Report descriptor parser prototype

report_descriptor/src/usage/mod.rs

@@ -0,0 +1,75 @@
+//! # References
+//!
+//! * https://www.usb.org/sites/default/files/hut1_3_0.pdf
+
+macro_rules! usage {
+    { [$page:literal] $($i:literal $v:ident)* } => {
+        pub const PAGE: u16 = $page;
+
+        #[derive(Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
+        #[non_exhaustive]
+        pub enum Usage {
+            $($v,)*
+            Unknown(u16),
+        }
+
+        pub(crate) fn from_raw(raw: u16) -> Usage {
+            use Usage::*;
+            match raw {
+                $($i => $v,)*
+                r => Unknown(r),
+            }
+        }
+    };
+}
+
+pub mod generic_desktop;
+pub mod button;
+
+macro_rules! page {
+    { $($v:ident $m:ident)* } => {
+        #[derive(Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
+        #[non_exhaustive]
+        pub enum UsagePage {
+            $($v,)*
+            Unknown(u16),
+        }
+
+        impl UsagePage {
+            pub(crate) fn from_raw(raw: u16) -> Self {
+                match raw {
+                    $($m::PAGE => Self::$v,)*
+                    r => Self::Unknown(r),
+                }
+            }
+
+            pub(crate) fn as_raw(&self) -> u16 {
+                match self {
+                    $(Self::$v => $m::PAGE,)*
+                    Self::Unknown(n) => *n,
+                }
+            }
+        }
+
+        #[derive(Debug, PartialEq, Eq, PartialOrd, Ord, Hash)]
+        #[non_exhaustive]
+        pub enum Usage {
+            $($v($m::Usage),)*
+            Unknown(u16, u16),
+        }
+
+        impl Usage {
+            pub(crate) fn from_raw(page: u16, id: u16) -> Self {
+                match page {
+                    $($m::PAGE => Self::$v($m::from_raw(id)),)*
+                    _ => Self::Unknown(page, id),
+                }
+            }
+        }
+    };
+}
+
+page! {
+    GenericDesktop generic_desktop
+    Button button
+}