bignum: rename bn_digitcount to bn_maxdigitcount (can return value one higher than the real result)

bignum.c

@@ -999,7 +999,7 @@ size_t bn_format(const bignum256 *amnt, const char *prefix, const char *suffix,
 		BN_FORMAT_PUSH(0);
 	}
 
-	unsigned int digits = bn_digitcount(&val);
+	unsigned int digits = bn_maxdigitcount(&val);
 	for (unsigned int i = 0; i < digits / 3; i++) {
 		uint32_t limb;
 		bn_divmod1000(&val, &limb);

bignum.h

@@ -83,7 +83,7 @@ static inline void bn_copy(const bignum256 *a, bignum256 *b) {
 
 int bn_bitcount(const bignum256 *a);
 
-static inline int bn_digitcount(const bignum256 *a)
+static inline int bn_maxdigitcount(const bignum256 *a)
 {
 	int bitcount = bn_bitcount(a);
 

test_check.c

@@ -371,7 +371,7 @@ START_TEST(test_bignum_digitcount)
 	bignum256 a;
 
 	bn_zero(&a);
-	ck_assert_int_eq(bn_digitcount(&a), 1);
+	ck_assert_int_eq(bn_maxdigitcount(&a), 1);
 
 	// test for 10000 and 99999 when i=5
 	for (int i = 1; i <= 19; i++) {
@@ -382,19 +382,19 @@ START_TEST(test_bignum_digitcount)
 			n = n * 10 + 9;
 		}
 		bn_read_uint64(m, &a);
-		ck_assert_int_eq(bn_digitcount(&a), i);
+		ck_assert_int_eq(bn_maxdigitcount(&a), i);
 		bn_read_uint64(n, &a);
-		ck_assert_int_eq(bn_digitcount(&a), i);
+		ck_assert_int_eq(bn_maxdigitcount(&a), i + 1);
 	}
 
 	bn_read_uint32(0x3fffffff, &a);
-	ck_assert_int_eq(bn_digitcount(&a), 10);
+	ck_assert_int_eq(bn_maxdigitcount(&a), 10);
 
 	bn_read_uint32(0xffffffff, &a);
-	ck_assert_int_eq(bn_digitcount(&a), 10);
+	ck_assert_int_eq(bn_maxdigitcount(&a), 10);
 
 	bn_read_be(fromhex("ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff"), &a);
-	ck_assert_int_eq(bn_digitcount(&a), 78);
+	ck_assert_int_eq(bn_maxdigitcount(&a), 78);
 }
 END_TEST