From 4e370e6ed8d6cfe3dee306dfbc298ba68722f12e Mon Sep 17 00:00:00 2001
From: gingerBill <bill@gingerbill.org>
Date: Mon, 23 Nov 2020 15:53:49 +0000
Subject: Add `equal` procedure field to `runtime.Type_Info_Struct`

---
 core/reflect/reflect.odin | 78 +++++++++++++++++++++++++++++++++++++++++++++++
 core/runtime/core.odin    |  5 +++
 2 files changed, 83 insertions(+)

(limited to 'core')

diff --git a/core/reflect/reflect.odin b/core/reflect/reflect.odin
index 947a10771..df183e2fd 100644
--- a/core/reflect/reflect.odin
+++ b/core/reflect/reflect.odin
@@ -1206,3 +1206,81 @@ as_raw_data :: proc(a: any) -> (value: rawptr, valid: bool) {
 
 	return;
 }
+
+
+not_equal :: proc(a, b: any) -> bool {
+	return !equal(a, b);
+}
+equal :: proc(a, b: any) -> bool {
+	if a == nil && b == nil {
+		return true;
+	}
+
+	if a.id != b.id {
+		return false;
+	}
+
+	if a.data == b.data {
+		return true;
+	}
+
+	t := type_info_of(a.id);
+	if .Comparable not_in t.flags {
+		return false;
+	}
+
+	if t.size == 0 {
+		return true;
+	}
+
+	if .Simple_Compare in t.flags {
+		return mem.compare_byte_ptrs((^byte)(a.data), (^byte)(b.data), t.size) == 0;
+	}
+
+	t = runtime.type_info_core(t);
+
+	#partial switch v in t.variant {
+	case Type_Info_String:
+		if v.is_cstring {
+			x := string((^cstring)(a.data)^);
+			y := string((^cstring)(b.data)^);
+			return x == y;
+		} else {
+			x := (^string)(a.data)^;
+			y := (^string)(b.data)^;
+			return x == y;
+		}
+
+	case Type_Info_Array:
+		for i in 0..<v.count {
+			x := rawptr(uintptr(a.data) + uintptr(v.elem_size*i));
+			y := rawptr(uintptr(b.data) + uintptr(v.elem_size*i));
+			if !equal(any{x, v.elem.id}, any{y, v.elem.id}) {
+				return false;
+			}
+		}
+	case Type_Info_Enumerated_Array:
+		for i in 0..<v.count {
+			x := rawptr(uintptr(a.data) + uintptr(v.elem_size*i));
+			y := rawptr(uintptr(b.data) + uintptr(v.elem_size*i));
+			if !equal(any{x, v.elem.id}, any{y, v.elem.id}) {
+				return false;
+			}
+		}
+	case Type_Info_Struct:
+		if v.equal != nil {
+			return v.equal(a.data, b.data);
+		} else {
+			for offset, i in v.offsets {
+				x := rawptr(uintptr(a.data) + offset);
+				y := rawptr(uintptr(b.data) + offset);
+				id := v.types[i].id;
+				if !equal(any{x, id}, any{y, id}) {
+					return false;
+				}
+			}
+		}
+	}
+
+	return true;
+}
diff --git a/core/runtime/core.odin b/core/runtime/core.odin
index 2989c4700..14d5c99ce 100644
--- a/core/runtime/core.odin
+++ b/core/runtime/core.odin
@@ -88,6 +88,8 @@ Type_Info_Tuple :: struct { // Only used for procedures parameters and results
 	types:        []^Type_Info,
 	names:        []string,
 };
+
+Type_Struct_Equal_Proc :: distinct proc "contextless" (rawptr, rawptr) -> bool;
 Type_Info_Struct :: struct {
 	types:        []^Type_Info,
 	names:        []string,
@@ -97,6 +99,9 @@ Type_Info_Struct :: struct {
 	is_packed:    bool,
 	is_raw_union: bool,
 	custom_align: bool,
+
+	equal: Type_Struct_Equal_Proc, // set only when the struct has .Comparable set but does not have .Simple_Compare set
+
 	// These are only set iff this structure is an SOA structure
 	soa_kind:      Type_Info_Struct_Soa_Kind,
 	soa_base_type: ^Type_Info,
-- 
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