From aa49e41a80d322575553598fb6f299f8e53b8e4a Mon Sep 17 00:00:00 2001
From: Stephen Seo <seo.disparate@gmail.com>
Date: Mon, 10 May 2021 14:32:47 +0900
Subject: [PATCH] Impl arg parsing

---
 cpp_impl/src/argparse.cpp | 62 ++++++++++++++++++++++++++++++++++++++-
 cpp_impl/src/argparse.hpp |  7 ++++-
 cpp_impl/src/main.cpp     |  8 +++++
 3 files changed, 75 insertions(+), 2 deletions(-)

diff --git a/cpp_impl/src/argparse.cpp b/cpp_impl/src/argparse.cpp
index aa6dbc7..611ab24 100644
--- a/cpp_impl/src/argparse.cpp
+++ b/cpp_impl/src/argparse.cpp
@@ -1,7 +1,67 @@
 #include "argparse.hpp"
 
-std::unordered_map<std::string, std::string> ArgParse::parseArgs(int argc, char **argv) {
+#include <cstring>
+#include <stdexcept>
+
+std::unordered_map<std::string, std::string> ArgParse::parseArgs(
+        int argc,
+        char **argv,
+        const std::vector<std::string> &simpleArgs,
+        const std::vector<std::string> &pairedArgs) {
     std::unordered_map<std::string, std::string> mapping;
 
+    --argc; ++argv;
+    std::string temp;
+    bool mappingFound;
+    while(argc > 0) {
+        mappingFound = false;
+        for(const auto &s : simpleArgs) {
+            if(s.size() == 1) {
+                temp = std::string("-") + s;
+            } else {
+                temp = std::string("--") + s;
+            }
+            if(std::strcmp(temp.c_str(), argv[0]) == 0) {
+                mapping.insert({s, ""});
+                mappingFound = true;
+                break;
+            }
+        }
+        if(mappingFound) {
+            --argc; ++argv;
+            continue;
+        }
+        for(const auto &s : pairedArgs) {
+            if(s.size() == 1) {
+                temp = std::string("-") + s;
+            } else {
+                temp = std::string("--") + s;
+            }
+            if(std::strncmp(temp.c_str(), argv[0], temp.size()) == 0) {
+                std::string arg;
+                if(argv[0][temp.size()] == '=') {
+                    arg = argv[0] + temp.size() + 1;
+                } else {
+                    if(argc > 1) {
+                        --argc;
+                        ++argv;
+                        arg = argv[0];
+                    } else {
+                        throw std::invalid_argument("Paired arg missing pair");
+                    }
+                }
+                mapping.insert({s, arg});
+                mappingFound = true;
+                break;
+            }
+        }
+
+        if(!mappingFound) {
+            throw std::invalid_argument("Got invalid arg");
+        }
+
+        --argc; ++argv;
+    }
+
     return mapping;
 }
diff --git a/cpp_impl/src/argparse.hpp b/cpp_impl/src/argparse.hpp
index 0fb0987..485778d 100644
--- a/cpp_impl/src/argparse.hpp
+++ b/cpp_impl/src/argparse.hpp
@@ -3,9 +3,14 @@
 
 #include <string>
 #include <unordered_map>
+#include <vector>
 
 namespace ArgParse {
-    std::unordered_map<std::string, std::string> parseArgs(int argc, char **argv);
+    std::unordered_map<std::string, std::string> parseArgs(
+        int argc,
+        char **argv,
+        const std::vector<std::string> &simpleArgs,
+        const std::vector<std::string> &pairedArgs);
 } // namespace ArgParse
 
 #endif
diff --git a/cpp_impl/src/main.cpp b/cpp_impl/src/main.cpp
index 95d6c1a..b36f90e 100644
--- a/cpp_impl/src/main.cpp
+++ b/cpp_impl/src/main.cpp
@@ -1,5 +1,13 @@
+#include <iostream>
 
+#include "argparse.hpp"
 
 int main(int argc, char **argv) {
+    auto parsed = ArgParse::parseArgs(argc, argv, {"a", "b"}, {"apple"});
+
+    for(auto pair : parsed) {
+        std::cout << pair.first << ", " << pair.second << std::endl;
+    }
+
     return 0;
 }