archive.cpp

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#include <fstream>

#include "settings.hpp"

#include "utils/archive.hpp"

#define ROUND_PAGE(_X) (((_X) % PAGE_SIZE == 0) ? (_X) : (((_X) / PAGE_SIZE + 1) * PAGE_SIZE))
#define PAGE_SIZE (64 * 1024)

Archive::Archive(const string& archPath)
    : archPath(archPath)
{
}

void Archive::addFile(const string& filePath)
{
    paths.push_back(filePath);
}

void Archive::write()
{
    std::ofstream out(archPath, std::ofstream::binary);
    if (!out.is_open())
        BOOST_THROW_EXCEPTION(excp::FileNotWritable()  << excp::InfoFileName(archPath));

    // magic number
    out.write(MAGIC, sizeof(MAGIC));

    // number of files
    uint32_t num = paths.size();
    out.write((char*) &num, sizeof(num));

    uint64_t header_size = (uint64_t) out.tellp();
    // length of offsets
    header_size += paths.size() * sizeof(entry_t);

    // write file offsets
    entry_t* entries = new entry_t[paths.size()];
    entries[0].offset = ROUND_PAGE(header_size);
    for (int i = 0; i < paths.size(); i++)
    {
        std::ifstream input(paths[i]);
        if (!input.is_open())
            BOOST_THROW_EXCEPTION(excp::FileNotFoundException()  << excp::InfoFileName(paths[i]));
        input.seekg(0, input.end);
        uint64_t length = input.tellg();
        entries[i].length = length;

        if (i < paths.size() - 1)
            entries[i+1].offset = ROUND_PAGE(entries[i].offset + length);
    }
    out.write((char*) entries, paths.size() * sizeof(entry_t));
    delete[] entries;

    // padding
    while (out.tellp() % PAGE_SIZE != 0)
        out.write("\0", 1);

    // write files
    for (int i = 0; i < paths.size(); i++)
    {
        std::ifstream input(paths[i], std::ifstream::binary);
        if (!input.is_open())
            BOOST_THROW_EXCEPTION(excp::FileNotFoundException()  << excp::InfoFileName(paths[i]));
        out << input.rdbuf();

        // padding
        while (out.tellp() % PAGE_SIZE != 0)
            out.write("\0", 1);
    }
}

void Archive::getEntries(std::vector<Archive::entry_t>& entries)
{
    std::ifstream in(archPath, std::ifstream::binary);
    if (!in.is_open())
        BOOST_THROW_EXCEPTION(excp::FileNotFoundException()  << excp::InfoFileName(archPath));

    char buf[sizeof(MAGIC)];
    in.read(buf, sizeof(MAGIC));
    // check if CARTE file
    if (strncmp(buf, MAGIC, sizeof(MAGIC)) != 0)
        BOOST_THROW_EXCEPTION(excp::InputFormatException()  << excp::InfoFileName(archPath));

    uint32_t num;
    in.read((char*) &num, sizeof(num));

    for (int i = 0; i < num; i++)
    {
        entry_t e;
        in.read((char*) &e, sizeof(e));
        entries.push_back(e);
    }
}