From aff81bea06f716b511a1d6f68f3db30e47e253fa Mon Sep 17 00:00:00 2001
From: Mark <alnyan@airmail.cc>
Date: Tue, 15 Sep 2020 11:35:23 +0300
Subject: [PATCH] Add configuration table iterator

---
 crates/efi/src/base.rs |  1 +
 crates/efi/src/lib.rs  | 57 +++++++++++++++++++++++++++++++++++++++++-
 src/main.rs            |  2 +-
 3 files changed, 58 insertions(+), 2 deletions(-)

diff --git a/crates/efi/src/base.rs b/crates/efi/src/base.rs
index 88ba067..6898d6a 100644
--- a/crates/efi/src/base.rs
+++ b/crates/efi/src/base.rs
@@ -77,6 +77,7 @@ impl<T> Termination for Result<T> {
     }
 }
 
+#[derive(Eq, PartialEq)]
 pub struct Guid {
     pub data1:  u32,
     pub data2:  u16,
diff --git a/crates/efi/src/lib.rs b/crates/efi/src/lib.rs
index a5b19df..93dd348 100644
--- a/crates/efi/src/lib.rs
+++ b/crates/efi/src/lib.rs
@@ -41,7 +41,62 @@ pub struct SystemTable {
     pub runtime_services:       &'static mut RuntimeServices,
     pub boot_services:          &'static mut BootServices,
     number_of_table_entries:    usize,
-    configuration_table:        *mut c_void         // TODO
+    configuration_table:        *mut ConfigurationTableRaw
+}
+
+#[repr(C)]
+struct ConfigurationTableRaw {
+    vendor_guid:    Guid,
+    vendor_table:   *mut c_void
+}
+
+pub enum ConfigurationTableEntry {
+    Acpi10Table(*mut c_void),       // RSDP
+    NotImplemented(*mut c_void)
+}
+
+pub struct ConfigurationTableIterator<'a> {
+    index:  usize,
+    st:     &'a SystemTable
+}
+
+const EFI_ACPI_10_TABLE_GUID: Guid = Guid {
+    data1: 0xeb9d2d30,
+    data2: 0x2d88,
+    data3: 0x11d3,
+    data4: [0x9a, 0x16, 0x00, 0x90, 0x27, 0x3f, 0xc1, 0x4d]
+};
+impl From<&ConfigurationTableRaw> for ConfigurationTableEntry {
+    fn from(raw: &ConfigurationTableRaw) -> Self {
+        use ConfigurationTableEntry::*;
+        match &raw.vendor_guid {
+            &EFI_ACPI_10_TABLE_GUID => Acpi10Table(raw.vendor_table),
+            _                       => NotImplemented(raw.vendor_table)
+        }
+    }
+}
+
+impl<'a> Iterator for ConfigurationTableIterator<'a> {
+    type Item = ConfigurationTableEntry;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        if self.index >= self.st.number_of_table_entries {
+            None
+        } else {
+            let raw = unsafe {&*self.st.configuration_table.offset(self.index as isize)};
+            self.index += 1;
+            Some(ConfigurationTableEntry::from(raw))
+        }
+    }
+}
+
+impl SystemTable {
+    pub fn config_iter(&self) -> ConfigurationTableIterator {
+        ConfigurationTableIterator {
+            st: self,
+            index: 0
+        }
+    }
 }
 
 static mut SYSTEM_TABLE: *mut SystemTable = null_mut();
diff --git a/src/main.rs b/src/main.rs
index 4941cdb..0a8613e 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -5,7 +5,7 @@
 extern crate efi;
 extern crate core_rt;
 
-use efi::{Status, Handle, SystemTable, system_table};
+use efi::{Status, Handle, SystemTable, ConfigurationTableEntry, system_table};
 
 #[macro_use]
 mod println;