From 13980b8cd2be2f42b9323aff1a85eac553f1e395 Mon Sep 17 00:00:00 2001
From: Avril <flanchan@cumallover.me>
Date: Sat, 26 Dec 2020 20:54:49 +0000
Subject: [PATCH] start map

---
 src/main.rs |  1 +
 src/map.rs  | 61 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 62 insertions(+)
 create mode 100644 src/map.rs

diff --git a/src/main.rs b/src/main.rs
index efaae78..26f2344 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -3,6 +3,7 @@
 
 mod state;
 mod pool;
+mod map;
 mod job;
 
 fn main() {
diff --git a/src/map.rs b/src/map.rs
new file mode 100644
index 0000000..ce9b8b0
--- /dev/null
+++ b/src/map.rs
@@ -0,0 +1,61 @@
+use std::ops::RangeBounds;
+use std::slice::SliceIndex;
+use std::{fs,io};
+use std::path::Path;
+
+use memmap::MmapMut;
+
+#[derive(Debug)]
+pub struct MemoryMapMut
+{
+    file: fs::File,
+    map: MmapMut,
+}
+
+impl AsRef<[u8]> for MemoryMapMut
+{
+    fn as_ref(&self) -> &[u8]
+    {
+	&self.map[..]
+    }
+}
+
+impl AsMut<[u8]> for MemoryMapMut
+{
+    fn as_mut(&mut self) -> &mut [u8]
+    {
+	&mut self.map[..]
+    }
+}
+
+
+impl MemoryMapMut
+{
+    #[inline] pub fn as_slice_mut(&mut self) -> &mut [u8]
+    {
+	self.as_mut()
+    }
+    #[inline] pub fn as_slice(&self) -> &[u8]
+    {
+	self.as_ref()
+    }
+    pub fn open(from: impl AsRef<Path>) -> io::Result<Self>
+    {
+	let file = fs::OpenOptions::new()
+	    .create(true)
+	    .truncate(true)
+	    .write(true)
+	    .open(from)?;
+	
+	Ok(Self{
+	    map: unsafe{ MmapMut::map_mut(&file)? },
+	    file,
+	})
+    }
+}
+
+#[inline] pub unsafe fn slice_mut<'a, 'b, T, R: RangeBounds<usize> + SliceIndex<[T], Output=[T]>>(what: &'a mut [T], range: R)-> &'b mut [T]
+where 'a: 'b
+{
+    &mut what[range]
+}