fix spurious overflows in strtoull with small bases

whenever the base was small enough that more than one digit could
still fit after UINTMAX_MAX/36-1 was reached, only the first would be
allowed; subsequent digits would trigger spurious overflow, making it
impossible to read the largest values in low bases.

diff --git a/src/internal/intparse.c b/src/internal/intparse.c
index ffd06fe06655e845ebbc742a8963dd4ac42f84ef..e30a1a5805847d1a986f433c1e33a01313d0fde4 100644 (file)
--- a/src/internal/intparse.c
+++ b/src/internal/intparse.c
@@ -25,12 +25,12 @@ static const unsigned char digits[] = {
 };
 
 #define SLIM (UINT_MAX/36-1)
-#define LLIM (UINTMAX_MAX/36-1)
 
 int __intparse(struct intparse *v, const void *buf, size_t n)
 {
        const unsigned char *s = buf;
        int d, b = v->base;
+       uintmax_t llim;
 
        v->cnt += n;
        for (; n; n--, s++) switch (v->state) {
@@ -83,16 +83,12 @@ int __intparse(struct intparse *v, const void *buf, size_t n)
                v->state++;
                v->val = v->small;
        case 5:
-               for (; n && (d=digits[*s])<b && v->val<=LLIM; n--, s++)
+               llim = UINTMAX_MAX/b;
+               for (; n && (d=digits[*s])<b && v->val<=llim && d<=UINTMAX_MAX-v->val*b; n--, s++)
                        v->val = v->val * b + d;
                if (!n) return 1;
                if (d >= b) goto finished;
-               if (v->val <= (UINTMAX_MAX-d)/b)
-                       v->val = v->val * b + d;
-               else
-                       v->err = ERANGE;
                v->state++;
-               n--; s++;
        case 6:
                if (n && digits[*s]<b) {
                        v->err = ERANGE;