Bug Summary

File:src/internal/floatscan.c
Warning:line 161, column 3
Value stored to 'j' is never read

Annotated Source Code

1#include <stdint.h>
2#include <stdio.h>
3#include <math.h>
4#include <float.h>
5#include <limits.h>
6#include <errno(*__errno_location()).h>
7#include <ctype.h>
8
9#include "shgetc.h"
10#include "floatscan.h"
11
12#if LDBL_MANT_DIG64 == 53 && LDBL_MAX_EXP16384 == 1024
13
14#define LD_B1B_DIG3 2
15#define LD_B1B_MAX18, 446744073, 709551615 9007199, 254740991
16#define KMAX2048 128
17
18#elif LDBL_MANT_DIG64 == 64 && LDBL_MAX_EXP16384 == 16384
19
20#define LD_B1B_DIG3 3
21#define LD_B1B_MAX18, 446744073, 709551615 18, 446744073, 709551615
22#define KMAX2048 2048
23
24#elif LDBL_MANT_DIG64 == 113 && LDBL_MAX_EXP16384 == 16384
25
26#define LD_B1B_DIG3 4
27#define LD_B1B_MAX18, 446744073, 709551615 10384593, 717069655, 257060992, 658440191
28#define KMAX2048 2048
29
30#else
31#error Unsupported long double representation
32#endif
33
34#define MASK(2048 -1) (KMAX2048-1)
35
36#define CONCAT2(x,y)xy x ## y
37#define CONCAT(x,y)xy CONCAT2(x,y)xy
38
39static long long scanexp(FILE *f, int pok)
40{
41 int c;
42 int x;
43 long long y;
44 int neg = 0;
45
46 c = shgetc(f)(((f)->rpos < (f)->shend) ? *(f)->rpos++ : __shgetc
(f));
47 if (c=='+' || c=='-') {
48 neg = (c=='-');
49 c = shgetc(f)(((f)->rpos < (f)->shend) ? *(f)->rpos++ : __shgetc
(f));
50 if (c-'0'>=10U && pok) shunget(f)((f)->shend ? (void)(f)->rpos-- : (void)0);
51 }
52 if (c-'0'>=10U) {
53 shunget(f)((f)->shend ? (void)(f)->rpos-- : (void)0);
54 return LLONG_MIN(-0x7fffffffffffffffLL -1);
55 }
56 for (x=0; c-'0'<10U && x<INT_MAX0x7fffffff/10; c = shgetc(f)(((f)->rpos < (f)->shend) ? *(f)->rpos++ : __shgetc
(f)))
57 x = 10*x + c-'0';
58 for (y=x; c-'0'<10U && y<LLONG_MAX0x7fffffffffffffffLL/100; c = shgetc(f)(((f)->rpos < (f)->shend) ? *(f)->rpos++ : __shgetc
(f)))
59 y = 10*y + c-'0';
60 for (; c-'0'<10U; c = shgetc(f)(((f)->rpos < (f)->shend) ? *(f)->rpos++ : __shgetc
(f)));
61 shunget(f)((f)->shend ? (void)(f)->rpos-- : (void)0);
62 return neg ? -y : y;
63}
64
65
66static long double decfloat(FILE *f, int c, int bits, int emin, int sign, int pok)
67{
68 uint32_t x[KMAX2048];
69 static const uint32_t th[] = { LD_B1B_MAX18, 446744073, 709551615 };
70 int i, j, k, a, z;
71 long long lrp=0, dc=0;
72 long long e10=0;
73 int lnz = 0;
74 int gotdig = 0, gotrad = 0;
75 int rp;
76 int e2;
77 int emax = -emin-bits+3;
78 int denormal = 0;
79 long double y;
80 long double frac=0;
81 long double bias=0;
82 static const int p10s[] = { 10, 100, 1000, 10000,
83 100000, 1000000, 10000000, 100000000 };
84
85 j=0;
86 k=0;
87
88 /* Don't let leading zeros consume buffer space */
89 for (; c=='0'; c = shgetc(f)(((f)->rpos < (f)->shend) ? *(f)->rpos++ : __shgetc
(f))) gotdig=1;
90 if (c=='.') {
91 gotrad = 1;
92 for (c = shgetc(f)(((f)->rpos < (f)->shend) ? *(f)->rpos++ : __shgetc
(f)); c=='0'; c = shgetc(f)(((f)->rpos < (f)->shend) ? *(f)->rpos++ : __shgetc
(f))) gotdig=1, lrp--;
93 }
94
95 x[0] = 0;
96 for (; c-'0'<10U || c=='.'; c = shgetc(f)(((f)->rpos < (f)->shend) ? *(f)->rpos++ : __shgetc
(f))) {
97 if (c == '.') {
98 if (gotrad) break;
99 gotrad = 1;
100 lrp = dc;
101 } else if (k < KMAX2048-3) {
102 dc++;
103 if (c!='0') lnz = dc;
104 if (j) x[k] = x[k]*10 + c-'0';
105 else x[k] = c-'0';
106 if (++j==9) {
107 k++;
108 j=0;
109 }
110 gotdig=1;
111 } else {
112 dc++;
113 if (c!='0') {
114 lnz = (KMAX2048-4)*9;
115 x[KMAX2048-4] |= 1;
116 }
117 }
118 }
119 if (!gotrad) lrp=dc;
120
121 if (gotdig && (c|32)=='e') {
122 e10 = scanexp(f, pok);
123 if (e10 == LLONG_MIN(-0x7fffffffffffffffLL -1)) {
124 if (pok) {
125 shunget(f)((f)->shend ? (void)(f)->rpos-- : (void)0);
126 } else {
127 shlim(f, 0)__shlim((f), (0));
128 return 0;
129 }
130 e10 = 0;
131 }
132 lrp += e10;
133 } else if (c>=0) {
134 shunget(f)((f)->shend ? (void)(f)->rpos-- : (void)0);
135 }
136 if (!gotdig) {
137 errno(*__errno_location()) = EINVAL22;
138 shlim(f, 0)__shlim((f), (0));
139 return 0;
140 }
141
142 /* Handle zero specially to avoid nasty special cases later */
143 if (!x[0]) return sign * 0.0;
144
145 /* Optimize small integers (w/no exponent) and over/under-flow */
146 if (lrp==dc && dc<10 && (bits>30 || x[0]>>bits==0))
147 return sign * (long double)x[0];
148 if (lrp > -emin/2) {
149 errno(*__errno_location()) = ERANGE34;
150 return sign * LDBL_MAX1.1897314953572317650e+4932L * LDBL_MAX1.1897314953572317650e+4932L;
151 }
152 if (lrp < emin-2*LDBL_MANT_DIG64) {
153 errno(*__errno_location()) = ERANGE34;
154 return sign * LDBL_MIN3.3621031431120935063e-4932L * LDBL_MIN3.3621031431120935063e-4932L;
155 }
156
157 /* Align incomplete final B1B digit */
158 if (j) {
159 for (; j<9; j++) x[k]*=10;
160 k++;
161 j=0;
Value stored to 'j' is never read
162 }
163
164 a = 0;
165 z = k;
166 e2 = 0;
167 rp = lrp;
168
169 /* Optimize small to mid-size integers (even in exp. notation) */
170 if (lnz<9 && lnz<=rp && rp < 18) {
171 if (rp == 9) return sign * (long double)x[0];
172 if (rp < 9) return sign * (long double)x[0] / p10s[8-rp];
173 int bitlim = bits-3*(int)(rp-9);
174 if (bitlim>30 || x[0]>>bitlim==0)
175 return sign * (long double)x[0] * p10s[rp-10];
176 }
177
178 /* Drop trailing zeros */
179 for (; !x[z-1]; z--);
180
181 /* Align radix point to B1B digit boundary */
182 if (rp % 9) {
183 int rpm9 = rp>=0 ? rp%9 : rp%9+9;
184 int p10 = p10s[8-rpm9];
185 uint32_t carry = 0;
186 for (k=a; k!=z; k++) {
187 uint32_t tmp = x[k] % p10;
188 x[k] = x[k]/p10 + carry;
189 carry = 1000000000/p10 * tmp;
190 if (k==a && !x[k]) {
191 a = (a+1 & MASK(2048 -1));
192 rp -= 9;
193 }
194 }
195 if (carry) x[z++] = carry;
196 rp += 9-rpm9;
197 }
198
199 /* Upscale until desired number of bits are left of radix point */
200 while (rp < 9*LD_B1B_DIG3 || (rp == 9*LD_B1B_DIG3 && x[a]<th[0])) {
201 uint32_t carry = 0;
202 e2 -= 29;
203 for (k=(z-1 & MASK(2048 -1)); ; k=(k-1 & MASK(2048 -1))) {
204 uint64_t tmp = ((uint64_t)x[k] << 29) + carry;
205 if (tmp > 1000000000) {
206 carry = tmp / 1000000000;
207 x[k] = tmp % 1000000000;
208 } else {
209 carry = 0;
210 x[k] = tmp;
211 }
212 if (k==(z-1 & MASK(2048 -1)) && k!=a && !x[k]) z = k;
213 if (k==a) break;
214 }
215 if (carry) {
216 rp += 9;
217 a = (a-1 & MASK(2048 -1));
218 if (a == z) {
219 z = (z-1 & MASK(2048 -1));
220 x[z-1 & MASK(2048 -1)] |= x[z];
221 }
222 x[a] = carry;
223 }
224 }
225
226 /* Downscale until exactly number of bits are left of radix point */
227 for (;;) {
228 uint32_t carry = 0;
229 int sh = 1;
230 for (i=0; i<LD_B1B_DIG3; i++) {
231 k = (a+i & MASK(2048 -1));
232 if (k == z || x[k] < th[i]) {
233 i=LD_B1B_DIG3;
234 break;
235 }
236 if (x[a+i & MASK(2048 -1)] > th[i]) break;
237 }
238 if (i==LD_B1B_DIG3 && rp==9*LD_B1B_DIG3) break;
239 /* FIXME: find a way to compute optimal sh */
240 if (rp > 9+9*LD_B1B_DIG3) sh = 9;
241 e2 += sh;
242 for (k=a; k!=z; k=(k+1 & MASK(2048 -1))) {
243 uint32_t tmp = x[k] & (1<<sh)-1;
244 x[k] = (x[k]>>sh) + carry;
245 carry = (1000000000>>sh) * tmp;
246 if (k==a && !x[k]) {
247 a = (a+1 & MASK(2048 -1));
248 i--;
249 rp -= 9;
250 }
251 }
252 if (carry) {
253 if ((z+1 & MASK(2048 -1)) != a) {
254 x[z] = carry;
255 z = (z+1 & MASK(2048 -1));
256 } else x[z-1 & MASK(2048 -1)] |= 1;
257 }
258 }
259
260 /* Assemble desired bits into floating point variable */
261 for (y=i=0; i<LD_B1B_DIG3; i++) {
262 if ((a+i & MASK(2048 -1))==z) x[(z=(z+1 & MASK(2048 -1)))-1] = 0;
263 y = 1000000000.0L * y + x[a+i & MASK(2048 -1)];
264 }
265
266 y *= sign;
267
268 /* Limit precision for denormal results */
269 if (bits > LDBL_MANT_DIG64+e2-emin) {
270 bits = LDBL_MANT_DIG64+e2-emin;
271 if (bits<0) bits=0;
272 denormal = 1;
273 }
274
275 /* Calculate bias term to force rounding, move out lower bits */
276 if (bits < LDBL_MANT_DIG64) {
277 bias = copysignl(scalbn(1, 2*LDBL_MANT_DIG64-bits-1), y);
278 frac = fmodl(y, scalbn(1, LDBL_MANT_DIG64-bits));
279 y -= frac;
280 y += bias;
281 }
282
283 /* Process tail of decimal input so it can affect rounding */
284 if ((a+i & MASK(2048 -1)) != z) {
285 uint32_t t = x[a+i & MASK(2048 -1)];
286 if (t < 500000000 && (t || (a+i+1 & MASK(2048 -1)) != z))
287 frac += 0.25*sign;
288 else if (t > 500000000)
289 frac += 0.75*sign;
290 else if (t == 500000000) {
291 if ((a+i+1 & MASK(2048 -1)) == z)
292 frac += 0.5*sign;
293 else
294 frac += 0.75*sign;
295 }
296 if (LDBL_MANT_DIG64-bits >= 2 && !fmodl(frac, 1))
297 frac++;
298 }
299
300 y += frac;
301 y -= bias;
302
303 if ((e2+LDBL_MANT_DIG64 & INT_MAX0x7fffffff) > emax-5) {
304 if (fabs(y) >= CONCAT(0x1p, LDBL_MANT_DIG)0x1p64) {
305 if (denormal && bits==LDBL_MANT_DIG64+e2-emin)
306 denormal = 0;
307 y *= 0.5;
308 e2++;
309 }
310 if (e2+LDBL_MANT_DIG64>emax || (denormal && frac))
311 errno(*__errno_location()) = ERANGE34;
312 }
313
314 return scalbnl(y, e2);
315}
316
317static long double hexfloat(FILE *f, int bits, int emin, int sign, int pok)
318{
319 uint32_t x = 0;
320 long double y = 0;
321 long double scale = 1;
322 long double bias = 0;
323 int gottail = 0, gotrad = 0, gotdig = 0;
324 long long rp = 0;
325 long long dc = 0;
326 long long e2 = 0;
327 int d;
328 int c;
329
330 c = shgetc(f)(((f)->rpos < (f)->shend) ? *(f)->rpos++ : __shgetc
(f));
331
332 /* Skip leading zeros */
333 for (; c=='0'; c = shgetc(f)(((f)->rpos < (f)->shend) ? *(f)->rpos++ : __shgetc
(f))) gotdig = 1;
334
335 if (c=='.') {
336 gotrad = 1;
337 c = shgetc(f)(((f)->rpos < (f)->shend) ? *(f)->rpos++ : __shgetc
(f));
338 /* Count zeros after the radix point before significand */
339 for (rp=0; c=='0'; c = shgetc(f)(((f)->rpos < (f)->shend) ? *(f)->rpos++ : __shgetc
(f)), rp--) gotdig = 1;
340 }
341
342 for (; c-'0'<10U || (c|32)-'a'<6U || c=='.'; c = shgetc(f)(((f)->rpos < (f)->shend) ? *(f)->rpos++ : __shgetc
(f))) {
343 if (c=='.') {
344 if (gotrad) break;
345 rp = dc;
346 gotrad = 1;
347 } else {
348 gotdig = 1;
349 if (c > '9') d = (c|32)+10-'a';
350 else d = c-'0';
351 if (dc<8) {
352 x = x*16 + d;
353 } else if (dc < LDBL_MANT_DIG64/4+1) {
354 y += d*(scale/=16);
355 } else if (d && !gottail) {
356 y += 0.5*scale;
357 gottail = 1;
358 }
359 dc++;
360 }
361 }
362 if (!gotdig) {
363 shunget(f)((f)->shend ? (void)(f)->rpos-- : (void)0);
364 if (pok) {
365 shunget(f)((f)->shend ? (void)(f)->rpos-- : (void)0);
366 if (gotrad) shunget(f)((f)->shend ? (void)(f)->rpos-- : (void)0);
367 } else {
368 shlim(f, 0)__shlim((f), (0));
369 }
370 return sign * 0.0;
371 }
372 if (!gotrad) rp = dc;
373 while (dc<8) x *= 16, dc++;
374 if ((c|32)=='p') {
375 e2 = scanexp(f, pok);
376 if (e2 == LLONG_MIN(-0x7fffffffffffffffLL -1)) {
377 if (pok) {
378 shunget(f)((f)->shend ? (void)(f)->rpos-- : (void)0);
379 } else {
380 shlim(f, 0)__shlim((f), (0));
381 return 0;
382 }
383 e2 = 0;
384 }
385 } else {
386 shunget(f)((f)->shend ? (void)(f)->rpos-- : (void)0);
387 }
388 e2 += 4*rp - 32;
389
390 if (!x) return sign * 0.0;
391 if (e2 > -emin) {
392 errno(*__errno_location()) = ERANGE34;
393 return sign * LDBL_MAX1.1897314953572317650e+4932L * LDBL_MAX1.1897314953572317650e+4932L;
394 }
395 if (e2 < emin-2*LDBL_MANT_DIG64) {
396 errno(*__errno_location()) = ERANGE34;
397 return sign * LDBL_MIN3.3621031431120935063e-4932L * LDBL_MIN3.3621031431120935063e-4932L;
398 }
399
400 while (x < 0x80000000) {
401 if (y>=0.5) {
402 x += x + 1;
403 y += y - 1;
404 } else {
405 x += x;
406 y += y;
407 }
408 e2--;
409 }
410
411 if (bits > 32+e2-emin) {
412 bits = 32+e2-emin;
413 if (bits<0) bits=0;
414 }
415
416 if (bits < LDBL_MANT_DIG64)
417 bias = copysignl(scalbn(1, 32+LDBL_MANT_DIG64-bits-1), sign);
418
419 if (bits<32 && y && !(x&1)) x++, y=0;
420
421 y = bias + sign*(long double)x + sign*y;
422 y -= bias;
423
424 if (!y) errno(*__errno_location()) = ERANGE34;
425
426 return scalbnl(y, e2);
427}
428
429long double __floatscan(FILE *f, int prec, int pok)
430{
431 int sign = 1;
432 size_t i;
433 int bits;
434 int emin;
435 int c;
436
437 switch (prec) {
438 case 0:
439 bits = FLT_MANT_DIG24;
440 emin = FLT_MIN_EXP(-125)-bits;
441 break;
442 case 1:
443 bits = DBL_MANT_DIG53;
444 emin = DBL_MIN_EXP(-1021)-bits;
445 break;
446 case 2:
447 bits = LDBL_MANT_DIG64;
448 emin = LDBL_MIN_EXP(-16381)-bits;
449 break;
450 default:
451 return 0;
452 }
453
454 while (isspace((c=shgetc(f)))__isspace((c=(((f)->rpos < (f)->shend) ? *(f)->rpos
++ : __shgetc(f)))));
455
456 if (c=='+' || c=='-') {
457 sign -= 2*(c=='-');
458 c = shgetc(f)(((f)->rpos < (f)->shend) ? *(f)->rpos++ : __shgetc
(f));
459 }
460
461 for (i=0; i<8 && (c|32)=="infinity"[i]; i++)
462 if (i<7) c = shgetc(f)(((f)->rpos < (f)->shend) ? *(f)->rpos++ : __shgetc
(f));
463 if (i==3 || i==8 || (i>3 && pok)) {
464 if (i!=8) {
465 shunget(f)((f)->shend ? (void)(f)->rpos-- : (void)0);
466 if (pok) for (; i>3; i--) shunget(f)((f)->shend ? (void)(f)->rpos-- : (void)0);
467 }
468 return sign * INFINITY__builtin_inff();
469 }
470 if (!i) for (i=0; i<3 && (c|32)=="nan"[i]; i++)
471 if (i<2) c = shgetc(f)(((f)->rpos < (f)->shend) ? *(f)->rpos++ : __shgetc
(f));
472 if (i==3) {
473 if (shgetc(f)(((f)->rpos < (f)->shend) ? *(f)->rpos++ : __shgetc
(f)) != '(') {
474 shunget(f)((f)->shend ? (void)(f)->rpos-- : (void)0);
475 return NAN__builtin_nanf("");
476 }
477 for (i=1; ; i++) {
478 c = shgetc(f)(((f)->rpos < (f)->shend) ? *(f)->rpos++ : __shgetc
(f));
479 if (c-'0'<10U || c-'A'<26U || c-'a'<26U || c=='_')
480 continue;
481 if (c==')') return NAN__builtin_nanf("");
482 shunget(f)((f)->shend ? (void)(f)->rpos-- : (void)0);
483 if (!pok) {
484 errno(*__errno_location()) = EINVAL22;
485 shlim(f, 0)__shlim((f), (0));
486 return 0;
487 }
488 while (i--) shunget(f)((f)->shend ? (void)(f)->rpos-- : (void)0);
489 return NAN__builtin_nanf("");
490 }
491 return NAN__builtin_nanf("");
492 }
493
494 if (i) {
495 shunget(f)((f)->shend ? (void)(f)->rpos-- : (void)0);
496 errno(*__errno_location()) = EINVAL22;
497 shlim(f, 0)__shlim((f), (0));
498 return 0;
499 }
500
501 if (c=='0') {
502 c = shgetc(f)(((f)->rpos < (f)->shend) ? *(f)->rpos++ : __shgetc
(f));
503 if ((c|32) == 'x')
504 return hexfloat(f, bits, emin, sign, pok);
505 shunget(f)((f)->shend ? (void)(f)->rpos-- : (void)0);
506 c = '0';
507 }
508
509 return decfloat(f, c, bits, emin, sign, pok);
510}