Fix for bug #30453: String not cast to int correctly.

Problem:

my_strntoull10rnd_8bit() handled incorrectly cases when the input
string contains a decimal point and is long enough to overrun the
'unsigned long long' type. The position of the decimal point was not
taken into account which resulted in miscalculated numbers and
truncation to appropriate SQL data type limits.

Solution:

Fix my_strntoull10rnd_8bit() to take the position of a decimal point
into account in such cases.

mysql-test/r/insert.result

@@ -461,4 +461,18 @@ i
 2
 2
 DROP TABLE t1, t2;
+CREATE TABLE t1 (c1 INT NOT NULL);
+INSERT INTO t1 VALUES(4188.32999999999992724042385816574096679687500),
+('4188.32999999999992724042385816574096679687500'), (4188);
+SELECT * FROM t1;
+c1
+4188
+4188
+4188
+CREATE TABLE t2 (c1 BIGINT);
+INSERT INTO t2 VALUES('15449237462.0000000000');
+SELECT * FROM t2;
+c1
+15449237462
+DROP TABLE t1, t2;
 End of 5.0 tests.

mysql-test/t/insert.test

@@ -353,5 +353,20 @@ SELECT * FROM t2;
 
 DROP TABLE t1, t2;
 
+#
+# Bug #30453: String not cast to int correctly
+#
+
+CREATE TABLE t1 (c1 INT NOT NULL);
+INSERT INTO t1 VALUES(4188.32999999999992724042385816574096679687500),
+('4188.32999999999992724042385816574096679687500'), (4188);
+SELECT * FROM t1;
+
+CREATE TABLE t2 (c1 BIGINT);
+INSERT INTO t2 VALUES('15449237462.0000000000');
+SELECT * FROM t2;
+
+DROP TABLE t1, t2;
+
 --echo End of 5.0 tests.
 

strings/ctype-simple.c

@@ -1538,14 +1538,18 @@ my_strntoull10rnd_8bit(CHARSET_INFO *cs __attribute__((unused)),
       }
       else
         addon= (*str >= '5');
-      for ( ; str < end && (ch= (unsigned char) (*str - '0')) < 10; str++)
+      if (!dot)
       {
-        if (!dot)
-          shift++;
+        for ( ; str < end && (ch= (unsigned char) (*str - '0')) < 10; shift++, str++);
+        if (str < end && *str == '.')
+        {
+          str++;
+          for ( ; str < end && (ch= (unsigned char) (*str - '0')) < 10; str++);
+        }
       }
-      if (str < end && *str == '.' && !dot)
+      else
       {
-        str++;
+        shift= dot - str;
         for ( ; str < end && (ch= (unsigned char) (*str - '0')) < 10; str++);
       }
       goto exp;