xref: /netbsd-src/lib/libc/stdio/vfprintf.c (revision 5aefcfdc06931dd97e76246d2fe0302f7b3fe094)
1 /*	$NetBSD: vfprintf.c,v 1.34 2000/12/23 13:19:31 itojun 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 1.34 2000/12/23 13:19:31 itojun 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 #include <wchar.h>
63 
64 #if __STDC__
65 #include <stdarg.h>
66 #else
67 #include <varargs.h>
68 #endif
69 
70 #include "local.h"
71 #include "fvwrite.h"
72 #include "extern.h"
73 #include "reentrant.h"
74 
75 static int __sprint __P((FILE *, struct __suio *));
76 static int __sbprintf __P((FILE *, const char *, va_list))
77      __attribute__((__format__(__printf__, 2, 0)));
78 
79 /*
80  * Flush out all the vectors defined by the given uio,
81  * then reset it so that it can be reused.
82  */
83 static int
84 __sprint(fp, uio)
85 	FILE *fp;
86 	struct __suio *uio;
87 {
88 	int err;
89 
90 	_DIAGASSERT(fp != NULL);
91 	_DIAGASSERT(uio != NULL);
92 
93 	if (uio->uio_resid == 0) {
94 		uio->uio_iovcnt = 0;
95 		return (0);
96 	}
97 	err = __sfvwrite(fp, uio);
98 	uio->uio_resid = 0;
99 	uio->uio_iovcnt = 0;
100 	return (err);
101 }
102 
103 /*
104  * Helper function for `fprintf to unbuffered unix file': creates a
105  * temporary buffer.  We only work on write-only files; this avoids
106  * worries about ungetc buffers and so forth.
107  */
108 static int
109 __sbprintf(fp, fmt, ap)
110 	FILE *fp;
111 	const char *fmt;
112 	va_list ap;
113 {
114 	int ret;
115 	FILE fake;
116 	unsigned char buf[BUFSIZ];
117 
118 	_DIAGASSERT(fp != NULL);
119 	_DIAGASSERT(fmt != NULL);
120 
121 	/* copy the important variables */
122 	fake._flags = fp->_flags & ~__SNBF;
123 	fake._file = fp->_file;
124 	fake._cookie = fp->_cookie;
125 	fake._write = fp->_write;
126 
127 	/* set up the buffer */
128 	fake._bf._base = fake._p = buf;
129 	fake._bf._size = fake._w = sizeof(buf);
130 	fake._lbfsize = 0;	/* not actually used, but Just In Case */
131 
132 	/* do the work, then copy any error status */
133 	ret = vfprintf(&fake, fmt, ap);
134 	if (ret >= 0 && fflush(&fake))
135 		ret = -1;
136 	if (fake._flags & __SERR)
137 		fp->_flags |= __SERR;
138 	return (ret);
139 }
140 
141 
142 #ifdef FLOATING_POINT
143 #include <locale.h>
144 #include <math.h>
145 #include "floatio.h"
146 
147 #define	BUF		(MAXEXP+MAXFRACT+1)	/* + decimal point */
148 #define	DEFPREC		6
149 
150 static char *cvt __P((double, int, int, char *, int *, int, int *));
151 static int exponent __P((char *, int, int));
152 
153 #else /* no FLOATING_POINT */
154 
155 #define	BUF		40
156 
157 #endif /* FLOATING_POINT */
158 
159 #ifdef lint
160 static __inline void *__UNCONST __P((const void *));
161 static __inline void *
162 __UNCONST(v)
163 	const void *v;
164 {
165 	/* LINTED */
166 	return (void *) v;
167 }
168 #else
169 #define __UNCONST(v)	(void *)(v)
170 #endif
171 
172 /*
173  * Macros for converting digits to letters and vice versa
174  */
175 #define	to_digit(c)	((c) - '0')
176 #define is_digit(c)	((unsigned)to_digit(c) <= 9)
177 #define	to_char(n)	((char)((n) + '0'))
178 
179 /*
180  * Flags used during conversion.
181  */
182 #define	ALT		0x001		/* alternate form */
183 #define	HEXPREFIX	0x002		/* add 0x or 0X prefix */
184 #define	LADJUST		0x004		/* left adjustment */
185 #define	LONGDBL		0x008		/* long double; unimplemented */
186 #define	LONGINT		0x010		/* long integer */
187 #define	QUADINT		0x020		/* quad integer */
188 #define	SHORTINT	0x040		/* short integer */
189 #define	ZEROPAD		0x080		/* zero (as opposed to blank) pad */
190 #define FPT		0x100		/* Floating point number */
191 int
192 vfprintf(fp, fmt0, ap)
193 	FILE *fp;
194 	const char *fmt0;
195 	_BSD_VA_LIST_ ap;
196 {
197 	const char *fmt;/* format string */
198 	int ch;	/* character from fmt */
199 	int n, m;	/* handy integers (short term usage) */
200 	const char *cp;	/* handy char pointer (short term usage) */
201 	char *bp;	/* handy char pointer (short term usage) */
202 	struct __siov *iovp;/* for PRINT macro */
203 	int flags;	/* flags as above */
204 	int ret;		/* return value accumulator */
205 	int width;		/* width from format (%8d), or 0 */
206 	int prec;		/* precision from format (%.3d), or -1 */
207 	char sign;		/* sign prefix (' ', '+', '-', or \0) */
208 	wchar_t wc;
209 	mbstate_t ps;
210 #ifdef FLOATING_POINT
211 	char *decimal_point = localeconv()->decimal_point;
212 	char softsign;		/* temporary negative sign for floats */
213 	double _double = 0;	/* double precision arguments %[eEfgG] */
214 	int expt;		/* integer value of exponent */
215 	int expsize = 0;	/* character count for expstr */
216 	int ndig;		/* actual number of digits returned by cvt */
217 	char expstr[7];		/* buffer for exponent string */
218 #endif
219 
220 #ifdef __GNUC__			/* gcc has builtin quad type (long long) SOS */
221 #define	quad_t	  long long
222 #define	u_quad_t  unsigned long long
223 #endif
224 
225 	u_quad_t _uquad;	/* integer arguments %[diouxX] */
226 	enum { OCT, DEC, HEX } base;/* base for [diouxX] conversion */
227 	int dprec;		/* a copy of prec if [diouxX], 0 otherwise */
228 	int realsz;		/* field size expanded by dprec */
229 	int size;		/* size of converted field or string */
230 	char *xdigs = NULL;	/* digits for [xX] conversion */
231 #define NIOV 8
232 	struct __suio uio;	/* output information: summary */
233 	struct __siov iov[NIOV];/* ... and individual io vectors */
234 	char buf[BUF];		/* space for %c, %[diouxX], %[eEfgG] */
235 	char ox[2];		/* space for 0x hex-prefix */
236 
237 	/*
238 	 * Choose PADSIZE to trade efficiency vs. size.  If larger printf
239 	 * fields occur frequently, increase PADSIZE and make the initialisers
240 	 * below longer.
241 	 */
242 #define	PADSIZE	16		/* pad chunk size */
243 	static const char blanks[PADSIZE] =
244 	 {' ',' ',' ',' ',' ',' ',' ',' ',' ',' ',' ',' ',' ',' ',' ',' '};
245 	static const char zeroes[PADSIZE] =
246 	 {'0','0','0','0','0','0','0','0','0','0','0','0','0','0','0','0'};
247 
248 	/*
249 	 * BEWARE, these `goto error' on error, and PAD uses `n'.
250 	 */
251 #define	PRINT(ptr, len) { \
252 	iovp->iov_base = __UNCONST(ptr); \
253 	iovp->iov_len = (len); \
254 	uio.uio_resid += (len); \
255 	iovp++; \
256 	if (++uio.uio_iovcnt >= NIOV) { \
257 		if (__sprint(fp, &uio)) \
258 			goto error; \
259 		iovp = iov; \
260 	} \
261 }
262 #define	PAD(howmany, with) { \
263 	if ((n = (howmany)) > 0) { \
264 		while (n > PADSIZE) { \
265 			PRINT(with, PADSIZE); \
266 			n -= PADSIZE; \
267 		} \
268 		PRINT(with, n); \
269 	} \
270 }
271 #define	FLUSH() { \
272 	if (uio.uio_resid && __sprint(fp, &uio)) \
273 		goto error; \
274 	uio.uio_iovcnt = 0; \
275 	iovp = iov; \
276 }
277 
278 	/*
279 	 * To extend shorts properly, we need both signed and unsigned
280 	 * argument extraction methods.
281 	 */
282 #define	SARG() \
283 	(flags&QUADINT ? va_arg(ap, quad_t) : \
284 	    flags&LONGINT ? va_arg(ap, long) : \
285 	    flags&SHORTINT ? (long)(short)va_arg(ap, int) : \
286 	    (long)va_arg(ap, int))
287 #define	UARG() \
288 	(flags&QUADINT ? va_arg(ap, u_quad_t) : \
289 	    flags&LONGINT ? va_arg(ap, u_long) : \
290 	    flags&SHORTINT ? (u_long)(u_short)va_arg(ap, int) : \
291 	    (u_long)va_arg(ap, u_int))
292 
293 	_DIAGASSERT(fp != NULL);
294 	_DIAGASSERT(fmt0 != NULL);
295 
296 	FLOCKFILE(fp);
297 
298 	/* sorry, fprintf(read_only_file, "") returns -1, not 0 */
299 	if (cantwrite(fp)) {
300 		errno = EBADF;
301 		FUNLOCKFILE(fp);
302 		return (-1);
303 	}
304 
305 	/* optimise fprintf(stderr) (and other unbuffered Unix files) */
306 	if ((fp->_flags & (__SNBF|__SWR|__SRW)) == (__SNBF|__SWR) &&
307 	    fp->_file >= 0) {
308 		ret = __sbprintf(fp, fmt0, ap);
309 		FUNLOCKFILE(fp);
310 		return (ret);
311 	}
312 
313 	fmt = fmt0;
314 	uio.uio_iov = iovp = iov;
315 	uio.uio_resid = 0;
316 	uio.uio_iovcnt = 0;
317 	ret = 0;
318 
319 	(void)mbrtowc(NULL, "", 1, &ps);
320 
321 	/*
322 	 * Scan the format for conversions (`%' character).
323 	 */
324 	for (;;) {
325 		cp = fmt;
326 		while ((n = mbrtowc(&wc, fmt, MB_CUR_MAX, &ps)) > 0) {
327 			fmt += n;
328 			if (wc == '%') {
329 				fmt--;
330 				break;
331 			}
332 		}
333 		if ((m = fmt - cp) != 0) {
334 			PRINT(cp, m);
335 			ret += m;
336 		}
337 		if (n <= 0)
338 			goto done;
339 		fmt++;		/* skip over '%' */
340 
341 		flags = 0;
342 		dprec = 0;
343 		width = 0;
344 		prec = -1;
345 		sign = '\0';
346 
347 rflag:		ch = *fmt++;
348 reswitch:	switch (ch) {
349 		case ' ':
350 			/*
351 			 * ``If the space and + flags both appear, the space
352 			 * flag will be ignored.''
353 			 *	-- ANSI X3J11
354 			 */
355 			if (!sign)
356 				sign = ' ';
357 			goto rflag;
358 		case '#':
359 			flags |= ALT;
360 			goto rflag;
361 		case '*':
362 			/*
363 			 * ``A negative field width argument is taken as a
364 			 * - flag followed by a positive field width.''
365 			 *	-- ANSI X3J11
366 			 * They don't exclude field widths read from args.
367 			 */
368 			if ((width = va_arg(ap, int)) >= 0)
369 				goto rflag;
370 			width = -width;
371 			/* FALLTHROUGH */
372 		case '-':
373 			flags |= LADJUST;
374 			goto rflag;
375 		case '+':
376 			sign = '+';
377 			goto rflag;
378 		case '.':
379 			if ((ch = *fmt++) == '*') {
380 				n = va_arg(ap, int);
381 				prec = n < 0 ? -1 : n;
382 				goto rflag;
383 			}
384 			n = 0;
385 			while (is_digit(ch)) {
386 				n = 10 * n + to_digit(ch);
387 				ch = *fmt++;
388 			}
389 			prec = n < 0 ? -1 : n;
390 			goto reswitch;
391 		case '0':
392 			/*
393 			 * ``Note that 0 is taken as a flag, not as the
394 			 * beginning of a field width.''
395 			 *	-- ANSI X3J11
396 			 */
397 			flags |= ZEROPAD;
398 			goto rflag;
399 		case '1': case '2': case '3': case '4':
400 		case '5': case '6': case '7': case '8': case '9':
401 			n = 0;
402 			do {
403 				n = 10 * n + to_digit(ch);
404 				ch = *fmt++;
405 			} while (is_digit(ch));
406 			width = n;
407 			goto reswitch;
408 #ifdef FLOATING_POINT
409 		case 'L':
410 			flags |= LONGDBL;
411 			goto rflag;
412 #endif
413 		case 'h':
414 			flags |= SHORTINT;
415 			goto rflag;
416 		case 'l':
417 			if (*fmt == 'l') {
418 				fmt++;
419 				flags |= QUADINT;
420 			} else {
421 				flags |= LONGINT;
422 			}
423 			goto rflag;
424 		case 'q':
425 			flags |= QUADINT;
426 			goto rflag;
427 		case 'c':
428 			*buf = va_arg(ap, int);
429 			cp = buf;
430 			size = 1;
431 			sign = '\0';
432 			break;
433 		case 'D':
434 			flags |= LONGINT;
435 			/*FALLTHROUGH*/
436 		case 'd':
437 		case 'i':
438 			_uquad = SARG();
439 			if ((quad_t)_uquad < 0) {
440 				_uquad = -_uquad;
441 				sign = '-';
442 			}
443 			base = DEC;
444 			goto number;
445 #ifdef FLOATING_POINT
446 		case 'e':
447 		case 'E':
448 		case 'f':
449 		case 'g':
450 		case 'G':
451 			if (prec == -1) {
452 				prec = DEFPREC;
453 			} else if ((ch == 'g' || ch == 'G') && prec == 0) {
454 				prec = 1;
455 			}
456 
457 			if (flags & LONGDBL) {
458 				_double = (double) va_arg(ap, long double);
459 			} else {
460 				_double = va_arg(ap, double);
461 			}
462 
463 			/* do this before tricky precision changes */
464 			if (isinf(_double)) {
465 				if (_double < 0)
466 					sign = '-';
467 				cp = "Inf";
468 				size = 3;
469 				break;
470 			}
471 			if (isnan(_double)) {
472 				cp = "NaN";
473 				size = 3;
474 				break;
475 			}
476 
477 			flags |= FPT;
478 			cp = cvt(_double, prec, flags, &softsign,
479 				&expt, ch, &ndig);
480 			if (ch == 'g' || ch == 'G') {
481 				if (expt <= -4 || expt > prec)
482 					ch = (ch == 'g') ? 'e' : 'E';
483 				else
484 					ch = 'g';
485 			}
486 			if (ch <= 'e') {	/* 'e' or 'E' fmt */
487 				--expt;
488 				expsize = exponent(expstr, expt, ch);
489 				size = expsize + ndig;
490 				if (ndig > 1 || flags & ALT)
491 					++size;
492 			} else if (ch == 'f') {		/* f fmt */
493 				if (expt > 0) {
494 					size = expt;
495 					if (prec || flags & ALT)
496 						size += prec + 1;
497 				} else	/* "0.X" */
498 					size = prec + 2;
499 			} else if (expt >= ndig) {	/* fixed g fmt */
500 				size = expt;
501 				if (flags & ALT)
502 					++size;
503 			} else
504 				size = ndig + (expt > 0 ?
505 					1 : 2 - expt);
506 
507 			if (softsign)
508 				sign = '-';
509 			break;
510 #endif /* FLOATING_POINT */
511 		case 'n':
512 			if (flags & QUADINT)
513 				*va_arg(ap, quad_t *) = ret;
514 			else if (flags & LONGINT)
515 				*va_arg(ap, long *) = ret;
516 			else if (flags & SHORTINT)
517 				*va_arg(ap, short *) = ret;
518 			else
519 				*va_arg(ap, int *) = ret;
520 			continue;	/* no output */
521 		case 'O':
522 			flags |= LONGINT;
523 			/*FALLTHROUGH*/
524 		case 'o':
525 			_uquad = UARG();
526 			base = OCT;
527 			goto nosign;
528 		case 'p':
529 			/*
530 			 * ``The argument shall be a pointer to void.  The
531 			 * value of the pointer is converted to a sequence
532 			 * of printable characters, in an implementation-
533 			 * defined manner.''
534 			 *	-- ANSI X3J11
535 			 */
536 			/* NOSTRICT */
537 			_uquad = (u_long)va_arg(ap, void *);
538 			base = HEX;
539 			xdigs = "0123456789abcdef";
540 			flags |= HEXPREFIX;
541 			ch = 'x';
542 			goto nosign;
543 		case 's':
544 			if ((cp = va_arg(ap, char *)) == NULL)
545 				cp = "(null)";
546 			if (prec >= 0) {
547 				/*
548 				 * can't use strlen; can only look for the
549 				 * NUL in the first `prec' characters, and
550 				 * strlen() will go further.
551 				 */
552 				char *p = memchr(cp, 0, (size_t)prec);
553 
554 				if (p != NULL) {
555 					size = p - cp;
556 					if (size > prec)
557 						size = prec;
558 				} else
559 					size = prec;
560 			} else
561 				size = strlen(cp);
562 			sign = '\0';
563 			break;
564 		case 'U':
565 			flags |= LONGINT;
566 			/*FALLTHROUGH*/
567 		case 'u':
568 			_uquad = UARG();
569 			base = DEC;
570 			goto nosign;
571 		case 'X':
572 			xdigs = "0123456789ABCDEF";
573 			goto hex;
574 		case 'x':
575 			xdigs = "0123456789abcdef";
576 hex:			_uquad = UARG();
577 			base = HEX;
578 			/* leading 0x/X only if non-zero */
579 			if (flags & ALT && _uquad != 0)
580 				flags |= HEXPREFIX;
581 
582 			/* unsigned conversions */
583 nosign:			sign = '\0';
584 			/*
585 			 * ``... diouXx conversions ... if a precision is
586 			 * specified, the 0 flag will be ignored.''
587 			 *	-- ANSI X3J11
588 			 */
589 number:			if ((dprec = prec) >= 0)
590 				flags &= ~ZEROPAD;
591 
592 			/*
593 			 * ``The result of converting a zero value with an
594 			 * explicit precision of zero is no characters.''
595 			 *	-- ANSI X3J11
596 			 */
597 			bp = buf + BUF;
598 			if (_uquad != 0 || prec != 0) {
599 				/*
600 				 * Unsigned mod is hard, and unsigned mod
601 				 * by a constant is easier than that by
602 				 * a variable; hence this switch.
603 				 */
604 				switch (base) {
605 				case OCT:
606 					do {
607 						*--bp = to_char(_uquad & 7);
608 						_uquad >>= 3;
609 					} while (_uquad);
610 					/* handle octal leading 0 */
611 					if (flags & ALT && *bp != '0')
612 						*--bp = '0';
613 					break;
614 
615 				case DEC:
616 					/* many numbers are 1 digit */
617 					while (_uquad >= 10) {
618 						*--bp = to_char(_uquad % 10);
619 						_uquad /= 10;
620 					}
621 					*--bp = to_char(_uquad);
622 					break;
623 
624 				case HEX:
625 					do {
626 						*--bp = xdigs[(size_t)
627 						    (_uquad & 15)];
628 						_uquad >>= 4;
629 					} while (_uquad);
630 					break;
631 
632 				default:
633 					cp = "bug in vfprintf: bad base";
634 					size = strlen(cp);
635 					goto skipsize;
636 				}
637 			}
638 			cp = bp;
639 			size = buf + BUF - bp;
640 		skipsize:
641 			break;
642 		default:	/* "%?" prints ?, unless ? is NUL */
643 			if (ch == '\0')
644 				goto done;
645 			/* pretend it was %c with argument ch */
646 			*buf = ch;
647 			cp = buf;
648 			size = 1;
649 			sign = '\0';
650 			break;
651 		}
652 
653 		/*
654 		 * All reasonable formats wind up here.  At this point, `cp'
655 		 * points to a string which (if not flags&LADJUST) should be
656 		 * padded out to `width' places.  If flags&ZEROPAD, it should
657 		 * first be prefixed by any sign or other prefix; otherwise,
658 		 * it should be blank padded before the prefix is emitted.
659 		 * After any left-hand padding and prefixing, emit zeroes
660 		 * required by a decimal [diouxX] precision, then print the
661 		 * string proper, then emit zeroes required by any leftover
662 		 * floating precision; finally, if LADJUST, pad with blanks.
663 		 *
664 		 * Compute actual size, so we know how much to pad.
665 		 * size excludes decimal prec; realsz includes it.
666 		 */
667 		realsz = dprec > size ? dprec : size;
668 		if (sign)
669 			realsz++;
670 		else if (flags & HEXPREFIX)
671 			realsz+= 2;
672 
673 		/* right-adjusting blank padding */
674 		if ((flags & (LADJUST|ZEROPAD)) == 0)
675 			PAD(width - realsz, blanks);
676 
677 		/* prefix */
678 		if (sign) {
679 			PRINT(&sign, 1);
680 		} else if (flags & HEXPREFIX) {
681 			ox[0] = '0';
682 			ox[1] = ch;
683 			PRINT(ox, 2);
684 		}
685 
686 		/* right-adjusting zero padding */
687 		if ((flags & (LADJUST|ZEROPAD)) == ZEROPAD)
688 			PAD(width - realsz, zeroes);
689 
690 		/* leading zeroes from decimal precision */
691 		PAD(dprec - size, zeroes);
692 
693 		/* the string or number proper */
694 #ifdef FLOATING_POINT
695 		if ((flags & FPT) == 0) {
696 			PRINT(cp, size);
697 		} else {	/* glue together f_p fragments */
698 			if (ch >= 'f') {	/* 'f' or 'g' */
699 				if (_double == 0) {
700 					/* kludge for __dtoa irregularity */
701 					PRINT("0", 1);
702 					if (expt < ndig || (flags & ALT) != 0) {
703 						PRINT(decimal_point, 1);
704 						PAD(ndig - 1, zeroes);
705 					}
706 				} else if (expt <= 0) {
707 					PRINT("0", 1);
708 					PRINT(decimal_point, 1);
709 					PAD(-expt, zeroes);
710 					PRINT(cp, ndig);
711 				} else if (expt >= ndig) {
712 					PRINT(cp, ndig);
713 					PAD(expt - ndig, zeroes);
714 					if (flags & ALT)
715 						PRINT(".", 1);
716 				} else {
717 					PRINT(cp, expt);
718 					cp += expt;
719 					PRINT(".", 1);
720 					PRINT(cp, ndig-expt);
721 				}
722 			} else {	/* 'e' or 'E' */
723 				if (ndig > 1 || flags & ALT) {
724 					ox[0] = *cp++;
725 					ox[1] = '.';
726 					PRINT(ox, 2);
727 					if (_double) {
728 						PRINT(cp, ndig-1);
729 					} else	/* 0.[0..] */
730 						/* __dtoa irregularity */
731 						PAD(ndig - 1, zeroes);
732 				} else	/* XeYYY */
733 					PRINT(cp, 1);
734 				PRINT(expstr, expsize);
735 			}
736 		}
737 #else
738 		PRINT(cp, size);
739 #endif
740 		/* left-adjusting padding (always blank) */
741 		if (flags & LADJUST)
742 			PAD(width - realsz, blanks);
743 
744 		/* finally, adjust ret */
745 		ret += width > realsz ? width : realsz;
746 
747 		FLUSH();	/* copy out the I/O vectors */
748 	}
749 done:
750 	FLUSH();
751 error:
752 	if (__sferror(fp))
753 		ret = -1;
754 	FUNLOCKFILE(fp);
755 	return (ret);
756 }
757 
758 #ifdef FLOATING_POINT
759 
760 static char *
761 cvt(value, ndigits, flags, sign, decpt, ch, length)
762 	double value;
763 	int ndigits, flags, *decpt, ch, *length;
764 	char *sign;
765 {
766 	int mode, dsgn;
767 	char *digits, *bp, *rve;
768 
769 	_DIAGASSERT(decpt != NULL);
770 	_DIAGASSERT(length != NULL);
771 	_DIAGASSERT(sign != NULL);
772 
773 	if (ch == 'f') {
774 		mode = 3;		/* ndigits after the decimal point */
775 	} else {
776 		/* To obtain ndigits after the decimal point for the 'e'
777 		 * and 'E' formats, round to ndigits + 1 significant
778 		 * figures.
779 		 */
780 		if (ch == 'e' || ch == 'E') {
781 			ndigits++;
782 		}
783 		mode = 2;		/* ndigits significant digits */
784 	}
785 
786 	if (value < 0) {
787 		value = -value;
788 		*sign = '-';
789 	} else
790 		*sign = '\000';
791 	digits = __dtoa(value, mode, ndigits, decpt, &dsgn, &rve);
792 	if ((ch != 'g' && ch != 'G') || flags & ALT) {	/* Print trailing zeros */
793 		bp = digits + ndigits;
794 		if (ch == 'f') {
795 			if (*digits == '0' && value)
796 				*decpt = -ndigits + 1;
797 			bp += *decpt;
798 		}
799 		if (value == 0)	/* kludge for __dtoa irregularity */
800 			rve = bp;
801 		while (rve < bp)
802 			*rve++ = '0';
803 	}
804 	*length = rve - digits;
805 	return (digits);
806 }
807 
808 static int
809 exponent(p0, exp, fmtch)
810 	char *p0;
811 	int exp, fmtch;
812 {
813 	char *p, *t;
814 	char expbuf[MAXEXP];
815 
816 	_DIAGASSERT(p0 != NULL);
817 
818 	p = p0;
819 	*p++ = fmtch;
820 	if (exp < 0) {
821 		exp = -exp;
822 		*p++ = '-';
823 	}
824 	else
825 		*p++ = '+';
826 	t = expbuf + MAXEXP;
827 	if (exp > 9) {
828 		do {
829 			*--t = to_char(exp % 10);
830 		} while ((exp /= 10) > 9);
831 		*--t = to_char(exp);
832 		for (; t < expbuf + MAXEXP; *p++ = *t++);
833 	}
834 	else {
835 		*p++ = '0';
836 		*p++ = to_char(exp);
837 	}
838 	return (p - p0);
839 }
840 #endif /* FLOATING_POINT */
841