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 static long long scanexp(FILE *f, int pok)
44 if (c=='+' || c=='-') {
47 if (c-'0'>=10U && pok) shunget(f);
53 for (x=0; c-'0'<10U && x<INT_MAX/10; c = shgetc(f))
55 for (y=x; c-'0'<10U && y<LLONG_MAX/100; c = shgetc(f))
57 for (; c-'0'<10U; c = shgetc(f));
63 static long double decfloat(FILE *f, int c, int bits, int emin, int sign, int pok)
66 static const uint32_t th[] = { LD_B1B_MAX };
68 long long lrp=0, dc=0;
71 int gotdig = 0, gotrad = 0;
74 int emax = -emin-bits+3;
79 static const int p10s[] = { 10, 100, 1000, 10000,
80 100000, 1000000, 10000000, 100000000 };
85 /* Don't let leading zeros consume buffer space */
86 for (; c=='0'; c = shgetc(f)) gotdig=1;
89 for (c = shgetc(f); c=='0'; c = shgetc(f)) gotdig=1, lrp--;
93 for (; c-'0'<10U || c=='.'; c = shgetc(f)) {
98 } else if (k < KMAX-3) {
100 if (c!='0') lnz = dc;
101 if (j) x[k] = x[k]*10 + c-'0';
118 if (gotdig && (c|32)=='e') {
119 e10 = scanexp(f, pok);
120 if (e10 == LLONG_MIN) {
139 /* Handle zero specially to avoid nasty special cases later */
140 if (!x[0]) return sign * 0.0;
142 /* Optimize small integers (w/no exponent) and over/under-flow */
143 if (lrp==dc && dc<10 && (bits>30 || x[0]>>bits==0))
144 return sign * (long double)x[0];
147 return sign * LDBL_MAX * LDBL_MAX;
149 if (lrp < emin-2*LDBL_MANT_DIG) {
151 return sign * LDBL_MIN * LDBL_MIN;
154 /* Align incomplete final B1B digit */
156 for (; j<9; j++) x[k]*=10;
166 /* Optimize small to mid-size integers (even in exp. notation) */
167 if (lnz<9 && lnz<=rp && rp < 18) {
168 if (rp == 9) return sign * (long double)x[0];
169 if (rp < 9) return sign * (long double)x[0] / p10s[8-rp];
170 int bitlim = bits-3*(int)(rp-9);
171 if (bitlim>30 || x[0]>>bitlim==0)
172 return sign * (long double)x[0] * p10s[rp-10];
175 /* Drop trailing zeros */
176 for (; !x[z-1]; z--);
178 /* Align radix point to B1B digit boundary */
180 int rpm9 = rp>=0 ? rp%9 : rp%9+9;
181 int p10 = p10s[8-rpm9];
183 for (k=a; k!=z; k++) {
184 uint32_t tmp = x[k] % p10;
185 x[k] = x[k]/p10 + carry;
186 carry = 1000000000/p10 * tmp;
192 if (carry) x[z++] = carry;
196 /* Upscale until desired number of bits are left of radix point */
197 while (rp < 9*LD_B1B_DIG || (rp == 9*LD_B1B_DIG && x[a]<th[0])) {
200 for (k=(z-1 & MASK); ; k=(k-1 & MASK)) {
201 uint64_t tmp = ((uint64_t)x[k] << 29) + carry;
202 if (tmp > 1000000000) {
203 carry = tmp / 1000000000;
204 x[k] = tmp % 1000000000;
209 if (k==(z-1 & MASK) && k!=a && !x[k]) z = k;
217 x[z-1 & MASK] |= x[z];
223 /* Downscale until exactly number of bits are left of radix point */
227 for (i=0; i<LD_B1B_DIG; i++) {
229 if (k == z || x[k] < th[i]) {
233 if (x[a+i & MASK] > th[i]) break;
235 if (i==LD_B1B_DIG && rp==9*LD_B1B_DIG) break;
236 /* FIXME: find a way to compute optimal sh */
237 if (rp > 9+9*LD_B1B_DIG) sh = 9;
239 for (k=a; k!=z; k=(k+1 & MASK)) {
240 uint32_t tmp = x[k] & (1<<sh)-1;
241 x[k] = (x[k]>>sh) + carry;
242 carry = (1000000000>>sh) * tmp;
250 if ((z+1 & MASK) != a) {
253 } else x[z-1 & MASK] |= 1;
257 /* Assemble desired bits into floating point variable */
258 for (y=i=0; i<LD_B1B_DIG; i++) {
259 if ((a+i & MASK)==z) x[(z=(z+1 & MASK))-1] = 0;
260 y = 1000000000.0L * y + x[a+i & MASK];
265 /* Limit precision for denormal results */
266 if (bits > LDBL_MANT_DIG+e2-emin) {
267 bits = LDBL_MANT_DIG+e2-emin;
272 /* Calculate bias term to force rounding, move out lower bits */
273 if (bits < LDBL_MANT_DIG) {
274 bias = copysignl(scalbn(1, 2*LDBL_MANT_DIG-bits-1), y);
275 frac = fmodl(y, scalbn(1, LDBL_MANT_DIG-bits));
280 /* Process tail of decimal input so it can affect rounding */
281 if ((a+i & MASK) != z) {
282 uint32_t t = x[a+i & MASK];
283 if (t < 500000000 && (t || (a+i+1 & MASK) != z))
285 else if (t > 500000000)
287 else if (t == 500000000) {
288 if ((a+i+1 & MASK) == z)
293 if (LDBL_MANT_DIG-bits >= 2 && !fmodl(frac, 1))
300 if ((e2+LDBL_MANT_DIG & INT_MAX) > emax-5) {
301 if (fabsl(y) >= 2/LDBL_EPSILON) {
302 if (denormal && bits==LDBL_MANT_DIG+e2-emin)
307 if (e2+LDBL_MANT_DIG>emax || (denormal && frac))
311 return scalbnl(y, e2);
314 static long double hexfloat(FILE *f, int bits, int emin, int sign, int pok)
318 long double scale = 1;
319 long double bias = 0;
320 int gottail = 0, gotrad = 0, gotdig = 0;
329 /* Skip leading zeros */
330 for (; c=='0'; c = shgetc(f)) gotdig = 1;
335 /* Count zeros after the radix point before significand */
336 for (rp=0; c=='0'; c = shgetc(f), rp--) gotdig = 1;
339 for (; c-'0'<10U || (c|32)-'a'<6U || c=='.'; c = shgetc(f)) {
346 if (c > '9') d = (c|32)+10-'a';
350 } else if (dc < LDBL_MANT_DIG/4+1) {
352 } else if (d && !gottail) {
363 if (gotrad) shunget(f);
369 if (!gotrad) rp = dc;
370 while (dc<8) x *= 16, dc++;
372 e2 = scanexp(f, pok);
373 if (e2 == LLONG_MIN) {
387 if (!x) return sign * 0.0;
390 return sign * LDBL_MAX * LDBL_MAX;
392 if (e2 < emin-2*LDBL_MANT_DIG) {
394 return sign * LDBL_MIN * LDBL_MIN;
397 while (x < 0x80000000) {
408 if (bits > 32+e2-emin) {
413 if (bits < LDBL_MANT_DIG)
414 bias = copysignl(scalbn(1, 32+LDBL_MANT_DIG-bits-1), sign);
416 if (bits<32 && y && !(x&1)) x++, y=0;
418 y = bias + sign*(long double)x + sign*y;
421 if (!y) errno = ERANGE;
423 return scalbnl(y, e2);
426 long double __floatscan(FILE *f, int prec, int pok)
437 emin = FLT_MIN_EXP-bits;
441 emin = DBL_MIN_EXP-bits;
444 bits = LDBL_MANT_DIG;
445 emin = LDBL_MIN_EXP-bits;
451 while (isspace((c=shgetc(f))));
453 if (c=='+' || c=='-') {
458 for (i=0; i<8 && (c|32)=="infinity"[i]; i++)
459 if (i<7) c = shgetc(f);
460 if (i==3 || i==8 || (i>3 && pok)) {
463 if (pok) for (; i>3; i--) shunget(f);
465 return sign * INFINITY;
467 if (!i) for (i=0; i<3 && (c|32)=="nan"[i]; i++)
468 if (i<2) c = shgetc(f);
470 if (shgetc(f) != '(') {
476 if (c-'0'<10U || c-'A'<26U || c-'a'<26U || c=='_')
478 if (c==')') return NAN;
485 while (i--) shunget(f);
501 return hexfloat(f, bits, emin, sign, pok);
506 return decfloat(f, c, bits, emin, sign, pok);