From 0420e85e4d8656595bf1d429c34b5b7b1968e611 Mon Sep 17 00:00:00 2001
From: WangRunji <wangrunji0408@163.com>
Date: Thu, 19 Apr 2018 00:22:03 +0800
Subject: [PATCH] Simple VMA & MM struct at extern crate.

---
 crate/memory/Cargo.toml        |  6 +++
 crate/memory/src/lib.rs        |  6 +++
 crate/memory/src/memory_set.rs | 89 ++++++++++++++++++++++++++++++++++
 3 files changed, 101 insertions(+)
 create mode 100644 crate/memory/Cargo.toml
 create mode 100644 crate/memory/src/lib.rs
 create mode 100644 crate/memory/src/memory_set.rs

diff --git a/crate/memory/Cargo.toml b/crate/memory/Cargo.toml
new file mode 100644
index 0000000..c914a0d
--- /dev/null
+++ b/crate/memory/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "memory"
+version = "0.1.0"
+authors = ["WangRunji <wangrunji0408@163.com>"]
+
+[dependencies]
diff --git a/crate/memory/src/lib.rs b/crate/memory/src/lib.rs
new file mode 100644
index 0000000..8eb011e
--- /dev/null
+++ b/crate/memory/src/lib.rs
@@ -0,0 +1,6 @@
+#![no_std]
+#![feature(alloc)]
+
+extern crate alloc;
+
+pub mod memory_set;
\ No newline at end of file
diff --git a/crate/memory/src/memory_set.rs b/crate/memory/src/memory_set.rs
new file mode 100644
index 0000000..7b2705f
--- /dev/null
+++ b/crate/memory/src/memory_set.rs
@@ -0,0 +1,89 @@
+use alloc::vec::Vec;
+
+type Addr = usize;
+
+/// 一片连续内存空间，有相同的访问权限
+/// 对应ucore中 `vma_struct`
+#[derive(Debug, Eq, PartialEq)]
+pub struct MemoryArea {
+    pub start_addr: Addr,
+    pub end_addr: Addr,
+    pub flags: u32,
+    pub name: &'static str,
+}
+
+impl MemoryArea {
+    pub fn contains(&self, addr: Addr) -> bool {
+        addr >= self.start_addr && addr < self.end_addr
+    }
+    fn is_overlap_with(&self, other: &MemoryArea) -> bool {
+        !(self.end_addr <= other.start_addr || self.start_addr >= other.end_addr)
+    }
+}
+
+/// 内存空间集合，包含若干段连续空间
+/// 对应ucore中 `mm_struct`
+#[derive(Debug)]
+pub struct MemorySet {
+    areas: Vec<MemoryArea>,
+}
+
+impl MemorySet {
+    pub fn new() -> Self {
+        MemorySet { areas: Vec::<MemoryArea>::new() }
+    }
+    pub fn find_area(&self, addr: Addr) -> Option<&MemoryArea> {
+        self.areas.iter().find(|area| area.contains(addr))
+    }
+    pub fn push(&mut self, area: MemoryArea) {
+        assert!(area.start_addr <= area.end_addr, "invalid memory area");
+        if self.areas.iter()
+            .find(|other| area.is_overlap_with(other))
+            .is_some() {
+            panic!("memory area overlap");
+        }
+        self.areas.push(area);
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use super::*;
+
+    #[test]
+    fn push_and_find() {
+        let mut ms = MemorySet::new();
+        ms.push(MemoryArea {
+            start_addr: 0x0,
+            end_addr: 0x8,
+            flags: 0x0,
+            name: "code",
+        });
+        ms.push(MemoryArea {
+            start_addr: 0x8,
+            end_addr: 0x10,
+            flags: 0x1,
+            name: "data",
+        });
+        assert_eq!(ms.find_area(0x6).unwrap().name, "code");
+        assert_eq!(ms.find_area(0x11), None);
+    }
+
+    #[test]
+    #[should_panic]
+    fn push_overlap() {
+        let mut ms = MemorySet::new();
+        ms.push(MemoryArea {
+            start_addr: 0x0,
+            end_addr: 0x8,
+            flags: 0x0,
+            name: "code",
+        });
+        ms.push(MemoryArea {
+            start_addr: 0x4,
+            end_addr: 0x10,
+            flags: 0x1,
+            name: "data",
+        });
+    }
+}