xref: /netbsd-src/lib/libc/stdio/vfprintf.c (revision f45c81bb89e4966334287a49732ec30b24d821f9)
1 /*	$NetBSD: vfprintf.c,v 1.54 2006/10/30 05:10:40 christos 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 1.54 2006/10/30 05:10:40 christos 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 /* NB: async-signal-safe when fp->_flags & __SAFE */
77 static int
78 __sprint(fp, uio)
79 	FILE *fp;
80 	struct __suio *uio;
81 {
82 	int err;
83 
84 	_DIAGASSERT(fp != NULL);
85 	_DIAGASSERT(uio != NULL);
86 
87 	if (uio->uio_resid == 0) {
88 		uio->uio_iovcnt = 0;
89 		return (0);
90 	}
91 	err = __sfvwrite(fp, uio);
92 	uio->uio_resid = 0;
93 	uio->uio_iovcnt = 0;
94 	return (err);
95 }
96 
97 /*
98  * Helper function for `fprintf to unbuffered unix file': creates a
99  * temporary buffer.  We only work on write-only files; this avoids
100  * worries about ungetc buffers and so forth.
101  */
102 static int
103 __sbprintf(fp, fmt, ap)
104 	FILE *fp;
105 	const char *fmt;
106 	va_list ap;
107 {
108 	int ret;
109 	FILE fake;
110 	struct __sfileext fakeext;
111 	unsigned char buf[BUFSIZ];
112 
113 	_DIAGASSERT(fp != NULL);
114 	_DIAGASSERT(fmt != NULL);
115 
116 	_FILEEXT_SETUP(&fake, &fakeext);
117 
118 	/* copy the important variables */
119 	fake._flags = fp->_flags & ~__SNBF;
120 	fake._file = fp->_file;
121 	fake._cookie = fp->_cookie;
122 	fake._write = fp->_write;
123 
124 	/* set up the buffer */
125 	fake._bf._base = fake._p = buf;
126 	fake._bf._size = fake._w = sizeof(buf);
127 	fake._lbfsize = 0;	/* not actually used, but Just In Case */
128 
129 	/* do the work, then copy any error status */
130 	ret = vfprintf(&fake, fmt, ap);
131 	if (ret >= 0 && fflush(&fake))
132 		ret = -1;
133 	if (fake._flags & __SERR)
134 		fp->_flags |= __SERR;
135 	return (ret);
136 }
137 
138 
139 #ifndef NO_FLOATING_POINT
140 #include <locale.h>
141 #include <math.h>
142 #include "floatio.h"
143 
144 #define	BUF		(MAXEXP+MAXFRACT+1)	/* + decimal point */
145 #define	DEFPREC		6
146 
147 static char *cvt __P((double, int, int, char *, int *, int, int *));
148 static int exponent __P((char *, int, int));
149 
150 #else /* FLOATING_POINT */
151 
152 #define	BUF		40
153 
154 #endif /* NO_FLOATING_POINT */
155 
156 /*
157  * Macros for converting digits to letters and vice versa
158  */
159 #define	to_digit(c)	((c) - '0')
160 #define is_digit(c)	((unsigned)to_digit(c) <= 9)
161 #define	to_char(n)	((char)((n) + '0'))
162 
163 /*
164  * Flags used during conversion.
165  */
166 #define	ALT		0x001		/* alternate form */
167 #define	HEXPREFIX	0x002		/* add 0x or 0X prefix */
168 #define	LADJUST		0x004		/* left adjustment */
169 #define	LONGDBL		0x008		/* long double; unimplemented */
170 #define	LONGINT		0x010		/* long integer */
171 #define	QUADINT		0x020		/* quad integer */
172 #define	SHORTINT	0x040		/* short integer */
173 #define	MAXINT		0x080		/* (unsigned) intmax_t */
174 #define	PTRINT		0x100		/* (unsigned) ptrdiff_t */
175 #define	SIZEINT		0x200		/* (signed) size_t */
176 #define	ZEROPAD		0x400		/* zero (as opposed to blank) pad */
177 #define FPT		0x800		/* Floating point number */
178 
179 int
180 vfprintf(fp, fmt0, ap)
181 	FILE *fp;
182 	const char *fmt0;
183 	_BSD_VA_LIST_ ap;
184 {
185 	int ret;
186 
187 	FLOCKFILE(fp);
188 	ret = __vfprintf_unlocked(fp, fmt0, ap);
189 	FUNLOCKFILE(fp);
190 
191 	return ret;
192 }
193 
194 
195 
196 /* NB: async-signal-safe when fp->_flags & __SAFE */
197 int
198 __vfprintf_unlocked(fp, fmt0, ap)
199 	FILE *fp;
200 	const char *fmt0;
201 	_BSD_VA_LIST_ ap;
202 {
203 	const char *fmt;/* format string */
204 	int ch;	/* character from fmt */
205 	int n, m;	/* handy integers (short term usage) */
206 	const char *cp;	/* handy char pointer (short term usage) */
207 	char *bp;	/* handy char pointer (short term usage) */
208 	struct __siov *iovp;/* for PRINT macro */
209 	int flags;	/* flags as above */
210 	int ret;		/* return value accumulator */
211 	int width;		/* width from format (%8d), or 0 */
212 	int prec;		/* precision from format (%.3d), or -1 */
213 	char sign;		/* sign prefix (' ', '+', '-', or \0) */
214 	wchar_t wc;
215 	mbstate_t ps;
216 #ifndef NO_FLOATING_POINT
217 	char *decimal_point = NULL;
218 	char softsign;		/* temporary negative sign for floats */
219 	double _double;		/* double precision arguments %[eEfgG] */
220 	int expt;		/* integer value of exponent */
221 	int expsize = 0;	/* character count for expstr */
222 	int ndig;		/* actual number of digits returned by cvt */
223 	char expstr[7];		/* buffer for exponent string */
224 	char *dtoaresult = NULL;
225 #endif
226 
227 #ifdef __GNUC__			/* gcc has builtin quad type (long long) SOS */
228 #define	quad_t	  long long
229 #define	u_quad_t  unsigned long long
230 #endif
231 
232 #define	INTMAX_T	intmax_t
233 #define	UINTMAX_T	uintmax_t
234 
235 	UINTMAX_T _uintmax;	/* integer arguments %[diouxX] */
236 	enum { OCT, DEC, HEX } base;/* base for [diouxX] conversion */
237 	int dprec;		/* a copy of prec if [diouxX], 0 otherwise */
238 	int realsz;		/* field size expanded by dprec */
239 	int size;		/* size of converted field or string */
240 	const char *xdigs = NULL;/* digits for [xX] conversion */
241 #define NIOV 8
242 	struct __suio uio;	/* output information: summary */
243 	struct __siov iov[NIOV];/* ... and individual io vectors */
244 	char buf[BUF];		/* space for %c, %[diouxX], %[eEfgG] */
245 	char ox[2];		/* space for 0x hex-prefix */
246 
247 	/*
248 	 * Choose PADSIZE to trade efficiency vs. size.  If larger printf
249 	 * fields occur frequently, increase PADSIZE and make the initialisers
250 	 * below longer.
251 	 */
252 #define	PADSIZE	16		/* pad chunk size */
253 	static const char blanks[PADSIZE] =
254 	 {' ',' ',' ',' ',' ',' ',' ',' ',' ',' ',' ',' ',' ',' ',' ',' '};
255 	static const char zeroes[PADSIZE] =
256 	 {'0','0','0','0','0','0','0','0','0','0','0','0','0','0','0','0'};
257 
258 	/*
259 	 * BEWARE, these `goto error' on error, and PAD uses `n'.
260 	 */
261 #define	PRINT(ptr, len) { \
262 	iovp->iov_base = __UNCONST(ptr); \
263 	iovp->iov_len = (len); \
264 	uio.uio_resid += (len); \
265 	iovp++; \
266 	if (++uio.uio_iovcnt >= NIOV) { \
267 		if (__sprint(fp, &uio)) \
268 			goto error; \
269 		iovp = iov; \
270 	} \
271 }
272 #define	PAD(howmany, with) { \
273 	if ((n = (howmany)) > 0) { \
274 		while (n > PADSIZE) { \
275 			PRINT(with, PADSIZE); \
276 			n -= PADSIZE; \
277 		} \
278 		PRINT(with, n); \
279 	} \
280 }
281 #define	FLUSH() { \
282 	if (uio.uio_resid && __sprint(fp, &uio)) \
283 		goto error; \
284 	uio.uio_iovcnt = 0; \
285 	iovp = iov; \
286 }
287 
288 	/*
289 	 * To extend shorts properly, we need both signed and unsigned
290 	 * argument extraction methods.
291 	 */
292 #define	SARG() \
293 	(flags&MAXINT ? va_arg(ap, intmax_t) : \
294 	    flags&PTRINT ? va_arg(ap, ptrdiff_t) : \
295 	    flags&SIZEINT ? va_arg(ap, ssize_t) : /* XXX */ \
296 	    flags&QUADINT ? va_arg(ap, quad_t) : \
297 	    flags&LONGINT ? va_arg(ap, long) : \
298 	    flags&SHORTINT ? (long)(short)va_arg(ap, int) : \
299 	    (long)va_arg(ap, int))
300 #define	UARG() \
301 	(flags&MAXINT ? va_arg(ap, uintmax_t) : \
302 	    flags&PTRINT ? va_arg(ap, uintptr_t) : /* XXX */ \
303 	    flags&SIZEINT ? va_arg(ap, size_t) : \
304 	    flags&QUADINT ? va_arg(ap, u_quad_t) : \
305 	    flags&LONGINT ? va_arg(ap, u_long) : \
306 	    flags&SHORTINT ? (u_long)(u_short)va_arg(ap, int) : \
307 	    (u_long)va_arg(ap, u_int))
308 
309 	_DIAGASSERT(fp != NULL);
310 	_DIAGASSERT(fmt0 != NULL);
311 
312 	_SET_ORIENTATION(fp, -1);
313 
314 	/* sorry, fprintf(read_only_file, "") returns -1, not 0 */
315 	if (cantwrite(fp)) {
316 		errno = EBADF;
317 		return (-1);
318 	}
319 
320 	/* optimise fprintf(stderr) (and other unbuffered Unix files) */
321 	if ((fp->_flags & (__SNBF|__SWR|__SRW)) == (__SNBF|__SWR) &&
322 	    fp->_file >= 0) {
323 		ret = __sbprintf(fp, fmt0, ap);
324 		return (ret);
325 	}
326 
327 	fmt = fmt0;
328 	uio.uio_iov = iovp = iov;
329 	uio.uio_resid = 0;
330 	uio.uio_iovcnt = 0;
331 	ret = 0;
332 
333 	memset(&ps, 0, sizeof(ps));
334 
335 	/*
336 	 * Scan the format for conversions (`%' character).
337 	 */
338 	for (;;) {
339 		cp = fmt;
340 		if (fp->_flags & __SAFE) {
341 			for (; *fmt && *fmt != '%'; fmt++)
342 				continue;
343 			n = *fmt == '%';
344 		} else {
345 			while ((n = mbrtowc(&wc, fmt, MB_CUR_MAX, &ps)) > 0) {
346 				fmt += n;
347 				if (wc == '%') {
348 					fmt--;
349 					break;
350 				}
351 			}
352 		}
353 		if ((m = fmt - cp) != 0) {
354 			PRINT(cp, m);
355 			ret += m;
356 		}
357 		if (n <= 0)
358 			goto done;
359 		fmt++;		/* skip over '%' */
360 
361 		flags = 0;
362 		dprec = 0;
363 		width = 0;
364 		prec = -1;
365 		sign = '\0';
366 
367 rflag:		ch = *fmt++;
368 reswitch:	switch (ch) {
369 		case ' ':
370 			/*
371 			 * ``If the space and + flags both appear, the space
372 			 * flag will be ignored.''
373 			 *	-- ANSI X3J11
374 			 */
375 			if (!sign)
376 				sign = ' ';
377 			goto rflag;
378 		case '#':
379 			flags |= ALT;
380 			goto rflag;
381 		case '*':
382 			/*
383 			 * ``A negative field width argument is taken as a
384 			 * - flag followed by a positive field width.''
385 			 *	-- ANSI X3J11
386 			 * They don't exclude field widths read from args.
387 			 */
388 			if ((width = va_arg(ap, int)) >= 0)
389 				goto rflag;
390 			width = -width;
391 			/* FALLTHROUGH */
392 		case '-':
393 			flags |= LADJUST;
394 			goto rflag;
395 		case '+':
396 			sign = '+';
397 			goto rflag;
398 		case '.':
399 			if ((ch = *fmt++) == '*') {
400 				n = va_arg(ap, int);
401 				prec = n < 0 ? -1 : n;
402 				goto rflag;
403 			}
404 			n = 0;
405 			while (is_digit(ch)) {
406 				n = 10 * n + to_digit(ch);
407 				ch = *fmt++;
408 			}
409 			prec = n < 0 ? -1 : n;
410 			goto reswitch;
411 		case '0':
412 			/*
413 			 * ``Note that 0 is taken as a flag, not as the
414 			 * beginning of a field width.''
415 			 *	-- ANSI X3J11
416 			 */
417 			flags |= ZEROPAD;
418 			goto rflag;
419 		case '1': case '2': case '3': case '4':
420 		case '5': case '6': case '7': case '8': case '9':
421 			n = 0;
422 			do {
423 				n = 10 * n + to_digit(ch);
424 				ch = *fmt++;
425 			} while (is_digit(ch));
426 			width = n;
427 			goto reswitch;
428 #ifndef NO_FLOATING_POINT
429 		case 'L':
430 			flags |= LONGDBL;
431 			goto rflag;
432 #endif
433 		case 'h':
434 			flags |= SHORTINT;
435 			goto rflag;
436 		case 'j':
437 			flags |= MAXINT;
438 			goto rflag;
439 		case 'l':
440 			if (*fmt == 'l') {
441 				fmt++;
442 				flags |= QUADINT;
443 			} else {
444 				flags |= LONGINT;
445 			}
446 			goto rflag;
447 		case 'q':
448 			flags |= QUADINT;
449 			goto rflag;
450 		case 't':
451 			flags |= PTRINT;
452 			goto rflag;
453 		case 'z':
454 			flags |= SIZEINT;
455 			goto rflag;
456 		case 'c':
457 			*buf = va_arg(ap, int);
458 			cp = buf;
459 			size = 1;
460 			sign = '\0';
461 			break;
462 		case 'D':
463 			flags |= LONGINT;
464 			/*FALLTHROUGH*/
465 		case 'd':
466 		case 'i':
467 			_uintmax = SARG();
468 			if ((intmax_t)_uintmax < 0) {
469 				_uintmax = -_uintmax;
470 				sign = '-';
471 			}
472 			base = DEC;
473 			goto number;
474 #ifndef NO_FLOATING_POINT
475 		case 'e':
476 		case 'E':
477 		case 'f':
478 		case 'F':
479 		case 'g':
480 		case 'G':
481 			if (prec == -1) {
482 				prec = DEFPREC;
483 			} else if ((ch == 'g' || ch == 'G') && prec == 0) {
484 				prec = 1;
485 			}
486 
487 			if (flags & LONGDBL) {
488 				_double = (double) va_arg(ap, long double);
489 			} else {
490 				_double = va_arg(ap, double);
491 			}
492 
493 			/* do this before tricky precision changes */
494 			if (isinf(_double)) {
495 				if (_double < 0)
496 					sign = '-';
497 				if (ch == 'E' || ch == 'F' || ch == 'G')
498 					cp = "INF";
499 				else
500 					cp = "inf";
501 				size = 3;
502 				break;
503 			}
504 			if (isnan(_double)) {
505 				if (ch == 'E' || ch == 'F' || ch == 'G')
506 					cp = "NAN";
507 				else
508 					cp = "nan";
509 				size = 3;
510 				break;
511 			}
512 			if (fp->_flags & __SAFE) {
513 				if (ch == 'E' || ch == 'F' || ch == 'G')
514 					cp = "UNK";
515 				else
516 					cp = "unk";
517 				size = 3;
518 				break;
519 			}
520 
521 			flags |= FPT;
522 			if (dtoaresult)
523 				__freedtoa(dtoaresult);
524 			cp = dtoaresult = cvt(_double, prec, flags, &softsign,
525 				&expt, ch, &ndig);
526 			if (ch == 'g' || ch == 'G') {
527 				if (expt <= -4 || expt > prec)
528 					ch = (ch == 'g') ? 'e' : 'E';
529 				else
530 					ch = 'g';
531 			}
532 			if (ch == 'e' || ch == 'E') {
533 				--expt;
534 				expsize = exponent(expstr, expt, ch);
535 				size = expsize + ndig;
536 				if (ndig > 1 || flags & ALT)
537 					++size;
538 			} else if (ch == 'f' || ch == 'F') {
539 				if (expt > 0) {
540 					size = expt;
541 					if (prec || flags & ALT)
542 						size += prec + 1;
543 				} else	/* "0.X" */
544 					size = prec + 2;
545 			} else if (expt >= ndig) {	/* fixed g fmt */
546 				size = expt;
547 				if (flags & ALT)
548 					++size;
549 			} else
550 				size = ndig + (expt > 0 ?
551 					1 : 2 - expt);
552 
553 			if (softsign)
554 				sign = '-';
555 			break;
556 #endif /* NO_FLOATING_POINT */
557 		case 'n':
558 			if (flags & MAXINT)
559 				*va_arg(ap, intmax_t *) = ret;
560 			else if (flags & PTRINT)
561 				*va_arg(ap, ptrdiff_t *) = ret;
562 			else if (flags & SIZEINT)
563 				*va_arg(ap, ssize_t *) = ret;	/* XXX */
564 			else if (flags & QUADINT)
565 				*va_arg(ap, quad_t *) = ret;
566 			else if (flags & LONGINT)
567 				*va_arg(ap, long *) = ret;
568 			else if (flags & SHORTINT)
569 				*va_arg(ap, short *) = ret;
570 			else
571 				*va_arg(ap, int *) = ret;
572 			continue;	/* no output */
573 		case 'O':
574 			flags |= LONGINT;
575 			/*FALLTHROUGH*/
576 		case 'o':
577 			_uintmax = UARG();
578 			base = OCT;
579 			goto nosign;
580 		case 'p':
581 			/*
582 			 * ``The argument shall be a pointer to void.  The
583 			 * value of the pointer is converted to a sequence
584 			 * of printable characters, in an implementation-
585 			 * defined manner.''
586 			 *	-- ANSI X3J11
587 			 */
588 			/* NOSTRICT */
589 			_uintmax = (u_long)va_arg(ap, void *);
590 			base = HEX;
591 			xdigs = "0123456789abcdef";
592 			flags |= HEXPREFIX;
593 			ch = 'x';
594 			goto nosign;
595 		case 's':
596 			if ((cp = va_arg(ap, char *)) == NULL)
597 				cp = "(null)";
598 			if (prec >= 0) {
599 				/*
600 				 * can't use strlen; can only look for the
601 				 * NUL in the first `prec' characters, and
602 				 * strlen() will go further.
603 				 */
604 				char *p = memchr(cp, 0, (size_t)prec);
605 
606 				if (p != NULL) {
607 					size = p - cp;
608 					if (size > prec)
609 						size = prec;
610 				} else
611 					size = prec;
612 			} else
613 				size = strlen(cp);
614 			sign = '\0';
615 			break;
616 		case 'U':
617 			flags |= LONGINT;
618 			/*FALLTHROUGH*/
619 		case 'u':
620 			_uintmax = UARG();
621 			base = DEC;
622 			goto nosign;
623 		case 'X':
624 			xdigs = "0123456789ABCDEF";
625 			goto hex;
626 		case 'x':
627 			xdigs = "0123456789abcdef";
628 hex:			_uintmax = UARG();
629 			base = HEX;
630 			/* leading 0x/X only if non-zero */
631 			if (flags & ALT && _uintmax != 0)
632 				flags |= HEXPREFIX;
633 
634 			/* unsigned conversions */
635 nosign:			sign = '\0';
636 			/*
637 			 * ``... diouXx conversions ... if a precision is
638 			 * specified, the 0 flag will be ignored.''
639 			 *	-- ANSI X3J11
640 			 */
641 number:			if ((dprec = prec) >= 0)
642 				flags &= ~ZEROPAD;
643 
644 			/*
645 			 * ``The result of converting a zero value with an
646 			 * explicit precision of zero is no characters.''
647 			 *	-- ANSI X3J11
648 			 */
649 			bp = buf + BUF;
650 			if (_uintmax != 0 || prec != 0) {
651 				/*
652 				 * Unsigned mod is hard, and unsigned mod
653 				 * by a constant is easier than that by
654 				 * a variable; hence this switch.
655 				 */
656 				switch (base) {
657 				case OCT:
658 					do {
659 						*--bp = to_char(_uintmax & 7);
660 						_uintmax >>= 3;
661 					} while (_uintmax);
662 					/* handle octal leading 0 */
663 					if (flags & ALT && *bp != '0')
664 						*--bp = '0';
665 					break;
666 
667 				case DEC:
668 					/* many numbers are 1 digit */
669 					while (_uintmax >= 10) {
670 						*--bp = to_char(_uintmax % 10);
671 						_uintmax /= 10;
672 					}
673 					*--bp = to_char(_uintmax);
674 					break;
675 
676 				case HEX:
677 					do {
678 						*--bp = xdigs[(size_t)
679 						    (_uintmax & 15)];
680 						_uintmax >>= 4;
681 					} while (_uintmax);
682 					break;
683 
684 				default:
685 					cp = "bug in vfprintf: bad base";
686 					size = strlen(cp);
687 					goto skipsize;
688 				}
689 			}
690 			cp = bp;
691 			size = buf + BUF - bp;
692 		skipsize:
693 			break;
694 		default:	/* "%?" prints ?, unless ? is NUL */
695 			if (ch == '\0')
696 				goto done;
697 			/* pretend it was %c with argument ch */
698 			*buf = ch;
699 			cp = buf;
700 			size = 1;
701 			sign = '\0';
702 			break;
703 		}
704 
705 		/*
706 		 * All reasonable formats wind up here.  At this point, `cp'
707 		 * points to a string which (if not flags&LADJUST) should be
708 		 * padded out to `width' places.  If flags&ZEROPAD, it should
709 		 * first be prefixed by any sign or other prefix; otherwise,
710 		 * it should be blank padded before the prefix is emitted.
711 		 * After any left-hand padding and prefixing, emit zeroes
712 		 * required by a decimal [diouxX] precision, then print the
713 		 * string proper, then emit zeroes required by any leftover
714 		 * floating precision; finally, if LADJUST, pad with blanks.
715 		 *
716 		 * Compute actual size, so we know how much to pad.
717 		 * size excludes decimal prec; realsz includes it.
718 		 */
719 		realsz = dprec > size ? dprec : size;
720 		if (sign)
721 			realsz++;
722 		else if (flags & HEXPREFIX)
723 			realsz+= 2;
724 
725 		/* right-adjusting blank padding */
726 		if ((flags & (LADJUST|ZEROPAD)) == 0)
727 			PAD(width - realsz, blanks);
728 
729 		/* prefix */
730 		if (sign) {
731 			PRINT(&sign, 1);
732 		} else if (flags & HEXPREFIX) {
733 			ox[0] = '0';
734 			ox[1] = ch;
735 			PRINT(ox, 2);
736 		}
737 
738 		/* right-adjusting zero padding */
739 		if ((flags & (LADJUST|ZEROPAD)) == ZEROPAD)
740 			PAD(width - realsz, zeroes);
741 
742 		/* leading zeroes from decimal precision */
743 		PAD(dprec - size, zeroes);
744 
745 		/* the string or number proper */
746 #ifndef NO_FLOATING_POINT
747 		if ((flags & FPT) == 0) {
748 			PRINT(cp, size);
749 		} else {	/* glue together f_p fragments */
750 			if (ch >= 'f') {	/* 'f' or 'g' */
751 				if (decimal_point == NULL)
752 					decimal_point =
753 					    localeconv()->decimal_point;
754 				if (_double == 0) {
755 					/* kludge for __dtoa irregularity */
756 					PRINT("0", 1);
757 					if (expt < ndig || (flags & ALT) != 0) {
758 						PRINT(decimal_point, 1);
759 						PAD(ndig - 1, zeroes);
760 					}
761 				} else if (expt <= 0) {
762 					PRINT("0", 1);
763 					PRINT(decimal_point, 1);
764 					PAD(-expt, zeroes);
765 					PRINT(cp, ndig);
766 				} else if (expt >= ndig) {
767 					PRINT(cp, ndig);
768 					PAD(expt - ndig, zeroes);
769 					if (flags & ALT)
770 						PRINT(".", 1);
771 				} else {
772 					PRINT(cp, expt);
773 					cp += expt;
774 					PRINT(".", 1);
775 					PRINT(cp, ndig-expt);
776 				}
777 			} else {	/* 'e' or 'E' */
778 				if (ndig > 1 || flags & ALT) {
779 					ox[0] = *cp++;
780 					ox[1] = '.';
781 					PRINT(ox, 2);
782 					if (_double) {
783 						PRINT(cp, ndig-1);
784 					} else	/* 0.[0..] */
785 						/* __dtoa irregularity */
786 						PAD(ndig - 1, zeroes);
787 				} else	/* XeYYY */
788 					PRINT(cp, 1);
789 				PRINT(expstr, expsize);
790 			}
791 		}
792 #else
793 		PRINT(cp, size);
794 #endif
795 		/* left-adjusting padding (always blank) */
796 		if (flags & LADJUST)
797 			PAD(width - realsz, blanks);
798 
799 		/* finally, adjust ret */
800 		ret += width > realsz ? width : realsz;
801 
802 		FLUSH();	/* copy out the I/O vectors */
803 	}
804 done:
805 	FLUSH();
806 error:
807 #ifndef NO_FLOATING_POINT
808 	if (dtoaresult)
809 		__freedtoa(dtoaresult);
810 #endif
811 	if (__sferror(fp))
812 		ret = -1;
813 	return (ret);
814 }
815 
816 #ifndef NO_FLOATING_POINT
817 
818 static char *
819 cvt(value, ndigits, flags, sign, decpt, ch, length)
820 	double value;
821 	int ndigits, flags, *decpt, ch, *length;
822 	char *sign;
823 {
824 	int mode, dsgn;
825 	char *digits, *bp, *rve;
826 
827 	_DIAGASSERT(decpt != NULL);
828 	_DIAGASSERT(length != NULL);
829 	_DIAGASSERT(sign != NULL);
830 
831 	if (ch == 'f') {
832 		mode = 3;		/* ndigits after the decimal point */
833 	} else {
834 		/* To obtain ndigits after the decimal point for the 'e'
835 		 * and 'E' formats, round to ndigits + 1 significant
836 		 * figures.
837 		 */
838 		if (ch == 'e' || ch == 'E') {
839 			ndigits++;
840 		}
841 		mode = 2;		/* ndigits significant digits */
842 	}
843 
844 	digits = __dtoa(value, mode, ndigits, decpt, &dsgn, &rve);
845 	if (dsgn) {
846 		value = -value;
847 		*sign = '-';
848 	} else
849 		*sign = '\000';
850 	if ((ch != 'g' && ch != 'G') || flags & ALT) {	/* Print trailing zeros */
851 		bp = digits + ndigits;
852 		if (ch == 'f') {
853 			if (*digits == '0' && value)
854 				*decpt = -ndigits + 1;
855 			bp += *decpt;
856 		}
857 		if (value == 0)	/* kludge for __dtoa irregularity */
858 			rve = bp;
859 		while (rve < bp)
860 			*rve++ = '0';
861 	}
862 	*length = rve - digits;
863 	return (digits);
864 }
865 
866 static int
867 exponent(p0, expon, fmtch)
868 	char *p0;
869 	int expon, fmtch;
870 {
871 	char *p, *t;
872 	char expbuf[MAXEXP];
873 
874 	_DIAGASSERT(p0 != NULL);
875 
876 	p = p0;
877 	*p++ = fmtch;
878 	if (expon < 0) {
879 		expon = -expon;
880 		*p++ = '-';
881 	}
882 	else
883 		*p++ = '+';
884 	t = expbuf + MAXEXP;
885 	if (expon > 9) {
886 		do {
887 			*--t = to_char(expon % 10);
888 		} while ((expon /= 10) > 9);
889 		*--t = to_char(expon);
890 		for (; t < expbuf + MAXEXP; *p++ = *t++);
891 	}
892 	else {
893 		*p++ = '0';
894 		*p++ = to_char(expon);
895 	}
896 	return (p - p0);
897 }
898 #endif /* NO_FLOATING_POINT */
899