feat(rands): initial implementation

ints.go

@@ -0,0 +1,37 @@
+package rands
+
+import (
+	"crypto/rand"
+	"fmt"
+	"math/big"
+)
+
+var errInvalidMaxInt = fmt.Errorf("%w: max cannot be less than 1", errBase)
+
+// Int generates a random int ranging between 0 and max.
+func Int(max int) (int, error) {
+	if max < 1 {
+		return 0, errInvalidMaxInt
+	}
+
+	r, err := rand.Int(rand.Reader, big.NewInt(int64(max)))
+	if err != nil {
+		return 0, err
+	}
+
+	return int(r.Int64()), nil
+}
+
+// Int64 generates a random int64 ranging between 0 and max.
+func Int64(max int64) (int64, error) {
+	if max < 1 {
+		return 0, errInvalidMaxInt
+	}
+
+	r, err := rand.Int(rand.Reader, big.NewInt(max))
+	if err != nil {
+		return 0, err
+	}
+
+	return r.Int64(), nil
+}