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 5.22 (Berkeley) 05/18/88"; 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 #define MAXBUF 512 23 24 #define PUTC(ch) {++cnt; putc((char)ch, fp);} 25 26 #define ARG() \ 27 _ulong = flags&LONGINT ? va_arg(argp, long) : \ 28 flags&SHORTINT ? va_arg(argp, short) : va_arg(argp, int); 29 30 /* have to deal with the negative buffer count kludge */ 31 #define NEGATIVE_COUNT_KLUDGE 32 33 #define LONGINT 0x01 /* long integer */ 34 #define LONGDBL 0x02 /* long double; unimplemented */ 35 #define SHORTINT 0x04 /* short integer */ 36 #define ALT 0x08 /* alternate form */ 37 #define LADJUST 0x10 /* left adjustment */ 38 39 _doprnt(fmt0, argp, fp) 40 u_char *fmt0; 41 va_list argp; 42 register FILE *fp; 43 { 44 register u_char *fmt; 45 register int ch, cnt, n; 46 register char *t; 47 double _double; 48 u_long _ulong; 49 int base, flags, prec, size, width; 50 char padc, sign, *digs, buf[MAXBUF], *_cvt(); 51 52 fmt = fmt0; 53 digs = "0123456789abcdef"; 54 for (cnt = 0;; ++fmt) { 55 n = fp->_cnt; 56 for (t = fp->_ptr; (ch = *fmt) && ch != '%'; ++cnt, ++fmt) 57 if (--n < 0 58 #ifdef NEGATIVE_COUNT_KLUDGE 59 && (!(fp->_flag & _IOLBF) || -n >= fp->_bufsiz) 60 #endif 61 || ch == '\n' && fp->_flag&_IOLBF) { 62 fp->_cnt = n; 63 fp->_ptr = t; 64 (void)_flsbuf(ch, fp); 65 n = fp->_cnt; 66 t = fp->_ptr; 67 } 68 else 69 *t++ = ch; 70 fp->_cnt = n; 71 fp->_ptr = t; 72 if (!ch) 73 return(cnt); 74 75 flags = width = 0; 76 prec = -1; 77 padc = ' '; 78 sign = '\0'; 79 80 rflag: switch (*++fmt) { 81 case ' ': 82 sign = ' '; 83 goto rflag; 84 case '#': 85 flags |= ALT; 86 goto rflag; 87 case '*': 88 /* 89 * ``A negative field width argument is taken as a 90 * - flag followed by a positive field width.'' 91 * -- ANSI X3J11 92 * They don't exclude field widths read from args. 93 */ 94 if ((width = va_arg(argp, int)) >= 0) 95 goto rflag; 96 width = -width; 97 /*FALLTHROUGH*/ 98 case '-': 99 flags |= LADJUST; 100 goto rflag; 101 case '+': 102 sign = '+'; 103 goto rflag; 104 case '.': 105 if (*++fmt == '*') 106 n = va_arg(argp, int); 107 else if (isascii(*fmt) && isdigit(*fmt)) { 108 n = 0; 109 do { 110 n = 10 * n + *fmt - '0'; 111 } while (isascii(*++fmt) && isdigit(*fmt)); 112 --fmt; 113 } 114 else { 115 --fmt; 116 prec = 0; 117 goto rflag; 118 } 119 prec = n < 0 ? -1 : n; 120 goto rflag; 121 case '0': 122 padc = '0'; 123 /*FALLTHROUGH*/ 124 case '1': case '2': case '3': case '4': 125 case '5': case '6': case '7': case '8': case '9': 126 n = 0; 127 do { 128 n = 10 * n + *fmt - '0'; 129 } while (isascii(*++fmt) && isdigit(*fmt)); 130 width = n; 131 --fmt; 132 goto rflag; 133 case 'L': 134 /* 135 * C doesn't have a long double; use long for now. 136 * flags |= LONGDBL; 137 */ 138 flags |= LONGINT; 139 goto rflag; 140 case 'h': 141 flags |= SHORTINT; 142 goto rflag; 143 case 'l': 144 flags |= LONGINT; 145 goto rflag; 146 case 'c': 147 buf[0] = va_arg(argp, int); 148 size = 1; 149 t = buf; 150 goto pforw; 151 case 'd': 152 case 'i': 153 ARG(); 154 if ((long)_ulong < 0) { 155 _ulong = -_ulong; 156 sign = '-'; 157 } 158 if (sign) 159 PUTC(sign); 160 base = 10; 161 goto num; 162 case 'e': 163 case 'E': 164 case 'f': 165 case 'g': 166 case 'G': 167 _double = va_arg(argp, double); 168 size = _cvt(_double, prec, flags, *fmt, sign, 169 buf, buf + sizeof(buf)) - buf; 170 t = buf; 171 goto pforw; 172 case 'n': 173 if (flags&LONGDBL || flags&LONGINT) 174 *va_arg(argp, long *) = cnt; 175 else if (flags&SHORTINT) 176 *va_arg(argp, short *) = cnt; 177 else 178 *va_arg(argp, int *) = cnt; 179 break; 180 case 'o': 181 ARG(); 182 base = 8; 183 goto num; 184 case 'p': 185 /* 186 * ``The argument shall be a pointer to void. The 187 * value of the pointer is converted to a sequence 188 * of printable characters, in an implementation- 189 * defined manner.'' 190 * -- ANSI X3J11 191 */ 192 _ulong = (u_long)va_arg(argp, void *); 193 base = 16; 194 goto num; 195 case 's': 196 if (!(t = va_arg(argp, char *))) 197 t = "(null)"; 198 if (prec >= 0) { 199 /* 200 * can't use strlen; can only look for the 201 * NUL in the first `prec' characters, and 202 * strlen() will go further. 203 */ 204 char *p, *memchr(); 205 206 if (p = memchr(t, 0, prec)) { 207 size = p - t; 208 if (size > prec) 209 size = prec; 210 } 211 else 212 size = prec; 213 } 214 else 215 size = strlen(t); 216 pforw: if (!(flags&LADJUST) && width) 217 for (n = size; n++ < width;) 218 PUTC(padc); 219 if (fp->_cnt - (n = size) >= 0) { 220 cnt += n; 221 fp->_cnt -= n; 222 bcopy(t, fp->_ptr, n); 223 fp->_ptr += n; 224 } 225 else for (; n--; ++t) 226 PUTC(*t); 227 if (flags&LADJUST) 228 while (width-- > size) 229 PUTC(' '); 230 break; 231 case 'u': 232 ARG(); 233 base = 10; 234 goto num; 235 case 'X': 236 digs = "0123456789ABCDEF"; 237 /*FALLTHROUGH*/ 238 case 'x': 239 ARG(); 240 base = 16; 241 /* leading 0x/X only if non-zero */ 242 if (!_ulong) 243 flags &= ~ALT; 244 /* 245 * ``The result of converting a zero value with an 246 * explicit precision of zero is no characters.'' 247 * -- ANSI X3J11 248 */ 249 num: if (!_ulong && !prec) 250 break; 251 t = buf + MAXBUF - 1; 252 do { 253 *t-- = digs[_ulong % base]; 254 _ulong /= base; 255 } while(_ulong); 256 digs = "0123456789abcdef"; 257 for (size = buf + MAXBUF - 1 - t; size < prec; ++size) 258 *t-- = '0'; 259 if (flags&ALT) 260 switch (base) { 261 case 16: 262 /* avoid "00000x35" */ 263 if (padc == '0') { 264 PUTC('0'); 265 PUTC(*fmt); 266 } 267 else { 268 *t-- = *fmt; 269 *t-- = '0'; 270 } 271 width -= 2; 272 break; 273 case 8: 274 if (t[1] != '0') { 275 *t-- = '0'; 276 --width; 277 } 278 break; 279 } 280 if (!(flags&LADJUST)) 281 while (size++ < width) 282 PUTC(padc); 283 while (++t < buf + MAXBUF) 284 PUTC(*t); 285 while (width-- > size) 286 PUTC(' '); 287 break; 288 case '\0': /* "%?" prints ?, unless ? is NULL */ 289 return(cnt); 290 default: 291 PUTC(*fmt); 292 } 293 } 294 /*NOTREACHED*/ 295 } 296 297 #define EFORMAT 0x01 298 #define FFORMAT 0x02 299 #define GFORMAT 0x04 300 #define DEFPREC 6 301 302 static char * 303 _cvt(number, prec, flags, fmtch, sign, startp, endp) 304 double number; 305 register int prec; 306 int flags; 307 u_char fmtch; 308 char sign, *startp, *endp; 309 { 310 register char *p; 311 register int expcnt, format; 312 double fract, integer, tmp, modf(); 313 int decpt; 314 char *savep; 315 316 if (prec == -1) 317 prec = DEFPREC; 318 319 if (number < 0) { 320 *startp++ = '-'; 321 number = -number; 322 } 323 else if (sign) 324 *startp++ = sign; 325 326 switch(fmtch) { 327 case 'e': 328 case 'E': 329 format = EFORMAT; 330 break; 331 case 'f': 332 format = FFORMAT; 333 break; 334 case 'g': 335 case 'G': 336 format = GFORMAT; 337 fmtch -= 2; 338 } 339 340 /* 341 * if the alternate flag is set, or, at least one digit of precision 342 * was requested, add a decimal point, unless it's the g/G format 343 * in which case we require two digits of precision, as it counts 344 * precision differently. 345 */ 346 decpt = flags&ALT || prec > (format&GFORMAT ? 1 : 0); 347 348 expcnt = 0; 349 p = endp - 1; 350 fract = modf(number, &integer); 351 if (integer) { 352 register char *p2; 353 354 /* get integer part of number; count decimal places */ 355 for (; integer; ++expcnt) { 356 tmp = modf(integer / 10, &integer); 357 *p-- = (int)((tmp + .03) * 10) + '0'; 358 } 359 360 /* copy, in reverse order, to start of buffer */ 361 p2 = startp; 362 *p2++ = *++p; 363 364 /* 365 * if the format is g/G, and the resulting exponent will be 366 * greater than the precision, use e/E format. If e/E format, 367 * put in a decimal point as needed, and decrement precision 368 * count for each digit after the decimal point. 369 */ 370 if (format&GFORMAT && expcnt - 1 > prec || format&EFORMAT) { 371 if (format&GFORMAT) { 372 format |= EFORMAT; 373 374 /* first digit is precision for g/G format */ 375 if (prec) 376 --prec; 377 } 378 if (decpt) 379 *p2++ = '.'; 380 for (; ++p < endp && prec; --prec, *p2++ = *p); 381 382 /* precision ran out, round */ 383 if (p < endp) { 384 if (*p > '4') { 385 for (savep = p2--;; *p2-- = '0') { 386 if (*p2 == '.') 387 --p2; 388 if (++*p2 <= '9') 389 break; 390 } 391 p2 = savep; 392 } 393 fract = 0; 394 } 395 } 396 /* 397 * g/G in f format; if out of precision, replace digits with 398 * zeroes, note, have to round first. 399 */ 400 else if (format&GFORMAT) { 401 for (; ++p < endp && prec; --prec, *p2++ = *p); 402 /* precision ran out; round and then add zeroes */ 403 if (p < endp) { 404 if (*p > '4') { 405 for (savep = p2--; ++*p2 > '9'; 406 *p2-- = '0'); 407 p2 = savep; 408 } 409 do { 410 *p2++ = '0'; 411 } while (++p < endp); 412 fract = 0; 413 } 414 if (decpt) 415 *p2++ = '.'; 416 } 417 /* f format */ 418 else { 419 for (; ++p < endp; *p2++ = *p); 420 if (decpt) 421 *p2++ = '.'; 422 } 423 p = p2; 424 } 425 /* 426 * if no fraction, the number was zero, and if no precision, can't 427 * show anything after the decimal point. 428 */ 429 else if (!fract || !prec) { 430 *startp++ = '0'; 431 if (decpt && !(format&GFORMAT)) 432 *startp++ = '.'; 433 *startp = '\0'; 434 return(startp); 435 } 436 /* 437 * if the format is g/G, and the resulting exponent will be less than 438 * -4 use e/E format. If e/E format, compute exponent value. 439 */ 440 else if (format&GFORMAT && fract < .0001 || format&EFORMAT) { 441 format |= EFORMAT; 442 if (fract) 443 for (p = startp; fract;) { 444 fract = modf(fract * 10, &tmp); 445 if (!tmp) { 446 --expcnt; 447 continue; 448 } 449 *p++ = (int)tmp + '0'; 450 break; 451 } 452 else 453 *p++ = '0'; 454 455 /* g/G format, decrement precision for first digit */ 456 if (format&GFORMAT && prec) 457 --prec; 458 459 /* add decimal after first non-zero digit */ 460 if (decpt) 461 *p++ = '.'; 462 } 463 /* 464 * f format or g/G printed as f format; don't worry about decimal 465 * point, if g/G format doesn't need it, will get stripped later. 466 */ 467 else { 468 p = startp; 469 *p++ = '0'; 470 *p++ = '.'; 471 } 472 473 /* finish out requested precision */ 474 while (fract && prec-- > 0) { 475 fract = modf(fract * 10, &tmp); 476 *p++ = (int)tmp + '0'; 477 } 478 while (prec-- > 0) 479 *p++ = '0'; 480 481 /* 482 * if any fractional value left, "round" it back up to the beginning 483 * of the number, fixing the exponent as necessary, and avoiding the 484 * decimal point. 485 */ 486 if (fract) { 487 (void)modf(fract * 10, &tmp); 488 if (tmp > 4) { 489 for (savep = p--;; *p-- = '0') { 490 if (*p == '.') 491 --p; 492 if (p == startp) { 493 *p = '1'; 494 ++expcnt; 495 break; 496 } 497 if (++*p <= '9') 498 break; 499 } 500 p = savep; 501 } 502 } 503 504 /* 505 * if a g/G format and not alternate flag, lose trailing zeroes, 506 * if e/E or g/G format, and last char is decimal point, lose it. 507 */ 508 if (!(flags&ALT)) { 509 if (format&GFORMAT) 510 for (; p[-1] == '0'; --p); 511 if (format&(GFORMAT|EFORMAT) && p[-1] == '.') 512 --p; 513 } 514 515 /* if an e/E format, add exponent */ 516 if (format&EFORMAT) { 517 *p++ = fmtch; 518 if (--expcnt < 0) { 519 expcnt = -expcnt; 520 *p++ = '-'; 521 } 522 else 523 *p++ = '+'; 524 *p++ = expcnt / 10 + '0'; 525 *p++ = expcnt % 10 + '0'; 526 } 527 return(p); 528 } 529