ZRCola/lib/libZRCola/include/zrcola/highlight.h

/*
    SPDX-License-Identifier: GPL-3.0-or-later
    Copyright © 2021-2022 Amebis
*/

#pragma once

#include "common.h"

#include <functional>

#pragma warning(push)
#pragma warning(disable: 4200)

///
/// Default highlight
///
#define ZRCOLA_HLGHTSETID_DEFAULT                           ((ZRCola::hlghtsetid_t)0x0000)


///
/// ZRCola Unicode Composed Issues
///
#define ZRCOLA_HLGHTSETID_ZRCOLA_UNICODE_COMPOSED_ISSUES    ((ZRCola::hlghtsetid_t)0x0001)

namespace ZRCola {
    ///
    /// Highlight set ID
    ///
    typedef uint16_t hlghtsetid_t;

    ///
    /// Highlight database
    ///
    class highlight_db {
    public:
#pragma pack(push)
#pragma pack(2)
        ///
        /// Highlight data
        ///
        struct highlight {
        public:
            hlghtsetid_t set;   ///< Highlight set ID

        protected:
            uint16_t chr_to;    ///< Character end in \c data
            char_t data[];      ///< Character

        private:
            inline highlight(_In_ const highlight &other);
            inline highlight& operator=(_In_ const highlight &other);

        public:
            ///
            /// Constructs the highlight
            ///
            /// \param[in] set      Highlight set ID
            /// \param[in] chr      Character
            /// \param[in] chr_len  Number of UTF-16 characters in \p chr
            ///
            inline highlight(
                _In_opt_                        hlghtsetid_t  set     = 0,
                _In_opt_z_count_(chr_len) const char_t       *chr     = NULL,
                _In_opt_                        size_t        chr_len = 0)
            {
                this->set    = set;
                this->chr_to = static_cast<uint16_t>(chr_len);
                if (chr && chr_len) memcpy(this->data, chr, sizeof(char_t)*chr_len);
            }

            inline const char_t*  chr    () const { return data;          };
            inline       char_t*  chr    ()       { return data;          };
            inline const char_t*  chr_end() const { return data + chr_to; };
            inline       char_t*  chr_end()       { return data + chr_to; };
            inline       uint16_t chr_len() const { return chr_to;        };

            inline char_t chr_at(_In_ size_t i) const
            {
                return i < chr_to ? data[i] : 0;
            }
        };
#pragma pack(pop)

        ///
        /// Highlight index
        ///
        class indexChr : public index<uint16_t, uint32_t, highlight>
        {
        public:
            ///
            /// Constructs the index
            ///
            /// \param[in] h  Reference to vector holding the data
            ///
            indexChr(_In_ std::vector<uint16_t> &h) : index<uint16_t, uint32_t, highlight>(h) {}

            ///
            /// Compares two highlights by string (for searching)
            ///
            /// \param[in] a  Pointer to first element
            /// \param[in] b  Pointer to second element
            ///
            /// \returns
            /// - <0 when a <  b
            /// - =0 when a == b
            /// - >0 when a >  b
            ///
            virtual int compare(_In_ const highlight &a, _In_ const highlight &b) const
            {
                int r = ZRCola::CompareString(a.chr(), a.chr_len(), b.chr(), b.chr_len());
                if (r != 0) return r;

                if (a.set < b.set) return -1;
                if (a.set > b.set) return +1;

                return 0;
            }

            ///
            /// Compares two highlights by string (for sorting)
            ///
            /// \param[in] a  Pointer to first element
            /// \param[in] b  Pointer to second element
            ///
            /// \returns
            /// - <0 when a <  b
            /// - =0 when a == b
            /// - >0 when a >  b
            ///
            virtual int compare_sort(_In_ const highlight &a, _In_ const highlight &b) const
            {
                // Revert to `compare()` by default.
                return compare(a, b);
            }
        } idxChr;   ///< Highlight index


        std::vector<uint16_t> data; ///< Highlight data

    public:
        ///
        /// Constructs the database
        ///
        inline highlight_db() : idxChr(data) {}

        ///
        /// Clears the database
        ///
        inline void clear()
        {
            idxChr.clear();
            data  .clear();
        }

        ///
        /// Highlights string
        ///
        /// \param[in] input     Input string (UTF-16)
        /// \param[in] inputMax  Length of the input string in characters. Can be (size_t)-1 if \p input is zero terminated.
        /// \param[in] callback  Function to be called on highlight switch
        ///
        void Highlight(_In_z_count_(inputMax) const char_t* input, _In_ size_t inputMax, _In_ std::function<void (hlghtsetid_t set, size_t start, size_t end)> callback) const;

        ///
        /// Writes highlight database to a stream
        ///
        /// \param[in] stream  Output stream
        /// \param[in] db      Highlight database
        ///
        /// \returns The stream \p stream
        ///
        friend std::ostream& operator <<(_In_ std::ostream& stream, _In_ const highlight_db& db)
        {
            // Write highlight index.
            if (stream.fail()) return stream;
            stream << db.idxChr;

            // Write data count.
            auto data_count = db.data.size();
#if defined(_WIN64) || defined(__x86_64__) || defined(__ppc64__)
            // 4G check
            if (data_count > 0xffffffff) {
                stream.setstate(std::ios_base::failbit);
                return stream;
            }
#endif
            if (stream.fail()) return stream;
            uint32_t count = (uint32_t)data_count;
            stream.write((const char*)&count, sizeof(count));

            // Write data.
            if (stream.fail()) return stream;
            stream.write((const char*)db.data.data(), sizeof(uint16_t) * static_cast<std::streamsize>(count));

            return stream;
        }


        ///
        /// Reads highlight database from a stream
        ///
        /// \param[in ] stream  Input stream
        /// \param[out] db      Highlight database
        ///
        /// \returns The stream \p stream
        ///
        friend std::istream& operator >>(_In_ std::istream& stream, _Out_ highlight_db& db)
        {
            // Read highlight index.
            stream >> db.idxChr;
            if (!stream.good()) return stream;

            // Read data count.
            uint32_t count;
            stream.read((char*)&count, sizeof(count));
            if (!stream.good()) return stream;

            if (count) {
                // Read data.
                db.data.resize(count);
                stream.read((char*)db.data.data(), sizeof(uint16_t) * static_cast<std::streamsize>(count));
            }
            else
                db.data.clear();

            return stream;
        }
    };
};

#pragma warning(pop)