From d8d171baa2a96a2db0f9e051325993d9abde4f11 Mon Sep 17 00:00:00 2001
From: Prem Chaitanya Prathi <chaitanyaprem@gmail.com>
Date: Fri, 16 Feb 2024 15:15:59 +0530
Subject: [PATCH] feat: add C wrapper and makefile

---
 cpp/Makefile             | 12 ++++++---
 cpp/negentropy_wrapper.h | 56 ++++++++++++++++++++++++++++++++++++++++
 2 files changed, 65 insertions(+), 3 deletions(-)
 create mode 100644 cpp/negentropy_wrapper.h

diff --git a/cpp/Makefile b/cpp/Makefile
index d90464a..c37e418 100644
--- a/cpp/Makefile
+++ b/cpp/Makefile
@@ -1,12 +1,16 @@
 # Build a shared library of negentropy
 
 #TODO: Need to add compilation flags based on OS
-INCS	= -I./ -I/opt/homebrew/include/
+INCS	= -I./ -I/opt/homebrew/include/ 
 TARGET  = libnegentropy.so
 
-.PHONY: all clean
+.PHONY: all clean install-deps
 
-all: negentropy-cpp shared-lib
+all: negentropy-cpp c-wrapper shared-lib 
+
+#TODO: Need to add compilation flags based on OS
+install-deps:
+	brew install lmdb openssl
 
 shared-lib: negentropy.o
 	g++ -o $(TARGET) negentropy.o -shared
@@ -14,6 +18,8 @@ shared-lib: negentropy.o
 negentropy-cpp:
 	g++ negentropy.h --std=c++20 -o negentropy.o $(INCS)
 
+c-wrapper:
+	g++ negentropy_wrapper.h --std=c++20 -o negentropy_wrapper.o $(INCS) -I../test/cpp/lmdbxx/include/
 
 clean: 
 	rm -f negentropy.o
\ No newline at end of file
diff --git a/cpp/negentropy_wrapper.h b/cpp/negentropy_wrapper.h
new file mode 100644
index 0000000..b59d90f
--- /dev/null
+++ b/cpp/negentropy_wrapper.h
@@ -0,0 +1,56 @@
+#pragma once
+
+#ifdef __cplusplus
+#define EXTERNC extern "C"
+#else
+#define EXTERNC
+#endif
+
+#include "negentropy.h"
+#include "negentropy/storage/BTreeLMDB.h"
+
+//This is a C-wrapper for the C++ library that helps in integrating negentropy with nim code.
+//TODO: Do error handling by catching exceptions
+
+EXTERNC void* storage_new(){
+    negentropy::storage::BTreeLMDB* storage;
+    //storage = new negentropy::storage::BTreeLMDB();
+    return storage;
+}
+
+EXTERNC void* negentropy_new(void* storage, uint64_t frameSizeLimit){
+    negentropy::storage::BTreeLMDB* lmdbStorage;
+    lmdbStorage = reinterpret_cast<negentropy::storage::BTreeLMDB*>(storage);
+
+    Negentropy<negentropy::storage::BTreeLMDB>* ne;
+    try{
+    ne = new Negentropy<negentropy::storage::BTreeLMDB>(*lmdbStorage, frameSizeLimit);
+    }catch(negentropy::err e){
+        //TODO:Find a way to return this error
+        return NULL;
+    }
+    return ne;
+}
+
+EXTERNC const char* negentropy_initiate(void* negentropy){
+    Negentropy<negentropy::storage::BTreeLMDB>* ngn_inst;
+    ngn_inst = reinterpret_cast<Negentropy<negentropy::storage::BTreeLMDB>*>(negentropy);
+
+    std::string* output = new std::string();
+    try {
+        *output = ngn_inst->initiate();
+    } catch(negentropy::err e){
+        //TODO:Find a way to return this error
+        return NULL;
+    }
+    return output->c_str();
+}
+
+EXTERNC void negentropy_setinitiator(void* negentropy){
+    Negentropy<negentropy::storage::BTreeLMDB> *ngn_inst;
+    ngn_inst = reinterpret_cast<Negentropy<negentropy::storage::BTreeLMDB>*>(negentropy);
+
+    ngn_inst->setInitiator();
+
+}
+