From 4ad36769342ae8f817e4956cf4ae8a28c9a6768e Mon Sep 17 00:00:00 2001
From: Kristin Laemmert <mildwonkey@users.noreply.github.com>
Date: Wed, 23 May 2018 12:41:55 -0700
Subject: [PATCH] port ceil function

---
 lang/funcs/number.go      | 33 ++++++++++++++++++++++++++++
 lang/funcs/number_test.go | 46 +++++++++++++++++++++++++++++++++++++++
 lang/functions.go         |  2 +-
 3 files changed, 80 insertions(+), 1 deletion(-)
 create mode 100644 lang/funcs/number.go
 create mode 100644 lang/funcs/number_test.go

diff --git a/lang/funcs/number.go b/lang/funcs/number.go
new file mode 100644
index 000000000..930b8ed48
--- /dev/null
+++ b/lang/funcs/number.go
@@ -0,0 +1,33 @@
+package funcs
+
+import (
+	"math"
+
+	"github.com/zclconf/go-cty/cty"
+	"github.com/zclconf/go-cty/cty/function"
+	"github.com/zclconf/go-cty/cty/gocty"
+)
+
+// CeilFunc contructs a function that returns the closest whole number greater
+// than or equal to the given value.
+var CeilFunc = function.New(&function.Spec{
+	Params: []function.Parameter{
+		{
+			Name: "num",
+			Type: cty.Number,
+		},
+	},
+	Type: function.StaticReturnType(cty.Number),
+	Impl: func(args []cty.Value, retType cty.Type) (ret cty.Value, err error) {
+		var val float64
+		if err := gocty.FromCtyValue(args[0], &val); err != nil {
+			return cty.UnknownVal(cty.String), err
+		}
+		return cty.NumberIntVal(int64(math.Ceil(val))), nil
+	},
+})
+
+// Ceil returns the closest whole number greater than or equal to the given value.
+func Ceil(num cty.Value) (cty.Value, error) {
+	return CeilFunc.Call([]cty.Value{num})
+}
diff --git a/lang/funcs/number_test.go b/lang/funcs/number_test.go
new file mode 100644
index 000000000..30896c2bb
--- /dev/null
+++ b/lang/funcs/number_test.go
@@ -0,0 +1,46 @@
+package funcs
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/zclconf/go-cty/cty"
+)
+
+func TestCeil(t *testing.T) {
+	tests := []struct {
+		Num  cty.Value
+		Want cty.Value
+		Err  bool
+	}{
+		{
+			cty.NumberFloatVal(-1.8),
+			cty.NumberFloatVal(-1),
+			false,
+		},
+		{
+			cty.NumberFloatVal(1.2),
+			cty.NumberFloatVal(2),
+			false,
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(fmt.Sprintf("Ceil(%#v)", test.Num), func(t *testing.T) {
+			got, err := Ceil(test.Num)
+
+			if test.Err {
+				if err == nil {
+					t.Fatal("succeeded; want error")
+				}
+				return
+			} else if err != nil {
+				t.Fatalf("unexpected error: %s", err)
+			}
+
+			if !got.RawEquals(test.Want) {
+				t.Errorf("wrong result\ngot:  %#v\nwant: %#v", got, test.Want)
+			}
+		})
+	}
+}
diff --git a/lang/functions.go b/lang/functions.go
index 7a9e9d5dd..93e2bdc3b 100644
--- a/lang/functions.go
+++ b/lang/functions.go
@@ -37,7 +37,7 @@ func (s *Scope) Functions() map[string]function.Function {
 			"base64sha256": funcs.Base64Sha256Func,
 			"base64sha512": funcs.Base64Sha512Func,
 			"bcrypt":       funcs.BcryptFunc,
-			"ceil":         unimplFunc, // TODO
+			"ceil":         funcs.CeilFunc,
 			"chomp":        unimplFunc, // TODO
 			"cidrhost":     unimplFunc, // TODO
 			"cidrnetmask":  unimplFunc, // TODO