refactor: refactor project layout

- move header files into an individual directory to prevent the possibility that file name is conflict in Linux include directory.
- update build script generator. use jinja2 template engine to get better view, rather than python code written by hand.
- add version number and version comparation macros in core library.

script/gen_build_script.py

@@ -0,0 +1,108 @@
+import jinja2
+import argparse
+import os
+import io
+import re
+import shlex
+
+def validate_cpp_ver(ver: str) -> str:
+    if re.match(r'^[0-9]+$', ver) is not None: return ver
+    else: raise argparse.ArgumentTypeError('invalid version of C++ standard.')
+
+def write_line(f: io.TextIOWrapper, val: str) -> None:
+    f.write(val)
+    f.write('\n')
+
+# Reference: https://stackoverflow.com/questions/29213106/how-to-securely-escape-command-line-arguments-for-the-cmd-exe-shell-on-windows
+def escape_for_cmd_exe(arg):
+    meta_re = re.compile(r'([()%!^"<>&|])')
+    return meta_re.sub('^\1', arg)
+def escape_cmd_argument(arg):
+    if not arg or re.search(r'(["\s])', arg):
+        arg = '"' + arg.replace('"', r'\"') + '"'
+    return escape_for_cmd_exe(arg)
+def escape_sh_argument(arg):
+    return shlex.quote(arg)
+
+class ScriptSettings:
+    m_CppVersion: str
+    m_BuildDoc: bool
+    m_PIC: bool
+
+    def __init__(self, cpp_ver: str, build_doc: bool, pic: bool):
+        self.m_CppVersion = cpp_ver
+        self.m_BuildDoc = build_doc
+        self.m_PIC = pic
+
+class TemplateRender:
+    m_Loader: jinja2.BaseLoader
+    m_Environment: jinja2.Environment
+
+    m_WinTemplate: jinja2.Template
+    m_LinuxTemplate: jinja2.Template
+
+    m_Settings: ScriptSettings
+
+    def __init__(self, settings: ScriptSettings) -> None:
+        self.m_Loader = jinja2.FileSystemLoader(self.__get_dir())
+        self.m_Environment = jinja2.Environment(loader=self.m_Loader)
+
+        self.m_WinTemplate = self.m_Environment.get_template('win_build.template.bat')
+        self.m_LinuxTemplate = self.m_Environment.get_template('linux_build.template.sh')
+
+        self.m_Settings = settings
+
+    def __get_dir(self) -> str:
+        return os.path.dirname(__file__)
+
+    def __escape_path(self, val: str, is_win: bool) -> str:
+        if is_win: return escape_cmd_argument(val)
+        else: return escape_sh_argument(val)
+
+    def __render(self, template: jinja2.Template, dest_file: str, is_win: bool) -> None:
+        with open(os.path.join(self.__get_dir(), dest_file), 'w', encoding='utf-8') as f:
+            f.write(template.render(
+                repo_root_dir = self.__escape_path(os.path.dirname(self.__get_dir()), is_win),
+                cpp_version = self.m_Settings.m_CppVersion,
+                build_doc = self.m_Settings.m_BuildDoc,
+                pic = settings.m_PIC
+            ))
+
+    def render_win_script(self) -> None:
+        self.__render(self.m_WinTemplate, 'win_build.bat', True)
+    
+    def render_linux_script(self) -> None:
+        self.__render(self.m_LinuxTemplate, 'linux_build.sh', False)
+    
+
+if __name__ == '__main__':
+    # parse argument
+    parser = argparse.ArgumentParser(
+        prog='YYCC Windows Build Script Generator',
+        description='YYCC Windows Build Script Generator'
+    )
+    parser.add_argument(
+        '-c', '--cpp',
+        action='store', default='17', dest='cpp', type=validate_cpp_ver,
+        help='The version of C++ standard used when building.'
+    )
+    parser.add_argument(
+        '-d', '--build-doc',
+        action='store_true', dest='build_doc',
+        help='Build YYCC without documentation.'
+    )
+    parser.add_argument(
+        '-p', '--pic',
+        action='store_true', dest='pic',
+        help='Enable Position Independent Code flag on non-Windows platform. This is crucial for compiling dynamic library using this library.'
+    )
+    args = parser.parse_args()
+
+    # build settings
+    settings = ScriptSettings(args.cpp, args.build_doc, args.pic)
+    # build template render and render result
+    render = TemplateRender(settings)
+    render.render_win_script()
+    render.render_linux_script()
+    
+