From 36c8661fe043c5a469b54a80fdc456d28566fbe6 Mon Sep 17 00:00:00 2001
From: Gerd Zellweger <mail@gerdzellweger.com>
Date: Fri, 15 Jul 2022 15:53:26 -0700
Subject: Implement Step for address types.

---
 CHANGELOG.md         |  8 +++++++-
 Cargo.toml           |  3 ++-
 src/bits64/paging.rs | 41 +++++++++++++++++++++++++++++++++++++++++
 src/lib.rs           |  1 +
 4 files changed, 51 insertions(+), 2 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 52cda70..7e5f69f 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,7 +7,13 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [unreleased]
 
-## [0.50.0] - 2022-07-29
+## [0.51.0] - 2022-07-15
+
+- Implement `core::iter::Step` for PAddr, VAddr, IOAddr types. This currently
+  requires nightly so added a `unstable` Cargo feature to enable it
+  conditionally.
+
+## [0.50.0] - 2022-06-29
 
 - `rdtscp` now returns a tuple in the form of `(cycles: u64, aux: u32)`, where
   `cycles` is the cycle count (as returned by this function in previous
diff --git a/Cargo.toml b/Cargo.toml
index af2eae8..fa1dcb0 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "x86"
-version = "0.50.0"
+version = "0.51.0"
 authors = [
   "Gerd Zellweger <mail@gerdzellweger.com>",
   "Eric Kidd <git@randomhacks.net>",
@@ -43,6 +43,7 @@ performance-counter = ["phf", "phf_codegen", "csv", "serde_json"]
 utest = []
 # Run VM tests, i.e., the #[x86test] ones
 vmtest = []
+unstable = []
 
 [[test]]
 name = "kvm"
diff --git a/src/bits64/paging.rs b/src/bits64/paging.rs
index 799fd43..71e6325 100644
--- a/src/bits64/paging.rs
+++ b/src/bits64/paging.rs
@@ -5,6 +5,8 @@ use bitflags::*;
 use core::convert::{From, Into};
 use core::fmt;
 use core::hash::{Hash, Hasher};
+#[cfg(feature = "unstable")]
+use core::iter::Step;
 use core::ops;
 
 macro_rules! check_flag {
@@ -160,6 +162,19 @@ impl PAddr {
     }
 }
 
+#[cfg(feature = "unstable")]
+impl Step for PAddr {
+    fn steps_between(start: &Self, end: &Self) -> Option<usize> {
+        <u64 as Step>::steps_between(&start.0, &end.0)
+    }
+    fn forward_checked(start: Self, count: usize) -> Option<Self> {
+        <u64 as Step>::forward_checked(start.0, count).map(|v| PAddr(v))
+    }
+    fn backward_checked(start: Self, count: usize) -> Option<Self> {
+        <u64 as Step>::backward_checked(start.0, count).map(|v| PAddr(v))
+    }
+}
+
 impl From<u64> for PAddr {
     fn from(num: u64) -> Self {
         PAddr(num)
@@ -487,6 +502,19 @@ impl IOAddr {
     }
 }
 
+#[cfg(feature = "unstable")]
+impl Step for IOAddr {
+    fn steps_between(start: &Self, end: &Self) -> Option<usize> {
+        <u64 as Step>::steps_between(&start.0, &end.0)
+    }
+    fn forward_checked(start: Self, count: usize) -> Option<Self> {
+        <u64 as Step>::forward_checked(start.0, count).map(|v| IOAddr(v))
+    }
+    fn backward_checked(start: Self, count: usize) -> Option<Self> {
+        <u64 as Step>::backward_checked(start.0, count).map(|v| IOAddr(v))
+    }
+}
+
 impl From<u64> for IOAddr {
     fn from(num: u64) -> Self {
         IOAddr(num)
@@ -829,6 +857,19 @@ impl VAddr {
     }
 }
 
+#[cfg(feature = "unstable")]
+impl Step for VAddr {
+    fn steps_between(start: &Self, end: &Self) -> Option<usize> {
+        <u64 as Step>::steps_between(&start.0, &end.0)
+    }
+    fn forward_checked(start: Self, count: usize) -> Option<Self> {
+        <u64 as Step>::forward_checked(start.0, count).map(|v| VAddr(v))
+    }
+    fn backward_checked(start: Self, count: usize) -> Option<Self> {
+        <u64 as Step>::backward_checked(start.0, count).map(|v| VAddr(v))
+    }
+}
+
 impl From<u64> for VAddr {
     fn from(num: u64) -> Self {
         VAddr(num)
diff --git a/src/lib.rs b/src/lib.rs
index 0c35999..42d22bc 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -3,6 +3,7 @@
 #![cfg_attr(test, allow(unused_features))]
 #![cfg_attr(all(test, feature = "vmtest"), feature(custom_test_frameworks))]
 #![cfg_attr(all(test, feature = "vmtest"), test_runner(x86test::runner::runner))]
+#![cfg_attr(feature = "unstable", feature(step_trait))]
 
 use core::arch::asm;
 #[cfg(target_arch = "x86")]
-- 
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