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Diffstat (limited to 'src/ArgParser.h')
| -rw-r--r-- | src/ArgParser.h | 219 |
1 files changed, 219 insertions, 0 deletions
diff --git a/src/ArgParser.h b/src/ArgParser.h new file mode 100644 index 0000000..c0f8cde --- /dev/null +++ b/src/ArgParser.h @@ -0,0 +1,219 @@ +/* + * A wrapper of getopt + * + * by WangLu + * 2012.09.10 + */ + + +#ifndef ARGPARSER_H__ +#define ARGPARSER_H__ + +#include <string> +#include <vector> +#include <ostream> +#include <sstream> +#include <memory> + +#ifndef nullptr +#define nullptr (NULL) +#endif + +namespace pdf2htmlEX { + +//helper +template<class T> +bool read_value(const char * arg, T * location) +{ + std::istringstream sin(arg); + return ((sin >> (*location)) && (sin.eof())); +} + +extern bool read_value(const char * arg, char * location); +extern bool read_value(const char * arg, std::string * location); + +template<class T> +void dump_value(std::ostream & out, const T & v) +{ + out << v; +} + +extern void dump_value(std::ostream & out, const std::string & v); + +class ArgParser +{ +public: + typedef void (*ArgParserCallBack) (const char * arg); + + /* + * The 1st is for arguments with callbacks(i.e. flags) + * The 2nd is for arguments linked to variables + * + * optname: + * - if not nullptr, it should be the name of the arg, should be in the format of "<long name>[,<short char>]", e.g. "help,h" + * - if nullptr, it denotes an optional arg, and description will be ignored + * description: + * - if description is nullptr or "", the argument won't be shown in show_usage() + * + * location: + * - if not nullptr, the argument for this arg is stored there + * - if nullptr, this arg does not need arguments + */ + ArgParser & add(const char * optname, const char * description, ArgParserCallBack callback, bool need_arg = false); + template <class T, class Tv> + ArgParser & add(const char * optname, T * location, const Tv & default_value, const char * description, bool dont_show_default = false); + + void parse(int argc, char ** argv) const; + void show_usage(std::ostream & out) const; + +private: + // type names helper + template<class> + static const char * get_type_name(void) { return "unknown"; } + + struct ArgEntryBase + { + /* name or description cannot be nullptr */ + ArgEntryBase(const char * name, const char * description, bool need_arg); + virtual ~ArgEntryBase() { } + char shortname; + std::string name; + std::string description; + bool need_arg; + virtual void parse (const char * arg) const = 0; + virtual void show_usage (std::ostream & out) const = 0; + }; + + template <class T, class Tv> + struct ArgEntry : public ArgEntryBase + { + ArgEntry(const char * name, + const char * description, + ArgParserCallBack callback, + bool need_arg); + + ArgEntry(const char * name, + T * location, const Tv & default_value, + const char * description, bool dont_show_default); + + virtual void parse (const char * arg) const; + virtual void show_usage (std::ostream & out) const; + + private: + T * location; + T default_value; + ArgParserCallBack callback; + bool dont_show_default; + }; + + std::vector<std::unique_ptr<ArgEntryBase>> arg_entries, optional_arg_entries; + static const int arg_col_width; +}; + +template<class T, class Tv> +ArgParser & ArgParser::add(const char * optname, T * location, const Tv & default_value, const char * description, bool dont_show_default) +{ + // ArgEntry does not accept nullptr as optname nor description + if((!optname) || (!optname[0])) + { + // when optname is nullptr or "", it's optional, and description is dropped + optional_arg_entries.emplace_back(new ArgEntry<T, Tv>("", location, default_value, "", dont_show_default)); + } + else + { + arg_entries.emplace_back(new ArgEntry<T, Tv>(optname, location, default_value, (description ? description : ""), dont_show_default)); + } + + return *this; +} + +// Known types +template<> const char * ArgParser::get_type_name<int> (void); +template<> const char * ArgParser::get_type_name<double> (void); +template<> const char * ArgParser::get_type_name<std::string> (void); + +template<class T, class Tv> +ArgParser::ArgEntry<T, Tv>::ArgEntry(const char * name, const char * description, ArgParserCallBack callback, bool need_arg) + : ArgEntryBase(name, description, need_arg) + , location(nullptr) + , default_value() + , callback(callback) + , dont_show_default(true) +{ +} + +template<class T, class Tv> +ArgParser::ArgEntry<T, Tv>::ArgEntry(const char * name, T * location, const Tv & default_value, const char * description, bool dont_show_default) + : ArgEntryBase(name, description, (location != nullptr)) + , location(location) + , default_value(default_value) + , callback(nullptr) + , dont_show_default(dont_show_default) +{ + if(need_arg) + *location = T(default_value); +} + +template<class T, class Tv> +void ArgParser::ArgEntry<T, Tv>::parse(const char * arg) const +{ + if(need_arg) + { + if(!arg) + throw std::string("Missing argument of option: --") + name; + + if((location != nullptr) && (!read_value(arg, location))) + throw std::string("Invalid argument: ") + arg; + } + + if(callback) + (*callback)(arg); +} + +template<class T, class Tv> +void ArgParser::ArgEntry<T, Tv>::show_usage(std::ostream & out) const +{ + if(description.empty()) + return; + + std::ostringstream sout; + sout << " "; + + if(shortname != 0) + { + sout << "-" << shortname; + } + + if(name != "") + { + if(shortname != 0) + sout << ","; + sout << "--" << name; + } + + if(need_arg) + { + sout << " <" << get_type_name<T>() << ">"; + } + + std::string s = sout.str(); + out << s; + + for(int i = s.size(); i < arg_col_width; ++i) + out << ' '; + + out << " " << description; + + if(need_arg && !dont_show_default) + { + out << " (default: "; + dump_value(out, default_value); + out << ")"; + } + + out << std::endl; +} + +} // namespace ArgParser + +#endif //ARGPARSER_H__ |