1 /* 2 * Copyright (c) 1988 Regents of the University of California. 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms are permitted 6 * provided that this notice is preserved and that due credit is given 7 * to the University of California at Berkeley. The name of the University 8 * may not be used to endorse or promote products derived from this 9 * software without specific prior written permission. This software 10 * is provided ``as is'' without express or implied warranty. 11 */ 12 13 #if defined(LIBC_SCCS) && !defined(lint) 14 static char sccsid[] = "@(#)vfprintf.c 5.29 (Berkeley) 05/23/88"; 15 #endif /* LIBC_SCCS and not lint */ 16 17 #include <sys/types.h> 18 #include <varargs.h> 19 #include <stdio.h> 20 #include <ctype.h> 21 22 /* 11-bit exponent (VAX G floating point) is 308 decimal digits */ 23 #define MAXEXP 308 24 /* 128 bit fraction takes up 39 decimal digits; max reasonable precision */ 25 #define MAXFRACT 39 26 27 #define BUF (MAXEXP+MAXFRACT+1) /* + decimal point */ 28 29 #define PUTC(ch) (void) putc(ch, fp) 30 31 #define ARG() \ 32 _ulong = flags&LONGINT ? va_arg(argp, long) : \ 33 flags&SHORTINT ? va_arg(argp, short) : va_arg(argp, int); 34 35 #define todigit(c) ((c) - '0') 36 #define tochar(n) ((n) + '0') 37 38 /* have to deal with the negative buffer count kludge */ 39 #define NEGATIVE_COUNT_KLUDGE 40 41 #define LONGINT 0x01 /* long integer */ 42 #define LONGDBL 0x02 /* long double; unimplemented */ 43 #define SHORTINT 0x04 /* short integer */ 44 #define ALT 0x08 /* alternate form */ 45 #define LADJUST 0x10 /* left adjustment */ 46 #define ZEROPAD 0x20 /* zero (as opposed to blank) pad */ 47 #define HEXPREFIX 0x40 /* add 0x or 0X prefix */ 48 49 _doprnt(fmt0, argp, fp) 50 u_char *fmt0; 51 va_list argp; 52 register FILE *fp; 53 { 54 register u_char *fmt; /* format string */ 55 register int ch; /* character from fmt */ 56 register int cnt; /* return value accumulator */ 57 register int n; /* random handy integer */ 58 register char *t; /* buffer pointer */ 59 double _double; /* double precision arguments %[eEfgG] */ 60 u_long _ulong; /* integer arguments %[diouxX] */ 61 int flags; /* flags as above */ 62 int dprec; /* decimal precision in [diouxX] */ 63 int fpprec; /* `extra' floating precision in [eEfgG] */ 64 int width; /* width from format (%8d), or 0 */ 65 int prec; /* precision from format (%.3d), or -1 */ 66 int size; /* size of converted field or string */ 67 int fieldsz; /* field size expanded by sign, etc */ 68 int realsz; /* field size expanded by decimal precision */ 69 char sign; /* sign prefix (+ - or \0) */ 70 int base; /* base for [diouxX] conversion */ 71 char *digs; /* digits for [diouxX] conversion */ 72 char buf[BUF]; /* space for %c, %[diouxX], %[eEfgG] */ 73 char *_cvt(); /* handles [eEfgG] formats */ 74 75 if (fp->_flag & _IORW) { 76 fp->_flag |= _IOWRT; 77 fp->_flag &= ~(_IOEOF|_IOREAD); 78 } 79 if ((fp->_flag & _IOWRT) == 0) 80 return (EOF); 81 82 fmt = fmt0; 83 digs = "0123456789abcdef"; 84 for (cnt = 0;; ++fmt) { 85 n = fp->_cnt; 86 for (t = (char *)fp->_ptr; (ch = *fmt) && ch != '%'; 87 ++cnt, ++fmt) 88 if (--n < 0 89 #ifdef NEGATIVE_COUNT_KLUDGE 90 && (!(fp->_flag & _IOLBF) || -n >= fp->_bufsiz) 91 #endif 92 || ch == '\n' && fp->_flag & _IOLBF) { 93 fp->_cnt = n; 94 fp->_ptr = (u_char *)t; 95 (void) _flsbuf((u_char)ch, fp); 96 n = fp->_cnt; 97 t = (char *)fp->_ptr; 98 } else 99 *t++ = ch; 100 fp->_cnt = n; 101 fp->_ptr = (u_char *)t; 102 if (!ch) 103 return (cnt); 104 105 flags = dprec = fpprec = width = 0; 106 prec = -1; 107 sign = '\0'; 108 109 rflag: switch (*++fmt) { 110 case ' ': 111 sign = ' '; 112 goto rflag; 113 case '#': 114 flags |= ALT; 115 goto rflag; 116 case '*': 117 /* 118 * ``A negative field width argument is taken as a 119 * - flag followed by a positive field width.'' 120 * -- ANSI X3J11 121 * They don't exclude field widths read from args. 122 */ 123 if ((width = va_arg(argp, int)) >= 0) 124 goto rflag; 125 width = -width; 126 /* FALLTHROUGH */ 127 case '-': 128 flags |= LADJUST; 129 goto rflag; 130 case '+': 131 sign = '+'; 132 goto rflag; 133 case '.': 134 if (*++fmt == '*') 135 n = va_arg(argp, int); 136 else { 137 n = 0; 138 while (isascii(*fmt) && isdigit(*fmt)) 139 n = 10 * n + todigit(*fmt++); 140 --fmt; 141 } 142 prec = n < 0 ? -1 : n; 143 goto rflag; 144 case '0': 145 /* 146 * ``Note that 0 is taken as a flag, not as the 147 * beginning of a field width.'' 148 * -- ANSI X3J11 149 */ 150 flags |= ZEROPAD; 151 goto rflag; 152 case '1': case '2': case '3': case '4': 153 case '5': case '6': case '7': case '8': case '9': 154 n = 0; 155 do { 156 n = 10 * n + todigit(*fmt); 157 } while (isascii(*++fmt) && isdigit(*fmt)); 158 width = n; 159 --fmt; 160 goto rflag; 161 case 'L': 162 flags |= LONGDBL; 163 goto rflag; 164 case 'h': 165 flags |= SHORTINT; 166 goto rflag; 167 case 'l': 168 flags |= LONGINT; 169 goto rflag; 170 case 'c': 171 *(t = buf) = va_arg(argp, int); 172 size = 1; 173 sign = '\0'; 174 goto pforw; 175 case 'd': 176 case 'i': 177 ARG(); 178 if ((long)_ulong < 0) { 179 _ulong = -_ulong; 180 sign = '-'; 181 } 182 base = 10; 183 goto number; 184 case 'e': 185 case 'E': 186 case 'f': 187 case 'g': 188 case 'G': 189 _double = va_arg(argp, double); 190 /* 191 * don't bother to do unrealistic precision; just 192 * pad it with zeroes later. This keeps buffer size 193 * rational. 194 */ 195 if (prec > MAXFRACT) { 196 fpprec = prec - MAXFRACT; 197 prec = MAXFRACT; 198 } 199 t = buf; 200 size = _cvt(_double, prec, flags, *fmt, &sign, 201 t, t + sizeof(buf)) - t; 202 goto pforw; 203 case 'n': 204 if (flags & LONGINT) 205 *va_arg(argp, long *) = cnt; 206 else if (flags & SHORTINT) 207 *va_arg(argp, short *) = cnt; 208 else 209 *va_arg(argp, int *) = cnt; 210 break; 211 case 'o': 212 ARG(); 213 base = 8; 214 goto nosign; 215 case 'p': 216 /* 217 * ``The argument shall be a pointer to void. The 218 * value of the pointer is converted to a sequence 219 * of printable characters, in an implementation- 220 * defined manner.'' 221 * -- ANSI X3J11 222 */ 223 /* NOSTRICT */ 224 _ulong = (u_long)va_arg(argp, void *); 225 base = 16; 226 goto nosign; 227 case 's': 228 if (!(t = va_arg(argp, char *))) 229 t = "(null)"; 230 if (prec >= 0) { 231 /* 232 * can't use strlen; can only look for the 233 * NUL in the first `prec' characters, and 234 * strlen() will go further. 235 */ 236 char *p, *memchr(); 237 238 if (p = memchr(t, 0, prec)) { 239 size = p - t; 240 if (size > prec) 241 size = prec; 242 } else 243 size = prec; 244 } else 245 size = strlen(t); 246 sign = '\0'; 247 goto pforw; 248 case 'u': 249 ARG(); 250 base = 10; 251 goto nosign; 252 case 'X': 253 digs = "0123456789ABCDEF"; 254 /* FALLTHROUGH */ 255 case 'x': 256 ARG(); 257 base = 16; 258 /* leading 0x/X only if non-zero */ 259 if (flags & ALT && _ulong != 0) 260 flags |= HEXPREFIX; 261 262 /* unsigned conversions */ 263 nosign: sign = '\0'; 264 /* 265 * ``... diouXx conversions ... if a precision is 266 * specified, the 0 flag will be ignored.'' 267 * -- ANSI X3J11 268 */ 269 number: if ((dprec = prec) >= 0) 270 flags &= ~ZEROPAD; 271 272 /* 273 * ``The result of converting a zero value with an 274 * explicit precision of zero is no characters.'' 275 * -- ANSI X3J11 276 */ 277 t = buf + BUF; 278 if (_ulong != 0 || prec != 0) { 279 do { 280 *--t = digs[_ulong % base]; 281 _ulong /= base; 282 } while (_ulong); 283 digs = "0123456789abcdef"; 284 if (flags & ALT && base == 8 && *t != '0') 285 *--t = '0'; /* octal leading 0 */ 286 } 287 size = buf + BUF - t; 288 289 pforw: 290 /* 291 * All reasonable formats wind up here. At this 292 * point, `t' points to a string which (if not 293 * flags&LADJUST) should be padded out to `width' 294 * places. If flags&ZEROPAD, it should first be 295 * prefixed by any sign or other prefix; otherwise, 296 * it should be blank padded before the prefix is 297 * emitted. After any left-hand padding and 298 * prefixing, emit zeroes required by a decimal 299 * [diouxX] precision, then print the string proper, 300 * then emit zeroes required by any leftover floating 301 * precision; finally, if LADJUST, pad with blanks. 302 */ 303 304 /* compute actual size, so we know how much to pad */ 305 /* this code is not terribly satisfactory */ 306 /* fieldsz excludes decimal prec; realsz includes it */ 307 fieldsz = size + fpprec; 308 if (sign) 309 fieldsz++; 310 if (flags & HEXPREFIX) 311 fieldsz += 2; 312 realsz = dprec > fieldsz ? dprec : fieldsz; 313 314 /* right-adjusting blank padding */ 315 if ((flags & (LADJUST|ZEROPAD)) == 0 && width) 316 for (n = realsz; n < width; n++) 317 PUTC(' '); 318 /* prefix */ 319 if (sign) 320 PUTC(sign); 321 if (flags & HEXPREFIX) { 322 PUTC('0'); 323 PUTC((char)*fmt); 324 } 325 /* right-adjusting zero padding */ 326 if ((flags & (LADJUST|ZEROPAD)) == ZEROPAD) 327 for (n = realsz; n < width; n++) 328 PUTC('0'); 329 /* leading zeroes from decimal precision */ 330 for (n = fieldsz; n < dprec; n++) 331 PUTC('0'); 332 333 /* the string or number proper */ 334 if (fp->_cnt - (n = size) >= 0 && 335 (fp->_flag & _IOLBF) == 0) { 336 fp->_cnt -= n; 337 bcopy(t, (char *)fp->_ptr, n); 338 fp->_ptr += n; 339 } else 340 while (--n >= 0) 341 PUTC(*t++); 342 /* trailing f.p. zeroes */ 343 while (--fpprec >= 0) 344 PUTC('0'); 345 /* left-adjusting padding (always blank) */ 346 if (flags & LADJUST) 347 for (n = realsz; n < width; n++) 348 PUTC(' '); 349 350 /* finally, adjust cnt */ 351 cnt += width > realsz ? width : realsz; 352 break; 353 case '\0': /* "%?" prints ?, unless ? is NULL */ 354 return (cnt); 355 default: 356 PUTC((char)*fmt); 357 cnt++; 358 } 359 } 360 /* NOTREACHED */ 361 } 362 363 #define EFORMAT 0x01 364 #define FFORMAT 0x02 365 #define GFORMAT 0x04 366 #define DEFPREC 6 367 368 static char * 369 _cvt(number, prec, flags, fmtch, sign, startp, endp) 370 double number; 371 register int prec; 372 int flags; 373 u_char fmtch; 374 char *sign, *startp, *endp; 375 { 376 register char *p, *t; 377 register int expcnt, format; 378 double fract, integer, tmp, modf(); 379 int decpt; 380 char *savep, exponent[MAXEXP]; 381 382 if (prec == -1) 383 prec = DEFPREC; 384 385 if (number < 0) { 386 *sign = '-'; 387 number = -number; 388 } 389 390 switch(fmtch) { 391 case 'e': 392 case 'E': 393 format = EFORMAT; 394 break; 395 case 'f': 396 format = FFORMAT; 397 break; 398 case 'g': 399 case 'G': 400 format = GFORMAT; 401 fmtch -= 2; 402 } 403 404 /* 405 * if the alternate flag is set, or, at least one digit of precision 406 * was requested, add a decimal point, unless it's the g/G format 407 * in which case we require two digits of precision, as it counts 408 * precision differently. 409 */ 410 decpt = flags&ALT || prec > (format&GFORMAT ? 1 : 0); 411 412 expcnt = 0; 413 p = endp - 1; 414 fract = modf(number, &integer); 415 if (integer) { 416 /* get integer part of number; count decimal places */ 417 for (; integer; ++expcnt) { 418 tmp = modf(integer / 10, &integer); 419 *p-- = tochar((int)((tmp + .03) * 10)); 420 } 421 422 /* copy, in reverse order, to start of buffer */ 423 t = startp; 424 *t++ = *++p; 425 426 /* 427 * if the format is g/G, and the resulting exponent will be 428 * greater than the precision, use e/E format. If e/E format, 429 * put in a decimal point as needed, and decrement precision 430 * count for each digit after the decimal point. 431 */ 432 if (format&GFORMAT && expcnt - 1 > prec || format&EFORMAT) { 433 if (format&GFORMAT) { 434 format |= EFORMAT; 435 436 /* first digit is precision for g/G format */ 437 if (prec) 438 --prec; 439 } 440 if (decpt) 441 *t++ = '.'; 442 for (; ++p < endp && prec; --prec, *t++ = *p); 443 444 /* precision ran out, round */ 445 if (p < endp) { 446 if (*p > '4') { 447 for (savep = t--;; *t-- = '0') { 448 if (*t == '.') 449 --t; 450 if (++*t <= '9') 451 break; 452 } 453 t = savep; 454 } 455 fract = 0; 456 } 457 } 458 /* 459 * g/G in f format; if out of precision, replace digits with 460 * zeroes, note, have to round first. 461 */ 462 else if (format&GFORMAT) { 463 for (; ++p < endp && prec; --prec, *t++ = *p); 464 /* precision ran out; round and then add zeroes */ 465 if (p < endp) { 466 if (*p > '4') { 467 for (savep = t--; ++*t > '9'; 468 *t-- = '0'); 469 t = savep; 470 } 471 do { 472 *t++ = '0'; 473 } while (++p < endp); 474 fract = 0; 475 } 476 if (decpt) 477 *t++ = '.'; 478 } 479 /* f format */ 480 else { 481 for (; ++p < endp; *t++ = *p); 482 if (decpt) 483 *t++ = '.'; 484 } 485 p = t; 486 } 487 /* 488 * if no fraction, the number was zero, and if no precision, can't 489 * show anything after the decimal point. 490 */ 491 else if (!fract || !prec) { 492 *startp++ = '0'; 493 if (decpt && !(format&GFORMAT)) 494 *startp++ = '.'; 495 *startp = '\0'; 496 return(startp); 497 } 498 /* 499 * if the format is g/G, and the resulting exponent will be less than 500 * -4 use e/E format. If e/E format, compute exponent value. 501 */ 502 else if (format&GFORMAT && fract < .0001 || format&EFORMAT) { 503 format |= EFORMAT; 504 if (fract) 505 for (p = startp; fract;) { 506 fract = modf(fract * 10, &tmp); 507 if (!tmp) { 508 --expcnt; 509 continue; 510 } 511 *p++ = tochar((int)tmp); 512 break; 513 } 514 else 515 *p++ = '0'; 516 517 /* g/G format, decrement precision for first digit */ 518 if (format&GFORMAT && prec) 519 --prec; 520 521 /* add decimal after first non-zero digit */ 522 if (decpt) 523 *p++ = '.'; 524 } 525 /* 526 * f format or g/G printed as f format; don't worry about decimal 527 * point, if g/G format doesn't need it, will get stripped later. 528 */ 529 else { 530 p = startp; 531 *p++ = '0'; 532 *p++ = '.'; 533 } 534 535 /* finish out requested precision */ 536 while (fract && prec-- > 0) { 537 fract = modf(fract * 10, &tmp); 538 *p++ = tochar((int)tmp); 539 } 540 while (prec-- > 0) 541 *p++ = '0'; 542 543 /* 544 * if any fractional value left, "round" it back up to the beginning 545 * of the number, fixing the exponent as necessary, and avoiding the 546 * decimal point. 547 */ 548 if (fract) { 549 (void)modf(fract * 10, &tmp); 550 if (tmp > 4) { 551 for (savep = p--;; *p-- = '0') { 552 if (*p == '.') 553 --p; 554 if (p == startp) { 555 *p = '1'; 556 ++expcnt; 557 break; 558 } 559 if (++*p <= '9') 560 break; 561 } 562 p = savep; 563 } 564 } 565 566 /* 567 * if a g/G format and not alternate flag, lose trailing zeroes, 568 * if e/E or g/G format, and last char is decimal point, lose it. 569 */ 570 if (!(flags&ALT)) { 571 if (format&GFORMAT) 572 for (; p[-1] == '0'; --p); 573 if (format&(GFORMAT|EFORMAT) && p[-1] == '.') 574 --p; 575 } 576 577 /* if an e/E format, add exponent */ 578 if (format&EFORMAT) { 579 *p++ = fmtch; 580 if (--expcnt < 0) { 581 expcnt = -expcnt; 582 *p++ = '-'; 583 } 584 else 585 *p++ = '+'; 586 t = exponent + MAXEXP; 587 if (expcnt > 9) { 588 do { 589 *--t = tochar(expcnt % 10); 590 } while ((expcnt /= 10) > 9); 591 *--t = tochar(expcnt); 592 for (; t < exponent + MAXEXP; *p++ = *t++); 593 } 594 else { 595 *p++ = '0'; 596 *p++ = tochar(expcnt); 597 } 598 } 599 return(p); 600 } 601