vfprintf.c revision 1.29
1 /* $NetBSD: vfprintf.c,v 1.29 1998/10/13 14:43:39 kleink 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 1.29 1998/10/13 14:43:39 kleink 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 #include <errno.h> 57 #include <stdio.h> 58 #include <stdlib.h> 59 #include <string.h> 60 61 #if __STDC__ 62 #include <stdarg.h> 63 #else 64 #include <varargs.h> 65 #endif 66 67 #include "local.h" 68 #include "fvwrite.h" 69 #include "extern.h" 70 #include "reentrant.h" 71 72 static int __sprint __P((FILE *, struct __suio *)); 73 static int __sbprintf __P((FILE *, const char *, va_list)); 74 75 /* 76 * Flush out all the vectors defined by the given uio, 77 * then reset it so that it can be reused. 78 */ 79 static int 80 __sprint(fp, uio) 81 FILE *fp; 82 struct __suio *uio; 83 { 84 int err; 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 unsigned char buf[BUFSIZ]; 110 111 /* copy the important variables */ 112 fake._flags = fp->_flags & ~__SNBF; 113 fake._file = fp->_file; 114 fake._cookie = fp->_cookie; 115 fake._write = fp->_write; 116 117 /* set up the buffer */ 118 fake._bf._base = fake._p = buf; 119 fake._bf._size = fake._w = sizeof(buf); 120 fake._lbfsize = 0; /* not actually used, but Just In Case */ 121 122 /* do the work, then copy any error status */ 123 ret = vfprintf(&fake, fmt, ap); 124 if (ret >= 0 && fflush(&fake)) 125 ret = -1; 126 if (fake._flags & __SERR) 127 fp->_flags |= __SERR; 128 return (ret); 129 } 130 131 132 #ifdef FLOATING_POINT 133 #include <locale.h> 134 #include <math.h> 135 #include "floatio.h" 136 137 #define BUF (MAXEXP+MAXFRACT+1) /* + decimal point */ 138 #define DEFPREC 6 139 140 static char *cvt __P((double, int, int, char *, int *, int, int *)); 141 static int exponent __P((char *, int, int)); 142 143 #else /* no FLOATING_POINT */ 144 145 #define BUF 40 146 147 #endif /* FLOATING_POINT */ 148 149 150 /* 151 * Macros for converting digits to letters and vice versa 152 */ 153 #define to_digit(c) ((c) - '0') 154 #define is_digit(c) ((unsigned)to_digit(c) <= 9) 155 #define to_char(n) ((n) + '0') 156 157 /* 158 * Flags used during conversion. 159 */ 160 #define ALT 0x001 /* alternate form */ 161 #define HEXPREFIX 0x002 /* add 0x or 0X prefix */ 162 #define LADJUST 0x004 /* left adjustment */ 163 #define LONGDBL 0x008 /* long double; unimplemented */ 164 #define LONGINT 0x010 /* long integer */ 165 #define QUADINT 0x020 /* quad integer */ 166 #define SHORTINT 0x040 /* short integer */ 167 #define ZEROPAD 0x080 /* zero (as opposed to blank) pad */ 168 #define FPT 0x100 /* Floating point number */ 169 int 170 vfprintf(fp, fmt0, ap) 171 FILE *fp; 172 const char *fmt0; 173 _BSD_VA_LIST_ ap; 174 { 175 const char *fmt;/* format string */ 176 int ch; /* character from fmt */ 177 int n, m; /* handy integers (short term usage) */ 178 const char *cp; /* handy char pointer (short term usage) */ 179 char *bp; /* handy char pointer (short term usage) */ 180 struct __siov *iovp;/* for PRINT macro */ 181 int flags; /* flags as above */ 182 int ret; /* return value accumulator */ 183 int width; /* width from format (%8d), or 0 */ 184 int prec; /* precision from format (%.3d), or -1 */ 185 char sign; /* sign prefix (' ', '+', '-', or \0) */ 186 wchar_t wc; 187 #ifdef FLOATING_POINT 188 char *decimal_point = localeconv()->decimal_point; 189 char softsign; /* temporary negative sign for floats */ 190 double _double = 0; /* double precision arguments %[eEfgG] */ 191 int expt; /* integer value of exponent */ 192 int expsize = 0; /* character count for expstr */ 193 int ndig; /* actual number of digits returned by cvt */ 194 char expstr[7]; /* buffer for exponent string */ 195 #endif 196 197 #ifdef __GNUC__ /* gcc has builtin quad type (long long) SOS */ 198 #define quad_t long long 199 #define u_quad_t unsigned long long 200 #endif 201 202 u_quad_t _uquad; /* integer arguments %[diouxX] */ 203 enum { OCT, DEC, HEX } base;/* base for [diouxX] conversion */ 204 int dprec; /* a copy of prec if [diouxX], 0 otherwise */ 205 int realsz; /* field size expanded by dprec */ 206 int size; /* size of converted field or string */ 207 char *xdigs = NULL; /* digits for [xX] conversion */ 208 #define NIOV 8 209 struct __suio uio; /* output information: summary */ 210 struct __siov iov[NIOV];/* ... and individual io vectors */ 211 char buf[BUF]; /* space for %c, %[diouxX], %[eEfgG] */ 212 char ox[2]; /* space for 0x hex-prefix */ 213 214 /* 215 * Choose PADSIZE to trade efficiency vs. size. If larger printf 216 * fields occur frequently, increase PADSIZE and make the initialisers 217 * below longer. 218 */ 219 #define PADSIZE 16 /* pad chunk size */ 220 static const char blanks[PADSIZE] = 221 {' ',' ',' ',' ',' ',' ',' ',' ',' ',' ',' ',' ',' ',' ',' ',' '}; 222 static const char zeroes[PADSIZE] = 223 {'0','0','0','0','0','0','0','0','0','0','0','0','0','0','0','0'}; 224 225 /* 226 * BEWARE, these `goto error' on error, and PAD uses `n'. 227 */ 228 #define PRINT(ptr, len) { \ 229 iovp->iov_base = (void *)(ptr); \ 230 iovp->iov_len = (len); \ 231 uio.uio_resid += (len); \ 232 iovp++; \ 233 if (++uio.uio_iovcnt >= NIOV) { \ 234 if (__sprint(fp, &uio)) \ 235 goto error; \ 236 iovp = iov; \ 237 } \ 238 } 239 #define PAD(howmany, with) { \ 240 if ((n = (howmany)) > 0) { \ 241 while (n > PADSIZE) { \ 242 PRINT(with, PADSIZE); \ 243 n -= PADSIZE; \ 244 } \ 245 PRINT(with, n); \ 246 } \ 247 } 248 #define FLUSH() { \ 249 if (uio.uio_resid && __sprint(fp, &uio)) \ 250 goto error; \ 251 uio.uio_iovcnt = 0; \ 252 iovp = iov; \ 253 } 254 255 /* 256 * To extend shorts properly, we need both signed and unsigned 257 * argument extraction methods. 258 */ 259 #define SARG() \ 260 (flags&QUADINT ? va_arg(ap, quad_t) : \ 261 flags&LONGINT ? va_arg(ap, long) : \ 262 flags&SHORTINT ? (long)(short)va_arg(ap, int) : \ 263 (long)va_arg(ap, int)) 264 #define UARG() \ 265 (flags&QUADINT ? va_arg(ap, u_quad_t) : \ 266 flags&LONGINT ? va_arg(ap, u_long) : \ 267 flags&SHORTINT ? (u_long)(u_short)va_arg(ap, int) : \ 268 (u_long)va_arg(ap, u_int)) 269 270 FLOCKFILE(fp); 271 272 /* sorry, fprintf(read_only_file, "") returns -1, not 0 */ 273 if (cantwrite(fp)) { 274 errno = EBADF; 275 FUNLOCKFILE(fp); 276 return (-1); 277 } 278 279 /* optimise fprintf(stderr) (and other unbuffered Unix files) */ 280 if ((fp->_flags & (__SNBF|__SWR|__SRW)) == (__SNBF|__SWR) && 281 fp->_file >= 0) { 282 ret = __sbprintf(fp, fmt0, ap); 283 FUNLOCKFILE(fp); 284 return (ret); 285 } 286 287 fmt = fmt0; 288 uio.uio_iov = iovp = iov; 289 uio.uio_resid = 0; 290 uio.uio_iovcnt = 0; 291 ret = 0; 292 293 /* 294 * Scan the format for conversions (`%' character). 295 */ 296 for (;;) { 297 cp = fmt; 298 while ((n = mbtowc(&wc, fmt, MB_CUR_MAX)) > 0) { 299 fmt += n; 300 if (wc == '%') { 301 fmt--; 302 break; 303 } 304 } 305 if ((m = fmt - cp) != 0) { 306 PRINT(cp, m); 307 ret += m; 308 } 309 if (n <= 0) 310 goto done; 311 fmt++; /* skip over '%' */ 312 313 flags = 0; 314 dprec = 0; 315 width = 0; 316 prec = -1; 317 sign = '\0'; 318 319 rflag: ch = *fmt++; 320 reswitch: switch (ch) { 321 case ' ': 322 /* 323 * ``If the space and + flags both appear, the space 324 * flag will be ignored.'' 325 * -- ANSI X3J11 326 */ 327 if (!sign) 328 sign = ' '; 329 goto rflag; 330 case '#': 331 flags |= ALT; 332 goto rflag; 333 case '*': 334 /* 335 * ``A negative field width argument is taken as a 336 * - flag followed by a positive field width.'' 337 * -- ANSI X3J11 338 * They don't exclude field widths read from args. 339 */ 340 if ((width = va_arg(ap, int)) >= 0) 341 goto rflag; 342 width = -width; 343 /* FALLTHROUGH */ 344 case '-': 345 flags |= LADJUST; 346 goto rflag; 347 case '+': 348 sign = '+'; 349 goto rflag; 350 case '.': 351 if ((ch = *fmt++) == '*') { 352 n = va_arg(ap, int); 353 prec = n < 0 ? -1 : n; 354 goto rflag; 355 } 356 n = 0; 357 while (is_digit(ch)) { 358 n = 10 * n + to_digit(ch); 359 ch = *fmt++; 360 } 361 prec = n < 0 ? -1 : n; 362 goto reswitch; 363 case '0': 364 /* 365 * ``Note that 0 is taken as a flag, not as the 366 * beginning of a field width.'' 367 * -- ANSI X3J11 368 */ 369 flags |= ZEROPAD; 370 goto rflag; 371 case '1': case '2': case '3': case '4': 372 case '5': case '6': case '7': case '8': case '9': 373 n = 0; 374 do { 375 n = 10 * n + to_digit(ch); 376 ch = *fmt++; 377 } while (is_digit(ch)); 378 width = n; 379 goto reswitch; 380 #ifdef FLOATING_POINT 381 case 'L': 382 flags |= LONGDBL; 383 goto rflag; 384 #endif 385 case 'h': 386 flags |= SHORTINT; 387 goto rflag; 388 case 'l': 389 if (*fmt == 'l') { 390 fmt++; 391 flags |= QUADINT; 392 } else { 393 flags |= LONGINT; 394 } 395 goto rflag; 396 case 'q': 397 flags |= QUADINT; 398 goto rflag; 399 case 'c': 400 *buf = va_arg(ap, int); 401 cp = buf; 402 size = 1; 403 sign = '\0'; 404 break; 405 case 'D': 406 flags |= LONGINT; 407 /*FALLTHROUGH*/ 408 case 'd': 409 case 'i': 410 _uquad = SARG(); 411 if ((quad_t)_uquad < 0) { 412 _uquad = -_uquad; 413 sign = '-'; 414 } 415 base = DEC; 416 goto number; 417 #ifdef FLOATING_POINT 418 case 'e': 419 case 'E': 420 case 'f': 421 case 'g': 422 case 'G': 423 if (prec == -1) { 424 prec = DEFPREC; 425 } else if ((ch == 'g' || ch == 'G') && prec == 0) { 426 prec = 1; 427 } 428 429 if (flags & LONGDBL) { 430 _double = (double) va_arg(ap, long double); 431 } else { 432 _double = va_arg(ap, double); 433 } 434 435 /* do this before tricky precision changes */ 436 if (isinf(_double)) { 437 if (_double < 0) 438 sign = '-'; 439 cp = "Inf"; 440 size = 3; 441 break; 442 } 443 if (isnan(_double)) { 444 cp = "NaN"; 445 size = 3; 446 break; 447 } 448 449 flags |= FPT; 450 cp = cvt(_double, prec, flags, &softsign, 451 &expt, ch, &ndig); 452 if (ch == 'g' || ch == 'G') { 453 if (expt <= -4 || expt > prec) 454 ch = (ch == 'g') ? 'e' : 'E'; 455 else 456 ch = 'g'; 457 } 458 if (ch <= 'e') { /* 'e' or 'E' fmt */ 459 --expt; 460 expsize = exponent(expstr, expt, ch); 461 size = expsize + ndig; 462 if (ndig > 1 || flags & ALT) 463 ++size; 464 } else if (ch == 'f') { /* f fmt */ 465 if (expt > 0) { 466 size = expt; 467 if (prec || flags & ALT) 468 size += prec + 1; 469 } else /* "0.X" */ 470 size = prec + 2; 471 } else if (expt >= ndig) { /* fixed g fmt */ 472 size = expt; 473 if (flags & ALT) 474 ++size; 475 } else 476 size = ndig + (expt > 0 ? 477 1 : 2 - expt); 478 479 if (softsign) 480 sign = '-'; 481 break; 482 #endif /* FLOATING_POINT */ 483 case 'n': 484 if (flags & QUADINT) 485 *va_arg(ap, quad_t *) = ret; 486 else if (flags & LONGINT) 487 *va_arg(ap, long *) = ret; 488 else if (flags & SHORTINT) 489 *va_arg(ap, short *) = ret; 490 else 491 *va_arg(ap, int *) = ret; 492 continue; /* no output */ 493 case 'O': 494 flags |= LONGINT; 495 /*FALLTHROUGH*/ 496 case 'o': 497 _uquad = UARG(); 498 base = OCT; 499 goto nosign; 500 case 'p': 501 /* 502 * ``The argument shall be a pointer to void. The 503 * value of the pointer is converted to a sequence 504 * of printable characters, in an implementation- 505 * defined manner.'' 506 * -- ANSI X3J11 507 */ 508 /* NOSTRICT */ 509 _uquad = (u_long)va_arg(ap, void *); 510 base = HEX; 511 xdigs = "0123456789abcdef"; 512 flags |= HEXPREFIX; 513 ch = 'x'; 514 goto nosign; 515 case 's': 516 if ((cp = va_arg(ap, char *)) == NULL) 517 cp = "(null)"; 518 if (prec >= 0) { 519 /* 520 * can't use strlen; can only look for the 521 * NUL in the first `prec' characters, and 522 * strlen() will go further. 523 */ 524 char *p = memchr(cp, 0, prec); 525 526 if (p != NULL) { 527 size = p - cp; 528 if (size > prec) 529 size = prec; 530 } else 531 size = prec; 532 } else 533 size = strlen(cp); 534 sign = '\0'; 535 break; 536 case 'U': 537 flags |= LONGINT; 538 /*FALLTHROUGH*/ 539 case 'u': 540 _uquad = UARG(); 541 base = DEC; 542 goto nosign; 543 case 'X': 544 xdigs = "0123456789ABCDEF"; 545 goto hex; 546 case 'x': 547 xdigs = "0123456789abcdef"; 548 hex: _uquad = UARG(); 549 base = HEX; 550 /* leading 0x/X only if non-zero */ 551 if (flags & ALT && _uquad != 0) 552 flags |= HEXPREFIX; 553 554 /* unsigned conversions */ 555 nosign: sign = '\0'; 556 /* 557 * ``... diouXx conversions ... if a precision is 558 * specified, the 0 flag will be ignored.'' 559 * -- ANSI X3J11 560 */ 561 number: if ((dprec = prec) >= 0) 562 flags &= ~ZEROPAD; 563 564 /* 565 * ``The result of converting a zero value with an 566 * explicit precision of zero is no characters.'' 567 * -- ANSI X3J11 568 */ 569 bp = buf + BUF; 570 if (_uquad != 0 || prec != 0) { 571 /* 572 * Unsigned mod is hard, and unsigned mod 573 * by a constant is easier than that by 574 * a variable; hence this switch. 575 */ 576 switch (base) { 577 case OCT: 578 do { 579 *--bp = to_char(_uquad & 7); 580 _uquad >>= 3; 581 } while (_uquad); 582 /* handle octal leading 0 */ 583 if (flags & ALT && *bp != '0') 584 *--bp = '0'; 585 break; 586 587 case DEC: 588 /* many numbers are 1 digit */ 589 while (_uquad >= 10) { 590 *--bp = to_char(_uquad % 10); 591 _uquad /= 10; 592 } 593 *--bp = to_char(_uquad); 594 break; 595 596 case HEX: 597 do { 598 *--bp = xdigs[_uquad & 15]; 599 _uquad >>= 4; 600 } while (_uquad); 601 break; 602 603 default: 604 cp = "bug in vfprintf: bad base"; 605 size = strlen(cp); 606 goto skipsize; 607 } 608 } 609 cp = bp; 610 size = buf + BUF - bp; 611 skipsize: 612 break; 613 default: /* "%?" prints ?, unless ? is NUL */ 614 if (ch == '\0') 615 goto done; 616 /* pretend it was %c with argument ch */ 617 *buf = ch; 618 cp = buf; 619 size = 1; 620 sign = '\0'; 621 break; 622 } 623 624 /* 625 * All reasonable formats wind up here. At this point, `cp' 626 * points to a string which (if not flags&LADJUST) should be 627 * padded out to `width' places. If flags&ZEROPAD, it should 628 * first be prefixed by any sign or other prefix; otherwise, 629 * it should be blank padded before the prefix is emitted. 630 * After any left-hand padding and prefixing, emit zeroes 631 * required by a decimal [diouxX] precision, then print the 632 * string proper, then emit zeroes required by any leftover 633 * floating precision; finally, if LADJUST, pad with blanks. 634 * 635 * Compute actual size, so we know how much to pad. 636 * size excludes decimal prec; realsz includes it. 637 */ 638 realsz = dprec > size ? dprec : size; 639 if (sign) 640 realsz++; 641 else if (flags & HEXPREFIX) 642 realsz+= 2; 643 644 /* right-adjusting blank padding */ 645 if ((flags & (LADJUST|ZEROPAD)) == 0) 646 PAD(width - realsz, blanks); 647 648 /* prefix */ 649 if (sign) { 650 PRINT(&sign, 1); 651 } else if (flags & HEXPREFIX) { 652 ox[0] = '0'; 653 ox[1] = ch; 654 PRINT(ox, 2); 655 } 656 657 /* right-adjusting zero padding */ 658 if ((flags & (LADJUST|ZEROPAD)) == ZEROPAD) 659 PAD(width - realsz, zeroes); 660 661 /* leading zeroes from decimal precision */ 662 PAD(dprec - size, zeroes); 663 664 /* the string or number proper */ 665 #ifdef FLOATING_POINT 666 if ((flags & FPT) == 0) { 667 PRINT(cp, size); 668 } else { /* glue together f_p fragments */ 669 if (ch >= 'f') { /* 'f' or 'g' */ 670 if (_double == 0) { 671 /* kludge for __dtoa irregularity */ 672 PRINT("0", 1); 673 if (expt < ndig || (flags & ALT) != 0) { 674 PRINT(decimal_point, 1); 675 PAD(ndig - 1, zeroes); 676 } 677 } else if (expt <= 0) { 678 PRINT("0", 1); 679 PRINT(decimal_point, 1); 680 PAD(-expt, zeroes); 681 PRINT(cp, ndig); 682 } else if (expt >= ndig) { 683 PRINT(cp, ndig); 684 PAD(expt - ndig, zeroes); 685 if (flags & ALT) 686 PRINT(".", 1); 687 } else { 688 PRINT(cp, expt); 689 cp += expt; 690 PRINT(".", 1); 691 PRINT(cp, ndig-expt); 692 } 693 } else { /* 'e' or 'E' */ 694 if (ndig > 1 || flags & ALT) { 695 ox[0] = *cp++; 696 ox[1] = '.'; 697 PRINT(ox, 2); 698 if (_double) { 699 PRINT(cp, ndig-1); 700 } else /* 0.[0..] */ 701 /* __dtoa irregularity */ 702 PAD(ndig - 1, zeroes); 703 } else /* XeYYY */ 704 PRINT(cp, 1); 705 PRINT(expstr, expsize); 706 } 707 } 708 #else 709 PRINT(cp, size); 710 #endif 711 /* left-adjusting padding (always blank) */ 712 if (flags & LADJUST) 713 PAD(width - realsz, blanks); 714 715 /* finally, adjust ret */ 716 ret += width > realsz ? width : realsz; 717 718 FLUSH(); /* copy out the I/O vectors */ 719 } 720 done: 721 FLUSH(); 722 error: 723 if (__sferror(fp)) 724 ret = -1; 725 FUNLOCKFILE(fp); 726 return (ret); 727 } 728 729 #ifdef FLOATING_POINT 730 731 static char * 732 cvt(value, ndigits, flags, sign, decpt, ch, length) 733 double value; 734 int ndigits, flags, *decpt, ch, *length; 735 char *sign; 736 { 737 int mode, dsgn; 738 char *digits, *bp, *rve; 739 740 if (ch == 'f') { 741 mode = 3; /* ndigits after the decimal point */ 742 } else { 743 /* To obtain ndigits after the decimal point for the 'e' 744 * and 'E' formats, round to ndigits + 1 significant 745 * figures. 746 */ 747 if (ch == 'e' || ch == 'E') { 748 ndigits++; 749 } 750 mode = 2; /* ndigits significant digits */ 751 } 752 753 if (value < 0) { 754 value = -value; 755 *sign = '-'; 756 } else 757 *sign = '\000'; 758 digits = __dtoa(value, mode, ndigits, decpt, &dsgn, &rve); 759 if ((ch != 'g' && ch != 'G') || flags & ALT) { /* Print trailing zeros */ 760 bp = digits + ndigits; 761 if (ch == 'f') { 762 if (*digits == '0' && value) 763 *decpt = -ndigits + 1; 764 bp += *decpt; 765 } 766 if (value == 0) /* kludge for __dtoa irregularity */ 767 rve = bp; 768 while (rve < bp) 769 *rve++ = '0'; 770 } 771 *length = rve - digits; 772 return (digits); 773 } 774 775 static int 776 exponent(p0, exp, fmtch) 777 char *p0; 778 int exp, fmtch; 779 { 780 char *p, *t; 781 char expbuf[MAXEXP]; 782 783 p = p0; 784 *p++ = fmtch; 785 if (exp < 0) { 786 exp = -exp; 787 *p++ = '-'; 788 } 789 else 790 *p++ = '+'; 791 t = expbuf + MAXEXP; 792 if (exp > 9) { 793 do { 794 *--t = to_char(exp % 10); 795 } while ((exp /= 10) > 9); 796 *--t = to_char(exp); 797 for (; t < expbuf + MAXEXP; *p++ = *t++); 798 } 799 else { 800 *p++ = '0'; 801 *p++ = to_char(exp); 802 } 803 return (p - p0); 804 } 805 #endif /* FLOATING_POINT */ 806
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