From b9e025a6dd499b8eca478bd56c824fc023c7df1e Mon Sep 17 00:00:00 2001
From: Michael Davidsaver <mdavidsaver@gmail.com>
Date: Fri, 3 Jul 2020 20:52:21 -0700
Subject: [PATCH] Value::compareType() -> Value::equalType()

---
 src/data.cpp      | 47 +++++++++++++++++++++++++++++++++++++++++++++++
 src/pvxs/data.h   | 12 ++++++++----
 test/testdata.cpp | 13 ++++++++-----
 3 files changed, 63 insertions(+), 9 deletions(-)

diff --git a/src/data.cpp b/src/data.cpp
index ddddba7..cb783a2 100644
--- a/src/data.cpp
+++ b/src/data.cpp
@@ -284,6 +284,53 @@ bool Value::idStartsWith(const std::string& prefix) const
     return ID.size()>=prefix.size() && prefix==ID.substr(0u, prefix.size());
 }
 
+bool Value::_equal(const impl::FieldDesc* A, const impl::FieldDesc* B)
+{
+    if(A==B) {
+        return true;
+
+    } else if(!A ^ !B) {
+        return false;
+
+    } else if(!A) { // !A && !B
+        return true;
+
+    } else if(A->size()!=B->size()) {
+        return false;
+    }
+
+    for(auto i : range(A->size())) {
+        if(A[i].code!=B[i].code)
+            return false;
+
+        if(A[i].code==TypeCode::StructA || A[i].code==TypeCode::UnionA) {
+            if(!_equal(&A[i].members[0], &B[i].members[0]))
+                return false;
+
+        } else if(A[i].code==TypeCode::Struct || A[i].code==TypeCode::Union) {
+            auto it = A[i].mlookup.begin();
+            auto end= A[i].mlookup.end();
+            auto it2= B[i].mlookup.begin();
+
+            for(;it!=end; ++it, ++it2) {
+                if(it->first!=it2->first) {
+                    return false; // different field name
+
+                } else if(it->second!=it2->second) {
+                    return false; // different field order
+
+                } else if(A[i].code==TypeCode::Union) {
+                    if(!_equal(&A[i].members[it->second], &B[i].members[it2->second]))
+                        return false;
+
+                } // else if A[i] is Struct, outer loop will reach members
+            }
+        }
+    }
+
+    return true;
+}
+
 const std::string &Value::nameOf(const Value& descendant) const
 {
     if(!store || !descendant.store)
diff --git a/src/pvxs/data.h b/src/pvxs/data.h
index ca23688..d1be4a0 100644
--- a/src/pvxs/data.h
+++ b/src/pvxs/data.h
@@ -528,10 +528,14 @@ public:
     //! Test prefix of Type ID string (Struct or Union only)
     bool idStartsWith(const std::string& prefix) const;
 
-    //! test for instance equality.
-    inline bool compareInst(const Value& o) const { return store==o.store; }
-//    int compareValue(const Value&) const;
-    inline int compareType(const Value& o) const { return desc==o.desc; }
+private:
+    static
+    bool _equal(const impl::FieldDesc* A, const impl::FieldDesc* B);
+public:
+    //! Test for instance equality.  aka. this==this
+    inline bool equalInst(const Value& o) const { return store==o.store; }
+    //! Test for equality of type only (including field names)
+    inline bool equalType(const Value& o) const { return _equal(desc, o.desc); }
 
     /** Return our name for a descendant field.
      * @code
diff --git a/test/testdata.cpp b/test/testdata.cpp
index fef98f8..1e6a88b 100644
--- a/test/testdata.cpp
+++ b/test/testdata.cpp
@@ -29,15 +29,18 @@ void testTraverse()
 
     {
         auto top2 = top["value<"];
-        testOk1(top.compareType(top2));
-        testOk1(top.compareInst(top2));
+        testOk1(top.equalType(top2));
+        testOk1(top.equalInst(top2));
     }
     {
         auto sevr1 = top["alarm.severity"];
         auto sevr2 = top["value<alarm.status<severity"];
-        testOk1(sevr1.compareType(sevr2));
-        testOk1(sevr1.compareInst(sevr2));
+        testOk1(sevr1.equalType(sevr2));
+        testOk1(sevr1.equalInst(sevr2));
     }
+
+    testFalse(top.equalType(top["alarm"]));
+    testFalse(top.equalType(top["value"]));
 }
 
 void testAssign()
@@ -261,7 +264,7 @@ void testAssignSimilar()
 
 MAIN(testdata)
 {
-    testPlan(78);
+    testPlan(80);
     testSetup();
     testTraverse();
     testAssign();