util: convenience utilities for fscrypt

This commit adds in the util package. This package provides
two functions for creating errors. These functions are:
	- InvalidInputErrorF - bad input from user or caller
	- SystemErrorF - low level failure

It also adds in a small function for converting Go byte slices into C
void pointers. This will be very useful for interoperating with C.

Change-Id: I87ad7946dd5fa26e28927590aff4bcc9fd5ce4f7

1 files changed, 33 insertions, 0 deletions

diff --git a/util/util.go b/util/util.go
new file mode 100644
index 0000000..9439d0e
--- /dev/null
+++ b/util/util.go
@@ -0,0 +1,33 @@
+/*
+ * util.go - Various helpers used throughout fscrypt
+ *
+ * Copyright 2017 Google Inc.
+ * Author: Joe Richey (joerichey@google.com)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+// Package util contains useful components for simplifying Go code.
+//
+// The package contains common error types (errors.go) and functions for
+// converting arrays to pointers.
+package util
+
+import (
+	"unsafe"
+)
+
+// Ptr converts an Go byte array to a pointer to the start of the array.
+func Ptr(slice []byte) unsafe.Pointer {
+	return unsafe.Pointer(&slice[0])
+}