xref: /netbsd-src/lib/libc/stdio/vfprintf.c (revision ae9172d6cd9432a6a1a56760d86b32c57a66c39c)
1 /*-
2  * Copyright (c) 1990 The Regents of the University of California.
3  * All rights reserved.
4  *
5  * This code is derived from software contributed to Berkeley by
6  * Chris Torek.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  * 3. All advertising materials mentioning features or use of this software
17  *    must display the following acknowledgement:
18  *	This product includes software developed by the University of
19  *	California, Berkeley and its contributors.
20  * 4. Neither the name of the University nor the names of its contributors
21  *    may be used to endorse or promote products derived from this software
22  *    without specific prior written permission.
23  *
24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34  * SUCH DAMAGE.
35  */
36 
37 #if defined(LIBC_SCCS) && !defined(lint)
38 /*static char *sccsid = "from: @(#)vfprintf.c	5.50 (Berkeley) 12/16/92";*/
39 static char *rcsid = "$Id: vfprintf.c,v 1.13 1994/10/20 03:56:56 jtc Exp $";
40 #endif /* LIBC_SCCS and not lint */
41 
42 /*
43  * Actual printf innards.
44  *
45  * This code is large and complicated...
46  */
47 
48 #include <sys/types.h>
49 
50 #include <stdio.h>
51 #include <stdlib.h>
52 #include <string.h>
53 
54 #if __STDC__
55 #include <stdarg.h>
56 #else
57 #include <varargs.h>
58 #endif
59 
60 #include "local.h"
61 #include "fvwrite.h"
62 
63 /*
64  * Flush out all the vectors defined by the given uio,
65  * then reset it so that it can be reused.
66  */
67 static int
68 __sprint(fp, uio)
69 	FILE *fp;
70 	register struct __suio *uio;
71 {
72 	register int err;
73 
74 	if (uio->uio_resid == 0) {
75 		uio->uio_iovcnt = 0;
76 		return (0);
77 	}
78 	err = __sfvwrite(fp, uio);
79 	uio->uio_resid = 0;
80 	uio->uio_iovcnt = 0;
81 	return (err);
82 }
83 
84 /*
85  * Helper function for `fprintf to unbuffered unix file': creates a
86  * temporary buffer.  We only work on write-only files; this avoids
87  * worries about ungetc buffers and so forth.
88  */
89 static int
90 __sbprintf(fp, fmt, ap)
91 	register FILE *fp;
92 	const char *fmt;
93 	va_list ap;
94 {
95 	int ret;
96 	FILE fake;
97 	unsigned char buf[BUFSIZ];
98 
99 	/* copy the important variables */
100 	fake._flags = fp->_flags & ~__SNBF;
101 	fake._file = fp->_file;
102 	fake._cookie = fp->_cookie;
103 	fake._write = fp->_write;
104 
105 	/* set up the buffer */
106 	fake._bf._base = fake._p = buf;
107 	fake._bf._size = fake._w = sizeof(buf);
108 	fake._lbfsize = 0;	/* not actually used, but Just In Case */
109 
110 	/* do the work, then copy any error status */
111 	ret = vfprintf(&fake, fmt, ap);
112 	if (ret >= 0 && fflush(&fake))
113 		ret = EOF;
114 	if (fake._flags & __SERR)
115 		fp->_flags |= __SERR;
116 	return (ret);
117 }
118 
119 
120 #ifdef FLOATING_POINT
121 #include <locale.h>
122 #include <math.h>
123 #include "floatio.h"
124 
125 #define	BUF		(MAXEXP+MAXFRACT+1)	/* + decimal point */
126 #define	DEFPREC		6
127 
128 static char *cvt __P((double, int, int, char *, int *, int, int *));
129 static int exponent __P((char *, int, int));
130 
131 #else /* no FLOATING_POINT */
132 
133 #define	BUF		40
134 
135 #endif /* FLOATING_POINT */
136 
137 
138 /*
139  * Macros for converting digits to letters and vice versa
140  */
141 #define	to_digit(c)	((c) - '0')
142 #define is_digit(c)	((unsigned)to_digit(c) <= 9)
143 #define	to_char(n)	((n) + '0')
144 
145 /*
146  * Flags used during conversion.
147  */
148 #define	ALT		0x001		/* alternate form */
149 #define	HEXPREFIX	0x002		/* add 0x or 0X prefix */
150 #define	LADJUST		0x004		/* left adjustment */
151 #define	LONGDBL		0x008		/* long double; unimplemented */
152 #define	LONGINT		0x010		/* long integer */
153 #define	QUADINT		0x020		/* quad integer */
154 #define	SHORTINT	0x040		/* short integer */
155 #define	ZEROPAD		0x080		/* zero (as opposed to blank) pad */
156 #define FPT		0x100		/* Floating point number */
157 int
158 vfprintf(fp, fmt0, ap)
159 	FILE *fp;
160 	const char *fmt0;
161 	_BSD_VA_LIST_ ap;
162 {
163 	register char *fmt;	/* format string */
164 	register int ch;	/* character from fmt */
165 	register int n;		/* handy integer (short term usage) */
166 	register char *cp;	/* handy char pointer (short term usage) */
167 	register struct __siov *iovp;/* for PRINT macro */
168 	register int flags;	/* flags as above */
169 	int ret;		/* return value accumulator */
170 	int width;		/* width from format (%8d), or 0 */
171 	int prec;		/* precision from format (%.3d), or -1 */
172 	char sign;		/* sign prefix (' ', '+', '-', or \0) */
173 #ifdef FLOATING_POINT
174 	char *decimal_point = localeconv()->decimal_point;
175 	char softsign;		/* temporary negative sign for floats */
176 	double _double;		/* double precision arguments %[eEfgG] */
177 	int expt;		/* integer value of exponent */
178 	int expsize;		/* character count for expstr */
179 	int ndig;		/* actual number of digits returned by cvt */
180 	char expstr[7];		/* buffer for exponent string */
181 #endif
182 
183 #ifdef __GNUC__			/* gcc has builtin quad type (long long) SOS */
184 #define	quad_t	  long long
185 #define	u_quad_t  unsigned long long
186 #endif
187 
188 	u_quad_t _uquad;	/* integer arguments %[diouxX] */
189 	enum { OCT, DEC, HEX } base;/* base for [diouxX] conversion */
190 	int dprec;		/* a copy of prec if [diouxX], 0 otherwise */
191 	int fieldsz;		/* field size expanded by sign, etc */
192 	int realsz;		/* field size expanded by dprec */
193 	int size;		/* size of converted field or string */
194 	char *xdigs;		/* digits for [xX] conversion */
195 #define NIOV 8
196 	struct __suio uio;	/* output information: summary */
197 	struct __siov iov[NIOV];/* ... and individual io vectors */
198 	char buf[BUF];		/* space for %c, %[diouxX], %[eEfgG] */
199 	char ox[2];		/* space for 0x hex-prefix */
200 
201 	/*
202 	 * Choose PADSIZE to trade efficiency vs. size.  If larger printf
203 	 * fields occur frequently, increase PADSIZE and make the initialisers
204 	 * below longer.
205 	 */
206 #define	PADSIZE	16		/* pad chunk size */
207 	static char blanks[PADSIZE] =
208 	 {' ',' ',' ',' ',' ',' ',' ',' ',' ',' ',' ',' ',' ',' ',' ',' '};
209 	static char zeroes[PADSIZE] =
210 	 {'0','0','0','0','0','0','0','0','0','0','0','0','0','0','0','0'};
211 
212 	/*
213 	 * BEWARE, these `goto error' on error, and PAD uses `n'.
214 	 */
215 #define	PRINT(ptr, len) { \
216 	iovp->iov_base = (ptr); \
217 	iovp->iov_len = (len); \
218 	uio.uio_resid += (len); \
219 	iovp++; \
220 	if (++uio.uio_iovcnt >= NIOV) { \
221 		if (__sprint(fp, &uio)) \
222 			goto error; \
223 		iovp = iov; \
224 	} \
225 }
226 #define	PAD(howmany, with) { \
227 	if ((n = (howmany)) > 0) { \
228 		while (n > PADSIZE) { \
229 			PRINT(with, PADSIZE); \
230 			n -= PADSIZE; \
231 		} \
232 		PRINT(with, n); \
233 	} \
234 }
235 #define	FLUSH() { \
236 	if (uio.uio_resid && __sprint(fp, &uio)) \
237 		goto error; \
238 	uio.uio_iovcnt = 0; \
239 	iovp = iov; \
240 }
241 
242 	/*
243 	 * To extend shorts properly, we need both signed and unsigned
244 	 * argument extraction methods.
245 	 */
246 #define	SARG() \
247 	(flags&QUADINT ? va_arg(ap, quad_t) : \
248 	    flags&LONGINT ? va_arg(ap, long) : \
249 	    flags&SHORTINT ? (long)(short)va_arg(ap, int) : \
250 	    (long)va_arg(ap, int))
251 #define	UARG() \
252 	(flags&QUADINT ? va_arg(ap, u_quad_t) : \
253 	    flags&LONGINT ? va_arg(ap, u_long) : \
254 	    flags&SHORTINT ? (u_long)(u_short)va_arg(ap, int) : \
255 	    (u_long)va_arg(ap, u_int))
256 
257 	/* sorry, fprintf(read_only_file, "") returns EOF, not 0 */
258 	if (cantwrite(fp))
259 		return (EOF);
260 
261 	/* optimise fprintf(stderr) (and other unbuffered Unix files) */
262 	if ((fp->_flags & (__SNBF|__SWR|__SRW)) == (__SNBF|__SWR) &&
263 	    fp->_file >= 0)
264 		return (__sbprintf(fp, fmt0, ap));
265 
266 	fmt = (char *)fmt0;
267 	uio.uio_iov = iovp = iov;
268 	uio.uio_resid = 0;
269 	uio.uio_iovcnt = 0;
270 	ret = 0;
271 
272 	/*
273 	 * Scan the format for conversions (`%' character).
274 	 */
275 	for (;;) {
276 		for (cp = fmt; (ch = *fmt) != '\0' && ch != '%'; fmt++)
277 			/* void */;
278 		if ((n = fmt - cp) != 0) {
279 			PRINT(cp, n);
280 			ret += n;
281 		}
282 		if (ch == '\0')
283 			goto done;
284 		fmt++;		/* skip over '%' */
285 
286 		flags = 0;
287 		dprec = 0;
288 		width = 0;
289 		prec = -1;
290 		sign = '\0';
291 
292 rflag:		ch = *fmt++;
293 reswitch:	switch (ch) {
294 		case ' ':
295 			/*
296 			 * ``If the space and + flags both appear, the space
297 			 * flag will be ignored.''
298 			 *	-- ANSI X3J11
299 			 */
300 			if (!sign)
301 				sign = ' ';
302 			goto rflag;
303 		case '#':
304 			flags |= ALT;
305 			goto rflag;
306 		case '*':
307 			/*
308 			 * ``A negative field width argument is taken as a
309 			 * - flag followed by a positive field width.''
310 			 *	-- ANSI X3J11
311 			 * They don't exclude field widths read from args.
312 			 */
313 			if ((width = va_arg(ap, int)) >= 0)
314 				goto rflag;
315 			width = -width;
316 			/* FALLTHROUGH */
317 		case '-':
318 			flags |= LADJUST;
319 			goto rflag;
320 		case '+':
321 			sign = '+';
322 			goto rflag;
323 		case '.':
324 			if ((ch = *fmt++) == '*') {
325 				n = va_arg(ap, int);
326 				prec = n < 0 ? -1 : n;
327 				goto rflag;
328 			}
329 			n = 0;
330 			while (is_digit(ch)) {
331 				n = 10 * n + to_digit(ch);
332 				ch = *fmt++;
333 			}
334 			prec = n < 0 ? -1 : n;
335 			goto reswitch;
336 		case '0':
337 			/*
338 			 * ``Note that 0 is taken as a flag, not as the
339 			 * beginning of a field width.''
340 			 *	-- ANSI X3J11
341 			 */
342 			flags |= ZEROPAD;
343 			goto rflag;
344 		case '1': case '2': case '3': case '4':
345 		case '5': case '6': case '7': case '8': case '9':
346 			n = 0;
347 			do {
348 				n = 10 * n + to_digit(ch);
349 				ch = *fmt++;
350 			} while (is_digit(ch));
351 			width = n;
352 			goto reswitch;
353 #ifdef FLOATING_POINT
354 		case 'L':
355 			flags |= LONGDBL;
356 			goto rflag;
357 #endif
358 		case 'h':
359 			flags |= SHORTINT;
360 			goto rflag;
361 		case 'l':
362 			flags |= LONGINT;
363 			goto rflag;
364 		case 'q':
365 			flags |= QUADINT;
366 			goto rflag;
367 		case 'c':
368 			*(cp = buf) = va_arg(ap, int);
369 			size = 1;
370 			sign = '\0';
371 			break;
372 		case 'D':
373 			flags |= LONGINT;
374 			/*FALLTHROUGH*/
375 		case 'd':
376 		case 'i':
377 			_uquad = SARG();
378 			if ((quad_t)_uquad < 0) {
379 				_uquad = -_uquad;
380 				sign = '-';
381 			}
382 			base = DEC;
383 			goto number;
384 #ifdef FLOATING_POINT
385 		case 'e':
386 		case 'E':
387 		case 'f':
388 		case 'g':
389 		case 'G':
390 			if (prec == -1) {
391 				prec = DEFPREC;
392 			} else if ((ch == 'g' || ch == 'G') && prec == 0) {
393 				prec = 1;
394 			}
395 
396 			if (flags & LONGDBL) {
397 				_double = (double) va_arg(ap, long double);
398 			} else {
399 				_double = va_arg(ap, double);
400 			}
401 
402 			/* do this before tricky precision changes */
403 			if (isinf(_double)) {
404 				if (_double < 0)
405 					sign = '-';
406 				cp = "Inf";
407 				size = 3;
408 				break;
409 			}
410 			if (isnan(_double)) {
411 				cp = "NaN";
412 				size = 3;
413 				break;
414 			}
415 
416 			flags |= FPT;
417 			cp = cvt(_double, prec, flags, &softsign,
418 				&expt, ch, &ndig);
419 			if (ch == 'g' || ch == 'G') {
420 				if (expt <= -4 || expt > prec)
421 					ch = (ch == 'g') ? 'e' : 'E';
422 				else
423 					ch = 'g';
424 			}
425 			if (ch <= 'e') {	/* 'e' or 'E' fmt */
426 				--expt;
427 				expsize = exponent(expstr, expt, ch);
428 				size = expsize + ndig;
429 				if (ndig > 1 || flags & ALT)
430 					++size;
431 			} else if (ch == 'f') {		/* f fmt */
432 				if (expt > 0) {
433 					size = expt;
434 					if (prec || flags & ALT)
435 						size += prec + 1;
436 				} else	/* "0.X" */
437 					size = prec + 2;
438 			} else if (expt >= ndig) {	/* fixed g fmt */
439 				size = expt;
440 				if (flags & ALT)
441 					++size;
442 			} else
443 				size = ndig + (expt > 0 ?
444 					1 : 2 - expt);
445 
446 			if (softsign)
447 				sign = '-';
448 			break;
449 #endif /* FLOATING_POINT */
450 		case 'n':
451 			if (flags & QUADINT)
452 				*va_arg(ap, quad_t *) = ret;
453 			else if (flags & LONGINT)
454 				*va_arg(ap, long *) = ret;
455 			else if (flags & SHORTINT)
456 				*va_arg(ap, short *) = ret;
457 			else
458 				*va_arg(ap, int *) = ret;
459 			continue;	/* no output */
460 		case 'O':
461 			flags |= LONGINT;
462 			/*FALLTHROUGH*/
463 		case 'o':
464 			_uquad = UARG();
465 			base = OCT;
466 			goto nosign;
467 		case 'p':
468 			/*
469 			 * ``The argument shall be a pointer to void.  The
470 			 * value of the pointer is converted to a sequence
471 			 * of printable characters, in an implementation-
472 			 * defined manner.''
473 			 *	-- ANSI X3J11
474 			 */
475 			/* NOSTRICT */
476 			_uquad = (u_quad_t)va_arg(ap, void *);
477 			base = HEX;
478 			xdigs = "0123456789abcdef";
479 			flags |= HEXPREFIX;
480 			ch = 'x';
481 			goto nosign;
482 		case 's':
483 			if ((cp = va_arg(ap, char *)) == NULL)
484 				cp = "(null)";
485 			if (prec >= 0) {
486 				/*
487 				 * can't use strlen; can only look for the
488 				 * NUL in the first `prec' characters, and
489 				 * strlen() will go further.
490 				 */
491 				char *p = memchr(cp, 0, prec);
492 
493 				if (p != NULL) {
494 					size = p - cp;
495 					if (size > prec)
496 						size = prec;
497 				} else
498 					size = prec;
499 			} else
500 				size = strlen(cp);
501 			sign = '\0';
502 			break;
503 		case 'U':
504 			flags |= LONGINT;
505 			/*FALLTHROUGH*/
506 		case 'u':
507 			_uquad = UARG();
508 			base = DEC;
509 			goto nosign;
510 		case 'X':
511 			xdigs = "0123456789ABCDEF";
512 			goto hex;
513 		case 'x':
514 			xdigs = "0123456789abcdef";
515 hex:			_uquad = UARG();
516 			base = HEX;
517 			/* leading 0x/X only if non-zero */
518 			if (flags & ALT && _uquad != 0)
519 				flags |= HEXPREFIX;
520 
521 			/* unsigned conversions */
522 nosign:			sign = '\0';
523 			/*
524 			 * ``... diouXx conversions ... if a precision is
525 			 * specified, the 0 flag will be ignored.''
526 			 *	-- ANSI X3J11
527 			 */
528 number:			if ((dprec = prec) >= 0)
529 				flags &= ~ZEROPAD;
530 
531 			/*
532 			 * ``The result of converting a zero value with an
533 			 * explicit precision of zero is no characters.''
534 			 *	-- ANSI X3J11
535 			 */
536 			cp = buf + BUF;
537 			if (_uquad != 0 || prec != 0) {
538 				/*
539 				 * Unsigned mod is hard, and unsigned mod
540 				 * by a constant is easier than that by
541 				 * a variable; hence this switch.
542 				 */
543 				switch (base) {
544 				case OCT:
545 					do {
546 						*--cp = to_char(_uquad & 7);
547 						_uquad >>= 3;
548 					} while (_uquad);
549 					/* handle octal leading 0 */
550 					if (flags & ALT && *cp != '0')
551 						*--cp = '0';
552 					break;
553 
554 				case DEC:
555 					/* many numbers are 1 digit */
556 					while (_uquad >= 10) {
557 						*--cp = to_char(_uquad % 10);
558 						_uquad /= 10;
559 					}
560 					*--cp = to_char(_uquad);
561 					break;
562 
563 				case HEX:
564 					do {
565 						*--cp = xdigs[_uquad & 15];
566 						_uquad >>= 4;
567 					} while (_uquad);
568 					break;
569 
570 				default:
571 					cp = "bug in vfprintf: bad base";
572 					size = strlen(cp);
573 					goto skipsize;
574 				}
575 			}
576 			size = buf + BUF - cp;
577 		skipsize:
578 			break;
579 		default:	/* "%?" prints ?, unless ? is NUL */
580 			if (ch == '\0')
581 				goto done;
582 			/* pretend it was %c with argument ch */
583 			cp = buf;
584 			*cp = ch;
585 			size = 1;
586 			sign = '\0';
587 			break;
588 		}
589 
590 		/*
591 		 * All reasonable formats wind up here.  At this point, `cp'
592 		 * points to a string which (if not flags&LADJUST) should be
593 		 * padded out to `width' places.  If flags&ZEROPAD, it should
594 		 * first be prefixed by any sign or other prefix; otherwise,
595 		 * it should be blank padded before the prefix is emitted.
596 		 * After any left-hand padding and prefixing, emit zeroes
597 		 * required by a decimal [diouxX] precision, then print the
598 		 * string proper, then emit zeroes required by any leftover
599 		 * floating precision; finally, if LADJUST, pad with blanks.
600 		 *
601 		 * Compute actual size, so we know how much to pad.
602 		 * fieldsz excludes decimal prec; realsz includes it.
603 		 */
604 		fieldsz = size;
605 		if (sign)
606 			fieldsz++;
607 		else if (flags & HEXPREFIX)
608 			fieldsz += 2;
609 		realsz = dprec > fieldsz ? dprec : fieldsz;
610 
611 		/* right-adjusting blank padding */
612 		if ((flags & (LADJUST|ZEROPAD)) == 0)
613 			PAD(width - realsz, blanks);
614 
615 		/* prefix */
616 		if (sign) {
617 			PRINT(&sign, 1);
618 		} else if (flags & HEXPREFIX) {
619 			ox[0] = '0';
620 			ox[1] = ch;
621 			PRINT(ox, 2);
622 		}
623 
624 		/* right-adjusting zero padding */
625 		if ((flags & (LADJUST|ZEROPAD)) == ZEROPAD)
626 			PAD(width - realsz, zeroes);
627 
628 		/* leading zeroes from decimal precision */
629 		PAD(dprec - size, zeroes);
630 
631 		/* the string or number proper */
632 #ifdef FLOATING_POINT
633 		if ((flags & FPT) == 0) {
634 			PRINT(cp, size);
635 		} else {	/* glue together f_p fragments */
636 			if (ch >= 'f') {	/* 'f' or 'g' */
637 				if (_double == 0) {
638 					/* kludge for __dtoa irregularity */
639 					PRINT("0", 1);
640 					if (expt < ndig || (flags & ALT) != 0) {
641 						PRINT(decimal_point, 1);
642 						PAD(ndig - 1, zeroes);
643 					}
644 				} else if (expt <= 0) {
645 					PRINT("0", 1);
646 					PRINT(decimal_point, 1);
647 					PAD(-expt, zeroes);
648 					PRINT(cp, ndig);
649 				} else if (expt >= ndig) {
650 					PRINT(cp, ndig);
651 					PAD(expt - ndig, zeroes);
652 					if (flags & ALT)
653 						PRINT(".", 1);
654 				} else {
655 					PRINT(cp, expt);
656 					cp += expt;
657 					PRINT(".", 1);
658 					PRINT(cp, ndig-expt);
659 				}
660 			} else {	/* 'e' or 'E' */
661 				if (ndig > 1 || flags & ALT) {
662 					ox[0] = *cp++;
663 					ox[1] = '.';
664 					PRINT(ox, 2);
665 					if (_double || flags & ALT == 0) {
666 						PRINT(cp, ndig-1);
667 					} else	/* 0.[0..] */
668 						/* __dtoa irregularity */
669 						PAD(ndig - 1, zeroes);
670 				} else	/* XeYYY */
671 					PRINT(cp, 1);
672 				PRINT(expstr, expsize);
673 			}
674 		}
675 #else
676 		PRINT(cp, size);
677 #endif
678 		/* left-adjusting padding (always blank) */
679 		if (flags & LADJUST)
680 			PAD(width - realsz, blanks);
681 
682 		/* finally, adjust ret */
683 		ret += width > realsz ? width : realsz;
684 
685 		FLUSH();	/* copy out the I/O vectors */
686 	}
687 done:
688 	FLUSH();
689 error:
690 	return (__sferror(fp) ? EOF : ret);
691 	/* NOTREACHED */
692 }
693 
694 #ifdef FLOATING_POINT
695 
696 extern char *__dtoa __P((double, int, int, int *, int *, char **));
697 
698 static char *
699 cvt(value, ndigits, flags, sign, decpt, ch, length)
700 	double value;
701 	int ndigits, flags, *decpt, ch, *length;
702 	char *sign;
703 {
704 	int mode, dsgn;
705 	char *digits, *bp, *rve;
706 
707 	if (ch == 'f') {
708 		mode = 3;		/* ndigits after the decimal point */
709 	} else {
710 		/* To obtain ndigits after the decimal point for the 'e'
711 		 * and 'E' formats, round to ndigits + 1 significant
712 		 * figures.
713 		 */
714 		if (ch == 'e' || ch == 'E') {
715 			ndigits++;
716 		}
717 		mode = 2;		/* ndigits significant digits */
718 	}
719 
720 	if (value < 0) {
721 		value = -value;
722 		*sign = '-';
723 	} else
724 		*sign = '\000';
725 	digits = __dtoa(value, mode, ndigits, decpt, &dsgn, &rve);
726 	if ((ch != 'g' && ch != 'G') || flags & ALT) {	/* Print trailing zeros */
727 		bp = digits + ndigits;
728 		if (ch == 'f') {
729 			if (*digits == '0' && value)
730 				*decpt = -ndigits + 1;
731 			bp += *decpt;
732 		}
733 		if (value == 0)	/* kludge for __dtoa irregularity */
734 			rve = bp;
735 		while (rve < bp)
736 			*rve++ = '0';
737 	}
738 	*length = rve - digits;
739 	return (digits);
740 }
741 
742 static int
743 exponent(p0, exp, fmtch)
744 	char *p0;
745 	int exp, fmtch;
746 {
747 	register char *p, *t;
748 	char expbuf[MAXEXP];
749 
750 	p = p0;
751 	*p++ = fmtch;
752 	if (exp < 0) {
753 		exp = -exp;
754 		*p++ = '-';
755 	}
756 	else
757 		*p++ = '+';
758 	t = expbuf + MAXEXP;
759 	if (exp > 9) {
760 		do {
761 			*--t = to_char(exp % 10);
762 		} while ((exp /= 10) > 9);
763 		*--t = to_char(exp);
764 		for (; t < expbuf + MAXEXP; *p++ = *t++);
765 	}
766 	else {
767 		*p++ = '0';
768 		*p++ = to_char(exp);
769 	}
770 	return (p - p0);
771 }
772 #endif /* FLOATING_POINT */
773