1 /* 2 * The authors of this software are Rob Pike and Ken Thompson. 3 * Copyright (c) 2002 by Lucent Technologies. 4 * Permission to use, copy, modify, and distribute this software for any 5 * purpose without fee is hereby granted, provided that this entire notice 6 * is included in all copies of any software which is or includes a copy 7 * or modification of this software and in all copies of the supporting 8 * documentation for such software. 9 * THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR IMPLIED 10 * WARRANTY. IN PARTICULAR, NEITHER THE AUTHORS NOR LUCENT TECHNOLOGIES MAKE ANY 11 * REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE MERCHANTABILITY 12 * OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR PURPOSE. 13 */ 14 #include <stdio.h> 15 #include <math.h> 16 #include <float.h> 17 #include <string.h> 18 #include <stdlib.h> 19 #include <errno.h> 20 #include <stdarg.h> 21 #include "fmt.h" 22 #include "fmtdef.h" 23 #include "nan.h" 24 25 enum 26 { 27 FDEFLT = 6, 28 NSIGNIF = 17 29 }; 30 31 /* 32 * first few powers of 10, enough for about 1/2 of the 33 * total space for doubles. 34 */ 35 static double pows10[] = 36 { 37 1e0, 1e1, 1e2, 1e3, 1e4, 1e5, 1e6, 1e7, 1e8, 1e9, 38 1e10, 1e11, 1e12, 1e13, 1e14, 1e15, 1e16, 1e17, 1e18, 1e19, 39 1e20, 1e21, 1e22, 1e23, 1e24, 1e25, 1e26, 1e27, 1e28, 1e29, 40 1e30, 1e31, 1e32, 1e33, 1e34, 1e35, 1e36, 1e37, 1e38, 1e39, 41 1e40, 1e41, 1e42, 1e43, 1e44, 1e45, 1e46, 1e47, 1e48, 1e49, 42 1e50, 1e51, 1e52, 1e53, 1e54, 1e55, 1e56, 1e57, 1e58, 1e59, 43 1e60, 1e61, 1e62, 1e63, 1e64, 1e65, 1e66, 1e67, 1e68, 1e69, 44 1e70, 1e71, 1e72, 1e73, 1e74, 1e75, 1e76, 1e77, 1e78, 1e79, 45 1e80, 1e81, 1e82, 1e83, 1e84, 1e85, 1e86, 1e87, 1e88, 1e89, 46 1e90, 1e91, 1e92, 1e93, 1e94, 1e95, 1e96, 1e97, 1e98, 1e99, 47 1e100, 1e101, 1e102, 1e103, 1e104, 1e105, 1e106, 1e107, 1e108, 1e109, 48 1e110, 1e111, 1e112, 1e113, 1e114, 1e115, 1e116, 1e117, 1e118, 1e119, 49 1e120, 1e121, 1e122, 1e123, 1e124, 1e125, 1e126, 1e127, 1e128, 1e129, 50 1e130, 1e131, 1e132, 1e133, 1e134, 1e135, 1e136, 1e137, 1e138, 1e139, 51 1e140, 1e141, 1e142, 1e143, 1e144, 1e145, 1e146, 1e147, 1e148, 1e149, 52 1e150, 1e151, 1e152, 1e153, 1e154, 1e155, 1e156, 1e157, 1e158, 1e159, 53 }; 54 55 static double 56 pow10(int n) 57 { 58 double d; 59 int neg; 60 61 neg = 0; 62 if(n < 0){ 63 if(n < DBL_MIN_10_EXP){ 64 return 0.; 65 } 66 neg = 1; 67 n = -n; 68 }else if(n > DBL_MAX_10_EXP){ 69 return HUGE_VAL; 70 } 71 if(n < (int)(sizeof(pows10)/sizeof(pows10[0]))) 72 d = pows10[n]; 73 else{ 74 d = pows10[sizeof(pows10)/sizeof(pows10[0]) - 1]; 75 for(;;){ 76 n -= sizeof(pows10)/sizeof(pows10[0]) - 1; 77 if(n < (int)(sizeof(pows10)/sizeof(pows10[0]))){ 78 d *= pows10[n]; 79 break; 80 } 81 d *= pows10[sizeof(pows10)/sizeof(pows10[0]) - 1]; 82 } 83 } 84 if(neg){ 85 return 1./d; 86 } 87 return d; 88 } 89 90 static int 91 xadd(char *a, int n, int v) 92 { 93 char *b; 94 int c; 95 96 if(n < 0 || n >= NSIGNIF) 97 return 0; 98 for(b = a+n; b >= a; b--) { 99 c = *b + v; 100 if(c <= '9') { 101 *b = c; 102 return 0; 103 } 104 *b = '0'; 105 v = 1; 106 } 107 *a = '1'; /* overflow adding */ 108 return 1; 109 } 110 111 static int 112 xsub(char *a, int n, int v) 113 { 114 char *b; 115 int c; 116 117 for(b = a+n; b >= a; b--) { 118 c = *b - v; 119 if(c >= '0') { 120 *b = c; 121 return 0; 122 } 123 *b = '9'; 124 v = 1; 125 } 126 *a = '9'; /* underflow subtracting */ 127 return 1; 128 } 129 130 static void 131 xaddexp(char *p, int e) 132 { 133 char se[9]; 134 int i; 135 136 *p++ = 'e'; 137 if(e < 0) { 138 *p++ = '-'; 139 e = -e; 140 } 141 i = 0; 142 while(e) { 143 se[i++] = e % 10 + '0'; 144 e /= 10; 145 } 146 if(i == 0) { 147 *p++ = '0'; 148 } else { 149 while(i > 0) 150 *p++ = se[--i]; 151 } 152 *p = '\0'; 153 } 154 155 static char* 156 xdodtoa(char *s1, double f, int chr, int prec, int *decpt, int *rsign) 157 { 158 char s2[NSIGNIF+10]; 159 double g, h; 160 int e, d, i; 161 int c2, sign, oerr; 162 163 if(chr == 'F') 164 chr = 'f'; 165 if(prec > NSIGNIF) 166 prec = NSIGNIF; 167 if(prec < 0) 168 prec = 0; 169 if(__isNaN(f)) { 170 *decpt = 9999; 171 *rsign = 0; 172 strcpy(s1, "nan"); 173 return &s1[3]; 174 } 175 sign = 0; 176 if(f < 0) { 177 f = -f; 178 sign++; 179 } 180 *rsign = sign; 181 if(__isInf(f, 1) || __isInf(f, -1)) { 182 *decpt = 9999; 183 strcpy(s1, "inf"); 184 return &s1[3]; 185 } 186 187 e = 0; 188 g = f; 189 if(g != 0) { 190 frexp(f, &e); 191 e = (int)(e * .301029995664); 192 if(e >= -150 && e <= +150) { 193 d = 0; 194 h = f; 195 } else { 196 d = e/2; 197 h = f * pow10(-d); 198 } 199 g = h * pow10(d-e); 200 while(g < 1) { 201 e--; 202 g = h * pow10(d-e); 203 } 204 while(g >= 10) { 205 e++; 206 g = h * pow10(d-e); 207 } 208 } 209 210 /* 211 * convert NSIGNIF digits and convert 212 * back to get accuracy. 213 */ 214 for(i=0; i<NSIGNIF; i++) { 215 d = (int)g; 216 s1[i] = d + '0'; 217 g = (g - d) * 10; 218 } 219 s1[i] = 0; 220 221 /* 222 * try decimal rounding to eliminate 9s 223 */ 224 c2 = prec + 1; 225 if(chr == 'f') 226 c2 += e; 227 oerr = errno; 228 if(c2 >= NSIGNIF-2) { 229 strcpy(s2, s1); 230 d = e; 231 s1[NSIGNIF-2] = '0'; 232 s1[NSIGNIF-1] = '0'; 233 xaddexp(s1+NSIGNIF, e-NSIGNIF+1); 234 g = fmtstrtod(s1, nil); 235 if(g == f) 236 goto found; 237 if(xadd(s1, NSIGNIF-3, 1)) { 238 e++; 239 xaddexp(s1+NSIGNIF, e-NSIGNIF+1); 240 } 241 g = fmtstrtod(s1, nil); 242 if(g == f) 243 goto found; 244 strcpy(s1, s2); 245 e = d; 246 } 247 248 /* 249 * convert back so s1 gets exact answer 250 */ 251 for(d = 0; d < 10; d++) { 252 xaddexp(s1+NSIGNIF, e-NSIGNIF+1); 253 g = fmtstrtod(s1, nil); 254 if(f > g) { 255 if(xadd(s1, NSIGNIF-1, 1)) 256 e--; 257 continue; 258 } 259 if(f < g) { 260 if(xsub(s1, NSIGNIF-1, 1)) 261 e++; 262 continue; 263 } 264 break; 265 } 266 267 found: 268 errno = oerr; 269 270 /* 271 * round & adjust 'f' digits 272 */ 273 c2 = prec + 1; 274 if(chr == 'f'){ 275 if(xadd(s1, c2+e, 5)) 276 e++; 277 c2 += e; 278 if(c2 < 0){ 279 c2 = 0; 280 e = -prec - 1; 281 } 282 }else{ 283 if(xadd(s1, c2, 5)) 284 e++; 285 } 286 if(c2 > NSIGNIF){ 287 c2 = NSIGNIF; 288 } 289 290 *decpt = e + 1; 291 292 /* 293 * terminate the converted digits 294 */ 295 s1[c2] = '\0'; 296 return &s1[c2]; 297 } 298 299 /* 300 * this function works like the standard dtoa, if you want it. 301 */ 302 #if 0 303 static char* 304 __dtoa(double f, int mode, int ndigits, int *decpt, int *rsign, char **rve) 305 { 306 static char s2[NSIGNIF + 10]; 307 char *es; 308 int chr, prec; 309 310 switch(mode) { 311 /* like 'e' */ 312 case 2: 313 case 4: 314 case 6: 315 case 8: 316 chr = 'e'; 317 break; 318 /* like 'g' */ 319 case 0: 320 case 1: 321 default: 322 chr = 'g'; 323 break; 324 /* like 'f' */ 325 case 3: 326 case 5: 327 case 7: 328 case 9: 329 chr = 'f'; 330 break; 331 } 332 333 if(chr != 'f' && ndigits){ 334 ndigits--; 335 } 336 prec = ndigits; 337 if(prec > NSIGNIF) 338 prec = NSIGNIF; 339 if(ndigits == 0) 340 prec = NSIGNIF; 341 es = xdodtoa(s2, f, chr, prec, decpt, rsign); 342 343 /* 344 * strip trailing 0 345 */ 346 for(; es > s2 + 1; es--){ 347 if(es[-1] != '0'){ 348 break; 349 } 350 } 351 *es = '\0'; 352 if(rve != NULL) 353 *rve = es; 354 return s2; 355 } 356 #endif 357 358 static int 359 fmtzdotpad(Fmt *f, int n, int pt) 360 { 361 char *t, *s; 362 int i; 363 Rune *rt, *rs; 364 365 if(f->runes){ 366 rt = (Rune*)f->to; 367 rs = (Rune*)f->stop; 368 for(i = 0; i < n; i++){ 369 if(i == pt){ 370 FMTRCHAR(f, rt, rs, '.'); 371 } 372 FMTRCHAR(f, rt, rs, '0'); 373 } 374 f->nfmt += rt - (Rune*)f->to; 375 f->to = rt; 376 }else{ 377 t = (char*)f->to; 378 s = (char*)f->stop; 379 for(i = 0; i < n; i++){ 380 if(i == pt){ 381 FMTCHAR(f, t, s, '.'); 382 } 383 FMTCHAR(f, t, s, '0'); 384 } 385 f->nfmt += t - (char *)f->to; 386 f->to = t; 387 } 388 return 0; 389 } 390 391 int 392 __efgfmt(Fmt *fmt) 393 { 394 double f; 395 char s1[NSIGNIF+10]; 396 int e, d, n; 397 int c1, c2, c3, c4, ucase, sign, chr, prec, fl; 398 399 f = va_arg(fmt->args, double); 400 prec = FDEFLT; 401 fl = fmt->flags; 402 fmt->flags = 0; 403 if(fl & FmtPrec) 404 prec = fmt->prec; 405 chr = fmt->r; 406 ucase = 0; 407 if(chr == 'E'){ 408 chr = 'e'; 409 ucase = 1; 410 }else if(chr == 'F'){ 411 chr = 'f'; 412 ucase = 1; 413 }else if(chr == 'G'){ 414 chr = 'g'; 415 ucase = 1; 416 } 417 if(prec > 0 && chr == 'g') 418 prec--; 419 if(prec < 0) 420 prec = 0; 421 422 xdodtoa(s1, f, chr, prec, &e, &sign); 423 e--; 424 if(*s1 == 'i' || *s1 == 'n'){ 425 if(ucase){ 426 if(*s1 == 'i'){ 427 strcpy(s1, "INF"); 428 }else{ 429 strcpy(s1, "NAN"); 430 } 431 } 432 fmt->flags = fl & (FmtWidth|FmtLeft); 433 return __fmtcpy(fmt, (const void*)s1, 3, 3); 434 } 435 436 /* 437 * copy into final place 438 * c1 digits of leading '0' 439 * c2 digits from conversion 440 * c3 digits of trailing '0' 441 * c4 digits after '.' 442 */ 443 c1 = 0; 444 c2 = prec + 1; 445 c3 = 0; 446 c4 = prec; 447 switch(chr) { 448 default: 449 chr = 'e'; 450 break; 451 case 'g': 452 /* 453 * decide on 'e' of 'f' style convers 454 */ 455 if(e >= -4 && e <= prec) { 456 c1 = -e; 457 c4 = prec - e; 458 chr = 'h'; /* flag for 'f' style */ 459 } 460 break; 461 case 'f': 462 c1 = -e; 463 if(c1 > prec) 464 c1 = prec + 1; 465 c2 += e; 466 break; 467 } 468 469 /* 470 * clean up c1 c2 and c3 471 */ 472 if(c1 < 0) 473 c1 = 0; 474 if(c2 < 0) 475 c2 = 0; 476 if(c2 > NSIGNIF) { 477 c3 = c2-NSIGNIF; 478 c2 = NSIGNIF; 479 } 480 481 /* 482 * trim trailing zeros for %g 483 */ 484 if(!(fl & FmtSharp) 485 && (chr == 'g' || chr == 'h')){ 486 if(c4 >= c3){ 487 c4 -= c3; 488 c3 = 0; 489 }else{ 490 c3 -= c4; 491 c4 = 0; 492 } 493 while(c4 && c2 > 1 && s1[c2 - 1] == '0'){ 494 c4--; 495 c2--; 496 } 497 } 498 499 /* 500 * calculate the total length 501 */ 502 n = c1 + c2 + c3; 503 if(sign || (fl & (FmtSign|FmtSpace))) 504 n++; 505 if(c4 || (fl & FmtSharp)){ 506 n++; 507 } 508 if(chr == 'e' || chr == 'g'){ 509 n += 4; 510 if(e >= 100) 511 n++; 512 } 513 514 /* 515 * pad to width if right justified 516 */ 517 if((fl & (FmtWidth|FmtLeft)) == FmtWidth && n < fmt->width){ 518 if(fl & FmtZero){ 519 c1 += fmt->width - n; 520 }else{ 521 if(__fmtpad(fmt, fmt->width - n) < 0){ 522 return -1; 523 } 524 } 525 } 526 527 /* 528 * sign 529 */ 530 d = 0; 531 if(sign) 532 d = '-'; 533 else if(fl & FmtSign) 534 d = '+'; 535 else if(fl & FmtSpace) 536 d = ' '; 537 if(d && fmtrune(fmt, d) < 0){ 538 return -1; 539 } 540 541 /* 542 * copy digits 543 */ 544 c4 = c1 + c2 + c3 - c4; 545 if(c1 > 0){ 546 if(fmtzdotpad(fmt, c1, c4) < 0){ 547 return -1; 548 } 549 c4 -= c1; 550 } 551 d = 0; 552 if(c4 >= 0 && c4 < c2){ 553 if(__fmtcpy(fmt, s1, c4, c4) < 0 || fmtrune(fmt, '.') < 0) 554 return -1; 555 d = c4; 556 c2 -= c4; 557 c4 = -1; 558 } 559 if(__fmtcpy(fmt, (const void*)(s1 + d), c2, c2) < 0){ 560 return -1; 561 } 562 c4 -= c2; 563 if(c3 > 0){ 564 if(fmtzdotpad(fmt, c3, c4) < 0){ 565 return -1; 566 } 567 c4 -= c3; 568 } 569 570 /* 571 * strip trailing '0' on g conv 572 */ 573 if((fl & FmtSharp) && c4 == 0 && fmtrune(fmt, '.') < 0){ 574 return -1; 575 } 576 if(chr == 'e' || chr == 'g') { 577 d = 0; 578 if(ucase) 579 s1[d++] = 'E'; 580 else 581 s1[d++] = 'e'; 582 c1 = e; 583 if(c1 < 0) { 584 s1[d++] = '-'; 585 c1 = -c1; 586 } else 587 s1[d++] = '+'; 588 if(c1 >= 100) { 589 s1[d++] = c1/100 + '0'; 590 c1 = c1%100; 591 } 592 s1[d++] = c1/10 + '0'; 593 s1[d++] = c1%10 + '0'; 594 if(__fmtcpy(fmt, s1, d, d) < 0){ 595 return -1; 596 } 597 } 598 if((fl & (FmtWidth|FmtLeft)) == (FmtWidth|FmtLeft) && n < fmt->width){ 599 if(__fmtpad(fmt, fmt->width - n) < 0){ 600 return -1; 601 } 602 } 603 return 0; 604 } 605