Initial QSfera import

Server/vendor/github.com/dgraph-io/ristretto/z/mmap.go

@@ -0,0 +1,44 @@
+/*
+ * Copyright 2019 Dgraph Labs, Inc. and Contributors
+ *
+ * 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 z
+
+import (
+	"os"
+)
+
+// Mmap uses the mmap system call to memory-map a file. If writable is true,
+// memory protection of the pages is set so that they may be written to as well.
+func Mmap(fd *os.File, writable bool, size int64) ([]byte, error) {
+	return mmap(fd, writable, size)
+}
+
+// Munmap unmaps a previously mapped slice.
+func Munmap(b []byte) error {
+	return munmap(b)
+}
+
+// Madvise uses the madvise system call to give advise about the use of memory
+// when using a slice that is memory-mapped to a file. Set the readahead flag to
+// false if page references are expected in random order.
+func Madvise(b []byte, readahead bool) error {
+	return madvise(b, readahead)
+}
+
+// Msync would call sync on the mmapped data.
+func Msync(b []byte) error {
+	return msync(b)
+}