initial commit

1 files changed, 74 insertions, 0 deletions

diff --git a/vendor/modernc.org/memory/mmap_unix.go b/vendor/modernc.org/memory/mmap_unix.go
new file mode 100644
index 0000000..de57b88
--- /dev/null
+++ b/vendor/modernc.org/memory/mmap_unix.go
@@ -0,0 +1,74 @@
+// Copyright 2011 Evan Shaw. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE-MMAP-GO file.
+
+//go:build darwin || dragonfly || freebsd || linux || (solaris && !illumos) || netbsd
+// +build darwin dragonfly freebsd linux solaris,!illumos netbsd
+
+// Modifications (c) 2017 The Memory Authors.
+
+package memory // import "modernc.org/memory"
+
+import (
+	"os"
+	"syscall"
+)
+
+const pageSizeLog = 20
+
+var (
+	osPageMask = osPageSize - 1
+	osPageSize = os.Getpagesize()
+)
+
+func unmap(addr uintptr, size int) error {
+	_, _, errno := syscall.Syscall(syscall.SYS_MUNMAP, addr, uintptr(size), 0)
+	if errno != 0 {
+		return errno
+	}
+
+	return nil
+}
+
+// pageSize aligned.
+func mmap(size int) (uintptr, int, error) {
+	size = roundup(size, osPageSize)
+
+	// The actual mmap syscall varies by architecture. mmapSyscall provides same
+	// functionality as the unexported funtion syscall.mmap and is declared in
+	// mmap_*_*.go and mmap_fallback.go. To add support for a new architecture,
+	// check function mmap in src/syscall/syscall_*_*.go or
+	// src/syscall/zsyscall_*_*.go in Go's source code.
+	p, err := mmapSyscall(0, uintptr(size+pageSize), syscall.PROT_READ|syscall.PROT_WRITE, syscall.MAP_PRIVATE|syscall.MAP_ANON, -1, 0)
+	if err != nil {
+		return 0, 0, err
+	}
+
+	n := size + pageSize
+	if p&uintptr(osPageMask) != 0 {
+		panic("internal error")
+	}
+
+	mod := int(p) & pageMask
+	if mod != 0 {
+		m := pageSize - mod
+		if err := unmap(p, m); err != nil {
+			return 0, 0, err
+		}
+
+		n -= m
+		p += uintptr(m)
+	}
+
+	if p&uintptr(pageMask) != 0 {
+		panic("internal error")
+	}
+
+	if n-size != 0 {
+		if err := unmap(p+uintptr(size), n-size); err != nil {
+			return 0, 0, err
+		}
+	}
+
+	return p, size, nil
+}