Add serialize/deserialize example.

examples/serialize_deserialize.rs

@@ -1,11 +1,51 @@
-use raw_cpuid::CpuId;
+//! An example that serializes CpuId state, deserializes it back and passes it to a
+//! CpuId instance with a custom reader.
+//!
+//! Run using:
+//! `cargo run --features serialize --features serde_json --example serialize_deserialize`
 
-fn take_cpuid(cpuid: CpuId) -> CpuId {
-    cpuid
+use raw_cpuid::{CpuId, CpuIdReader, CpuIdResult};
+use std::collections::HashMap;
+
+#[derive(Clone)]
+struct HashMapCpuIdReader {
+    ht: HashMap<u64, CpuIdResult>,
 }
 
+impl CpuIdReader for HashMapCpuIdReader {
+    fn cpuid2(&self, eax: u32, ecx: u32) -> CpuIdResult {
+        let key = (eax as u64) << u32::BITS | ecx as u64;
+        self.ht
+            .get(&key)
+            .unwrap_or(&CpuIdResult {
+                eax: 0,
+                ebx: 0,
+                ecx: 0,
+                edx: 0,
+            })
+            .clone()
+    }
+}
 
 fn main() {
-    let cpuid = CpuId::new();
+    let mut ht = HashMap::new();
+    ht.insert(
+        0x00000000_00000000u64,
+        CpuIdResult {
+            eax: 0x00000020,
+            ebx: 0x756e6547,
+            ecx: 0x6c65746e,
+            edx: 0x49656e69,
+        },
+    );
 
-}
+    // Serialize to JSON and back
+    let cpuid_as_json = serde_json::to_string(&ht).unwrap();
+    let deserialized_ht: HashMap<u64, CpuIdResult> = serde_json::from_str(&cpuid_as_json).unwrap();
+
+    // Create a CpuId instance with a custom reader
+    let cpuid = CpuId::with_cpuid_reader(HashMapCpuIdReader {
+        ht: deserialized_ht,
+    });
+    assert!(cpuid.get_vendor_info().unwrap().as_str() == "GenuineIntel");
+}

src/lib.rs

@@ -347,7 +347,7 @@ impl<R: CpuIdReader> CpuId<R> {
     ///
     /// This is useful for example when testing code or if we want to interpose
     /// on the CPUID calls this library makes.
-    pub fn with_cpuid_fn(cpuid_fn: R) -> Self {
+    pub fn with_cpuid_reader(cpuid_fn: R) -> Self {
         let vendor_leaf = cpuid_fn.cpuid1(EAX_VENDOR_INFO);
         let extended_leaf = cpuid_fn.cpuid1(EAX_EXTENDED_FUNCTION_INFO);
         CpuId {
@@ -358,6 +358,15 @@ impl<R: CpuIdReader> CpuId<R> {
         }
     }
 
+    /// See [`CpuId::with_cpuid_reader`].
+    ///
+    /// # Note
+    /// This function will likely be deprecated in the future. Use the identical
+    /// `with_cpuid_reader` function instead.
+    pub fn with_cpuid_fn(cpuid_fn: R) -> Self {
+        CpuId::with_cpuid_reader(cpuid_fn)
+    }
+
     /// Check if a non extended leaf  (`val`) is supported.
     fn leaf_is_supported(&self, val: u32) -> bool {
         // Exclude reserved functions/leafs on AMD