[feature] execution methods added

include/cvm/execute_engine/cvm_execute.hpp

@@ -17,7 +17,8 @@ class CVM
  private:
   std::string getUtf8FromConstantPool(const Classfile& cf, uint16_t index);
   const method_info* findMehodByName(const Classfile& cf, const std::string& methodName);
-  const uint8_t* getByteCode(const method_info* methodInfo);
+  const uint8_t* getByteCode(const Classfile& cf, const method_info* methodInfo);
+  void interprete(const uint8_t* byteCode, const Classfile& cf);
 };
 
 #endif  //__CVM_EXECUTE_HPP__

src/execute_engine/cvm_execute.cpp

@@ -1 +1,84 @@
 #include "../../include/cvm/execute_engine/cvm_execute.hpp"
+
+#include <stdexcept>
+
+/**
+ * Helper methods
+ * for validating execution and
+ * interpreting
+ */
+
+void validateMethod(const method_info* methodInfo, std::string methodName)
+{
+  if (methodInfo != nullptr)
+  {
+    spdlog::info("{} The given [method: {}] has been found on classfile", LOG_OK, methodName);
+  }
+  else
+  {
+    spdlog::error("{} The given [method: {}] cannot be foudn on classfile", LOG_NOK, methodName);
+    throw std::runtime_error("Method not found");
+  }
+}
+
+void validateByteCode(const uint8_t* byteCode)
+{
+  if (byteCode != nullptr)
+  {
+    spdlog::info("{} Bytcode is obtained from given method:", LOG_OK);
+  }
+  else
+  {
+    throw std::runtime_error("Could not get bytecode for given method");
+  }
+}
+
+/**
+ * Helper methods ends
+ */
+
+void CVM::execute(const Classfile& cf, const std::string& methodName)
+{
+  spdlog::info("CVM executing method: {} on parsed classfile.", methodName);
+  const method_info* methodInfo = findMehodByName(cf, methodName);
+  validateMethod(methodInfo, methodName);
+
+  const uint8_t* bytecode = getByteCode(cf, methodInfo);
+  validateByteCode(bytecode);
+}
+
+std::string CVM::getUtf8FromConstantPool(const Classfile& cf, uint16_t index)
+{
+  const cp_info& cpEntry = cf.constant_pool.at(index - 1);
+  if (cpEntry.tag == CONSTANT_Utf8)
+  {
+    return std::string(cpEntry.info.Utf8.bytes, cpEntry.info.Utf8.bytes + cpEntry.info.Utf8.length);
+  }
+  return "";
+}
+
+const method_info* CVM::findMehodByName(const Classfile& cf, const std::string& methodName)
+{
+  for (auto& method : cf.methods)
+  {
+    std::string name = getUtf8FromConstantPool(cf, method.name_index);
+    if (name == methodName)
+    {
+      return &method;
+    }
+  }
+  return nullptr;
+}
+
+const uint8_t* CVM::getByteCode(const Classfile& cf, const method_info* methodInfo)
+{
+  for (auto& attr : methodInfo->attributes)
+  {
+    std::string codeAttribute = getUtf8FromConstantPool(cf, attr.attribute_name_index);
+    if (codeAttribute == "Code")
+    {
+      return attr.info;
+    }
+  }
+  return nullptr;
+}

src/main.cpp

@@ -1,6 +1,8 @@
 #include "../include/cvm/banner.hpp"
 #include "../include/cvm/classfile/classfile.hpp"
+#include "../include/cvm/execute_engine/cvm_execute.hpp"
 #include "../include/cvm/fmt_commons.hpp"
+#include "../include/cvm/stack/cvm_stack.hpp"
 #include "../include/cvm/stack/frame.hpp"
 
 int main(int argc, char** argv)
@@ -35,7 +37,9 @@ int main(int argc, char** argv)
   Classfile cf;
   cf = cf.parseClassfile(buffer.data(), fileSize);
 
-  classFile.close();
+  CVM cvm;
+  cvm.execute(cf, "add");
 
+  classFile.close();
   return 0;
 }