X-Git-Url: http://nsz.repo.hu/git/?p=musl;a=blobdiff_plain;f=src%2Finternal%2Ffloatscan.c;h=0e1f6d06a4ad7593bf909d9c7f38586ee469f147;hp=3875719b42e064bd5b15e104a9ddb8b4abee8cf5;hb=fe514951af4e67f05d17d796251af9a8229761eb;hpb=c5ff29699cb3cccf8dcd8e44ddf4dcb7599e585c

diff --git a/src/internal/floatscan.c b/src/internal/floatscan.c
index 3875719b..0e1f6d06 100644
--- a/src/internal/floatscan.c
+++ b/src/internal/floatscan.c
@@ -44,7 +44,7 @@ static long long scanexp(FILE *f, int pok)
 	}
 	for (x=0; c-'0'<10U && x<INT_MAX/10; c = shgetc(f))
 		x = 10*x + c-'0';
-	for (y=x; c-'0'<10U && x<LLONG_MAX/10; c = shgetc(f))
+	for (y=x; c-'0'<10U && x<LLONG_MAX/100; c = shgetc(f))
 		y = 10*y + c-'0';
 	for (; c-'0'<10U; c = shgetc(f));
 	shunget(f);
@@ -52,26 +52,26 @@ static long long scanexp(FILE *f, int pok)
 }
 
 
-static long double decfloat(FILE *f, int bits, int emin, int sign, int pok)
+static long double decfloat(FILE *f, int c, int bits, int emin, int sign, int pok)
 {
 	uint32_t x[KMAX];
 	static const uint32_t th[] = { LD_B1B_MAX };
 	int i, j, k, a, z;
 	long long lrp=-1, dc=0;
 	long long e10=0;
+	int lnz = 0;
 	int gotdig = 0;
 	int rp;
 	int e2;
 	long double y;
 	long double frac=0;
 	long double bias=0;
-	int c;
+	static const int p10s[] = { 10, 100, 1000, 10000,
+		100000, 1000000, 10000000, 100000000 };
 
 	j=0;
 	k=0;
 
-	c = shgetc(f);
-
 	/* Don't let leading zeros consume buffer space */
 	for (; c=='0'; c = shgetc(f)) gotdig=1;
 
@@ -80,7 +80,8 @@ static long double decfloat(FILE *f, int bits, int emin, int sign, int pok)
 		if (c == '.') {
 			if (lrp!=-1) break;
 			lrp = dc;
-		} else if (k < KMAX) {
+		} else if (k < KMAX-2) {
+			if (c!='0') lnz = dc;
 			dc++;
 			if (j) x[k] = x[k]*10 + c-'0';
 			else x[k] = c-'0';
@@ -91,7 +92,7 @@ static long double decfloat(FILE *f, int bits, int emin, int sign, int pok)
 			gotdig=1;
 		} else {
 			dc++;
-			x[KMAX-1] |= c-'0';
+			if (c!='0') x[KMAX-3] |= 1;
 		}
 	}
 	if (lrp==-1) lrp=dc;
@@ -117,9 +118,11 @@ static long double decfloat(FILE *f, int bits, int emin, int sign, int pok)
 		return 0;
 	}
 
-	if (!x[0])
-		return sign * 0.0;
-	if (lrp==dc && (!k || (k==1 && !j)) && (bits>30 || x[0]>>bits==0))
+	/* Handle zero specially to avoid nasty special cases later */
+	if (!x[0]) return sign * 0.0;
+
+	/* Optimize small integers (w/no exponent) and over/under-flow */
+	if (lrp==dc && dc<10 && (bits>30 || x[0]>>bits==0))
 		return sign * (long double)x[0];
 	if (lrp > -emin/2) {
 		errno = ERANGE;
@@ -130,6 +133,7 @@ static long double decfloat(FILE *f, int bits, int emin, int sign, int pok)
 		return sign * LDBL_MIN * LDBL_MIN;
 	}
 
+	/* Align incomplete final B1B digit */
 	if (k<KMAX && j) {
 		for (; j<9; j++) x[k]*=10;
 		k++;
@@ -141,7 +145,35 @@ static long double decfloat(FILE *f, int bits, int emin, int sign, int pok)
 	e2 = 0;
 	rp = lrp;
 
-	while (rp < 18+9*LD_B1B_DIG) {
+	/* Optimize small to mid-size integers (even in exp. notation) */
+	if (lnz<9 && lnz<=rp && rp < 18) {
+		if (rp == 9) return sign * (long double)x[0];
+		if (rp < 9) return sign * (long double)x[0] / p10s[8-rp];
+		int bitlim = bits-3*(int)(rp-9);
+		if (bitlim>30 || x[0]>>bitlim==0)
+			return sign * (long double)x[0] * p10s[rp-10];
+	}
+
+	/* Align radix point to B1B digit boundary */
+	if (rp % 9) {
+		int rpm9 = rp>=0 ? rp%9 : rp%9+9;
+		int p10 = p10s[8-rpm9];
+		uint32_t carry = 0;
+		for (k=a; k!=z; k++) {
+			uint32_t tmp = x[k] % p10;
+			x[k] = x[k]/p10 + carry;
+			carry = 1000000000/p10 * tmp;
+			if (k==a && !x[k]) {
+				a = (a+1 & MASK);
+				rp -= 9;
+			}
+		}
+		if (carry) x[z++] = carry;
+		rp += 9-rpm9;
+	}
+
+	/* Upscale until desired number of bits are left of radix point */
+	while (rp < 9*LD_B1B_DIG || (rp == 9*LD_B1B_DIG && x[a]<th[0])) {
 		uint32_t carry = 0;
 		e2 -= 29;
 		for (k=(z-1 & MASK); ; k=(k-1 & MASK)) {
@@ -167,32 +199,7 @@ static long double decfloat(FILE *f, int bits, int emin, int sign, int pok)
 		}
 	}
 
-	if (rp % 9) {
-		static const int p10s[] = {
-			100000000, 10000000, 1000000, 100000,
-			10000, 1000, 100, 10
-		};
-		int rpm9 = rp % 9;
-		int p10 = p10s[rpm9-1];
-		uint32_t carry = 0;
-		for (k=a; k!=z; k=(k+1 & MASK)) {
-			uint32_t tmp = x[k] % p10;
-			x[k] = x[k]/p10 + carry;
-			carry = 1000000000/p10 * tmp;
-			if (k==a && !x[k]) {
-				a = (a+1 & MASK);
-				rp -= 9;
-			}
-		}
-		if (carry) {
-			if ((z+1 & MASK) != a) {
-				x[z] = carry;
-				z = (z+1 & MASK);
-			} else x[z-1 & MASK] |= 1;
-		}
-		rp += 9-rpm9;
-	}
-
+	/* Downscale until exactly number of bits are left of radix point */
 	for (;;) {
 		uint32_t carry = 0;
 		int sh = 1;
@@ -214,6 +221,7 @@ static long double decfloat(FILE *f, int bits, int emin, int sign, int pok)
 			carry = (1000000000>>sh) * tmp;
 			if (k==a && !x[k]) {
 				a = (a+1 & MASK);
+				i--;
 				rp -= 9;
 			}
 		}
@@ -225,16 +233,21 @@ static long double decfloat(FILE *f, int bits, int emin, int sign, int pok)
 		}
 	}
 
-	for (y=i=0; i<LD_B1B_DIG && (a+i & MASK)!=z; i++)
+	/* Assemble desired bits into floating point variable */
+	for (y=i=0; i<LD_B1B_DIG; i++) {
+		if ((a+i & MASK)==z) x[z=(z+1 & MASK)] = 0;
 		y = 1000000000.0L * y + x[a+i & MASK];
+	}
 
 	y *= sign;
 
+	/* Limit precision for denormal results */
 	if (bits > LDBL_MANT_DIG+e2-emin) {
 		bits = LDBL_MANT_DIG+e2-emin;
 		if (bits<0) bits=0;
 	}
 
+	/* Calculate bias term to force rounding, move out lower bits */
 	if (bits < LDBL_MANT_DIG) {
 		bias = copysignl(scalbn(1, 2*LDBL_MANT_DIG-bits-1), y);
 		frac = fmodl(y, scalbn(1, LDBL_MANT_DIG-bits));
@@ -242,6 +255,7 @@ static long double decfloat(FILE *f, int bits, int emin, int sign, int pok)
 		y += bias;
 	}
 
+	/* Process tail of decimal input so it can affect rounding */
 	if ((a+i & MASK) != z) {
 		uint32_t t = x[a+i & MASK];
 		if (t < 500000000 && (t || (a+i+1 & MASK) != z))
@@ -336,6 +350,8 @@ static long double hexfloat(FILE *f, int bits, int emin, int sign, int pok)
 			}
 			e2 = 0;
 		}
+	} else {
+		shunget(f);
 	}
 	e2 += 4*rp - 32;
 
@@ -434,9 +450,9 @@ long double __floatscan(FILE *f, int c, int prec, int pok)
 		c = shgetc(f);
 		if ((c|32) == 'x')
 			return hexfloat(f, bits, emin, sign, pok);
+		shunget(f);
 		c = '0';
 	}
 
-	shunget(f);
-	return decfloat(f, bits, emin, sign, pok);
+	return decfloat(f, c, bits, emin, sign, pok);
 }