vfprintf.c

Newlib 嵌入式 C库 标准实现代码

				if (expt > 0) {
					size = expt;
					if (prec || flags & ALT)
						size += prec + 1;
				} else	/* "0.X" */
					size = (prec || flags & ALT)
						  ? prec + 2
						  : 1;
			} else if (expt >= ndig) {	/* fixed g fmt */
				size = expt;
				if (flags & ALT)
					++size;
			} else
				size = ndig + (expt > 0 ?
					1 : 2 - expt);

			if (softsign)
				sign = '-';
			break;
#endif /* FLOATING_POINT */
		case 'n':
#ifndef _NO_LONGLONG
			if (flags & QUADINT)
				*GET_ARG (N, ap, quad_ptr_t) = ret;
			else 
#endif
			if (flags & LONGINT)
				*GET_ARG (N, ap, long_ptr_t) = ret;
			else if (flags & SHORTINT)
				*GET_ARG (N, ap, short_ptr_t) = ret;
#ifdef _WANT_IO_C99_FORMATS
			else if (flags & CHARINT)
				*GET_ARG (N, ap, char_ptr_t) = ret;
#endif
			else
				*GET_ARG (N, ap, int_ptr_t) = ret;
			continue;	/* no output */
		case 'O': /* extension */
			flags |= LONGINT;
			/*FALLTHROUGH*/
		case 'o':
			_uquad = UARG ();
			base = OCT;
			goto nosign;
		case 'p':
			/*
			 * ``The argument shall be a pointer to void.  The
			 * value of the pointer is converted to a sequence
			 * of printable characters, in an implementation-
			 * defined manner.''
			 *	-- ANSI X3J11
			 */
			/* NOSTRICT */
			_uquad = (uintptr_t) GET_ARG (N, ap, void_ptr_t);
			base = HEX;
			xdigs = "0123456789abcdef";
			flags |= HEXPREFIX;
			ox[0] = '0';
			ox[1] = ch = 'x';
			goto nosign;
		case 's':
#ifdef _WANT_IO_C99_FORMATS
		case 'S':
#endif
			sign = '\0';
			cp = GET_ARG (N, ap, char_ptr_t);
#ifndef __OPTIMIZE_SIZE__
			/* Behavior is undefined if the user passed a
			   NULL string when precision is not 0.
			   However, if we are not optimizing for size,
			   we might as well mirror glibc behavior.  */
			if (cp == NULL) {
				cp = "(null)";
				size = ((unsigned) prec > 6U) ? 6 : prec;
			}
			else
#endif /* __OPTIMIZE_SIZE__ */
#ifdef _MB_CAPABLE
			if (ch == 'S' || (flags & LONGINT)) {
				mbstate_t ps;
				_CONST wchar_t *wcp;

				wcp = (_CONST wchar_t *)cp;
				size = m = 0;
				memset ((_PTR)&ps, '\0', sizeof (mbstate_t));

				/* Count number of bytes needed for multibyte
				   string that will be produced from widechar
				   string.  */
				if (prec >= 0) {
					while (1) {
						if (wcp[m] == L'\0')
							break;
						if ((n = (int)_wcrtomb_r (data,
						     buf, wcp[m], &ps)) == -1) {
							fp->_flags |= __SERR;
							goto error;
						}
						if (n + size > prec)
							break;
						m += 1;
						size += n;
						if (size == prec)
							break;
					}
				}
				else {
					if ((size = (int)_wcsrtombs_r (data,
						   NULL, &wcp, 0, &ps)) == -1) {
						fp->_flags |= __SERR;
						goto error;
					}
					wcp = (_CONST wchar_t *)cp;
				}

				if (size == 0)
					break;

				if (size >= BUF) {
					if ((malloc_buf =
					     (char *)_malloc_r (data, size + 1))
					    == NULL) {
						fp->_flags |= __SERR;
						goto error;
					}
					cp = malloc_buf;
				} else
					cp = buf;

				/* Convert widechar string to multibyte string. */
				memset ((_PTR)&ps, '\0', sizeof (mbstate_t));
				if (_wcsrtombs_r (data, cp, &wcp, size, &ps)
				    != size) {
					fp->_flags |= __SERR;
					goto error;
				}
				cp[size] = '\0';
			}
			else
#endif /* _MB_CAPABLE */
			if (prec >= 0) {
				/*
				 * can't use strlen; can only look for the
				 * NUL in the first `prec' characters, and
				 * strlen () will go further.
				 */
				char *p = memchr (cp, 0, prec);

				if (p != NULL) {
					size = p - cp;
					if (size > prec)
						size = prec;
				} else
					size = prec;
			} else
				size = strlen (cp);

			break;
		case 'U': /* extension */
			flags |= LONGINT;
			/*FALLTHROUGH*/
		case 'u':
			_uquad = UARG ();
			base = DEC;
			goto nosign;
		case 'X':
			xdigs = "0123456789ABCDEF";
			goto hex;
		case 'x':
			xdigs = "0123456789abcdef";
hex:			_uquad = UARG ();
			base = HEX;
			/* leading 0x/X only if non-zero */
			if (flags & ALT && _uquad != 0) {
				ox[0] = '0';
				ox[1] = ch;
				flags |= HEXPREFIX;
			}

			/* unsigned conversions */
nosign:			sign = '\0';
			/*
			 * ``... diouXx conversions ... if a precision is
			 * specified, the 0 flag will be ignored.''
			 *	-- ANSI X3J11
			 */
number:			if ((dprec = prec) >= 0)
				flags &= ~ZEROPAD;

			/*
			 * ``The result of converting a zero value with an
			 * explicit precision of zero is no characters.''
			 *	-- ANSI X3J11
			 */
			cp = buf + BUF;
			if (_uquad != 0 || prec != 0) {
				/*
				 * Unsigned mod is hard, and unsigned mod
				 * by a constant is easier than that by
				 * a variable; hence this switch.
				 */
				switch (base) {
				case OCT:
					do {
						*--cp = to_char (_uquad & 7);
						_uquad >>= 3;
					} while (_uquad);
					/* handle octal leading 0 */
					if (flags & ALT && *cp != '0')
						*--cp = '0';
					break;

				case DEC:
					/* many numbers are 1 digit */
					while (_uquad >= 10) {
						*--cp = to_char (_uquad % 10);
						_uquad /= 10;
					}
					*--cp = to_char (_uquad);
					break;

				case HEX:
					do {
						*--cp = xdigs[_uquad & 15];
						_uquad >>= 4;
					} while (_uquad);
					break;

				default:
					cp = "bug in vfprintf: bad base";
					size = strlen (cp);
					goto skipsize;
				}
			}
                       /*
			* ...result is to be converted to an 'alternate form'.
			* For o conversion, it increases the precision to force
			* the first digit of the result to be a zero."
			*     -- ANSI X3J11
			*
			* To demonstrate this case, compile and run:
                        *    printf ("%#.0o",0);
			*/
                       else if (base == OCT && (flags & ALT))
                         *--cp = '0';

			size = buf + BUF - cp;
		skipsize:
			break;
		default:	/* "%?" prints ?, unless ? is NUL */
			if (ch == '\0')
				goto done;
			/* pretend it was %c with argument ch */
			cp = buf;
			*cp = ch;
			size = 1;
			sign = '\0';
			break;
		}

		/*
		 * All reasonable formats wind up here.  At this point, `cp'
		 * points to a string which (if not flags&LADJUST) should be
		 * padded out to `width' places.  If flags&ZEROPAD, it should
		 * first be prefixed by any sign or other prefix; otherwise,
		 * it should be blank padded before the prefix is emitted.
		 * After any left-hand padding and prefixing, emit zeroes
		 * required by a decimal [diouxX] precision, then print the
		 * string proper, then emit zeroes required by any leftover
		 * floating precision; finally, if LADJUST, pad with blanks.
		 * If flags&FPT, ch must be in [aAeEfg].
		 *
		 * Compute actual size, so we know how much to pad.
		 * size excludes decimal prec; realsz includes it.
		 */
		realsz = dprec > size ? dprec : size;
		if (sign)
			realsz++;
		if (flags & HEXPREFIX)
			realsz+= 2;

		/* right-adjusting blank padding */
		if ((flags & (LADJUST|ZEROPAD)) == 0)
			PAD (width - realsz, blanks);

		/* prefix */
		if (sign)
			PRINT (&sign, 1);
		if (flags & HEXPREFIX)
			PRINT (ox, 2);

		/* right-adjusting zero padding */
		if ((flags & (LADJUST|ZEROPAD)) == ZEROPAD)
			PAD (width - realsz, zeroes);

		/* leading zeroes from decimal precision */
		PAD (dprec - size, zeroes);

		/* the string or number proper */
#ifdef FLOATING_POINT
		if ((flags & FPT) == 0) {
			PRINT (cp, size);
		} else {	/* glue together f_p fragments */
			if (ch >= 'f') {	/* 'f' or 'g' */
				if (_fpvalue == 0) {
					/* kludge for __dtoa irregularity */
					PRINT ("0", 1);
					if (expt < ndig || flags & ALT) {
						PRINT (decimal_point, 1);
						PAD (ndig - 1, zeroes);
					}
				} else if (expt <= 0) {
					PRINT ("0", 1);
					if (expt || ndig || flags & ALT) {
						PRINT (decimal_point, 1);
						PAD (-expt, zeroes);
						PRINT (cp, ndig);
					}
				} else if (expt >= ndig) {
					PRINT (cp, ndig);
					PAD (expt - ndig, zeroes);
					if (flags & ALT)
						PRINT (decimal_point, 1);
				} else {
					PRINT (cp, expt);
					cp += expt;
					PRINT (decimal_point, 1);
					PRINT (cp, ndig - expt);
				}
			} else {	/* 'a', 'A', 'e', or 'E' */
				if (ndig > 1 || flags & ALT) {
					PRINT (cp, 1);
					cp++;
					PRINT (decimal_point, 1);
					if (_fpvalue) {
						PRINT (cp, ndig - 1);
					} else	/* 0.[0..] */
						/* __dtoa irregularity */
						PAD (ndig - 1, zeroes);
				} else	/* XeYYY */
					PRINT (cp, 1);
				PRINT (expstr, expsize);
			}
		}
#else /* !FLOATING_POINT */
		PRINT (cp, size);
#endif
		/* left-adjusting padding (always blank) */
		if (flags & LADJUST)
			PAD (width - realsz, blanks);

		/* finally, adjust ret */
		ret += width > realsz ? width : realsz;

		FLUSH ();	/* copy out the I/O vectors */

                if (malloc_buf != NULL) {
			_free_r (data, malloc_buf);
			malloc_buf = NULL;
		}
	}
done:
	FLUSH ();
error:
	if (malloc_buf != NULL)
		_free_r (data, malloc_buf);
	_funlockfile (fp);
	return (__sferror (fp) ? EOF : ret);
	/* NOTREACHED */
}

#ifdef FLOATING_POINT

/* Using reentrant DATA, convert finite VALUE into a string of digits
   with no decimal point, using NDIGITS precision and FLAGS as guides
   to whether trailing zeros must be included.  Set *SIGN to nonzero
   if VALUE was negative.  Set *DECPT to the exponent plus one.  Set
   *LENGTH to the length of the returned string.  CH must be one of
   [aAeEfFgG]; if it is [aA], then the return string lives in BUF,
   otherwise the return value shares the mprec reentrant storage.  */
static char *
cvt(struct _reent *data, _PRINTF_FLOAT_TYPE value, int ndigits, int flags,
    char *sign, int *decpt, int ch, int *length, char *buf)
{
	int mode, dsgn;
	char *digits, *bp, *rve;
# ifdef _NO_LONGDBL
	union double_union tmp;

	tmp.d = value;
	if (word0 (tmp) & Sign_bit) { /* this will check for < 0 and -0.0 */
		value = -value;
		*sign = '-';
	} else
		*sign = '\000';
# else /* !_NO_LONGDBL */
	union
	{
	  struct ldieee ieee;
	  _LONG_DOUBLE val;
	} ld;

	ld.val = value;
	if (ld.ieee.sign) { /* this will check for < 0 and -0.0 */
		value = -value;
		*sign = '-';
	} else
		*sign = '\000';
# endif /* !_NO_LONGDBL */

# ifdef _WANT_IO_C99_FORMATS
	if (ch == 'a' || ch == 'A') {
		/* This code assumes FLT_RADIX is a power of 2.  The initial
		   division ensures the digit before the decimal will be less
		   than FLT_RADIX (unless it is rounded later).	 There is no
		   loss of precision in these calculations.  */
		value = FREXP (value, decpt) / 8;
		if (!value)
			*decpt = 1;
		digits = ch == 'a' ? "0123456789abcdef" : "0123456789ABCDEF";
		bp = buf;
		do {
			value *= 16;
			mode = (int) value;
			value -= mode;
			*bp++ = digits[mode];
		} while (ndigits-- && value);
		if (value > 0.5 || (value == 0.5 && mode & 1)) {
			/* round to even */
			rve = bp;
			while (*--rve == digits[0xf]) {
				*rve = '0';
			}
			*rve = *rve == '9' ? digits[0xa] : *rve + 1;
		} else {
			while (ndigits-- >= 0) {
				*bp++ = '0';
			}
		}
		*length = bp - buf;
		return buf;
	}
# endif /* _WANT_IO_C99_FORMATS */
	if (ch == 'f' || ch == 'F') {
		mode = 3;		/* ndigits after the decimal point */
	} else {
		/* To obtain ndigits after the decimal point for the 'e'
		 * and 'E' formats, round to ndigits + 1 significant
		 * figures.
		 */
		if (ch == 'e' || ch == 'E') {
			ndigits++;
		}
		mode = 2;		/* ndigits significant digits */
	}

	digits = _DTOA_R (data, value, mode, ndigits, decpt, &dsgn, &rve);

	if ((ch != 'g' && ch != 'G') || flags & ALT) {	/* Print trailing zeros */
		bp = digits + ndigits;
		if (ch == 'f' || ch == 'F') {
			if (*digits == '0' && value)
				*decpt = -ndigits + 1;
			bp += *decpt;
		}
		if (value == 0)	/* kludge for __dtoa irregularity */
			rve = bp;
		while (rve < bp)
			*rve++ = '0';
	}
	*length = rve - digits;
	return (digits);
}

static int
exponent(char *p0, int exp, int fmtch)
{
	register char *p, *t;
	char expbuf[MAXEXPLEN];
# ifdef _WANT_IO_C99_FORMATS
	int isa = fmtch == 'a' || fmtch == 'A';
# else
#  define isa 0