      ip = va_arg (ap, int *);
		      *ip++ = res;
		    }
		  else
		    {
		      if (!looped)
			ch_dest = vec_buf.c;
		      *ch_dest++ = (char)res;
		    }
		}
	      if (!(flags & VECTOR))
		nassigned++;
	    }
	  nread += p - buf + skips;
	  break;
	  }

#ifdef FLOATING_POINT
	case CT_FLOAT:
	{
	  /* scan a floating point number as if by strtod */
	  /* This code used to assume that the number of digits is reasonable.
	     However, ANSI / ISO C makes no such stipulation; we have to get
	     exact results even when there is an unreasonable amount of
	     leading zeroes.  */
	  long leading_zeroes = 0;
	  long zeroes, exp_adjust;
	  char *exp_start = NULL;
	  unsigned fl_width = width;
	  unsigned width_left = 0;
#ifdef hardway
	  if (fl_width == 0 || fl_width > sizeof (buf) - 1)
#else
	  /* size_t is unsigned, hence this optimisation */
	  if (fl_width - 1 > sizeof (buf) - 2)
#endif
	    {
	      width_left = fl_width - (sizeof (buf) - 1);
	      fl_width = sizeof (buf) - 1;
	    }
	  flags |= SIGNOK | NDIGITS | DPTOK | EXPOK;
	  zeroes = 0;
	  exp_adjust = 0;
	  for (p = buf; fl_width; )
	    {
	      c = *fp->_p;
	      /*
	       * This code mimicks the integer conversion
	       * code, but is much simpler.
	       */
	      switch (c)
		{

		case '0':
		  if (flags & NDIGITS)
		    {
		      flags &= ~SIGNOK;
		      zeroes++;
		      if (width_left)
			{
			  width_left--;
			  fl_width++;
			}
		      goto fskip;
		    }
		  /* Fall through.  */
		case '1':
		case '2':
		case '3':
		case '4':
		case '5':
		case '6':
		case '7':
		case '8':
		case '9':
		  flags &= ~(SIGNOK | NDIGITS);
		  goto fok;

		case '+':
		case '-':
		  if (flags & SIGNOK)
		    {
		      flags &= ~SIGNOK;
		      goto fok;
		    }
		  break;
		case '.':
		  if (flags & DPTOK)
		    {
		      flags &= ~(SIGNOK | DPTOK);
		      leading_zeroes = zeroes;
		      goto fok;
		    }
		  break;
		case 'e':
		case 'E':
		  /* no exponent without some digits */
		  if ((flags & (NDIGITS | EXPOK)) == EXPOK
		      || ((flags & EXPOK) && zeroes))
		    {
		      if (! (flags & DPTOK))
			{
			  exp_adjust = zeroes - leading_zeroes;
			  exp_start = p;
			}
		      flags =
			(flags & ~(EXPOK | DPTOK)) |
			SIGNOK | NDIGITS;
		      zeroes = 0;
		      goto fok;
		    }
		  break;
		}
	      break;
	    fok:
	      *p++ = c;
	    fskip:
	      fl_width--;
              ++nread;
	      if (--fp->_r > 0)
		fp->_p++;
	      else
#ifndef CYGNUS_NEC
	      if (__srefill (fp))
#endif
		break;		/* EOF */
	    }
	  if (zeroes)
	    flags &= ~NDIGITS;
	  /*
	   * If no digits, might be missing exponent digits
	   * (just give back the exponent) or might be missing
	   * regular digits, but had sign and/or decimal point.
	   */
	  if (flags & NDIGITS)
	    {
	      if (flags & EXPOK)
		{
		  /* no digits at all */
		  while (p > buf)
                    {
		      ungetc (*(u_char *)-- p, fp);
                      --nread;
                    }
		  goto match_failure;
		}
	      /* just a bad exponent (e and maybe sign) */
	      c = *(u_char *)-- p;
              --nread;
	      if (c != 'e' && c != 'E')
		{
		  _CAST_VOID ungetc (c, fp);	/* sign */
		  c = *(u_char *)-- p;
                  --nread;
		}
	      _CAST_VOID ungetc (c, fp);
	    }
	  if ((flags & SUPPRESS) == 0)
	    {
#ifdef _NO_LONGDBL
	      double res;
#else  /* !_NO_LONG_DBL */
	      long double res;
#endif /* !_NO_LONG_DBL */
	      long new_exp = 0;

	      *p = 0;
	      if ((flags & (DPTOK | EXPOK)) == EXPOK)
		{
		  exp_adjust = zeroes - leading_zeroes;
		  new_exp = -exp_adjust;
		  exp_start = p;
		}
	      else if (exp_adjust)
                new_exp = _strtol_r (rptr, (exp_start + 1), NULL, 10) - exp_adjust;
	      if (exp_adjust)
		{

		  /* If there might not be enough space for the new exponent,
		     truncate some trailing digits to make room.  */
		  if (exp_start >= buf + sizeof (buf) - MAX_LONG_LEN)
		    exp_start = buf + sizeof (buf) - MAX_LONG_LEN - 1;
                 sprintf (exp_start, "e%ld", new_exp);
		}
#ifdef __SPE__
	      if (flags & FIXEDPOINT)
		{
		  __uint64_t ufix64;
		  if (flags & SIGNED)
		    ufix64 = (__uint64_t)_strtosfix64_r (rptr, buf, NULL);
                  else
		    ufix64 = _strtoufix64_r (rptr, buf, NULL);
		  if (flags & SHORT)
		    {
		      __uint16_t *sp = va_arg (ap, __uint16_t *);
		      *sp = (__uint16_t)(ufix64 >> 48);
		    }
		  else if (flags & LONG)
		    {
		      __uint64_t *llp = va_arg (ap, __uint64_t *);
		      *llp = ufix64;
		    }
		  else
		    {
		      __uint32_t *lp = va_arg (ap, __uint32_t *);
		      *lp = (__uint32_t)(ufix64 >> 32);
		    }
		  nassigned++;
		  break;
		}
	      
#endif /* __SPE__ */
#ifdef _NO_LONGDBL
	      res = _strtod_r (rptr, buf, NULL);
#else  /* !_NO_LONGDBL */
	      res = _strtold (buf, NULL);
#endif /* !_NO_LONGDBL */
	      if (flags & LONG)
		{
		  dp = va_arg (ap, double *);
		  *dp = res;
		}
	      else if (flags & LONGDBL)
		{
		  ldp = va_arg (ap, _LONG_DOUBLE *);
		  *ldp = res;
		}
	      else
		{
		  if (!(flags & VECTOR))
		    flp = va_arg (ap, float *);
		  else if (!looped)
		    flp = vec_buf.f;
		  *flp++ = res;
		}
	      if (!(flags & VECTOR))
		nassigned++;
	    }
	  break;
	}
#endif /* FLOATING_POINT */
	}
      if (vec_read_count-- > 1)
	{
	  looped = 1;
	  goto process;
	}
      if (flags & VECTOR)
	{
	  int i;
	  unsigned long *vp = va_arg (ap, unsigned long *);
	  for (i = 0; i < 4; ++i)
	    *vp++ = vec_buf.l[i];
	  nassigned++;
	}
    }
input_failure:
  return nassigned ? nassigned : -1;
match_failure:
  return nassigned;
}