10 #include "floatscan.h"
12 #if LDBL_MANT_DIG == 53 && LDBL_MAX_EXP == 1024
15 #define LD_B1B_MAX 9007199, 254740991
18 #elif LDBL_MANT_DIG == 64 && LDBL_MAX_EXP == 16384
21 #define LD_B1B_MAX 18, 446744073, 709551615
24 #elif LDBL_MANT_DIG == 113 && LDBL_MAX_EXP == 16384
27 #define LD_B1B_MAX 10384593, 717069655, 257060992, 658440191
31 #error Unsupported long double representation
36 #define CONCAT2(x,y) x ## y
37 #define CONCAT(x,y) CONCAT2(x,y)
39 static long long scanexp(FILE *f, int pok)
47 if (c=='+' || c=='-') {
50 if (c-'0'>=10U && pok) shunget(f);
56 for (x=0; c-'0'<10U && x<INT_MAX/10; c = shgetc(f))
58 for (y=x; c-'0'<10U && y<LLONG_MAX/100; c = shgetc(f))
60 for (; c-'0'<10U; c = shgetc(f));
66 static long double decfloat(FILE *f, int c, int bits, int emin, int sign, int pok)
69 static const uint32_t th[] = { LD_B1B_MAX };
71 long long lrp=0, dc=0;
74 int gotdig = 0, gotrad = 0;
77 int emax = -emin-bits+3;
82 static const int p10s[] = { 10, 100, 1000, 10000,
83 100000, 1000000, 10000000, 100000000 };
88 /* Don't let leading zeros consume buffer space */
89 for (; c=='0'; c = shgetc(f)) gotdig=1;
92 for (c = shgetc(f); c=='0'; c = shgetc(f)) gotdig=1, lrp--;
96 for (; c-'0'<10U || c=='.'; c = shgetc(f)) {
101 } else if (k < KMAX-3) {
103 if (c!='0') lnz = dc;
104 if (j) x[k] = x[k]*10 + c-'0';
121 if (gotdig && (c|32)=='e') {
122 e10 = scanexp(f, pok);
123 if (e10 == LLONG_MIN) {
142 /* Handle zero specially to avoid nasty special cases later */
143 if (!x[0]) return sign * 0.0;
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];
150 return sign * LDBL_MAX * LDBL_MAX;
152 if (lrp < emin-2*LDBL_MANT_DIG) {
154 return sign * LDBL_MIN * LDBL_MIN;
157 /* Align incomplete final B1B digit */
159 for (; j<9; j++) x[k]*=10;
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];
178 /* Drop trailing zeros */
179 for (; !x[z-1]; z--);
181 /* Align radix point to B1B digit boundary */
183 int rpm9 = rp>=0 ? rp%9 : rp%9+9;
184 int p10 = p10s[8-rpm9];
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;
195 if (carry) x[z++] = carry;
199 /* Upscale until desired number of bits are left of radix point */
200 while (rp < 9*LD_B1B_DIG || (rp == 9*LD_B1B_DIG && x[a]<th[0])) {
203 for (k=(z-1 & MASK); ; k=(k-1 & MASK)) {
204 uint64_t tmp = ((uint64_t)x[k] << 29) + carry;
205 if (tmp > 1000000000) {
206 carry = tmp / 1000000000;
207 x[k] = tmp % 1000000000;
212 if (k==(z-1 & MASK) && k!=a && !x[k]) z = k;
220 x[z-1 & MASK] |= x[z];
226 /* Downscale until exactly number of bits are left of radix point */
230 for (i=0; i<LD_B1B_DIG; i++) {
232 if (k == z || x[k] < th[i]) {
236 if (x[a+i & MASK] > th[i]) break;
238 if (i==LD_B1B_DIG && rp==9*LD_B1B_DIG) break;
239 /* FIXME: find a way to compute optimal sh */
240 if (rp > 9+9*LD_B1B_DIG) sh = 9;
242 for (k=a; k!=z; k=(k+1 & MASK)) {
243 uint32_t tmp = x[k] & (1<<sh)-1;
244 x[k] = (x[k]>>sh) + carry;
245 carry = (1000000000>>sh) * tmp;
253 if ((z+1 & MASK) != a) {
256 } else x[z-1 & MASK] |= 1;
260 /* Assemble desired bits into floating point variable */
261 for (y=i=0; i<LD_B1B_DIG; i++) {
262 if ((a+i & MASK)==z) x[(z=(z+1 & MASK))-1] = 0;
263 y = 1000000000.0L * y + x[a+i & MASK];
268 /* Limit precision for denormal results */
269 if (bits > LDBL_MANT_DIG+e2-emin) {
270 bits = LDBL_MANT_DIG+e2-emin;
275 /* Calculate bias term to force rounding, move out lower bits */
276 if (bits < LDBL_MANT_DIG) {
277 bias = copysignl(scalbn(1, 2*LDBL_MANT_DIG-bits-1), y);
278 frac = fmodl(y, scalbn(1, LDBL_MANT_DIG-bits));
283 /* Process tail of decimal input so it can affect rounding */
284 if ((a+i & MASK) != z) {
285 uint32_t t = x[a+i & MASK];
286 if (t < 500000000 && (t || (a+i+1 & MASK) != z))
288 else if (t > 500000000)
290 else if (t == 500000000) {
291 if ((a+i+1 & MASK) == z)
296 if (LDBL_MANT_DIG-bits >= 2 && !fmodl(frac, 1))
303 if ((e2+LDBL_MANT_DIG & INT_MAX) > emax-5) {
304 if (fabs(y) >= CONCAT(0x1p, LDBL_MANT_DIG)) {
305 if (denormal && bits==LDBL_MANT_DIG+e2-emin)
310 if (e2+LDBL_MANT_DIG>emax || (denormal && frac))
314 return scalbnl(y, e2);
317 static long double hexfloat(FILE *f, int bits, int emin, int sign, int pok)
321 long double scale = 1;
322 long double bias = 0;
323 int gottail = 0, gotrad = 0, gotdig = 0;
332 /* Skip leading zeros */
333 for (; c=='0'; c = shgetc(f)) gotdig = 1;
338 /* Count zeros after the radix point before significand */
339 for (rp=0; c=='0'; c = shgetc(f), rp--) gotdig = 1;
342 for (; c-'0'<10U || (c|32)-'a'<6U || c=='.'; c = shgetc(f)) {
349 if (c > '9') d = (c|32)+10-'a';
353 } else if (dc < LDBL_MANT_DIG/4+1) {
355 } else if (d && !gottail) {
366 if (gotrad) shunget(f);
372 if (!gotrad) rp = dc;
373 while (dc<8) x *= 16, dc++;
375 e2 = scanexp(f, pok);
376 if (e2 == LLONG_MIN) {
390 if (!x) return sign * 0.0;
393 return sign * LDBL_MAX * LDBL_MAX;
395 if (e2 < emin-2*LDBL_MANT_DIG) {
397 return sign * LDBL_MIN * LDBL_MIN;
400 while (x < 0x80000000) {
411 if (bits > 32+e2-emin) {
416 if (bits < LDBL_MANT_DIG)
417 bias = copysignl(scalbn(1, 32+LDBL_MANT_DIG-bits-1), sign);
419 if (bits<32 && y && !(x&1)) x++, y=0;
421 y = bias + sign*(long double)x + sign*y;
424 if (!y) errno = ERANGE;
426 return scalbnl(y, e2);
429 long double __floatscan(FILE *f, int prec, int pok)
440 emin = FLT_MIN_EXP-bits;
444 emin = DBL_MIN_EXP-bits;
447 bits = LDBL_MANT_DIG;
448 emin = LDBL_MIN_EXP-bits;
454 while (isspace((c=shgetc(f))));
456 if (c=='+' || c=='-') {
461 for (i=0; i<8 && (c|32)=="infinity"[i]; i++)
462 if (i<7) c = shgetc(f);
463 if (i==3 || i==8 || (i>3 && pok)) {
466 if (pok) for (; i>3; i--) shunget(f);
468 return sign * INFINITY;
470 if (!i) for (i=0; i<3 && (c|32)=="nan"[i]; i++)
471 if (i<2) c = shgetc(f);
473 if (shgetc(f) != '(') {
479 if (c-'0'<10U || c-'A'<26U || c-'a'<26U || c=='_')
481 if (c==')') return NAN;
488 while (i--) shunget(f);
504 return hexfloat(f, bits, emin, sign, pok);
509 return decfloat(f, c, bits, emin, sign, pok);