OffsetContainer serialization (#1093)

* OffsetContainer with unit tests.

* State serialization working with OffsetContainer.

* Fixes to make work with OffsetContainer.

* Added OffsetContainer documentation.

* Remove RelativeContainer.

* Fix problem with + on Offset32Ptr on windows x86 target.

* * Made OffsetBase a base class of OffsetContainer.
* Added MemoryOffsetBase to just handle being a chunk of memory.

* * Use operator[] to access contents of OffsetContainer

* Fix the type hash to work across different size_t sizes.

* Fixed some Offset type related comments.

* Fix bug around using asBase, because it returns a reference just using 'auto' will means it becomes a value type.
Remove assignment and copy ctor from OffsetBase.

* Evaluation order of assignment can lead to wrong behavior with Offset32Ptr/raw pointers. Document the fact, and fix in StateSerializeUtil.

4 files changed, 121 insertions, 96 deletions

diff --git a/tools/slang-test/slang-test.vcxproj b/tools/slang-test/slang-test.vcxproj
index d1326d655..b22a3fe60 100644
--- a/tools/slang-test/slang-test.vcxproj
+++ b/tools/slang-test/slang-test.vcxproj
@@ -175,7 +175,7 @@
     <ClCompile Include="slangc-tool.cpp" />
     <ClCompile Include="test-context.cpp" />
     <ClCompile Include="test-reporter.cpp" />
-    <ClCompile Include="unit-relative-container.cpp" />
+    <ClCompile Include="unit-offset-container.cpp" />
     <ClCompile Include="unit-test-byte-encode.cpp" />
     <ClCompile Include="unit-test-free-list.cpp" />
     <ClCompile Include="unit-test-memory-arena.cpp" />
diff --git a/tools/slang-test/slang-test.vcxproj.filters b/tools/slang-test/slang-test.vcxproj.filters
index 9bf6f9b26..b88490559 100644
--- a/tools/slang-test/slang-test.vcxproj.filters
+++ b/tools/slang-test/slang-test.vcxproj.filters
@@ -44,7 +44,7 @@
     <ClCompile Include="test-reporter.cpp">
       <Filter>Source Files</Filter>
     </ClCompile>
-    <ClCompile Include="unit-relative-container.cpp">
+    <ClCompile Include="unit-offset-container.cpp">
       <Filter>Source Files</Filter>
     </ClCompile>
     <ClCompile Include="unit-test-byte-encode.cpp">
diff --git a/tools/slang-test/unit-offset-container.cpp b/tools/slang-test/unit-offset-container.cpp
new file mode 100644
index 000000000..d0990d9bb
--- /dev/null
+++ b/tools/slang-test/unit-offset-container.cpp
@@ -0,0 +1,119 @@
+// unit-test-path.cpp
+
+#include "../../source/core/slang-offset-container.h"
+
+#include "test-context.h"
+
+using namespace Slang;
+
+static void _checkEncodeDecode(uint32_t size)
+{
+    uint8_t encode[OffsetString::kMaxSizeEncodeSize];
+
+    size_t encodeSize = OffsetString::calcEncodedSize(size, encode);
+
+    size_t decodedSize;
+    const char* chars = OffsetString::decodeSize((const char*)encode, decodedSize);
+
+    SLANG_CHECK(decodedSize == size);
+    SLANG_CHECK(chars - (const char*)encode == encodeSize);
+}
+
+namespace { // anonymous
+
+struct Root
+{
+    Offset32Array<Offset32Ptr<OffsetString> > dirs;
+    Offset32Ptr<OffsetString> name;
+    float value;
+};
+
+} // anonymous
+
+static void offsetContainerUnitTest()
+{
+    _checkEncodeDecode(253);
+
+    for (int64_t i = 0; i < 0x100000000; i += (i / 2) + 1)
+    {
+        _checkEncodeDecode(uint32_t(i));
+    }
+
+    {
+        OffsetContainer container;
+        
+        const char* strings[] =
+        {
+            "Hello",
+            "World",
+            nullptr,
+        };
+
+        {
+            auto& base = container.asBase();
+
+            Offset32Ptr<Root> root = container.newObject<Root>();
+
+            auto array = container.newArray<Offset32Ptr<OffsetString>>(SLANG_COUNT_OF(strings));
+            for (Int i = 0; i < SLANG_COUNT_OF(strings); ++i)
+            {
+                base[array[i]] = container.newString(strings[i]);
+            }
+            base[root]->dirs = array;
+        }
+
+        {
+            List<uint8_t> copy;
+            copy.addRange(container.getData(), container.getDataCount());
+            
+            MemoryOffsetBase base;
+            base.set(copy.getBuffer(), copy.getCount());
+
+            Root* root = (Root*)(copy.getBuffer() + kStartOffset);
+
+            SLANG_CHECK(root->dirs.getCount() == SLANG_COUNT_OF(strings));
+
+            Int count = root->dirs.getCount();
+            for (Int i = 0; i < count; ++i)
+            {
+                OffsetString* str = base.asRaw(base.asRaw(root->dirs[i]));
+
+                const char* check = strings[i];
+
+                if (check)
+                {
+                    SLANG_CHECK(str != nullptr);
+                    const char* strCstr = str->getCstr();
+                    SLANG_CHECK(strcmp(strCstr, check) == 0);
+                }
+                else
+                {
+                    SLANG_CHECK(str == nullptr);
+                }
+            }
+
+            {
+                Index index = 0;
+                for (const auto v : root->dirs)
+                {
+                    OffsetString* str = base.asRaw(base.asRaw(v));
+                    const char* check = strings[index];
+                    if (check)
+                    {
+                        SLANG_CHECK(str != nullptr);
+                        const char* strCstr = str->getCstr();
+                        SLANG_CHECK(strcmp(strCstr, check) == 0);
+                    }
+                    else
+                    {
+                        SLANG_CHECK(str == nullptr);
+                    }
+
+                    index ++;
+                }
+            }
+        }
+    }
+}
+
+SLANG_UNIT_TEST("OffsetContainer", offsetContainerUnitTest);
diff --git a/tools/slang-test/unit-relative-container.cpp b/tools/slang-test/unit-relative-container.cpp
deleted file mode 100644
index a9ff7c0fe..000000000
--- a/tools/slang-test/unit-relative-container.cpp
+++ /dev/null
@@ -1,94 +0,0 @@
-// unit-test-path.cpp
-
-#include "../../source/core/slang-relative-container.h"
-
-#include "test-context.h"
-
-using namespace Slang;
-
-static void _checkEncodeDecode(uint32_t size)
-{
-    uint8_t encode[RelativeString::kMaxSizeEncodeSize];
-
-    size_t encodeSize = RelativeString::calcEncodedSize(size, encode);
-
-    size_t decodedSize;
-    const char* chars = RelativeString::decodeSize((const char*)encode, decodedSize);
-
-    SLANG_CHECK(decodedSize == size);
-    SLANG_CHECK(chars - (const char*)encode == encodeSize);
-}
-
-namespace { // anonymous
-
-struct Root
-{
-    Relative32Array<Relative32Ptr<RelativeString> > dirs;
-    Relative32Ptr<RelativeString> name;
-    float value;
-};
-
-} // anonymous
-
-static void relativeContainerUnitTest()
-{
-    _checkEncodeDecode(253);
-
-    for (int64_t i = 0; i < 0x100000000; i += (i / 2) + 1)
-    {
-        _checkEncodeDecode(uint32_t(i));
-    }
-
-    {
-        RelativeContainer container;
-
-        const char* strings[] =
-        {
-            "Hello",
-            "World",
-            nullptr,
-        };
-
-        {
-            Safe32Ptr<Root> root = container.newObject<Root>();
-
-            auto array = container.newArray<Relative32Ptr<RelativeString>>(SLANG_COUNT_OF(strings));
-            for (Int i = 0; i < SLANG_COUNT_OF(strings); ++i)
-            {
-                array[i] = container.newString(strings[i]);
-            }
-
-            root->dirs = array;
-        }
-
-        {
-            RelativeContainer copy;
-            copy.set(container.getData(), container.getDataCount()); 
-
-            Root* root = (Root*)copy.getData();
-
-            SLANG_CHECK(root->dirs.getCount() == SLANG_COUNT_OF(strings));
-
-            Int count = root->dirs.getCount();
-            for (Int i = 0; i < count; ++i)
-            {
-                RelativeString* str = root->dirs[i];
-
-                const char* check = strings[i];
-
-                if (check)
-                {
-                    SLANG_CHECK(str != nullptr);
-                    const char* strCstr = str->getCstr();
-                    SLANG_CHECK(strcmp(strCstr, check) == 0);
-                }
-                else
-                {
-                    SLANG_CHECK(str == nullptr);
-                }
-            }
-        }
-    }
-}
-
-SLANG_UNIT_TEST("RelativeContainer", relativeContainerUnitTest);