From 43931c7e187bda85e2be12bccb14bd826a6c34c0 Mon Sep 17 00:00:00 2001
From: Markus Mittendrein <git@maxmitti.tk>
Date: Sat, 20 Apr 2019 01:54:54 +0200
Subject: Add custom memory management strategies to cppc4group

---
 src/cppc4group.cpp | 81 ++++++++++++++++++++++++++++++++++++++++++++----------
 1 file changed, 66 insertions(+), 15 deletions(-)

(limited to 'src/cppc4group.cpp')

diff --git a/src/cppc4group.cpp b/src/cppc4group.cpp
index 2d85537..329d6de 100644
--- a/src/cppc4group.cpp
+++ b/src/cppc4group.cpp
@@ -39,6 +39,66 @@ struct CppC4Group::Private {
 	}
 };
 
+struct CppC4Group::MemoryManagement::Private {
+	bool predefined;
+	MemoryManagementStrategy strategy;
+
+	Start start;
+	End end;
+};
+
+CppC4Group::MemoryManagement::MemoryManagement(MemoryManagementStrategy strategy) : p{new Private{true, strategy}}
+{
+
+}
+
+CppC4Group::MemoryManagement::MemoryManagement(Start&& start, End&& end) : p{new Private{false, {}, start, end}}
+{
+
+}
+
+CppC4Group::MemoryManagement::~MemoryManagement()
+{
+	delete p;
+}
+
+CppC4Group::MemoryManagement::MemoryManagementStrategy CppC4Group::MemoryManagement::operator()() const
+{
+	if(p->predefined)
+	{
+		return p->strategy;
+	}
+	else
+	{
+		struct CustomMemoryManagement {
+			CC4Group_MemoryManagement_t realMemoryManagement;
+
+			Start start;
+			End end;
+
+			static void* callStart(void* const data, size_t const size, void* const arg)
+			{
+				return reinterpret_cast<CustomMemoryManagement*>(arg)->start(data, size);
+			}
+
+			static void callEndAndCleanup(void* const data, void* const arg)
+			{
+				auto customMemoryManagement = reinterpret_cast<CustomMemoryManagement*>(arg);
+				customMemoryManagement->end(data);
+				delete customMemoryManagement;
+			}
+		};
+
+		auto customManagement = new CustomMemoryManagement{{CustomMemoryManagement::callStart, CustomMemoryManagement::callEndAndCleanup}, p->start, p->end};
+		customManagement->realMemoryManagement.arg = static_cast<void*>(customManagement);
+		return reinterpret_cast<MemoryManagementStrategy>(&customManagement->realMemoryManagement);
+	}
+}
+
+const CppC4Group::MemoryManagement CppC4Group::MemoryManagement::Take{reinterpret_cast<MemoryManagement::MemoryManagementStrategy>(cc4group.MemoryManagement.Take)};
+const CppC4Group::MemoryManagement CppC4Group::MemoryManagement::Copy{reinterpret_cast<MemoryManagement::MemoryManagementStrategy>(cc4group.MemoryManagement.Copy)};
+const CppC4Group::MemoryManagement CppC4Group::MemoryManagement::Reference{reinterpret_cast<MemoryManagement::MemoryManagementStrategy>(cc4group.MemoryManagement.Reference)};
+
 namespace {
 	CC4Group_TmpMemoryStrategy convertTmpMemoryStrategy(const CppC4Group::TmpMemoryStrategy strategy)
 	{
@@ -54,22 +114,13 @@ namespace {
 		return cc4group.TmpMemoryStrategies.Auto;
 	}
 
-	CC4Group_MemoryManagement convertMemoryManagement(const CppC4Group::MemoryManagement management)
+	CC4Group_MemoryManagement convertMemoryManagement(const CppC4Group::MemoryManagement& memoryManagement)
 	{
-		switch(management)
-		{
-			case CppC4Group::Take:
-				return cc4group.MemoryManagement.Take;
-			case CppC4Group::Copy:
-				return cc4group.MemoryManagement.Copy;
-			case CppC4Group::Reference:
-				return cc4group.MemoryManagement.Reference;
-		}
-		return cc4group.MemoryManagement.Copy;
+		return reinterpret_cast<CC4Group_MemoryManagement>(memoryManagement());
 	}
 }
 
-CppC4Group::CppC4Group() : p{new CppC4Group::Private{}}
+CppC4Group::CppC4Group() : p{new Private{}}
 {
 
 }
@@ -110,12 +161,12 @@ bool CppC4Group::openFilePointer(FILE* file)
 	return cc4group.openFilePointer(p->g, file);
 }
 
-bool CppC4Group::openMemory(const void* const data, const size_t size, const MemoryManagement management)
+bool CppC4Group::openMemory(const void* const data, const size_t size, const MemoryManagement& management)
 {
 	return cc4group.openMemory(p->g, data, size, convertMemoryManagement(management));
 }
 
-bool CppC4Group::openWithReadCallback(const ReadCallback callback, void* const callbackArg, const MemoryManagement management, SetupCallback initCallback, SetupCallback deinitCallback)
+bool CppC4Group::openWithReadCallback(const ReadCallback callback, void* const callbackArg, const MemoryManagement& management, SetupCallback initCallback, SetupCallback deinitCallback)
 {
 	return cc4group.openWithReadCallback(p->g, callback, callbackArg, convertMemoryManagement(management), initCallback, deinitCallback);
 }
@@ -311,7 +362,7 @@ bool CppC4Group::createFile(const std::string& path)
 	return cc4group.createFile(p->g, path.c_str());
 }
 
-bool CppC4Group::setEntryData(const std::string& path, const void*const data, const size_t size, const MemoryManagement management)
+bool CppC4Group::setEntryData(const std::string& path, const void*const data, const size_t size, const MemoryManagement& management)
 {
 	return cc4group.setEntryData(p->g, path.c_str(), data, size, convertMemoryManagement(management));
 }
-- 
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