line_number_table_attribute.hh

/**
* Copyright 2019 Anthony Calandra
*
* 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 LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/

#pragma once

#include <algorithm>
#include <memory>
#include <optional>
#include <vector>

#include "attribute_info.hh"
#include "constant_pool.hh"
#include "util.hh"

struct line_number_table_entry
{
    uint16_t start_pc;
    uint16_t line_number;

    explicit line_number_table_entry(uint16_t start_pc, uint16_t line_number) :
        start_pc{start_pc},
        line_number{line_number}
    {}
};

class line_number_table_attribute: public attribute_info {
    std::vector<line_number_table_entry> line_number_table;

public:
    explicit line_number_table_attribute(std::vector<line_number_table_entry> line_number_table) :
        line_number_table{std::move(line_number_table)}
    {}

    std::optional<uint16_t> find_line_number_from_pc(uint16_t pc) const
    {
        if (line_number_table.empty())
        {
            return std::nullopt;
        }

        auto it = std::adjacent_find(line_number_table.cbegin(), line_number_table.cend(),
            [pc](const auto& curr_entry, const auto& next_entry)
            {
                return next_entry.start_pc > pc;
            });
        // Past the end, so use the last element.
        if (it == line_number_table.cend())
        {
            return line_number_table.back().line_number;
        }

        return it->line_number;
    }

    virtual attribute_info_type get_type() const
    {
        return attribute_info_type::line_number_table;
    }
};

std::unique_ptr<attribute_info> parse_line_number_table_attribute(std::ifstream& file,
    const constant_pool& cp);