wip args parser

engine/include/vull/support/args_parser.hh

@@ -0,0 +1,59 @@
+#pragma once
+
+#include <vull/container/vector.hh>
+#include <vull/support/function.hh>
+#include <vull/support/optional.hh>
+#include <vull/support/string.hh>
+#include <vull/support/string_builder.hh>
+
+namespace vull {
+
+enum class ArgsParseResult {
+    Continue,
+    ExitFailure,
+    ExitSuccess,
+};
+
+class ArgsParser {
+    struct Argument {
+        String name;
+        uint32_t min_values;
+        uint32_t max_values;
+        Function<ArgsParseResult(StringView, StringView)> accept_value;
+
+        String to_string() const;
+    };
+
+    struct Option {
+        String help_string;
+        String long_name;
+        char short_name;
+        bool has_argument;
+        Function<ArgsParseResult(StringView, StringView)> accept_value;
+    };
+
+private:
+    String m_name;
+    String m_description;
+    String m_version;
+    Vector<Argument> m_arguments;
+    Vector<Option> m_options;
+
+    void print_help(StringView program_path);
+    ArgsParseResult handle_long_option(Option *&option_waiting_for_argument, StringView program_path,
+                                       StringView option_name);
+    ArgsParseResult handle_short_option(Option *&option_waiting_for_argument, StringView program_path,
+                                        char option_name);
+
+public:
+    ArgsParser(String name, String description, String version);
+
+    template <typename T>
+    void add_argument(T &value, String name, bool required);
+    void add_flag(bool &present, String help_string, String long_name, char short_name = '\0');
+    template <typename T>
+    void add_option(T &value, String help_string, String long_name, char short_name = '\0');
+    ArgsParseResult parse_args(int argc, const char *const *argv);
+};
+
+} // namespace vull

engine/include/vull/support/string.hh

@@ -16,6 +16,7 @@ class String {
 public:
     static String copy_raw(const char *data, size_t length);
     static String move_raw(char *data, size_t length);
+    static String repeated(char ch, size_t length);
 
     constexpr String() = default;
     explicit String(size_t length);
@@ -28,6 +29,14 @@ public:
     String &operator=(const String &) = delete;
     String &operator=(String &&);
 
+    int compare(StringView other) const;
+
+    bool starts_with(char ch) const;
+    bool ends_with(char ch) const;
+
+    bool starts_with(StringView other) const;
+    bool ends_with(StringView other) const;
+
     char *begin() const { return m_data; }
     char *end() const { return m_data + m_length; }
 
@@ -37,8 +46,6 @@ public:
     char &operator[](size_t index) { return m_data[index]; }
     const char &operator[](size_t index) const { return m_data[index]; }
 
-    bool ends_with(StringView end);
-
     operator StringView() const { return view(); }
     StringView view() const { return {m_data, m_length}; }
 

engine/include/vull/support/string_view.hh

@@ -1,5 +1,6 @@
 #pragma once
 
+#include <vull/maths/common.hh>
 #include <vull/support/assert.hh>
 #include <vull/support/span.hh>
 
@@ -12,12 +13,32 @@ public:
     using Span::Span;
     constexpr StringView(const char *c_string) : Span(c_string, __builtin_strlen(c_string)) {}
 
+    constexpr int compare(StringView other) const;
     constexpr StringView substr(size_t offset) const;
     constexpr StringView substr(size_t offset, size_t length) const;
+
+    constexpr bool starts_with(char ch) const;
+    constexpr bool ends_with(char ch) const;
+
+    constexpr bool starts_with(StringView other) const;
+    constexpr bool ends_with(StringView other) const;
+
     constexpr bool operator==(StringView other) const;
     constexpr size_t length() const { return size(); }
 };
 
+constexpr int StringView::compare(StringView other) const {
+    int ret = __builtin_memcmp(data(), other.data(), vull::min(length(), other.length()));
+    if (ret == 0) {
+        if (length() < other.length()) {
+            ret = -1;
+        } else if (length() > other.length()) {
+            ret = 1;
+        }
+    }
+    return ret;
+}
+
 constexpr StringView StringView::substr(size_t offset) const {
     return substr(offset, length() - offset);
 }
@@ -27,6 +48,22 @@ constexpr StringView StringView::substr(size_t offset, size_t length) const {
     return {data() + offset, length};
 }
 
+constexpr bool StringView::starts_with(char ch) const {
+    return !empty() && begin()[0] == ch;
+}
+
+constexpr bool StringView::ends_with(char ch) const {
+    return !empty() && end()[-1] == ch;
+}
+
+constexpr bool StringView::starts_with(StringView other) const {
+    return length() >= other.length() && substr(0, other.length()).compare(other) == 0;
+}
+
+constexpr bool StringView::ends_with(StringView other) const {
+    return length() >= other.length() && substr(length() - other.length()).compare(other) == 0;
+}
+
 constexpr bool StringView::operator==(StringView other) const {
     if (data() == nullptr) {
         return other.data() == nullptr;

engine/sources/CMakeLists.txt

@@ -7,6 +7,7 @@ target_sources(vull-core PRIVATE
     platform/linux.cc
     scene/scene.cc
     scene/transform.cc
+    support/args_parser.cc
     support/assert.cc
     support/stream.cc
     support/string.cc