xref: /netbsd-src/lib/libc/stdio/vfprintf.c (revision 21e37cc72a480a47828990a439cde7ac9ffaf0c6)
1 /*	$NetBSD: vfprintf.c,v 1.46 2004/03/03 11:19:05 drochner 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. Neither the name of the University nor the names of its contributors
19  *    may be used to endorse or promote products derived from this software
20  *    without specific prior written permission.
21  *
22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32  * SUCH DAMAGE.
33  */
34 
35 #include <sys/cdefs.h>
36 #if defined(LIBC_SCCS) && !defined(lint)
37 #if 0
38 static char *sccsid = "@(#)vfprintf.c	5.50 (Berkeley) 12/16/92";
39 #else
40 __RCSID("$NetBSD: vfprintf.c,v 1.46 2004/03/03 11:19:05 drochner Exp $");
41 #endif
42 #endif /* LIBC_SCCS and not lint */
43 
44 /*
45  * Actual printf innards.
46  *
47  * This code is large and complicated...
48  */
49 
50 #include "namespace.h"
51 #include <sys/types.h>
52 
53 #include <assert.h>
54 #include <errno.h>
55 #include <stdarg.h>
56 #include <stddef.h>
57 #include <stdint.h>
58 #include <stdio.h>
59 #include <stdlib.h>
60 #include <string.h>
61 #include <wchar.h>
62 
63 #include "reentrant.h"
64 #include "local.h"
65 #include "fvwrite.h"
66 #include "extern.h"
67 
68 static int __sprint __P((FILE *, struct __suio *));
69 static int __sbprintf __P((FILE *, const char *, va_list))
70      __attribute__((__format__(__printf__, 2, 0)));
71 
72 /*
73  * Flush out all the vectors defined by the given uio,
74  * then reset it so that it can be reused.
75  */
76 static int
77 __sprint(fp, uio)
78 	FILE *fp;
79 	struct __suio *uio;
80 {
81 	int err;
82 
83 	_DIAGASSERT(fp != NULL);
84 	_DIAGASSERT(uio != NULL);
85 
86 	if (uio->uio_resid == 0) {
87 		uio->uio_iovcnt = 0;
88 		return (0);
89 	}
90 	err = __sfvwrite(fp, uio);
91 	uio->uio_resid = 0;
92 	uio->uio_iovcnt = 0;
93 	return (err);
94 }
95 
96 /*
97  * Helper function for `fprintf to unbuffered unix file': creates a
98  * temporary buffer.  We only work on write-only files; this avoids
99  * worries about ungetc buffers and so forth.
100  */
101 static int
102 __sbprintf(fp, fmt, ap)
103 	FILE *fp;
104 	const char *fmt;
105 	va_list ap;
106 {
107 	int ret;
108 	FILE fake;
109 	struct __sfileext fakeext;
110 	unsigned char buf[BUFSIZ];
111 
112 	_DIAGASSERT(fp != NULL);
113 	_DIAGASSERT(fmt != NULL);
114 
115 	_FILEEXT_SETUP(&fake, &fakeext);
116 
117 	/* copy the important variables */
118 	fake._flags = fp->_flags & ~__SNBF;
119 	fake._file = fp->_file;
120 	fake._cookie = fp->_cookie;
121 	fake._write = fp->_write;
122 
123 	/* set up the buffer */
124 	fake._bf._base = fake._p = buf;
125 	fake._bf._size = fake._w = sizeof(buf);
126 	fake._lbfsize = 0;	/* not actually used, but Just In Case */
127 
128 	/* do the work, then copy any error status */
129 	ret = vfprintf(&fake, fmt, ap);
130 	if (ret >= 0 && fflush(&fake))
131 		ret = -1;
132 	if (fake._flags & __SERR)
133 		fp->_flags |= __SERR;
134 	return (ret);
135 }
136 
137 
138 #ifdef FLOATING_POINT
139 #include <locale.h>
140 #include <math.h>
141 #include "floatio.h"
142 
143 #define	BUF		(MAXEXP+MAXFRACT+1)	/* + decimal point */
144 #define	DEFPREC		6
145 
146 static char *cvt __P((double, int, int, char *, int *, int, int *));
147 static int exponent __P((char *, int, int));
148 
149 #else /* no FLOATING_POINT */
150 
151 #define	BUF		40
152 
153 #endif /* FLOATING_POINT */
154 
155 #ifdef lint
156 static __inline void *__UNCONST __P((const void *));
157 static __inline void *
158 __UNCONST(v)
159 	const void *v;
160 {
161 	/* LINTED */
162 	return (void *) v;
163 }
164 #else
165 #define __UNCONST(v)	(void *)(v)
166 #endif
167 
168 /*
169  * Macros for converting digits to letters and vice versa
170  */
171 #define	to_digit(c)	((c) - '0')
172 #define is_digit(c)	((unsigned)to_digit(c) <= 9)
173 #define	to_char(n)	((char)((n) + '0'))
174 
175 /*
176  * Flags used during conversion.
177  */
178 #define	ALT		0x001		/* alternate form */
179 #define	HEXPREFIX	0x002		/* add 0x or 0X prefix */
180 #define	LADJUST		0x004		/* left adjustment */
181 #define	LONGDBL		0x008		/* long double; unimplemented */
182 #define	LONGINT		0x010		/* long integer */
183 #define	QUADINT		0x020		/* quad integer */
184 #define	SHORTINT	0x040		/* short integer */
185 #define	MAXINT		0x080		/* (unsigned) intmax_t */
186 #define	PTRINT		0x100		/* (unsigned) ptrdiff_t */
187 #define	SIZEINT		0x200		/* (signed) size_t */
188 #define	ZEROPAD		0x400		/* zero (as opposed to blank) pad */
189 #define FPT		0x800		/* Floating point number */
190 
191 int
192 vfprintf(fp, fmt0, ap)
193 	FILE *fp;
194 	const char *fmt0;
195 	_BSD_VA_LIST_ ap;
196 {
197 	int ret;
198 
199 	FLOCKFILE(fp);
200 	ret = vfprintf_unlocked(fp, fmt0, ap);
201 	FUNLOCKFILE(fp);
202 
203 	return ret;
204 }
205 
206 
207 
208 int
209 vfprintf_unlocked(fp, fmt0, ap)
210 	FILE *fp;
211 	const char *fmt0;
212 	_BSD_VA_LIST_ ap;
213 {
214 	const char *fmt;/* format string */
215 	int ch;	/* character from fmt */
216 	int n, m;	/* handy integers (short term usage) */
217 	const char *cp;	/* handy char pointer (short term usage) */
218 	char *bp;	/* handy char pointer (short term usage) */
219 	struct __siov *iovp;/* for PRINT macro */
220 	int flags;	/* flags as above */
221 	int ret;		/* return value accumulator */
222 	int width;		/* width from format (%8d), or 0 */
223 	int prec;		/* precision from format (%.3d), or -1 */
224 	char sign;		/* sign prefix (' ', '+', '-', or \0) */
225 	wchar_t wc;
226 	mbstate_t ps;
227 #ifdef FLOATING_POINT
228 	char *decimal_point = localeconv()->decimal_point;
229 	char softsign;		/* temporary negative sign for floats */
230 	double _double;		/* double precision arguments %[eEfgG] */
231 	int expt;		/* integer value of exponent */
232 	int expsize = 0;	/* character count for expstr */
233 	int ndig;		/* actual number of digits returned by cvt */
234 	char expstr[7];		/* buffer for exponent string */
235 #endif
236 
237 #ifdef __GNUC__			/* gcc has builtin quad type (long long) SOS */
238 #define	quad_t	  long long
239 #define	u_quad_t  unsigned long long
240 #endif
241 
242 #define	INTMAX_T	intmax_t
243 #define	UINTMAX_T	uintmax_t
244 
245 	UINTMAX_T _uintmax;	/* integer arguments %[diouxX] */
246 	enum { OCT, DEC, HEX } base;/* base for [diouxX] conversion */
247 	int dprec;		/* a copy of prec if [diouxX], 0 otherwise */
248 	int realsz;		/* field size expanded by dprec */
249 	int size;		/* size of converted field or string */
250 	char *xdigs = NULL;	/* digits for [xX] conversion */
251 #define NIOV 8
252 	struct __suio uio;	/* output information: summary */
253 	struct __siov iov[NIOV];/* ... and individual io vectors */
254 	char buf[BUF];		/* space for %c, %[diouxX], %[eEfgG] */
255 	char ox[2];		/* space for 0x hex-prefix */
256 
257 	/*
258 	 * Choose PADSIZE to trade efficiency vs. size.  If larger printf
259 	 * fields occur frequently, increase PADSIZE and make the initialisers
260 	 * below longer.
261 	 */
262 #define	PADSIZE	16		/* pad chunk size */
263 	static const char blanks[PADSIZE] =
264 	 {' ',' ',' ',' ',' ',' ',' ',' ',' ',' ',' ',' ',' ',' ',' ',' '};
265 	static const char zeroes[PADSIZE] =
266 	 {'0','0','0','0','0','0','0','0','0','0','0','0','0','0','0','0'};
267 
268 	/*
269 	 * BEWARE, these `goto error' on error, and PAD uses `n'.
270 	 */
271 #define	PRINT(ptr, len) { \
272 	iovp->iov_base = __UNCONST(ptr); \
273 	iovp->iov_len = (len); \
274 	uio.uio_resid += (len); \
275 	iovp++; \
276 	if (++uio.uio_iovcnt >= NIOV) { \
277 		if (__sprint(fp, &uio)) \
278 			goto error; \
279 		iovp = iov; \
280 	} \
281 }
282 #define	PAD(howmany, with) { \
283 	if ((n = (howmany)) > 0) { \
284 		while (n > PADSIZE) { \
285 			PRINT(with, PADSIZE); \
286 			n -= PADSIZE; \
287 		} \
288 		PRINT(with, n); \
289 	} \
290 }
291 #define	FLUSH() { \
292 	if (uio.uio_resid && __sprint(fp, &uio)) \
293 		goto error; \
294 	uio.uio_iovcnt = 0; \
295 	iovp = iov; \
296 }
297 
298 	/*
299 	 * To extend shorts properly, we need both signed and unsigned
300 	 * argument extraction methods.
301 	 */
302 #define	SARG() \
303 	(flags&MAXINT ? va_arg(ap, intmax_t) : \
304 	    flags&PTRINT ? va_arg(ap, ptrdiff_t) : \
305 	    flags&SIZEINT ? va_arg(ap, ssize_t) : /* XXX */ \
306 	    flags&QUADINT ? va_arg(ap, quad_t) : \
307 	    flags&LONGINT ? va_arg(ap, long) : \
308 	    flags&SHORTINT ? (long)(short)va_arg(ap, int) : \
309 	    (long)va_arg(ap, int))
310 #define	UARG() \
311 	(flags&MAXINT ? va_arg(ap, uintmax_t) : \
312 	    flags&PTRINT ? va_arg(ap, uintptr_t) : /* XXX */ \
313 	    flags&SIZEINT ? va_arg(ap, size_t) : \
314 	    flags&QUADINT ? va_arg(ap, u_quad_t) : \
315 	    flags&LONGINT ? va_arg(ap, u_long) : \
316 	    flags&SHORTINT ? (u_long)(u_short)va_arg(ap, int) : \
317 	    (u_long)va_arg(ap, u_int))
318 
319 	_DIAGASSERT(fp != NULL);
320 	_DIAGASSERT(fmt0 != NULL);
321 
322 	_SET_ORIENTATION(fp, -1);
323 
324 	/* sorry, fprintf(read_only_file, "") returns -1, not 0 */
325 	if (cantwrite(fp)) {
326 		errno = EBADF;
327 		return (-1);
328 	}
329 
330 	/* optimise fprintf(stderr) (and other unbuffered Unix files) */
331 	if ((fp->_flags & (__SNBF|__SWR|__SRW)) == (__SNBF|__SWR) &&
332 	    fp->_file >= 0) {
333 		ret = __sbprintf(fp, fmt0, ap);
334 		return (ret);
335 	}
336 
337 	fmt = fmt0;
338 	uio.uio_iov = iovp = iov;
339 	uio.uio_resid = 0;
340 	uio.uio_iovcnt = 0;
341 	ret = 0;
342 
343 	memset(&ps, 0, sizeof(ps));
344 
345 	/*
346 	 * Scan the format for conversions (`%' character).
347 	 */
348 	for (;;) {
349 		cp = fmt;
350 		while ((n = mbrtowc(&wc, fmt, MB_CUR_MAX, &ps)) > 0) {
351 			fmt += n;
352 			if (wc == '%') {
353 				fmt--;
354 				break;
355 			}
356 		}
357 		if ((m = fmt - cp) != 0) {
358 			PRINT(cp, m);
359 			ret += m;
360 		}
361 		if (n <= 0)
362 			goto done;
363 		fmt++;		/* skip over '%' */
364 
365 		flags = 0;
366 		dprec = 0;
367 		width = 0;
368 		prec = -1;
369 		sign = '\0';
370 
371 rflag:		ch = *fmt++;
372 reswitch:	switch (ch) {
373 		case ' ':
374 			/*
375 			 * ``If the space and + flags both appear, the space
376 			 * flag will be ignored.''
377 			 *	-- ANSI X3J11
378 			 */
379 			if (!sign)
380 				sign = ' ';
381 			goto rflag;
382 		case '#':
383 			flags |= ALT;
384 			goto rflag;
385 		case '*':
386 			/*
387 			 * ``A negative field width argument is taken as a
388 			 * - flag followed by a positive field width.''
389 			 *	-- ANSI X3J11
390 			 * They don't exclude field widths read from args.
391 			 */
392 			if ((width = va_arg(ap, int)) >= 0)
393 				goto rflag;
394 			width = -width;
395 			/* FALLTHROUGH */
396 		case '-':
397 			flags |= LADJUST;
398 			goto rflag;
399 		case '+':
400 			sign = '+';
401 			goto rflag;
402 		case '.':
403 			if ((ch = *fmt++) == '*') {
404 				n = va_arg(ap, int);
405 				prec = n < 0 ? -1 : n;
406 				goto rflag;
407 			}
408 			n = 0;
409 			while (is_digit(ch)) {
410 				n = 10 * n + to_digit(ch);
411 				ch = *fmt++;
412 			}
413 			prec = n < 0 ? -1 : n;
414 			goto reswitch;
415 		case '0':
416 			/*
417 			 * ``Note that 0 is taken as a flag, not as the
418 			 * beginning of a field width.''
419 			 *	-- ANSI X3J11
420 			 */
421 			flags |= ZEROPAD;
422 			goto rflag;
423 		case '1': case '2': case '3': case '4':
424 		case '5': case '6': case '7': case '8': case '9':
425 			n = 0;
426 			do {
427 				n = 10 * n + to_digit(ch);
428 				ch = *fmt++;
429 			} while (is_digit(ch));
430 			width = n;
431 			goto reswitch;
432 #ifdef FLOATING_POINT
433 		case 'L':
434 			flags |= LONGDBL;
435 			goto rflag;
436 #endif
437 		case 'h':
438 			flags |= SHORTINT;
439 			goto rflag;
440 		case 'j':
441 			flags |= MAXINT;
442 			goto rflag;
443 		case 'l':
444 			if (*fmt == 'l') {
445 				fmt++;
446 				flags |= QUADINT;
447 			} else {
448 				flags |= LONGINT;
449 			}
450 			goto rflag;
451 		case 'q':
452 			flags |= QUADINT;
453 			goto rflag;
454 		case 't':
455 			flags |= PTRINT;
456 			goto rflag;
457 		case 'z':
458 			flags |= SIZEINT;
459 			goto rflag;
460 		case 'c':
461 			*buf = va_arg(ap, int);
462 			cp = buf;
463 			size = 1;
464 			sign = '\0';
465 			break;
466 		case 'D':
467 			flags |= LONGINT;
468 			/*FALLTHROUGH*/
469 		case 'd':
470 		case 'i':
471 			_uintmax = SARG();
472 			if ((intmax_t)_uintmax < 0) {
473 				_uintmax = -_uintmax;
474 				sign = '-';
475 			}
476 			base = DEC;
477 			goto number;
478 #ifdef FLOATING_POINT
479 		case 'e':
480 		case 'E':
481 		case 'f':
482 		case 'F':
483 		case 'g':
484 		case 'G':
485 			if (prec == -1) {
486 				prec = DEFPREC;
487 			} else if ((ch == 'g' || ch == 'G') && prec == 0) {
488 				prec = 1;
489 			}
490 
491 			if (flags & LONGDBL) {
492 				_double = (double) va_arg(ap, long double);
493 			} else {
494 				_double = va_arg(ap, double);
495 			}
496 
497 			/* do this before tricky precision changes */
498 			if (isinf(_double)) {
499 				if (_double < 0)
500 					sign = '-';
501 				if (ch == 'E' || ch == 'F' || ch == 'G')
502 					cp = "INF";
503 				else
504 					cp = "inf";
505 				size = 3;
506 				break;
507 			}
508 			if (isnan(_double)) {
509 				if (ch == 'E' || ch == 'F' || ch == 'G')
510 					cp = "NAN";
511 				else
512 					cp = "nan";
513 				size = 3;
514 				break;
515 			}
516 
517 			flags |= FPT;
518 			cp = cvt(_double, prec, flags, &softsign,
519 				&expt, ch, &ndig);
520 			if (ch == 'g' || ch == 'G') {
521 				if (expt <= -4 || expt > prec)
522 					ch = (ch == 'g') ? 'e' : 'E';
523 				else
524 					ch = 'g';
525 			}
526 			if (ch == 'e' || ch == 'E') {
527 				--expt;
528 				expsize = exponent(expstr, expt, ch);
529 				size = expsize + ndig;
530 				if (ndig > 1 || flags & ALT)
531 					++size;
532 			} else if (ch == 'f' || ch == 'F') {
533 				if (expt > 0) {
534 					size = expt;
535 					if (prec || flags & ALT)
536 						size += prec + 1;
537 				} else	/* "0.X" */
538 					size = prec + 2;
539 			} else if (expt >= ndig) {	/* fixed g fmt */
540 				size = expt;
541 				if (flags & ALT)
542 					++size;
543 			} else
544 				size = ndig + (expt > 0 ?
545 					1 : 2 - expt);
546 
547 			if (softsign)
548 				sign = '-';
549 			break;
550 #endif /* FLOATING_POINT */
551 		case 'n':
552 			if (flags & MAXINT)
553 				*va_arg(ap, intmax_t *) = ret;
554 			else if (flags & PTRINT)
555 				*va_arg(ap, ptrdiff_t *) = ret;
556 			else if (flags & SIZEINT)
557 				*va_arg(ap, ssize_t *) = ret;	/* XXX */
558 			else if (flags & QUADINT)
559 				*va_arg(ap, quad_t *) = ret;
560 			else if (flags & LONGINT)
561 				*va_arg(ap, long *) = ret;
562 			else if (flags & SHORTINT)
563 				*va_arg(ap, short *) = ret;
564 			else
565 				*va_arg(ap, int *) = ret;
566 			continue;	/* no output */
567 		case 'O':
568 			flags |= LONGINT;
569 			/*FALLTHROUGH*/
570 		case 'o':
571 			_uintmax = UARG();
572 			base = OCT;
573 			goto nosign;
574 		case 'p':
575 			/*
576 			 * ``The argument shall be a pointer to void.  The
577 			 * value of the pointer is converted to a sequence
578 			 * of printable characters, in an implementation-
579 			 * defined manner.''
580 			 *	-- ANSI X3J11
581 			 */
582 			/* NOSTRICT */
583 			_uintmax = (u_long)va_arg(ap, void *);
584 			base = HEX;
585 			xdigs = "0123456789abcdef";
586 			flags |= HEXPREFIX;
587 			ch = 'x';
588 			goto nosign;
589 		case 's':
590 			if ((cp = va_arg(ap, char *)) == NULL)
591 				cp = "(null)";
592 			if (prec >= 0) {
593 				/*
594 				 * can't use strlen; can only look for the
595 				 * NUL in the first `prec' characters, and
596 				 * strlen() will go further.
597 				 */
598 				char *p = memchr(cp, 0, (size_t)prec);
599 
600 				if (p != NULL) {
601 					size = p - cp;
602 					if (size > prec)
603 						size = prec;
604 				} else
605 					size = prec;
606 			} else
607 				size = strlen(cp);
608 			sign = '\0';
609 			break;
610 		case 'U':
611 			flags |= LONGINT;
612 			/*FALLTHROUGH*/
613 		case 'u':
614 			_uintmax = UARG();
615 			base = DEC;
616 			goto nosign;
617 		case 'X':
618 			xdigs = "0123456789ABCDEF";
619 			goto hex;
620 		case 'x':
621 			xdigs = "0123456789abcdef";
622 hex:			_uintmax = UARG();
623 			base = HEX;
624 			/* leading 0x/X only if non-zero */
625 			if (flags & ALT && _uintmax != 0)
626 				flags |= HEXPREFIX;
627 
628 			/* unsigned conversions */
629 nosign:			sign = '\0';
630 			/*
631 			 * ``... diouXx conversions ... if a precision is
632 			 * specified, the 0 flag will be ignored.''
633 			 *	-- ANSI X3J11
634 			 */
635 number:			if ((dprec = prec) >= 0)
636 				flags &= ~ZEROPAD;
637 
638 			/*
639 			 * ``The result of converting a zero value with an
640 			 * explicit precision of zero is no characters.''
641 			 *	-- ANSI X3J11
642 			 */
643 			bp = buf + BUF;
644 			if (_uintmax != 0 || prec != 0) {
645 				/*
646 				 * Unsigned mod is hard, and unsigned mod
647 				 * by a constant is easier than that by
648 				 * a variable; hence this switch.
649 				 */
650 				switch (base) {
651 				case OCT:
652 					do {
653 						*--bp = to_char(_uintmax & 7);
654 						_uintmax >>= 3;
655 					} while (_uintmax);
656 					/* handle octal leading 0 */
657 					if (flags & ALT && *bp != '0')
658 						*--bp = '0';
659 					break;
660 
661 				case DEC:
662 					/* many numbers are 1 digit */
663 					while (_uintmax >= 10) {
664 						*--bp = to_char(_uintmax % 10);
665 						_uintmax /= 10;
666 					}
667 					*--bp = to_char(_uintmax);
668 					break;
669 
670 				case HEX:
671 					do {
672 						*--bp = xdigs[(size_t)
673 						    (_uintmax & 15)];
674 						_uintmax >>= 4;
675 					} while (_uintmax);
676 					break;
677 
678 				default:
679 					cp = "bug in vfprintf: bad base";
680 					size = strlen(cp);
681 					goto skipsize;
682 				}
683 			}
684 			cp = bp;
685 			size = buf + BUF - bp;
686 		skipsize:
687 			break;
688 		default:	/* "%?" prints ?, unless ? is NUL */
689 			if (ch == '\0')
690 				goto done;
691 			/* pretend it was %c with argument ch */
692 			*buf = ch;
693 			cp = buf;
694 			size = 1;
695 			sign = '\0';
696 			break;
697 		}
698 
699 		/*
700 		 * All reasonable formats wind up here.  At this point, `cp'
701 		 * points to a string which (if not flags&LADJUST) should be
702 		 * padded out to `width' places.  If flags&ZEROPAD, it should
703 		 * first be prefixed by any sign or other prefix; otherwise,
704 		 * it should be blank padded before the prefix is emitted.
705 		 * After any left-hand padding and prefixing, emit zeroes
706 		 * required by a decimal [diouxX] precision, then print the
707 		 * string proper, then emit zeroes required by any leftover
708 		 * floating precision; finally, if LADJUST, pad with blanks.
709 		 *
710 		 * Compute actual size, so we know how much to pad.
711 		 * size excludes decimal prec; realsz includes it.
712 		 */
713 		realsz = dprec > size ? dprec : size;
714 		if (sign)
715 			realsz++;
716 		else if (flags & HEXPREFIX)
717 			realsz+= 2;
718 
719 		/* right-adjusting blank padding */
720 		if ((flags & (LADJUST|ZEROPAD)) == 0)
721 			PAD(width - realsz, blanks);
722 
723 		/* prefix */
724 		if (sign) {
725 			PRINT(&sign, 1);
726 		} else if (flags & HEXPREFIX) {
727 			ox[0] = '0';
728 			ox[1] = ch;
729 			PRINT(ox, 2);
730 		}
731 
732 		/* right-adjusting zero padding */
733 		if ((flags & (LADJUST|ZEROPAD)) == ZEROPAD)
734 			PAD(width - realsz, zeroes);
735 
736 		/* leading zeroes from decimal precision */
737 		PAD(dprec - size, zeroes);
738 
739 		/* the string or number proper */
740 #ifdef FLOATING_POINT
741 		if ((flags & FPT) == 0) {
742 			PRINT(cp, size);
743 		} else {	/* glue together f_p fragments */
744 			if (ch >= 'f') {	/* 'f' or 'g' */
745 				if (_double == 0) {
746 					/* kludge for __dtoa irregularity */
747 					PRINT("0", 1);
748 					if (expt < ndig || (flags & ALT) != 0) {
749 						PRINT(decimal_point, 1);
750 						PAD(ndig - 1, zeroes);
751 					}
752 				} else if (expt <= 0) {
753 					PRINT("0", 1);
754 					PRINT(decimal_point, 1);
755 					PAD(-expt, zeroes);
756 					PRINT(cp, ndig);
757 				} else if (expt >= ndig) {
758 					PRINT(cp, ndig);
759 					PAD(expt - ndig, zeroes);
760 					if (flags & ALT)
761 						PRINT(".", 1);
762 				} else {
763 					PRINT(cp, expt);
764 					cp += expt;
765 					PRINT(".", 1);
766 					PRINT(cp, ndig-expt);
767 				}
768 			} else {	/* 'e' or 'E' */
769 				if (ndig > 1 || flags & ALT) {
770 					ox[0] = *cp++;
771 					ox[1] = '.';
772 					PRINT(ox, 2);
773 					if (_double) {
774 						PRINT(cp, ndig-1);
775 					} else	/* 0.[0..] */
776 						/* __dtoa irregularity */
777 						PAD(ndig - 1, zeroes);
778 				} else	/* XeYYY */
779 					PRINT(cp, 1);
780 				PRINT(expstr, expsize);
781 			}
782 		}
783 #else
784 		PRINT(cp, size);
785 #endif
786 		/* left-adjusting padding (always blank) */
787 		if (flags & LADJUST)
788 			PAD(width - realsz, blanks);
789 
790 		/* finally, adjust ret */
791 		ret += width > realsz ? width : realsz;
792 
793 		FLUSH();	/* copy out the I/O vectors */
794 	}
795 done:
796 	FLUSH();
797 error:
798 	if (__sferror(fp))
799 		ret = -1;
800 	return (ret);
801 }
802 
803 #ifdef FLOATING_POINT
804 
805 static char *
806 cvt(value, ndigits, flags, sign, decpt, ch, length)
807 	double value;
808 	int ndigits, flags, *decpt, ch, *length;
809 	char *sign;
810 {
811 	int mode, dsgn;
812 	char *digits, *bp, *rve;
813 
814 	_DIAGASSERT(decpt != NULL);
815 	_DIAGASSERT(length != NULL);
816 	_DIAGASSERT(sign != NULL);
817 
818 	if (ch == 'f') {
819 		mode = 3;		/* ndigits after the decimal point */
820 	} else {
821 		/* To obtain ndigits after the decimal point for the 'e'
822 		 * and 'E' formats, round to ndigits + 1 significant
823 		 * figures.
824 		 */
825 		if (ch == 'e' || ch == 'E') {
826 			ndigits++;
827 		}
828 		mode = 2;		/* ndigits significant digits */
829 	}
830 
831 	digits = __dtoa(value, mode, ndigits, decpt, &dsgn, &rve);
832 	if (dsgn) {
833 		value = -value;
834 		*sign = '-';
835 	} else
836 		*sign = '\000';
837 	if ((ch != 'g' && ch != 'G') || flags & ALT) {	/* Print trailing zeros */
838 		bp = digits + ndigits;
839 		if (ch == 'f') {
840 			if (*digits == '0' && value)
841 				*decpt = -ndigits + 1;
842 			bp += *decpt;
843 		}
844 		if (value == 0)	/* kludge for __dtoa irregularity */
845 			rve = bp;
846 		while (rve < bp)
847 			*rve++ = '0';
848 	}
849 	*length = rve - digits;
850 	return (digits);
851 }
852 
853 static int
854 exponent(p0, expon, fmtch)
855 	char *p0;
856 	int expon, fmtch;
857 {
858 	char *p, *t;
859 	char expbuf[MAXEXP];
860 
861 	_DIAGASSERT(p0 != NULL);
862 
863 	p = p0;
864 	*p++ = fmtch;
865 	if (expon < 0) {
866 		expon = -expon;
867 		*p++ = '-';
868 	}
869 	else
870 		*p++ = '+';
871 	t = expbuf + MAXEXP;
872 	if (expon > 9) {
873 		do {
874 			*--t = to_char(expon % 10);
875 		} while ((expon /= 10) > 9);
876 		*--t = to_char(expon);
877 		for (; t < expbuf + MAXEXP; *p++ = *t++);
878 	}
879 	else {
880 		*p++ = '0';
881 		*p++ = to_char(expon);
882 	}
883 	return (p - p0);
884 }
885 #endif /* FLOATING_POINT */
886