From ae65fb6808a2de39646d9cf0fa878ae7ed1b6b4a Mon Sep 17 00:00:00 2001
From: Burkhard Mittelbach <wasabi37a@googlemail.com>
Date: Sun, 14 Jul 2024 15:47:37 +0200
Subject: [PATCH] Add size and len for PageRange, PhysFrameRange etc

---
 Changelog.md                   |  4 +++
 src/structures/paging/frame.rs | 49 ++++++++++++++++++++++++++++++++++
 src/structures/paging/page.rs  | 45 +++++++++++++++++++++++++++++++
 3 files changed, 98 insertions(+)

diff --git a/Changelog.md b/Changelog.md
index 10772bf7..f517e673 100644
--- a/Changelog.md
+++ b/Changelog.md
@@ -1,5 +1,9 @@
 # Unreleased
 
+## New Features
+
+- [add `size` and `len` for `PageRange`, `PhysFrameRange`, `PageRangeInclusive` and `PhysFrameRangeInclusive`](https://github.com/rust-osdev/x86_64/pull/491)
+
 # 0.15.1 – 2024-03-19
 
 ## New Features
diff --git a/src/structures/paging/frame.rs b/src/structures/paging/frame.rs
index 1e5862b6..c4a8c97a 100644
--- a/src/structures/paging/frame.rs
+++ b/src/structures/paging/frame.rs
@@ -148,6 +148,22 @@ impl<S: PageSize> PhysFrameRange<S> {
     pub fn is_empty(&self) -> bool {
         self.start >= self.end
     }
+
+    /// Returns the number of frames in the range.
+    #[inline]
+    pub fn len(&self) -> u64 {
+        if !self.is_empty() {
+            self.end - self.start
+        } else {
+            0
+        }
+    }
+
+    /// Returns the size in bytes of all frames within the range.
+    #[inline]
+    pub fn size(&self) -> u64 {
+        S::SIZE * self.len()
+    }
 }
 
 impl<S: PageSize> Iterator for PhysFrameRange<S> {
@@ -190,6 +206,22 @@ impl<S: PageSize> PhysFrameRangeInclusive<S> {
     pub fn is_empty(&self) -> bool {
         self.start > self.end
     }
+
+    /// Returns the number of frames in the range.
+    #[inline]
+    pub fn len(&self) -> u64 {
+        if !self.is_empty() {
+            self.end - self.start + 1
+        } else {
+            0
+        }
+    }
+
+    /// Returns the size in bytes of all frames within the range.
+    #[inline]
+    pub fn size(&self) -> u64 {
+        S::SIZE * self.len()
+    }
 }
 
 impl<S: PageSize> Iterator for PhysFrameRangeInclusive<S> {
@@ -215,3 +247,20 @@ impl<S: PageSize> fmt::Debug for PhysFrameRangeInclusive<S> {
             .finish()
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    #[test]
+    pub fn test_frame_range_len() {
+        let start_addr = PhysAddr::new(0xdead_beaf);
+        let start = PhysFrame::<Size4KiB>::containing_address(start_addr);
+        let end = start + 50;
+
+        let range = PhysFrameRange { start, end };
+        assert_eq!(range.len(), 50);
+
+        let range_inclusive = PhysFrameRangeInclusive { start, end };
+        assert_eq!(range_inclusive.len(), 51);
+    }
+}
diff --git a/src/structures/paging/page.rs b/src/structures/paging/page.rs
index 445abd26..55720cf4 100644
--- a/src/structures/paging/page.rs
+++ b/src/structures/paging/page.rs
@@ -327,6 +327,22 @@ impl<S: PageSize> PageRange<S> {
     pub fn is_empty(&self) -> bool {
         self.start >= self.end
     }
+
+    /// Returns the number of pages in the range.
+    #[inline]
+    pub fn len(&self) -> u64 {
+        if !self.is_empty() {
+            self.end - self.start
+        } else {
+            0
+        }
+    }
+
+    /// Returns the size in bytes of all pages within the range.
+    #[inline]
+    pub fn size(&self) -> u64 {
+        S::SIZE * self.len()
+    }
 }
 
 impl<S: PageSize> Iterator for PageRange<S> {
@@ -380,6 +396,22 @@ impl<S: PageSize> PageRangeInclusive<S> {
     pub fn is_empty(&self) -> bool {
         self.start > self.end
     }
+
+    /// Returns the number of frames in the range.
+    #[inline]
+    pub fn len(&self) -> u64 {
+        if !self.is_empty() {
+            self.end - self.start + 1
+        } else {
+            0
+        }
+    }
+
+    /// Returns the size in bytes of all frames within the range.
+    #[inline]
+    pub fn size(&self) -> u64 {
+        S::SIZE * self.len()
+    }
 }
 
 impl<S: PageSize> Iterator for PageRangeInclusive<S> {
@@ -484,4 +516,17 @@ mod tests {
         }
         assert_eq!(range_inclusive.next(), None);
     }
+
+    #[test]
+    pub fn test_page_range_len() {
+        let start_addr = VirtAddr::new(0xdead_beaf);
+        let start = Page::<Size4KiB>::containing_address(start_addr);
+        let end = start + 50;
+
+        let range = PageRange { start, end };
+        assert_eq!(range.len(), 50);
+
+        let range_inclusive = PageRangeInclusive { start, end };
+        assert_eq!(range_inclusive.len(), 51);
+    }
 }