string_traits.h

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/**
 
    @file      string_traits.h
    @author    Khrapov
    @date      24.03.2020
    @copyright © Nick Khrapov, 2021. All right reserved.
 
**/
#pragma once
 
#include <qx/containers/string/string_utils.h>
#include <qx/containers/string/string_view.h>
#include <qx/macros/config.h>
#include <qx/macros/static_assert.h>
#include <qx/macros/suppress_warnings.h>
 
#include <cctype>
#include <cstdarg>
#include <cstring>
#include <cwctype>
#include <sstream>
 
namespace qx::string_traits
{
 
// ------------------------------------------------- usings_char_traits ------------------------------------------------
 
template<class value_t>
struct usings_traits
{
    using value_type       = value_t;
    using pointer          = value_t*;
    using const_pointer    = const value_t*;
    using reference        = value_t&;
    using const_reference  = const value_t&;
    using difference_type  = std::ptrdiff_t;
    using size_type        = size_t;
    using string_view_type = basic_string_view<value_t>;
};
 
 
 
// -------------------------------------------------- hash_char_traits -------------------------------------------------
 
template<class value_t, class usings_char_traits_t>
struct hash_traits
{
    static constexpr typename usings_char_traits_t::size_type hash_function(
        typename usings_char_traits_t::const_pointer pszStr,
        size_t                                       nSeed,
        typename usings_char_traits_t::size_type     nLen) noexcept
    {
        return djb2a_hash(pszStr, nSeed, nLen);
    }
 
    static constexpr u32 hash_seed() noexcept
    {
        return 5712564;
    }
};
 
 
 
// ------------------------------------------------- allocation_traits -------------------------------------------------
 
template<class value_t, class usings_char_traits_t>
struct allocation_traits;
 
template<class usings_char_traits_t>
struct allocation_traits<char, usings_char_traits_t>
{
    static constexpr typename usings_char_traits_t::size_type small_string_size() noexcept
    {
        return 64;
    }
 
    static constexpr bool shrink_to_fit_when_small() noexcept
    {
        return false;
    }
};
 
template<class usings_char_traits_t>
struct allocation_traits<wchar_t, usings_char_traits_t>
{
    static constexpr typename usings_char_traits_t::size_type small_string_size() noexcept
    {
#if QX_MSVC
        // sizeof(wchar_t) == 2
        return 32;
#else
        // sizeof(wchar_t) == 4
        return 16;
#endif
    }
 
    static constexpr bool shrink_to_fit_when_small() noexcept
    {
        return false;
    }
};
 
template<class value_t, class usings_char_traits_t>
struct small_string_allocation_traits;
 
template<class usings_char_traits_t>
struct small_string_allocation_traits<char, usings_char_traits_t> : public allocation_traits<char, usings_char_traits_t>
{
    static constexpr typename usings_char_traits_t::size_type small_string_size() noexcept
    {
        return 32;
    }
};
 
template<class usings_char_traits_t>
struct small_string_allocation_traits<wchar_t, usings_char_traits_t>
    : public allocation_traits<wchar_t, usings_char_traits_t>
{
    static constexpr typename usings_char_traits_t::size_type small_string_size() noexcept
    {
#if QX_MSVC
        // sizeof(wchar_t) == 2
        return 16;
#else
        // sizeof(wchar_t) == 4
        return 8;
#endif
    }
};
 
template<class value_t, class usings_char_traits_t>
struct big_string_allocation_traits;
 
template<class usings_char_traits_t>
struct big_string_allocation_traits<char, usings_char_traits_t> : public allocation_traits<char, usings_char_traits_t>
{
    static constexpr typename usings_char_traits_t::size_type small_string_size() noexcept
    {
        return 256;
    }
};
 
template<class usings_char_traits_t>
struct big_string_allocation_traits<wchar_t, usings_char_traits_t>
    : public allocation_traits<wchar_t, usings_char_traits_t>
{
    static constexpr typename usings_char_traits_t::size_type small_string_size() noexcept
    {
#if QX_MSVC
        // sizeof(wchar_t) == 2
        return 128;
#else
        // sizeof(wchar_t) == 4
        return 64;
#endif
    }
};
 
 
 
// -------------------------------------------------- test_char_traits -------------------------------------------------
 
template<class value_t, class usings_char_traits_t>
struct test_char_traits;
 
template<class value_t>
struct base_test_char_traits
{
    static bool is_eng_alpha(value_t ch) noexcept
    {
        return (ch >= QX_CHAR_PREFIX(value_t, 'A') && ch <= QX_CHAR_PREFIX(value_t, 'Z'))
               || (ch >= QX_CHAR_PREFIX(value_t, 'a') && ch <= QX_CHAR_PREFIX(value_t, 'z'));
    }
};
 
template<class usings_char_traits_t>
struct test_char_traits<char, usings_char_traits_t> : base_test_char_traits<char>
{
    static bool is_space(typename usings_char_traits_t::value_type ch) noexcept
    {
        return std::isspace(static_cast<int>(ch)) != 0;
    }
 
    static bool is_digit(typename usings_char_traits_t::value_type ch) noexcept
    {
        return std::isdigit(ch) != 0;
    }
};
 
template<class usings_char_traits_t>
struct test_char_traits<wchar_t, usings_char_traits_t> : base_test_char_traits<wchar_t>
{
    static bool is_space(typename usings_char_traits_t::value_type ch) noexcept
    {
        return std::iswspace(static_cast<wint_t>(ch)) != 0;
    }
 
    static bool is_digit(typename usings_char_traits_t::value_type ch) noexcept
    {
        return std::iswdigit(ch) != 0;
    }
};
 
 
 
// ----------------------------------------------- transform_char_traits -----------------------------------------------
 
template<class value_t, class usings_char_traits_t>
struct transform_char_traits;
 
template<class usings_char_traits_t>
struct transform_char_traits<char, usings_char_traits_t>
{
    static typename usings_char_traits_t::value_type to_lower(typename usings_char_traits_t::value_type ch) noexcept
    {
        return static_cast<char>(std::tolower(ch));
    }
 
    static typename usings_char_traits_t::value_type to_upper(typename usings_char_traits_t::value_type ch) noexcept
    {
        return static_cast<char>(std::toupper(ch));
    }
};
 
template<class usings_char_traits_t>
struct transform_char_traits<wchar_t, usings_char_traits_t>
{
    static typename usings_char_traits_t::value_type to_lower(typename usings_char_traits_t::value_type ch) noexcept
    {
        return std::towlower(ch);
    }
 
    static typename usings_char_traits_t::value_type to_upper(typename usings_char_traits_t::value_type ch) noexcept
    {
        return std::towupper(ch);
    }
};
 
 
 
// --------------------------------------------------- length_traits ---------------------------------------------------
 
template<class value_t, class usings_char_traits_t>
struct length_traits;
 
template<class usings_char_traits_t>
struct length_traits<char, usings_char_traits_t>
{
    static constexpr typename usings_char_traits_t::size_type length(
        typename usings_char_traits_t::const_pointer pszStr) noexcept
    {
        if (std::is_constant_evaluated())
            return static_cast<typename usings_char_traits_t::size_type>(qx::strlen(pszStr));
        else
            return static_cast<typename usings_char_traits_t::size_type>(std::strlen(pszStr));
    }
};
 
template<class usings_char_traits_t>
struct length_traits<wchar_t, usings_char_traits_t>
{
    static constexpr typename usings_char_traits_t::size_type length(
        typename usings_char_traits_t::const_pointer pszStr) noexcept
    {
        if (std::is_constant_evaluated())
            return static_cast<typename usings_char_traits_t::size_type>(qx::strlen(pszStr));
        else
            return static_cast<typename usings_char_traits_t::size_type>(std::wcslen(pszStr));
    }
};
 
 
 
// --------------------------------------------------- compare_traits --------------------------------------------------
 
template<class value_t, class usings_char_traits_t>
struct compare_traits;
 
template<class usings_char_traits_t>
struct compare_traits<char, usings_char_traits_t>
{
    static int compare(
        typename usings_char_traits_t::const_pointer pszFirst,
        typename usings_char_traits_t::const_pointer pszSecond) noexcept
    {
        return std::strcmp(pszFirst, pszSecond);
    }
 
    static int compare_n(
        typename usings_char_traits_t::const_pointer pszFirst,
        typename usings_char_traits_t::const_pointer pszSecond,
        typename usings_char_traits_t::size_type     nCount) noexcept
    {
        return std::strncmp(pszFirst, pszSecond, nCount);
    }
};
 
template<class usings_char_traits_t>
struct compare_traits<wchar_t, usings_char_traits_t>
{
    static int compare(
        typename usings_char_traits_t::const_pointer pszFirst,
        typename usings_char_traits_t::const_pointer pszSecond) noexcept
    {
        return std::wcscmp(pszFirst, pszSecond);
    }
 
    static int compare_n(
        typename usings_char_traits_t::const_pointer pszFirst,
        typename usings_char_traits_t::const_pointer pszSecond,
        typename usings_char_traits_t::size_type     nCount) noexcept
    {
        return std::wcsncmp(pszFirst, pszSecond, nCount);
    }
};
 
 
 
// ------------------------------------------------ format_string_traits -----------------------------------------------
 
template<class value_t, class usings_char_traits_t>
struct format_string_traits
{
    template<class... args_t>
    using format_string = QX_FMT_NS::basic_format_string<value_t, args_t...>;
};
 
 
 
// --------------------------------------------------- format_traits ---------------------------------------------------
 
template<class value_t, class usings_char_traits_t>
struct format_traits;
 
template<class usings_char_traits_t>
struct format_traits<char, usings_char_traits_t>
{
    static constexpr typename usings_char_traits_t::size_type nMemoryBufferSize = 1024;
 
    template<class... args_t>
    static auto make_format_args(args_t&... args)
    {
        return QX_FMT_NS::make_format_args(args...);
    }
 
    template<class... args_t>
    static int sscanf(
        typename usings_char_traits_t::const_pointer pszString,
        typename usings_char_traits_t::const_pointer pszFormat,
        args_t&&... args) noexcept
    {
        QX_PUSH_SUPPRESS_ALL_WARNINGS();
        return std::sscanf(pszString, pszFormat, std::forward<args_t>(args)...);
        QX_POP_SUPPRESS_WARNINGS();
    }
};
 
template<class usings_char_traits_t>
struct format_traits<wchar_t, usings_char_traits_t>
{
    static constexpr typename usings_char_traits_t::size_type nMemoryBufferSize =
#if QX_WIN
        512;
#else
        256;
#endif
 
    template<class... args_t>
    static auto make_format_args(args_t&... args)
    {
        return QX_FMT_NS::make_wformat_args(args...);
    }
 
    template<class... args_t>
    static int sscanf(
        typename usings_char_traits_t::const_pointer pszString,
        typename usings_char_traits_t::const_pointer pszFormat,
        args_t&&... args) noexcept
    {
        QX_PUSH_SUPPRESS_ALL_WARNINGS();
        return std::swscanf(pszString, pszFormat, std::forward<args_t>(args)...);
        QX_POP_SUPPRESS_WARNINGS();
    }
};
 
template<class... args_t>
struct constructor : public args_t...
{
};
 
/**
    @brief Common string traits type. User may use it with user-defined traits to override the required behaviour.
    @tparam value_t - char type
**/
template<class value_t>
using traits = constructor<
    usings_traits<value_t>,
    hash_traits<value_t, usings_traits<value_t>>,
    allocation_traits<value_t, usings_traits<value_t>>,
    test_char_traits<value_t, usings_traits<value_t>>,
    transform_char_traits<value_t, usings_traits<value_t>>,
    length_traits<value_t, usings_traits<value_t>>,
    compare_traits<value_t, usings_traits<value_t>>,
    format_string_traits<value_t, usings_traits<value_t>>,
    format_traits<value_t, usings_traits<value_t>>>;
 
} // namespace qx::string_traits