csv_cell_string_buffer.h

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/**************************************************************************
Copyright: (C) 2021 - 2025 Alexander Shaduri
License: Zlib
***************************************************************************/
 
#ifndef CSV_CELL_STRING_BUFFER_H
#define CSV_CELL_STRING_BUFFER_H
 
#include <string_view>
#include <stdexcept>
#include <array>
 
#include "csv_util.h"
 
namespace Csv {
 
 
 
template<std::size_t Size>
class CellStringBuffer {
    public:
 
        constexpr inline explicit CellStringBuffer(std::string_view cell, bool has_escaped_quotes);
 
        [[nodiscard]] constexpr std::string_view getStringView() const;
 
        [[nodiscard]] constexpr std::size_t getBufferSize() const noexcept;
 
 
    private:
 
        struct Buffer {
            std::array<char, Size> buffer = { };
            std::size_t size = 0;
        };
 
        [[nodiscard]] constexpr static Buffer prepareBuffer(std::string_view input, bool has_escaped_quotes);
 
        [[nodiscard]] constexpr static Buffer cleanString(std::string_view input);
 
        Buffer buffer_;
};
 
 
 
// ----- Implementation
 
 
 
template<std::size_t Size>
constexpr CellStringBuffer<Size>::CellStringBuffer(std::string_view cell, bool has_escaped_quotes)
        : buffer_(prepareBuffer(cell, has_escaped_quotes))
{ }
 
 
 
template<std::size_t Size>
constexpr std::string_view CellStringBuffer<Size>::getStringView() const
{
    return {buffer_.buffer.data(), buffer_.size};
}
 
 
 
template<std::size_t Size>
constexpr std::size_t CellStringBuffer<Size>::getBufferSize() const noexcept
{
    return Size;
}
 
 
 
template<std::size_t Size>
constexpr typename CellStringBuffer<Size>::Buffer CellStringBuffer<Size>::prepareBuffer(
        std::string_view input, bool has_escaped_quotes)
{
    if (has_escaped_quotes) {
        // cleanString will throw if the buffer is too small
        return cleanString(input);
    }
 
    if (Size < input.size()) {
        throw std::out_of_range("Insufficient buffer size");
    }
    std::array<char, Size> buffer = { };
    for (std::size_t pos = 0; pos < input.size(); ++pos) {
        buffer[pos] = input[pos];
    }
    return Buffer{buffer, input.size()};
}
 
 
 
template<std::size_t Size>
constexpr typename CellStringBuffer<Size>::Buffer CellStringBuffer<Size>::cleanString(std::string_view input)
{
    if (Size < getCleanStringSize(input)) {
        throw std::out_of_range("Insufficient buffer size");
    }
    std::array<char, Size> buffer = { };
    std::size_t output_pos = 0;
    for (std::size_t input_pos = 0; input_pos < input.size(); ++input_pos) {
        char c = input[input_pos];
        buffer[output_pos] = c;
        ++output_pos;
        if (c == '\"' && (input_pos + 1) < input.size() && input[input_pos + 1] == '\"') {
            ++input_pos;
        }
    }
    return {buffer, output_pos};
}
 
 
 
 
}  // end ns
 
 
 
#endif