ansi.hpp

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/*
 
Copyright 2025 | Leong Fan FUNG | funglf | stanleyfunglf@gmail.com
 
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the “Software”), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
 
The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.
 
THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
 
*/
 
#pragma once
#include <ostream>
#include <sstream>
#include <string>
#include <concepts>
#include <utility>
 
#include <comppare/internal/concepts.hpp>
 
namespace comppare::internal::ansi
{
    template <comppare::internal::concepts::Streamable T>
    class ScopedAnsiWrapper
    {
        const char *on_;
        const char *off_;
        T val_;
 
    public:
        ScopedAnsiWrapper(const char *on, const char *off, T v)
            : on_(on), off_(off), val_(std::move(v)) {}
 
        friend std::ostream &operator<<(std::ostream &os, ScopedAnsiWrapper const &w)
        {
            // Save the current state of the stream
            std::ios saved(nullptr);
            saved.copyfmt(os);
 
            // convert the value into a string
            std::ostringstream tmp;
            tmp.copyfmt(os);
            tmp << w.val_;
            std::string body = std::move(tmp).str();
 
            // apply the ANSI codes
            os.width(0);
            os << w.on_ << body << w.off_;
 
            // Restore the original state of the stream -- formatting, precision, etc.
            os.copyfmt(saved);
            return os;
        }
    };
 
#define ANSI_DEFINE(NAME, ON, OFF)                                                                          \
    /* Actual ANSI codes for the style/color (eg: BLACK_ON_CODE = "\033[30m") */                            \
    inline constexpr const char *NAME##_ON_CODE = "\033[" ON "m";                                           \
    inline constexpr const char *NAME##_OFF_CODE = "\033[" OFF "m";                                         \
                                                                                                            \
    class NAME##_ON_t                                                                                       \
    {                                                                                                       \
    public:                                                                                                 \
        /* Usage: std::cout << comppare::internal::ansi::BOLD << "Hello world"; */                          \
        friend std::ostream &operator<<(std::ostream &os, NAME##_ON_t)                                      \
        {                                                                                                   \
            /* Save the current state of the stream and apply the ANSI code */                              \
            std::ios saved(nullptr);                                                                        \
            saved.copyfmt(os);                                                                              \
            os.width(0);                                                                                    \
            os << NAME##_ON_CODE;                                                                           \
            os.copyfmt(saved);                                                                              \
            return os;                                                                                      \
        }                                                                                                   \
                                                                                                            \
        /* Usage: std::cout << comppare::internal::ansi::BOLD("Hello world") */                             \
        template <comppare::internal::concepts::Streamable T>                                               \
        auto operator()(T &&v) const                                                                        \
        {                                                                                                   \
            return ScopedAnsiWrapper<std::decay_t<T>>(NAME##_ON_CODE, NAME##_OFF_CODE, std::forward<T>(v)); \
        }                                                                                                   \
    };                                                                                                      \
    /* Instance of the ON class */                                                                          \
    inline constexpr NAME##_ON_t NAME{};                                                                    \
    class NAME##_OFF_t                                                                                      \
    {                                                                                                       \
    public:                                                                                                 \
        /* Usage: std::cout << ... << comppare::internal::ansi::BOLD_OFF; */                                \
        friend std::ostream &operator<<(std::ostream &os, NAME##_OFF_t)                                     \
        {                                                                                                   \
            /* Save the current state of the stream and apply the ANSI code */                              \
            std::ios saved(nullptr);                                                                        \
            saved.copyfmt(os);                                                                              \
            os.width(0);                                                                                    \
            os << NAME##_OFF_CODE;                                                                          \
            os.copyfmt(saved);                                                                              \
            return os;                                                                                      \
        }                                                                                                   \
    };                                                                                                      \
    /* Instance of the OFF class */                                                                         \
    inline constexpr NAME##_OFF_t NAME##_OFF{};
 
    // Each style/color is defined with its ON and OFF codes
    // https://man7.org/linux/man-pages/man4/console_codes.4.html
 
    /* STYLES 0-9 */
    ANSI_DEFINE(RESET, "0", "0");
    ANSI_DEFINE(BOLD, "1", "22");
    ANSI_DEFINE(DIM, "2", "22");
    ANSI_DEFINE(ITALIC, "3", "23");
    ANSI_DEFINE(UNDERLINE, "4", "24");
    ANSI_DEFINE(BLINK, "5", "25");
    ANSI_DEFINE(REVERSE, "7", "27");
    ANSI_DEFINE(HIDDEN, "8", "28");
    ANSI_DEFINE(STRIKE, "9", "29");
 
    /* FOREGROUND (TEXT) COLOURS 30-37/90-97 */
    ANSI_DEFINE(BLACK, "30", "39");
    ANSI_DEFINE(RED, "31", "39");
    ANSI_DEFINE(GREEN, "32", "39");
    ANSI_DEFINE(YELLOW, "33", "39");
    ANSI_DEFINE(BLUE, "34", "39");
    ANSI_DEFINE(MAGENTA, "35", "39");
    ANSI_DEFINE(CYAN, "36", "39");
    ANSI_DEFINE(WHITE, "37", "39");
 
    ANSI_DEFINE(BRIGHT_BLACK, "90", "39");
    ANSI_DEFINE(BRIGHT_RED, "91", "39");
    ANSI_DEFINE(BRIGHT_GREEN, "92", "39");
    ANSI_DEFINE(BRIGHT_YELLOW, "93", "39");
    ANSI_DEFINE(BRIGHT_BLUE, "94", "39");
    ANSI_DEFINE(BRIGHT_MAGENTA, "95", "39");
    ANSI_DEFINE(BRIGHT_CYAN, "96", "39");
    ANSI_DEFINE(BRIGHT_WHITE, "97", "39");
 
    /* BACKGROUND COLOURS (40-47 / 100-107) */
    ANSI_DEFINE(BG_BLACK, "40", "49");
    ANSI_DEFINE(BG_RED, "41", "49");
    ANSI_DEFINE(BG_GREEN, "42", "49");
    ANSI_DEFINE(BG_YELLOW, "43", "49");
    ANSI_DEFINE(BG_BLUE, "44", "49");
    ANSI_DEFINE(BG_MAGENTA, "45", "49");
    ANSI_DEFINE(BG_CYAN, "46", "49");
    ANSI_DEFINE(BG_WHITE, "47", "49");
 
    ANSI_DEFINE(BG_BRIGHT_BLACK, "100", "49");
    ANSI_DEFINE(BG_BRIGHT_RED, "101", "49");
    ANSI_DEFINE(BG_BRIGHT_GREEN, "102", "49");
    ANSI_DEFINE(BG_BRIGHT_YELLOW, "103", "49");
    ANSI_DEFINE(BG_BRIGHT_BLUE, "104", "49");
    ANSI_DEFINE(BG_BRIGHT_MAGENTA, "105", "49");
    ANSI_DEFINE(BG_BRIGHT_CYAN, "106", "49");
    ANSI_DEFINE(BG_BRIGHT_WHITE, "107", "49");
 
    // undefine the macro as no longer needed
#undef ANSI_DEFINE
}