tr.h

#ifndef KTR_H_INCLUDED_
#define KTR_H_INCLUDED_

#include "kblib/kblib.h"
#include "tinyutf8.h"
#include "utf8.h"

namespace tr {

std::u32string expand_set(std::u32string_view set);

std::string filter(std::string whitelist, std::string_view input);
std::string translate(std::string_view set1, std::string set2,
                      std::string_view input);

inline std::u32string widen(std::string_view str) {
    std::u32string ret;
    utf8::utf8to32(str.begin(), str.end(), std::back_inserter(ret));
    return ret;
}

inline std::string narrow(std::u32string_view str) {
    std::string ret;
    utf8::utf32to8(str.begin(), str.end(), std::back_inserter(ret));
    return ret;
}

inline bool match(std::string_view whitelist, std::string_view input) {
    // if every character in the input is present in the whitelist
    return widen(input).find_first_not_of(expand_set(widen(whitelist))) ==
           std::u32string::npos;
}

inline bool find(std::u32string_view set, char32_t c) {
    auto p = std::find(set.begin(), set.end(), c);
    return p != set.end();
}

#if 0
//Currently, only filter. match, and translate are needed by the program.

enum Mode : unsigned {
    def = 0,
    
    complement = 1,
    c = complement,
    C = complement,
    
    del = 2,
    d = del,
    
    squeeze = 4,
    s = squeeze,
    
    truncate = 8,
    t = truncate,
};

template <typename Char>
std::basic_string<Char> tr(Mode mode, std::basic_string_view<Char> set1, std::basic_string_view<Char> set2, std::basic_string_view<Char> input)
{
    if (mode == tr::squeeze) {
        
    } else if (mode & tr::complement) {
        
    } else if (mode & tr::del) {
        
    } else {
        
    }
}

template <Mode mode, typename Char>
std::basic_string<Char> tr(std::basic_string_view<Char> set1, std::basic_string_view<Char> set2, std::basic_string_view<Char> input)
{
    if constexpr (mode == tr::def) {
        return translate(set1, set2, input);
    } else if constexpr (mode == (tr::c | tr::d)) {
        return filter(set1, input);
    }
}
#endif

} // namespace tr

#endif // KTR_H_INCLUDED_