ints: stricter numbers (#4939)

libs/math/safemath.go

@@ -0,0 +1,41 @@
+package math
+
+import (
+	"errors"
+	"math"
+)
+
+var ErrOverflowInt32 = errors.New("int32 overflow")
+
+// SafeAddInt32 adds two int32 integers
+// If there is an overflow this will panic
+func SafeAddInt32(a, b int32) int32 {
+	if b > 0 && (a > math.MaxInt32-b) {
+		panic(ErrOverflowInt32)
+	} else if b < 0 && (a < math.MinInt32-b) {
+		panic(ErrOverflowInt32)
+	}
+	return a + b
+}
+
+// SafeSubInt32 subtracts two int32 integers
+// If there is an overflow this will panic
+func SafeSubInt32(a, b int32) int32 {
+	if b > 0 && (a < math.MinInt32+b) {
+		panic(ErrOverflowInt32)
+	} else if b < 0 && (a > math.MaxInt32+b) {
+		panic(ErrOverflowInt32)
+	}
+	return a - b
+}
+
+// SafeConvertInt32 takes a int and checks if it overflows
+// If there is an overflow this will panic
+func SafeConvertInt32(a int64) int32 {
+	if a > math.MaxInt32 {
+		panic(ErrOverflowInt32)
+	} else if a < math.MinInt32 {
+		panic(ErrOverflowInt32)
+	}
+	return int32(a)
+}