zip-wrapper.h

/*
  Copyright (c) 2017 Sven Willner <sven.willner@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 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.
*/

#ifndef ZIP_WRAPPER_H
#define ZIP_WRAPPER_H

#include <zip.h>

#include <exception>
#include <iostream>
#include <string>
#include <vector>

namespace libzip {
class exception : public std::runtime_error {
  public:
    explicit exception(const std::string& msg) : std::runtime_error(msg) {}
};

class streambuf : public std::streambuf {
  private:
    zip_file* m;
    std::vector<char> buffer;

  public:
    explicit streambuf(zip_file* file, std::size_t buffer_size = 4096) : m(file), buffer(buffer_size) {
        char* end = &buffer[0] + buffer_size;
        setg(end, end, end);
    }
    streambuf(const streambuf&) = delete;
    streambuf(streambuf&&) = default;
    streambuf& operator=(const streambuf&) = delete;
    streambuf& operator=(streambuf&&) = default;

  private:
    std::streambuf::int_type underflow() override {
        if (gptr() < egptr()) {
            return traits_type::to_int_type(*gptr());
        }
        char* start = &buffer[0];
        const size_t n = zip_fread(m, start, buffer.size());
        if (n < 0) {
            throw exception("could not read from zipped file");
        }
        if (n == 0) {
            return traits_type::eof();
        }
        setg(start, start, start + n);
        return traits_type::to_int_type(*gptr());
    }
};

class ifstream : public std::istream {
  private:
    zip_file* m;

  public:
    explicit ifstream(zip_file* file) : m(file), std::istream(new streambuf(file)) {}
    ifstream(ifstream&& other) = default;
    virtual ~ifstream() {
        delete rdbuf();
        zip_fclose(m);
    };
};

class File {};

class Archive {
  private:
    zip* m;

  public:
    explicit Archive(const std::string& filename) {
        int err;
        m = zip_open(filename.c_str(), 0, &err);
        if (!m) {
            char buf[256];
            zip_error_to_str(buf, sizeof(buf), err, errno);
            throw exception(buf);
        }
    }
    ~Archive() { zip_close(m); }
    zip* get_handle() { return m; }
    ifstream open(const std::string& name, zip_flags_t flags = 0, const std::string& password = "") {
        zip_file* file;

        if (password.size() > 0) {
            file = zip_fopen_encrypted(m, name.c_str(), flags, password.c_str());
        } else {
            file = zip_fopen(m, name.c_str(), flags);
        }

        if (file == nullptr) {
            throw exception(zip_strerror(m));
        }

        return ifstream(file);
    }
};
}  // namespace libzip

#endif