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vfprintf.c revision 1.32
      1 /*	$NetBSD: vfprintf.c,v 1.32 1999/09/20 04:39:33 lukem Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 1990 The Regents of the University of California.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to Berkeley by
      8  * Chris Torek.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  * 3. All advertising materials mentioning features or use of this software
     19  *    must display the following acknowledgement:
     20  *	This product includes software developed by the University of
     21  *	California, Berkeley and its contributors.
     22  * 4. Neither the name of the University nor the names of its contributors
     23  *    may be used to endorse or promote products derived from this software
     24  *    without specific prior written permission.
     25  *
     26  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     27  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     28  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     29  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     30  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     31  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     32  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     33  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     34  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     35  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     36  * SUCH DAMAGE.
     37  */
     38 
     39 #include <sys/cdefs.h>
     40 #if defined(LIBC_SCCS) && !defined(lint)
     41 #if 0
     42 static char *sccsid = "@(#)vfprintf.c	5.50 (Berkeley) 12/16/92";
     43 #else
     44 __RCSID("$NetBSD: vfprintf.c,v 1.32 1999/09/20 04:39:33 lukem Exp $");
     45 #endif
     46 #endif /* LIBC_SCCS and not lint */
     47 
     48 /*
     49  * Actual printf innards.
     50  *
     51  * This code is large and complicated...
     52  */
     53 
     54 #include "namespace.h"
     55 #include <sys/types.h>
     56 
     57 #include <assert.h>
     58 #include <errno.h>
     59 #include <stdio.h>
     60 #include <stdlib.h>
     61 #include <string.h>
     62 
     63 #if __STDC__
     64 #include <stdarg.h>
     65 #else
     66 #include <varargs.h>
     67 #endif
     68 
     69 #include "local.h"
     70 #include "fvwrite.h"
     71 #include "extern.h"
     72 #include "reentrant.h"
     73 
     74 static int __sprint __P((FILE *, struct __suio *));
     75 static int __sbprintf __P((FILE *, const char *, va_list));
     76 
     77 /*
     78  * Flush out all the vectors defined by the given uio,
     79  * then reset it so that it can be reused.
     80  */
     81 static int
     82 __sprint(fp, uio)
     83 	FILE *fp;
     84 	struct __suio *uio;
     85 {
     86 	int err;
     87 
     88 	_DIAGASSERT(fp != NULL);
     89 	_DIAGASSERT(uio != NULL);
     90 
     91 	if (uio->uio_resid == 0) {
     92 		uio->uio_iovcnt = 0;
     93 		return (0);
     94 	}
     95 	err = __sfvwrite(fp, uio);
     96 	uio->uio_resid = 0;
     97 	uio->uio_iovcnt = 0;
     98 	return (err);
     99 }
    100 
    101 /*
    102  * Helper function for `fprintf to unbuffered unix file': creates a
    103  * temporary buffer.  We only work on write-only files; this avoids
    104  * worries about ungetc buffers and so forth.
    105  */
    106 static int
    107 __sbprintf(fp, fmt, ap)
    108 	FILE *fp;
    109 	const char *fmt;
    110 	va_list ap;
    111 {
    112 	int ret;
    113 	FILE fake;
    114 	unsigned char buf[BUFSIZ];
    115 
    116 	_DIAGASSERT(fp != NULL);
    117 	_DIAGASSERT(fmt != NULL);
    118 
    119 	/* copy the important variables */
    120 	fake._flags = fp->_flags & ~__SNBF;
    121 	fake._file = fp->_file;
    122 	fake._cookie = fp->_cookie;
    123 	fake._write = fp->_write;
    124 
    125 	/* set up the buffer */
    126 	fake._bf._base = fake._p = buf;
    127 	fake._bf._size = fake._w = sizeof(buf);
    128 	fake._lbfsize = 0;	/* not actually used, but Just In Case */
    129 
    130 	/* do the work, then copy any error status */
    131 	ret = vfprintf(&fake, fmt, ap);
    132 	if (ret >= 0 && fflush(&fake))
    133 		ret = -1;
    134 	if (fake._flags & __SERR)
    135 		fp->_flags |= __SERR;
    136 	return (ret);
    137 }
    138 
    139 
    140 #ifdef FLOATING_POINT
    141 #include <locale.h>
    142 #include <math.h>
    143 #include "floatio.h"
    144 
    145 #define	BUF		(MAXEXP+MAXFRACT+1)	/* + decimal point */
    146 #define	DEFPREC		6
    147 
    148 static char *cvt __P((double, int, int, char *, int *, int, int *));
    149 static int exponent __P((char *, int, int));
    150 
    151 #else /* no FLOATING_POINT */
    152 
    153 #define	BUF		40
    154 
    155 #endif /* FLOATING_POINT */
    156 
    157 #ifdef lint
    158 static __inline void *__UNCONST __P((const void *));
    159 static __inline void *
    160 __UNCONST(v)
    161 	const void *v;
    162 {
    163 	/* LINTED */
    164 	return (void *) v;
    165 }
    166 #else
    167 #define __UNCONST(v)	(void *)(v)
    168 #endif
    169 
    170 /*
    171  * Macros for converting digits to letters and vice versa
    172  */
    173 #define	to_digit(c)	((c) - '0')
    174 #define is_digit(c)	((unsigned)to_digit(c) <= 9)
    175 #define	to_char(n)	((char)((n) + '0'))
    176 
    177 /*
    178  * Flags used during conversion.
    179  */
    180 #define	ALT		0x001		/* alternate form */
    181 #define	HEXPREFIX	0x002		/* add 0x or 0X prefix */
    182 #define	LADJUST		0x004		/* left adjustment */
    183 #define	LONGDBL		0x008		/* long double; unimplemented */
    184 #define	LONGINT		0x010		/* long integer */
    185 #define	QUADINT		0x020		/* quad integer */
    186 #define	SHORTINT	0x040		/* short integer */
    187 #define	ZEROPAD		0x080		/* zero (as opposed to blank) pad */
    188 #define FPT		0x100		/* Floating point number */
    189 int
    190 vfprintf(fp, fmt0, ap)
    191 	FILE *fp;
    192 	const char *fmt0;
    193 	_BSD_VA_LIST_ ap;
    194 {
    195 	const char *fmt;/* format string */
    196 	int ch;	/* character from fmt */
    197 	int n, m;	/* handy integers (short term usage) */
    198 	const char *cp;	/* handy char pointer (short term usage) */
    199 	char *bp;	/* handy char pointer (short term usage) */
    200 	struct __siov *iovp;/* for PRINT macro */
    201 	int flags;	/* flags as above */
    202 	int ret;		/* return value accumulator */
    203 	int width;		/* width from format (%8d), or 0 */
    204 	int prec;		/* precision from format (%.3d), or -1 */
    205 	char sign;		/* sign prefix (' ', '+', '-', or \0) */
    206 	wchar_t wc;
    207 #ifdef FLOATING_POINT
    208 	char *decimal_point = localeconv()->decimal_point;
    209 	char softsign;		/* temporary negative sign for floats */
    210 	double _double = 0;	/* double precision arguments %[eEfgG] */
    211 	int expt;		/* integer value of exponent */
    212 	int expsize = 0;	/* character count for expstr */
    213 	int ndig;		/* actual number of digits returned by cvt */
    214 	char expstr[7];		/* buffer for exponent string */
    215 #endif
    216 
    217 #ifdef __GNUC__			/* gcc has builtin quad type (long long) SOS */
    218 #define	quad_t	  long long
    219 #define	u_quad_t  unsigned long long
    220 #endif
    221 
    222 	u_quad_t _uquad;	/* integer arguments %[diouxX] */
    223 	enum { OCT, DEC, HEX } base;/* base for [diouxX] conversion */
    224 	int dprec;		/* a copy of prec if [diouxX], 0 otherwise */
    225 	int realsz;		/* field size expanded by dprec */
    226 	int size;		/* size of converted field or string */
    227 	char *xdigs = NULL;	/* digits for [xX] conversion */
    228 #define NIOV 8
    229 	struct __suio uio;	/* output information: summary */
    230 	struct __siov iov[NIOV];/* ... and individual io vectors */
    231 	char buf[BUF];		/* space for %c, %[diouxX], %[eEfgG] */
    232 	char ox[2];		/* space for 0x hex-prefix */
    233 
    234 	/*
    235 	 * Choose PADSIZE to trade efficiency vs. size.  If larger printf
    236 	 * fields occur frequently, increase PADSIZE and make the initialisers
    237 	 * below longer.
    238 	 */
    239 #define	PADSIZE	16		/* pad chunk size */
    240 	static const char blanks[PADSIZE] =
    241 	 {' ',' ',' ',' ',' ',' ',' ',' ',' ',' ',' ',' ',' ',' ',' ',' '};
    242 	static const char zeroes[PADSIZE] =
    243 	 {'0','0','0','0','0','0','0','0','0','0','0','0','0','0','0','0'};
    244 
    245 	/*
    246 	 * BEWARE, these `goto error' on error, and PAD uses `n'.
    247 	 */
    248 #define	PRINT(ptr, len) { \
    249 	iovp->iov_base = __UNCONST(ptr); \
    250 	iovp->iov_len = (len); \
    251 	uio.uio_resid += (len); \
    252 	iovp++; \
    253 	if (++uio.uio_iovcnt >= NIOV) { \
    254 		if (__sprint(fp, &uio)) \
    255 			goto error; \
    256 		iovp = iov; \
    257 	} \
    258 }
    259 #define	PAD(howmany, with) { \
    260 	if ((n = (howmany)) > 0) { \
    261 		while (n > PADSIZE) { \
    262 			PRINT(with, PADSIZE); \
    263 			n -= PADSIZE; \
    264 		} \
    265 		PRINT(with, n); \
    266 	} \
    267 }
    268 #define	FLUSH() { \
    269 	if (uio.uio_resid && __sprint(fp, &uio)) \
    270 		goto error; \
    271 	uio.uio_iovcnt = 0; \
    272 	iovp = iov; \
    273 }
    274 
    275 	/*
    276 	 * To extend shorts properly, we need both signed and unsigned
    277 	 * argument extraction methods.
    278 	 */
    279 #define	SARG() \
    280 	(flags&QUADINT ? va_arg(ap, quad_t) : \
    281 	    flags&LONGINT ? va_arg(ap, long) : \
    282 	    flags&SHORTINT ? (long)(short)va_arg(ap, int) : \
    283 	    (long)va_arg(ap, int))
    284 #define	UARG() \
    285 	(flags&QUADINT ? va_arg(ap, u_quad_t) : \
    286 	    flags&LONGINT ? va_arg(ap, u_long) : \
    287 	    flags&SHORTINT ? (u_long)(u_short)va_arg(ap, int) : \
    288 	    (u_long)va_arg(ap, u_int))
    289 
    290 	_DIAGASSERT(fp != NULL);
    291 	_DIAGASSERT(fmt0 != NULL);
    292 
    293 	FLOCKFILE(fp);
    294 
    295 	/* sorry, fprintf(read_only_file, "") returns -1, not 0 */
    296 	if (cantwrite(fp)) {
    297 		errno = EBADF;
    298 		FUNLOCKFILE(fp);
    299 		return (-1);
    300 	}
    301 
    302 	/* optimise fprintf(stderr) (and other unbuffered Unix files) */
    303 	if ((fp->_flags & (__SNBF|__SWR|__SRW)) == (__SNBF|__SWR) &&
    304 	    fp->_file >= 0) {
    305 		ret = __sbprintf(fp, fmt0, ap);
    306 		FUNLOCKFILE(fp);
    307 		return (ret);
    308 	}
    309 
    310 	fmt = fmt0;
    311 	uio.uio_iov = iovp = iov;
    312 	uio.uio_resid = 0;
    313 	uio.uio_iovcnt = 0;
    314 	ret = 0;
    315 
    316 	/*
    317 	 * Scan the format for conversions (`%' character).
    318 	 */
    319 	for (;;) {
    320 		cp = fmt;
    321 		while ((n = mbtowc(&wc, fmt, MB_CUR_MAX)) > 0) {
    322 			fmt += n;
    323 			if (wc == '%') {
    324 				fmt--;
    325 				break;
    326 			}
    327 		}
    328 		if ((m = fmt - cp) != 0) {
    329 			PRINT(cp, m);
    330 			ret += m;
    331 		}
    332 		if (n <= 0)
    333 			goto done;
    334 		fmt++;		/* skip over '%' */
    335 
    336 		flags = 0;
    337 		dprec = 0;
    338 		width = 0;
    339 		prec = -1;
    340 		sign = '\0';
    341 
    342 rflag:		ch = *fmt++;
    343 reswitch:	switch (ch) {
    344 		case ' ':
    345 			/*
    346 			 * ``If the space and + flags both appear, the space
    347 			 * flag will be ignored.''
    348 			 *	-- ANSI X3J11
    349 			 */
    350 			if (!sign)
    351 				sign = ' ';
    352 			goto rflag;
    353 		case '#':
    354 			flags |= ALT;
    355 			goto rflag;
    356 		case '*':
    357 			/*
    358 			 * ``A negative field width argument is taken as a
    359 			 * - flag followed by a positive field width.''
    360 			 *	-- ANSI X3J11
    361 			 * They don't exclude field widths read from args.
    362 			 */
    363 			if ((width = va_arg(ap, int)) >= 0)
    364 				goto rflag;
    365 			width = -width;
    366 			/* FALLTHROUGH */
    367 		case '-':
    368 			flags |= LADJUST;
    369 			goto rflag;
    370 		case '+':
    371 			sign = '+';
    372 			goto rflag;
    373 		case '.':
    374 			if ((ch = *fmt++) == '*') {
    375 				n = va_arg(ap, int);
    376 				prec = n < 0 ? -1 : n;
    377 				goto rflag;
    378 			}
    379 			n = 0;
    380 			while (is_digit(ch)) {
    381 				n = 10 * n + to_digit(ch);
    382 				ch = *fmt++;
    383 			}
    384 			prec = n < 0 ? -1 : n;
    385 			goto reswitch;
    386 		case '0':
    387 			/*
    388 			 * ``Note that 0 is taken as a flag, not as the
    389 			 * beginning of a field width.''
    390 			 *	-- ANSI X3J11
    391 			 */
    392 			flags |= ZEROPAD;
    393 			goto rflag;
    394 		case '1': case '2': case '3': case '4':
    395 		case '5': case '6': case '7': case '8': case '9':
    396 			n = 0;
    397 			do {
    398 				n = 10 * n + to_digit(ch);
    399 				ch = *fmt++;
    400 			} while (is_digit(ch));
    401 			width = n;
    402 			goto reswitch;
    403 #ifdef FLOATING_POINT
    404 		case 'L':
    405 			flags |= LONGDBL;
    406 			goto rflag;
    407 #endif
    408 		case 'h':
    409 			flags |= SHORTINT;
    410 			goto rflag;
    411 		case 'l':
    412 			if (*fmt == 'l') {
    413 				fmt++;
    414 				flags |= QUADINT;
    415 			} else {
    416 				flags |= LONGINT;
    417 			}
    418 			goto rflag;
    419 		case 'q':
    420 			flags |= QUADINT;
    421 			goto rflag;
    422 		case 'c':
    423 			*buf = va_arg(ap, int);
    424 			cp = buf;
    425 			size = 1;
    426 			sign = '\0';
    427 			break;
    428 		case 'D':
    429 			flags |= LONGINT;
    430 			/*FALLTHROUGH*/
    431 		case 'd':
    432 		case 'i':
    433 			_uquad = SARG();
    434 			if ((quad_t)_uquad < 0) {
    435 				_uquad = -_uquad;
    436 				sign = '-';
    437 			}
    438 			base = DEC;
    439 			goto number;
    440 #ifdef FLOATING_POINT
    441 		case 'e':
    442 		case 'E':
    443 		case 'f':
    444 		case 'g':
    445 		case 'G':
    446 			if (prec == -1) {
    447 				prec = DEFPREC;
    448 			} else if ((ch == 'g' || ch == 'G') && prec == 0) {
    449 				prec = 1;
    450 			}
    451 
    452 			if (flags & LONGDBL) {
    453 				_double = (double) va_arg(ap, long double);
    454 			} else {
    455 				_double = va_arg(ap, double);
    456 			}
    457 
    458 			/* do this before tricky precision changes */
    459 			if (isinf(_double)) {
    460 				if (_double < 0)
    461 					sign = '-';
    462 				cp = "Inf";
    463 				size = 3;
    464 				break;
    465 			}
    466 			if (isnan(_double)) {
    467 				cp = "NaN";
    468 				size = 3;
    469 				break;
    470 			}
    471 
    472 			flags |= FPT;
    473 			cp = cvt(_double, prec, flags, &softsign,
    474 				&expt, ch, &ndig);
    475 			if (ch == 'g' || ch == 'G') {
    476 				if (expt <= -4 || expt > prec)
    477 					ch = (ch == 'g') ? 'e' : 'E';
    478 				else
    479 					ch = 'g';
    480 			}
    481 			if (ch <= 'e') {	/* 'e' or 'E' fmt */
    482 				--expt;
    483 				expsize = exponent(expstr, expt, ch);
    484 				size = expsize + ndig;
    485 				if (ndig > 1 || flags & ALT)
    486 					++size;
    487 			} else if (ch == 'f') {		/* f fmt */
    488 				if (expt > 0) {
    489 					size = expt;
    490 					if (prec || flags & ALT)
    491 						size += prec + 1;
    492 				} else	/* "0.X" */
    493 					size = prec + 2;
    494 			} else if (expt >= ndig) {	/* fixed g fmt */
    495 				size = expt;
    496 				if (flags & ALT)
    497 					++size;
    498 			} else
    499 				size = ndig + (expt > 0 ?
    500 					1 : 2 - expt);
    501 
    502 			if (softsign)
    503 				sign = '-';
    504 			break;
    505 #endif /* FLOATING_POINT */
    506 		case 'n':
    507 			if (flags & QUADINT)
    508 				*va_arg(ap, quad_t *) = ret;
    509 			else if (flags & LONGINT)
    510 				*va_arg(ap, long *) = ret;
    511 			else if (flags & SHORTINT)
    512 				*va_arg(ap, short *) = ret;
    513 			else
    514 				*va_arg(ap, int *) = ret;
    515 			continue;	/* no output */
    516 		case 'O':
    517 			flags |= LONGINT;
    518 			/*FALLTHROUGH*/
    519 		case 'o':
    520 			_uquad = UARG();
    521 			base = OCT;
    522 			goto nosign;
    523 		case 'p':
    524 			/*
    525 			 * ``The argument shall be a pointer to void.  The
    526 			 * value of the pointer is converted to a sequence
    527 			 * of printable characters, in an implementation-
    528 			 * defined manner.''
    529 			 *	-- ANSI X3J11
    530 			 */
    531 			/* NOSTRICT */
    532 			_uquad = (u_long)va_arg(ap, void *);
    533 			base = HEX;
    534 			xdigs = "0123456789abcdef";
    535 			flags |= HEXPREFIX;
    536 			ch = 'x';
    537 			goto nosign;
    538 		case 's':
    539 			if ((cp = va_arg(ap, char *)) == NULL)
    540 				cp = "(null)";
    541 			if (prec >= 0) {
    542 				/*
    543 				 * can't use strlen; can only look for the
    544 				 * NUL in the first `prec' characters, and
    545 				 * strlen() will go further.
    546 				 */
    547 				char *p = memchr(cp, 0, (size_t)prec);
    548 
    549 				if (p != NULL) {
    550 					size = p - cp;
    551 					if (size > prec)
    552 						size = prec;
    553 				} else
    554 					size = prec;
    555 			} else
    556 				size = strlen(cp);
    557 			sign = '\0';
    558 			break;
    559 		case 'U':
    560 			flags |= LONGINT;
    561 			/*FALLTHROUGH*/
    562 		case 'u':
    563 			_uquad = UARG();
    564 			base = DEC;
    565 			goto nosign;
    566 		case 'X':
    567 			xdigs = "0123456789ABCDEF";
    568 			goto hex;
    569 		case 'x':
    570 			xdigs = "0123456789abcdef";
    571 hex:			_uquad = UARG();
    572 			base = HEX;
    573 			/* leading 0x/X only if non-zero */
    574 			if (flags & ALT && _uquad != 0)
    575 				flags |= HEXPREFIX;
    576 
    577 			/* unsigned conversions */
    578 nosign:			sign = '\0';
    579 			/*
    580 			 * ``... diouXx conversions ... if a precision is
    581 			 * specified, the 0 flag will be ignored.''
    582 			 *	-- ANSI X3J11
    583 			 */
    584 number:			if ((dprec = prec) >= 0)
    585 				flags &= ~ZEROPAD;
    586 
    587 			/*
    588 			 * ``The result of converting a zero value with an
    589 			 * explicit precision of zero is no characters.''
    590 			 *	-- ANSI X3J11
    591 			 */
    592 			bp = buf + BUF;
    593 			if (_uquad != 0 || prec != 0) {
    594 				/*
    595 				 * Unsigned mod is hard, and unsigned mod
    596 				 * by a constant is easier than that by
    597 				 * a variable; hence this switch.
    598 				 */
    599 				switch (base) {
    600 				case OCT:
    601 					do {
    602 						*--bp = to_char(_uquad & 7);
    603 						_uquad >>= 3;
    604 					} while (_uquad);
    605 					/* handle octal leading 0 */
    606 					if (flags & ALT && *bp != '0')
    607 						*--bp = '0';
    608 					break;
    609 
    610 				case DEC:
    611 					/* many numbers are 1 digit */
    612 					while (_uquad >= 10) {
    613 						*--bp = to_char(_uquad % 10);
    614 						_uquad /= 10;
    615 					}
    616 					*--bp = to_char(_uquad);
    617 					break;
    618 
    619 				case HEX:
    620 					do {
    621 						*--bp = xdigs[(size_t)
    622 						    (_uquad & 15)];
    623 						_uquad >>= 4;
    624 					} while (_uquad);
    625 					break;
    626 
    627 				default:
    628 					cp = "bug in vfprintf: bad base";
    629 					size = strlen(cp);
    630 					goto skipsize;
    631 				}
    632 			}
    633 			cp = bp;
    634 			size = buf + BUF - bp;
    635 		skipsize:
    636 			break;
    637 		default:	/* "%?" prints ?, unless ? is NUL */
    638 			if (ch == '\0')
    639 				goto done;
    640 			/* pretend it was %c with argument ch */
    641 			*buf = ch;
    642 			cp = buf;
    643 			size = 1;
    644 			sign = '\0';
    645 			break;
    646 		}
    647 
    648 		/*
    649 		 * All reasonable formats wind up here.  At this point, `cp'
    650 		 * points to a string which (if not flags&LADJUST) should be
    651 		 * padded out to `width' places.  If flags&ZEROPAD, it should
    652 		 * first be prefixed by any sign or other prefix; otherwise,
    653 		 * it should be blank padded before the prefix is emitted.
    654 		 * After any left-hand padding and prefixing, emit zeroes
    655 		 * required by a decimal [diouxX] precision, then print the
    656 		 * string proper, then emit zeroes required by any leftover
    657 		 * floating precision; finally, if LADJUST, pad with blanks.
    658 		 *
    659 		 * Compute actual size, so we know how much to pad.
    660 		 * size excludes decimal prec; realsz includes it.
    661 		 */
    662 		realsz = dprec > size ? dprec : size;
    663 		if (sign)
    664 			realsz++;
    665 		else if (flags & HEXPREFIX)
    666 			realsz+= 2;
    667 
    668 		/* right-adjusting blank padding */
    669 		if ((flags & (LADJUST|ZEROPAD)) == 0)
    670 			PAD(width - realsz, blanks);
    671 
    672 		/* prefix */
    673 		if (sign) {
    674 			PRINT(&sign, 1);
    675 		} else if (flags & HEXPREFIX) {
    676 			ox[0] = '0';
    677 			ox[1] = ch;
    678 			PRINT(ox, 2);
    679 		}
    680 
    681 		/* right-adjusting zero padding */
    682 		if ((flags & (LADJUST|ZEROPAD)) == ZEROPAD)
    683 			PAD(width - realsz, zeroes);
    684 
    685 		/* leading zeroes from decimal precision */
    686 		PAD(dprec - size, zeroes);
    687 
    688 		/* the string or number proper */
    689 #ifdef FLOATING_POINT
    690 		if ((flags & FPT) == 0) {
    691 			PRINT(cp, size);
    692 		} else {	/* glue together f_p fragments */
    693 			if (ch >= 'f') {	/* 'f' or 'g' */
    694 				if (_double == 0) {
    695 					/* kludge for __dtoa irregularity */
    696 					PRINT("0", 1);
    697 					if (expt < ndig || (flags & ALT) != 0) {
    698 						PRINT(decimal_point, 1);
    699 						PAD(ndig - 1, zeroes);
    700 					}
    701 				} else if (expt <= 0) {
    702 					PRINT("0", 1);
    703 					PRINT(decimal_point, 1);
    704 					PAD(-expt, zeroes);
    705 					PRINT(cp, ndig);
    706 				} else if (expt >= ndig) {
    707 					PRINT(cp, ndig);
    708 					PAD(expt - ndig, zeroes);
    709 					if (flags & ALT)
    710 						PRINT(".", 1);
    711 				} else {
    712 					PRINT(cp, expt);
    713 					cp += expt;
    714 					PRINT(".", 1);
    715 					PRINT(cp, ndig-expt);
    716 				}
    717 			} else {	/* 'e' or 'E' */
    718 				if (ndig > 1 || flags & ALT) {
    719 					ox[0] = *cp++;
    720 					ox[1] = '.';
    721 					PRINT(ox, 2);
    722 					if (_double) {
    723 						PRINT(cp, ndig-1);
    724 					} else	/* 0.[0..] */
    725 						/* __dtoa irregularity */
    726 						PAD(ndig - 1, zeroes);
    727 				} else	/* XeYYY */
    728 					PRINT(cp, 1);
    729 				PRINT(expstr, expsize);
    730 			}
    731 		}
    732 #else
    733 		PRINT(cp, size);
    734 #endif
    735 		/* left-adjusting padding (always blank) */
    736 		if (flags & LADJUST)
    737 			PAD(width - realsz, blanks);
    738 
    739 		/* finally, adjust ret */
    740 		ret += width > realsz ? width : realsz;
    741 
    742 		FLUSH();	/* copy out the I/O vectors */
    743 	}
    744 done:
    745 	FLUSH();
    746 error:
    747 	if (__sferror(fp))
    748 		ret = -1;
    749 	FUNLOCKFILE(fp);
    750 	return (ret);
    751 }
    752 
    753 #ifdef FLOATING_POINT
    754 
    755 static char *
    756 cvt(value, ndigits, flags, sign, decpt, ch, length)
    757 	double value;
    758 	int ndigits, flags, *decpt, ch, *length;
    759 	char *sign;
    760 {
    761 	int mode, dsgn;
    762 	char *digits, *bp, *rve;
    763 
    764 	_DIAGASSERT(decpt != NULL);
    765 	_DIAGASSERT(length != NULL);
    766 	_DIAGASSERT(sign != NULL);
    767 
    768 	if (ch == 'f') {
    769 		mode = 3;		/* ndigits after the decimal point */
    770 	} else {
    771 		/* To obtain ndigits after the decimal point for the 'e'
    772 		 * and 'E' formats, round to ndigits + 1 significant
    773 		 * figures.
    774 		 */
    775 		if (ch == 'e' || ch == 'E') {
    776 			ndigits++;
    777 		}
    778 		mode = 2;		/* ndigits significant digits */
    779 	}
    780 
    781 	if (value < 0) {
    782 		value = -value;
    783 		*sign = '-';
    784 	} else
    785 		*sign = '\000';
    786 	digits = __dtoa(value, mode, ndigits, decpt, &dsgn, &rve);
    787 	if ((ch != 'g' && ch != 'G') || flags & ALT) {	/* Print trailing zeros */
    788 		bp = digits + ndigits;
    789 		if (ch == 'f') {
    790 			if (*digits == '0' && value)
    791 				*decpt = -ndigits + 1;
    792 			bp += *decpt;
    793 		}
    794 		if (value == 0)	/* kludge for __dtoa irregularity */
    795 			rve = bp;
    796 		while (rve < bp)
    797 			*rve++ = '0';
    798 	}
    799 	*length = rve - digits;
    800 	return (digits);
    801 }
    802 
    803 static int
    804 exponent(p0, exp, fmtch)
    805 	char *p0;
    806 	int exp, fmtch;
    807 {
    808 	char *p, *t;
    809 	char expbuf[MAXEXP];
    810 
    811 	_DIAGASSERT(p0 != NULL);
    812 
    813 	p = p0;
    814 	*p++ = fmtch;
    815 	if (exp < 0) {
    816 		exp = -exp;
    817 		*p++ = '-';
    818 	}
    819 	else
    820 		*p++ = '+';
    821 	t = expbuf + MAXEXP;
    822 	if (exp > 9) {
    823 		do {
    824 			*--t = to_char(exp % 10);
    825 		} while ((exp /= 10) > 9);
    826 		*--t = to_char(exp);
    827 		for (; t < expbuf + MAXEXP; *p++ = *t++);
    828 	}
    829 	else {
    830 		*p++ = '0';
    831 		*p++ = to_char(exp);
    832 	}
    833 	return (p - p0);
    834 }
    835 #endif /* FLOATING_POINT */
    836