// compile with: g++ -rdynamic -c -std=c++11 -o caller.o getcaller.cpp
#include <string>

#include <execinfo.h>
#define BT_BUF_SIZE 10

#include <memory.h>
#include <stdlib.h>
#include <sstream>

static int depth = 2;

std::string demangle(std::string& in) {
	if(in.size() < 5) return in;
	if(in.find("_Z") > 0) return in;

	std::ostringstream out;
	std::istringstream is(in.substr(2));
	bool first = true;
	while(is) {
		char c = is.peek();
		while(c == 'N' || c == 'K') {
			is.get();
			c = is.peek();
		}
		unsigned int len = 0;
		is >> len;
		if(len == 0)
			break;
		if(!first)
			out << "::";
		first = false;

		char* buf = new char[len+1];
		buf[len] = '\0';
		is.read(buf, len);
		out << buf;
		delete[] buf;
	}
	return out.str();
}

std::string getCaller() {
	if(depth+1 > BT_BUF_SIZE) return "UNKNOWN";
	void* buffer[BT_BUF_SIZE];
	int nptrs = backtrace(buffer, BT_BUF_SIZE);

	char** strings = backtrace_symbols(buffer, nptrs);
	if (!strings)
		return "UNKNOWN";
	std::string out(strings[depth]);
	free(strings);
	size_t startoffset = out.rfind('(')+1;
	size_t plusoffset = out.find('+', startoffset)-1;
	if(plusoffset == std::string::npos)
		return "UNKNOWN";

	out = out.substr(startoffset, plusoffset-startoffset);
	return demangle(out);
}