1 /* $NetBSD: vfprintf.c,v 1.22 1997/12/19 14:08:44 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 1.22 1997/12/19 14:08:44 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 <sys/types.h> 55 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 71 static int __sprint __P((FILE *, struct __suio *)); 72 static int __sbprintf __P((FILE *, const char *, va_list)); 73 74 /* 75 * Flush out all the vectors defined by the given uio, 76 * then reset it so that it can be reused. 77 */ 78 static int 79 __sprint(fp, uio) 80 FILE *fp; 81 register struct __suio *uio; 82 { 83 register int err; 84 85 if (uio->uio_resid == 0) { 86 uio->uio_iovcnt = 0; 87 return (0); 88 } 89 err = __sfvwrite(fp, uio); 90 uio->uio_resid = 0; 91 uio->uio_iovcnt = 0; 92 return (err); 93 } 94 95 /* 96 * Helper function for `fprintf to unbuffered unix file': creates a 97 * temporary buffer. We only work on write-only files; this avoids 98 * worries about ungetc buffers and so forth. 99 */ 100 static int 101 __sbprintf(fp, fmt, ap) 102 register FILE *fp; 103 const char *fmt; 104 va_list ap; 105 { 106 int ret; 107 FILE fake; 108 unsigned char buf[BUFSIZ]; 109 110 /* copy the important variables */ 111 fake._flags = fp->_flags & ~__SNBF; 112 fake._file = fp->_file; 113 fake._cookie = fp->_cookie; 114 fake._write = fp->_write; 115 116 /* set up the buffer */ 117 fake._bf._base = fake._p = buf; 118 fake._bf._size = fake._w = sizeof(buf); 119 fake._lbfsize = 0; /* not actually used, but Just In Case */ 120 121 /* do the work, then copy any error status */ 122 ret = vfprintf(&fake, fmt, ap); 123 if (ret >= 0 && fflush(&fake)) 124 ret = -1; 125 if (fake._flags & __SERR) 126 fp->_flags |= __SERR; 127 return (ret); 128 } 129 130 131 #ifdef FLOATING_POINT 132 #include <locale.h> 133 #include <math.h> 134 #include "floatio.h" 135 136 #define BUF (MAXEXP+MAXFRACT+1) /* + decimal point */ 137 #define DEFPREC 6 138 139 static char *cvt __P((double, int, int, char *, int *, int, int *)); 140 static int exponent __P((char *, int, int)); 141 142 #else /* no FLOATING_POINT */ 143 144 #define BUF 40 145 146 #endif /* FLOATING_POINT */ 147 148 149 /* 150 * Macros for converting digits to letters and vice versa 151 */ 152 #define to_digit(c) ((c) - '0') 153 #define is_digit(c) ((unsigned)to_digit(c) <= 9) 154 #define to_char(n) ((n) + '0') 155 156 /* 157 * Flags used during conversion. 158 */ 159 #define ALT 0x001 /* alternate form */ 160 #define HEXPREFIX 0x002 /* add 0x or 0X prefix */ 161 #define LADJUST 0x004 /* left adjustment */ 162 #define LONGDBL 0x008 /* long double; unimplemented */ 163 #define LONGINT 0x010 /* long integer */ 164 #define QUADINT 0x020 /* quad integer */ 165 #define SHORTINT 0x040 /* short integer */ 166 #define ZEROPAD 0x080 /* zero (as opposed to blank) pad */ 167 #define FPT 0x100 /* Floating point number */ 168 int 169 vfprintf(fp, fmt0, ap) 170 FILE *fp; 171 const char *fmt0; 172 _BSD_VA_LIST_ ap; 173 { 174 register char *fmt; /* format string */ 175 register int ch; /* character from fmt */ 176 register int n, m; /* handy integers (short term usage) */ 177 register char *cp; /* handy char pointer (short term usage) */ 178 register struct __siov *iovp;/* for PRINT macro */ 179 register int flags; /* flags as above */ 180 int ret; /* return value accumulator */ 181 int width; /* width from format (%8d), or 0 */ 182 int prec; /* precision from format (%.3d), or -1 */ 183 char sign; /* sign prefix (' ', '+', '-', or \0) */ 184 wchar_t wc; 185 #ifdef FLOATING_POINT 186 char *decimal_point = localeconv()->decimal_point; 187 char softsign; /* temporary negative sign for floats */ 188 double _double = 0; /* double precision arguments %[eEfgG] */ 189 int expt; /* integer value of exponent */ 190 int expsize = 0; /* character count for expstr */ 191 int ndig; /* actual number of digits returned by cvt */ 192 char expstr[7]; /* buffer for exponent string */ 193 #endif 194 195 #ifdef __GNUC__ /* gcc has builtin quad type (long long) SOS */ 196 #define quad_t long long 197 #define u_quad_t unsigned long long 198 #endif 199 200 u_quad_t _uquad; /* integer arguments %[diouxX] */ 201 enum { OCT, DEC, HEX } base;/* base for [diouxX] conversion */ 202 int dprec; /* a copy of prec if [diouxX], 0 otherwise */ 203 int realsz; /* field size expanded by dprec */ 204 int size; /* size of converted field or string */ 205 char *xdigs = NULL; /* digits for [xX] conversion */ 206 #define NIOV 8 207 struct __suio uio; /* output information: summary */ 208 struct __siov iov[NIOV];/* ... and individual io vectors */ 209 char buf[BUF]; /* space for %c, %[diouxX], %[eEfgG] */ 210 char ox[2]; /* space for 0x hex-prefix */ 211 212 /* 213 * Choose PADSIZE to trade efficiency vs. size. If larger printf 214 * fields occur frequently, increase PADSIZE and make the initialisers 215 * below longer. 216 */ 217 #define PADSIZE 16 /* pad chunk size */ 218 static char blanks[PADSIZE] = 219 {' ',' ',' ',' ',' ',' ',' ',' ',' ',' ',' ',' ',' ',' ',' ',' '}; 220 static char zeroes[PADSIZE] = 221 {'0','0','0','0','0','0','0','0','0','0','0','0','0','0','0','0'}; 222 223 /* 224 * BEWARE, these `goto error' on error, and PAD uses `n'. 225 */ 226 #define PRINT(ptr, len) { \ 227 iovp->iov_base = (ptr); \ 228 iovp->iov_len = (len); \ 229 uio.uio_resid += (len); \ 230 iovp++; \ 231 if (++uio.uio_iovcnt >= NIOV) { \ 232 if (__sprint(fp, &uio)) \ 233 goto error; \ 234 iovp = iov; \ 235 } \ 236 } 237 #define PAD(howmany, with) { \ 238 if ((n = (howmany)) > 0) { \ 239 while (n > PADSIZE) { \ 240 PRINT(with, PADSIZE); \ 241 n -= PADSIZE; \ 242 } \ 243 PRINT(with, n); \ 244 } \ 245 } 246 #define FLUSH() { \ 247 if (uio.uio_resid && __sprint(fp, &uio)) \ 248 goto error; \ 249 uio.uio_iovcnt = 0; \ 250 iovp = iov; \ 251 } 252 253 /* 254 * To extend shorts properly, we need both signed and unsigned 255 * argument extraction methods. 256 */ 257 #define SARG() \ 258 (flags&QUADINT ? va_arg(ap, quad_t) : \ 259 flags&LONGINT ? va_arg(ap, long) : \ 260 flags&SHORTINT ? (long)(short)va_arg(ap, int) : \ 261 (long)va_arg(ap, int)) 262 #define UARG() \ 263 (flags&QUADINT ? va_arg(ap, u_quad_t) : \ 264 flags&LONGINT ? va_arg(ap, u_long) : \ 265 flags&SHORTINT ? (u_long)(u_short)va_arg(ap, int) : \ 266 (u_long)va_arg(ap, u_int)) 267 268 /* sorry, fprintf(read_only_file, "") returns -1, not 0 */ 269 if (cantwrite(fp)) { 270 errno = EBADF; 271 return (-1); 272 } 273 274 /* optimise fprintf(stderr) (and other unbuffered Unix files) */ 275 if ((fp->_flags & (__SNBF|__SWR|__SRW)) == (__SNBF|__SWR) && 276 fp->_file >= 0) 277 return (__sbprintf(fp, fmt0, ap)); 278 279 fmt = (char *)fmt0; 280 uio.uio_iov = iovp = iov; 281 uio.uio_resid = 0; 282 uio.uio_iovcnt = 0; 283 ret = 0; 284 285 /* 286 * Scan the format for conversions (`%' character). 287 */ 288 for (;;) { 289 cp = fmt; 290 while ((n = mbtowc(&wc, fmt, MB_CUR_MAX)) > 0) { 291 fmt += n; 292 if (wc == '%') { 293 fmt--; 294 break; 295 } 296 } 297 if ((m = fmt - cp) != 0) { 298 PRINT(cp, m); 299 ret += m; 300 } 301 if (n <= 0) 302 goto done; 303 fmt++; /* skip over '%' */ 304 305 flags = 0; 306 dprec = 0; 307 width = 0; 308 prec = -1; 309 sign = '\0'; 310 311 rflag: ch = *fmt++; 312 reswitch: switch (ch) { 313 case ' ': 314 /* 315 * ``If the space and + flags both appear, the space 316 * flag will be ignored.'' 317 * -- ANSI X3J11 318 */ 319 if (!sign) 320 sign = ' '; 321 goto rflag; 322 case '#': 323 flags |= ALT; 324 goto rflag; 325 case '*': 326 /* 327 * ``A negative field width argument is taken as a 328 * - flag followed by a positive field width.'' 329 * -- ANSI X3J11 330 * They don't exclude field widths read from args. 331 */ 332 if ((width = va_arg(ap, int)) >= 0) 333 goto rflag; 334 width = -width; 335 /* FALLTHROUGH */ 336 case '-': 337 flags |= LADJUST; 338 goto rflag; 339 case '+': 340 sign = '+'; 341 goto rflag; 342 case '.': 343 if ((ch = *fmt++) == '*') { 344 n = va_arg(ap, int); 345 prec = n < 0 ? -1 : n; 346 goto rflag; 347 } 348 n = 0; 349 while (is_digit(ch)) { 350 n = 10 * n + to_digit(ch); 351 ch = *fmt++; 352 } 353 prec = n < 0 ? -1 : n; 354 goto reswitch; 355 case '0': 356 /* 357 * ``Note that 0 is taken as a flag, not as the 358 * beginning of a field width.'' 359 * -- ANSI X3J11 360 */ 361 flags |= ZEROPAD; 362 goto rflag; 363 case '1': case '2': case '3': case '4': 364 case '5': case '6': case '7': case '8': case '9': 365 n = 0; 366 do { 367 n = 10 * n + to_digit(ch); 368 ch = *fmt++; 369 } while (is_digit(ch)); 370 width = n; 371 goto reswitch; 372 #ifdef FLOATING_POINT 373 case 'L': 374 flags |= LONGDBL; 375 goto rflag; 376 #endif 377 case 'h': 378 flags |= SHORTINT; 379 goto rflag; 380 case 'l': 381 if (*fmt == 'l') { 382 fmt++; 383 flags |= QUADINT; 384 } else { 385 flags |= LONGINT; 386 } 387 goto rflag; 388 case 'q': 389 flags |= QUADINT; 390 goto rflag; 391 case 'c': 392 *(cp = buf) = va_arg(ap, int); 393 size = 1; 394 sign = '\0'; 395 break; 396 case 'D': 397 flags |= LONGINT; 398 /*FALLTHROUGH*/ 399 case 'd': 400 case 'i': 401 _uquad = SARG(); 402 if ((quad_t)_uquad < 0) { 403 _uquad = -_uquad; 404 sign = '-'; 405 } 406 base = DEC; 407 goto number; 408 #ifdef FLOATING_POINT 409 case 'e': 410 case 'E': 411 case 'f': 412 case 'g': 413 case 'G': 414 if (prec == -1) { 415 prec = DEFPREC; 416 } else if ((ch == 'g' || ch == 'G') && prec == 0) { 417 prec = 1; 418 } 419 420 if (flags & LONGDBL) { 421 _double = (double) va_arg(ap, long double); 422 } else { 423 _double = va_arg(ap, double); 424 } 425 426 /* do this before tricky precision changes */ 427 if (isinf(_double)) { 428 if (_double < 0) 429 sign = '-'; 430 cp = "Inf"; 431 size = 3; 432 break; 433 } 434 if (isnan(_double)) { 435 cp = "NaN"; 436 size = 3; 437 break; 438 } 439 440 flags |= FPT; 441 cp = cvt(_double, prec, flags, &softsign, 442 &expt, ch, &ndig); 443 if (ch == 'g' || ch == 'G') { 444 if (expt <= -4 || expt > prec) 445 ch = (ch == 'g') ? 'e' : 'E'; 446 else 447 ch = 'g'; 448 } 449 if (ch <= 'e') { /* 'e' or 'E' fmt */ 450 --expt; 451 expsize = exponent(expstr, expt, ch); 452 size = expsize + ndig; 453 if (ndig > 1 || flags & ALT) 454 ++size; 455 } else if (ch == 'f') { /* f fmt */ 456 if (expt > 0) { 457 size = expt; 458 if (prec || flags & ALT) 459 size += prec + 1; 460 } else /* "0.X" */ 461 size = prec + 2; 462 } else if (expt >= ndig) { /* fixed g fmt */ 463 size = expt; 464 if (flags & ALT) 465 ++size; 466 } else 467 size = ndig + (expt > 0 ? 468 1 : 2 - expt); 469 470 if (softsign) 471 sign = '-'; 472 break; 473 #endif /* FLOATING_POINT */ 474 case 'n': 475 if (flags & QUADINT) 476 *va_arg(ap, quad_t *) = ret; 477 else if (flags & LONGINT) 478 *va_arg(ap, long *) = ret; 479 else if (flags & SHORTINT) 480 *va_arg(ap, short *) = ret; 481 else 482 *va_arg(ap, int *) = ret; 483 continue; /* no output */ 484 case 'O': 485 flags |= LONGINT; 486 /*FALLTHROUGH*/ 487 case 'o': 488 _uquad = UARG(); 489 base = OCT; 490 goto nosign; 491 case 'p': 492 /* 493 * ``The argument shall be a pointer to void. The 494 * value of the pointer is converted to a sequence 495 * of printable characters, in an implementation- 496 * defined manner.'' 497 * -- ANSI X3J11 498 */ 499 /* NOSTRICT */ 500 _uquad = (u_long)va_arg(ap, void *); 501 base = HEX; 502 xdigs = "0123456789abcdef"; 503 flags |= HEXPREFIX; 504 ch = 'x'; 505 goto nosign; 506 case 's': 507 if ((cp = va_arg(ap, char *)) == NULL) 508 cp = "(null)"; 509 if (prec >= 0) { 510 /* 511 * can't use strlen; can only look for the 512 * NUL in the first `prec' characters, and 513 * strlen() will go further. 514 */ 515 char *p = memchr(cp, 0, prec); 516 517 if (p != NULL) { 518 size = p - cp; 519 if (size > prec) 520 size = prec; 521 } else 522 size = prec; 523 } else 524 size = strlen(cp); 525 sign = '\0'; 526 break; 527 case 'U': 528 flags |= LONGINT; 529 /*FALLTHROUGH*/ 530 case 'u': 531 _uquad = UARG(); 532 base = DEC; 533 goto nosign; 534 case 'X': 535 xdigs = "0123456789ABCDEF"; 536 goto hex; 537 case 'x': 538 xdigs = "0123456789abcdef"; 539 hex: _uquad = UARG(); 540 base = HEX; 541 /* leading 0x/X only if non-zero */ 542 if (flags & ALT && _uquad != 0) 543 flags |= HEXPREFIX; 544 545 /* unsigned conversions */ 546 nosign: sign = '\0'; 547 /* 548 * ``... diouXx conversions ... if a precision is 549 * specified, the 0 flag will be ignored.'' 550 * -- ANSI X3J11 551 */ 552 number: if ((dprec = prec) >= 0) 553 flags &= ~ZEROPAD; 554 555 /* 556 * ``The result of converting a zero value with an 557 * explicit precision of zero is no characters.'' 558 * -- ANSI X3J11 559 */ 560 cp = buf + BUF; 561 if (_uquad != 0 || prec != 0) { 562 /* 563 * Unsigned mod is hard, and unsigned mod 564 * by a constant is easier than that by 565 * a variable; hence this switch. 566 */ 567 switch (base) { 568 case OCT: 569 do { 570 *--cp = to_char(_uquad & 7); 571 _uquad >>= 3; 572 } while (_uquad); 573 /* handle octal leading 0 */ 574 if (flags & ALT && *cp != '0') 575 *--cp = '0'; 576 break; 577 578 case DEC: 579 /* many numbers are 1 digit */ 580 while (_uquad >= 10) { 581 *--cp = to_char(_uquad % 10); 582 _uquad /= 10; 583 } 584 *--cp = to_char(_uquad); 585 break; 586 587 case HEX: 588 do { 589 *--cp = xdigs[_uquad & 15]; 590 _uquad >>= 4; 591 } while (_uquad); 592 break; 593 594 default: 595 cp = "bug in vfprintf: bad base"; 596 size = strlen(cp); 597 goto skipsize; 598 } 599 } 600 size = buf + BUF - cp; 601 skipsize: 602 break; 603 default: /* "%?" prints ?, unless ? is NUL */ 604 if (ch == '\0') 605 goto done; 606 /* pretend it was %c with argument ch */ 607 cp = buf; 608 *cp = ch; 609 size = 1; 610 sign = '\0'; 611 break; 612 } 613 614 /* 615 * All reasonable formats wind up here. At this point, `cp' 616 * points to a string which (if not flags&LADJUST) should be 617 * padded out to `width' places. If flags&ZEROPAD, it should 618 * first be prefixed by any sign or other prefix; otherwise, 619 * it should be blank padded before the prefix is emitted. 620 * After any left-hand padding and prefixing, emit zeroes 621 * required by a decimal [diouxX] precision, then print the 622 * string proper, then emit zeroes required by any leftover 623 * floating precision; finally, if LADJUST, pad with blanks. 624 * 625 * Compute actual size, so we know how much to pad. 626 * size excludes decimal prec; realsz includes it. 627 */ 628 realsz = dprec > size ? dprec : size; 629 if (sign) 630 realsz++; 631 else if (flags & HEXPREFIX) 632 realsz+= 2; 633 634 /* right-adjusting blank padding */ 635 if ((flags & (LADJUST|ZEROPAD)) == 0) 636 PAD(width - realsz, blanks); 637 638 /* prefix */ 639 if (sign) { 640 PRINT(&sign, 1); 641 } else if (flags & HEXPREFIX) { 642 ox[0] = '0'; 643 ox[1] = ch; 644 PRINT(ox, 2); 645 } 646 647 /* right-adjusting zero padding */ 648 if ((flags & (LADJUST|ZEROPAD)) == ZEROPAD) 649 PAD(width - realsz, zeroes); 650 651 /* leading zeroes from decimal precision */ 652 PAD(dprec - size, zeroes); 653 654 /* the string or number proper */ 655 #ifdef FLOATING_POINT 656 if ((flags & FPT) == 0) { 657 PRINT(cp, size); 658 } else { /* glue together f_p fragments */ 659 if (ch >= 'f') { /* 'f' or 'g' */ 660 if (_double == 0) { 661 /* kludge for __dtoa irregularity */ 662 PRINT("0", 1); 663 if (expt < ndig || (flags & ALT) != 0) { 664 PRINT(decimal_point, 1); 665 PAD(ndig - 1, zeroes); 666 } 667 } else if (expt <= 0) { 668 PRINT("0", 1); 669 PRINT(decimal_point, 1); 670 PAD(-expt, zeroes); 671 PRINT(cp, ndig); 672 } else if (expt >= ndig) { 673 PRINT(cp, ndig); 674 PAD(expt - ndig, zeroes); 675 if (flags & ALT) 676 PRINT(".", 1); 677 } else { 678 PRINT(cp, expt); 679 cp += expt; 680 PRINT(".", 1); 681 PRINT(cp, ndig-expt); 682 } 683 } else { /* 'e' or 'E' */ 684 if (ndig > 1 || flags & ALT) { 685 ox[0] = *cp++; 686 ox[1] = '.'; 687 PRINT(ox, 2); 688 if (_double) { 689 PRINT(cp, ndig-1); 690 } else /* 0.[0..] */ 691 /* __dtoa irregularity */ 692 PAD(ndig - 1, zeroes); 693 } else /* XeYYY */ 694 PRINT(cp, 1); 695 PRINT(expstr, expsize); 696 } 697 } 698 #else 699 PRINT(cp, size); 700 #endif 701 /* left-adjusting padding (always blank) */ 702 if (flags & LADJUST) 703 PAD(width - realsz, blanks); 704 705 /* finally, adjust ret */ 706 ret += width > realsz ? width : realsz; 707 708 FLUSH(); /* copy out the I/O vectors */ 709 } 710 done: 711 FLUSH(); 712 error: 713 return (__sferror(fp) ? -1 : ret); 714 /* NOTREACHED */ 715 } 716 717 #ifdef FLOATING_POINT 718 719 static char * 720 cvt(value, ndigits, flags, sign, decpt, ch, length) 721 double value; 722 int ndigits, flags, *decpt, ch, *length; 723 char *sign; 724 { 725 int mode, dsgn; 726 char *digits, *bp, *rve; 727 728 if (ch == 'f') { 729 mode = 3; /* ndigits after the decimal point */ 730 } else { 731 /* To obtain ndigits after the decimal point for the 'e' 732 * and 'E' formats, round to ndigits + 1 significant 733 * figures. 734 */ 735 if (ch == 'e' || ch == 'E') { 736 ndigits++; 737 } 738 mode = 2; /* ndigits significant digits */ 739 } 740 741 if (value < 0) { 742 value = -value; 743 *sign = '-'; 744 } else 745 *sign = '\000'; 746 digits = __dtoa(value, mode, ndigits, decpt, &dsgn, &rve); 747 if ((ch != 'g' && ch != 'G') || flags & ALT) { /* Print trailing zeros */ 748 bp = digits + ndigits; 749 if (ch == 'f') { 750 if (*digits == '0' && value) 751 *decpt = -ndigits + 1; 752 bp += *decpt; 753 } 754 if (value == 0) /* kludge for __dtoa irregularity */ 755 rve = bp; 756 while (rve < bp) 757 *rve++ = '0'; 758 } 759 *length = rve - digits; 760 return (digits); 761 } 762 763 static int 764 exponent(p0, exp, fmtch) 765 char *p0; 766 int exp, fmtch; 767 { 768 register char *p, *t; 769 char expbuf[MAXEXP]; 770 771 p = p0; 772 *p++ = fmtch; 773 if (exp < 0) { 774 exp = -exp; 775 *p++ = '-'; 776 } 777 else 778 *p++ = '+'; 779 t = expbuf + MAXEXP; 780 if (exp > 9) { 781 do { 782 *--t = to_char(exp % 10); 783 } while ((exp /= 10) > 9); 784 *--t = to_char(exp); 785 for (; t < expbuf + MAXEXP; *p++ = *t++); 786 } 787 else { 788 *p++ = '0'; 789 *p++ = to_char(exp); 790 } 791 return (p - p0); 792 } 793 #endif /* FLOATING_POINT */ 794