simplify/debloat radix point alignment code in floatscan

[musl] / src / internal / floatscan.c

diff --git a/src/internal/floatscan.c b/src/internal/floatscan.c
index 3875719..6390d46 100644 (file)
--- 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);
@@ -52,7 +52,7 @@ 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 };
@@ -65,13 +65,10 @@ static long double decfloat(FILE *f, int bits, int emin, int sign, int pok)
        long double y;
        long double frac=0;
        long double bias=0;
-       int c;
 
        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 +77,7 @@ 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) {
                        dc++;
                        if (j) x[k] = x[k]*10 + c-'0';
                        else x[k] = c-'0';
@@ -91,7 +88,7 @@ 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;
@@ -141,7 +138,28 @@ 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) {
+       if (rp % 9) {
+               static const int p10s[] = {
+                       100000000, 10000000, 1000000, 100000,
+                       10000, 1000, 100, 10
+               };
+               int rpm9 = rp>=0 ? rp%9 : rp%9+9;
+               int p10 = p10s[rpm9-1];
+               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;
+       }
+
+       while (rp < 9*LD_B1B_DIG || (rp == 9*LD_B1B_DIG && x[0]<th[0])) {
                uint32_t carry = 0;
                e2 -= 29;
                for (k=(z-1 & MASK); ; k=(k-1 & MASK)) {
@@ -167,32 +185,6 @@ 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;
-       }
-
        for (;;) {
                uint32_t carry = 0;
                int sh = 1;
@@ -225,8 +217,10 @@ 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++)
+       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;
 
@@ -336,6 +330,8 @@ 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 +430,9 @@ 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);
 }