Add commandline arguments, implement --config, --version, --help

src/ArgsParser.cpp

@@ -0,0 +1,94 @@
+#include "ArgsParser.h"
+#include "Common.h"
+#include <algorithm>
+
+void ArgsParser::Parse(const std::vector<std::string_view>& ArgList) {
+    for (const auto& Arg : ArgList) {
+        if (Arg.size() > 2 && Arg.substr(0, 2) == "--") {
+            // long arg
+            if (Arg.find("=") != Arg.npos) {
+                ConsumeLongAssignment(std::string(Arg));
+            } else {
+                ConsumeLongFlag(std::string(Arg));
+            }
+        } else {
+            beammp_error("Error parsing commandline arguments: Supplied argument '" + std::string(Arg) + "' is not a valid argument and was ignored.");
+        }
+    }
+}
+
+bool ArgsParser::Verify() {
+    bool Ok = true;
+    for (const auto& RegisteredArg : mRegisteredArguments) {
+        if (RegisteredArg.Flags & Flags::REQUIRED && !FoundArgument(RegisteredArg.Names)) {
+            beammp_error("Error in commandline arguments: Argument '" + std::string(RegisteredArg.Names.at(0)) + "' is required but wasn't found.");
+            Ok = false;
+            continue;
+        } else if (FoundArgument(RegisteredArg.Names)) {
+            if (RegisteredArg.Flags & Flags::HAS_VALUE) {
+                if (!GetValueOfArgument(RegisteredArg.Names).has_value()) {
+                    beammp_error("Error in commandline arguments: Argument '" + std::string(RegisteredArg.Names.at(0)) + "' expects a value, but no value was given.");
+                    Ok = false;
+                }
+            } else if (GetValueOfArgument(RegisteredArg.Names).has_value()) {
+                beammp_error("Error in commandline arguments: Argument '" + std::string(RegisteredArg.Names.at(0)) + "' does not expect a value, but one was given.");
+                Ok = false;
+            }
+        }
+    }
+    return Ok;
+}
+
+void ArgsParser::RegisterArgument(std::vector<std::string>&& ArgumentNames, int Flags) {
+    mRegisteredArguments.push_back({ ArgumentNames, Flags });
+}
+
+bool ArgsParser::FoundArgument(const std::vector<std::string>& Names) {
+    // if any of the found args match any of the names
+    return std::any_of(mFoundArgs.begin(), mFoundArgs.end(),
+        [&Names](const Argument& Arg) -> bool {
+            // if any of the names match this arg's name
+            return std::any_of(Names.begin(), Names.end(), [&Arg](const std::string& Name) -> bool {
+                return Arg.Name == Name;
+            });
+        });
+}
+
+std::optional<std::string> ArgsParser::GetValueOfArgument(const std::vector<std::string>& Names) {
+    // finds an entry which has a name that is any of the names in 'Names'
+    auto Found = std::find_if(mFoundArgs.begin(), mFoundArgs.end(), [&Names](const Argument& Arg) -> bool {
+        return std::any_of(Names.begin(), Names.end(), [&Arg](const std::string_view& Name) -> bool {
+            return Arg.Name == Name;
+        });
+    });
+    if (Found != mFoundArgs.end()) {
+        // found
+        return Found->Value;
+    } else {
+        return std::nullopt;
+    }
+}
+
+bool ArgsParser::IsRegistered(const std::string& Name) {
+    return std::any_of(mRegisteredArguments.begin(), mRegisteredArguments.end(), [&Name](const RegisteredArgument& Arg) {
+        auto Iter = std::find(Arg.Names.begin(), Arg.Names.end(), Name);
+        return Iter != Arg.Names.end();
+    });
+}
+
+void ArgsParser::ConsumeLongAssignment(const std::string& Arg) {
+    auto Value = Arg.substr(Arg.rfind("=") + 1);
+    auto Name = Arg.substr(2, Arg.rfind("=") - 2);
+    if (!IsRegistered(Name)) {
+        beammp_warn("Argument '" + Name + "' was supplied but isn't a known argument, so it is likely being ignored.");
+    }
+    mFoundArgs.push_back({ Name, Value });
+}
+
+void ArgsParser::ConsumeLongFlag(const std::string& Arg) {
+    auto Name = Arg.substr(2, Arg.rfind("=") - 2);
+    mFoundArgs.push_back({ Name, std::nullopt });
+    if (!IsRegistered(Name)) {
+        beammp_warn("Argument '" + Name + "' was supplied but isn't a known argument, so it is likely being ignored.");
+    }
+}