transmission/libtransmission/file-piece-map.h

188 lines
4.7 KiB
C++

// This file Copyright © Mnemosyne LLC.
// It may be used under GPLv2 (SPDX: GPL-2.0-only), GPLv3 (SPDX: GPL-3.0-only),
// or any future license endorsed by Mnemosyne LLC.
// License text can be found in the licenses/ folder.
#pragma once
#ifndef __TRANSMISSION__
#error only libtransmission should #include this header.
#endif
#include <algorithm> // for std::binary_search()
#include <cstdint> // for uint64_t
#include <cstddef> // for size_t
#include <vector>
#include "libtransmission/transmission.h"
#include "libtransmission/bitfield.h"
#include "libtransmission/tr-macros.h" // TR_CONSTEXPR20
#include "libtransmission/utils.h"
struct tr_block_info;
struct tr_torrent_metainfo;
class tr_file_piece_map
{
public:
template<typename T>
struct index_span_t
{
T begin;
T end;
};
using file_span_t = index_span_t<tr_file_index_t>;
using piece_span_t = index_span_t<tr_piece_index_t>;
template<typename T>
struct offset_t
{
T index;
uint64_t offset;
};
using file_offset_t = offset_t<tr_file_index_t>;
explicit tr_file_piece_map(tr_torrent_metainfo const& tm)
{
reset(tm);
}
tr_file_piece_map(tr_block_info const& block_info, uint64_t const* file_sizes, size_t n_files)
{
reset(block_info, file_sizes, n_files);
}
void reset(tr_torrent_metainfo const& tm);
[[nodiscard]] TR_CONSTEXPR20 piece_span_t piece_span(tr_file_index_t file) const noexcept
{
return file_pieces_[file];
}
[[nodiscard]] file_span_t file_span(tr_piece_index_t piece) const;
[[nodiscard]] file_offset_t file_offset(uint64_t offset, bool include_empty_files) const;
[[nodiscard]] TR_CONSTEXPR20 size_t size() const
{
return std::size(file_pieces_);
}
[[nodiscard]] TR_CONSTEXPR20 bool empty() const noexcept
{
return std::empty(file_pieces_);
}
// TODO(ckerr) minor wart here, two identical span types
[[nodiscard]] TR_CONSTEXPR20 tr_byte_span_t byte_span(tr_file_index_t file) const
{
auto const& span = file_bytes_[file];
return tr_byte_span_t{ span.begin, span.end };
}
[[nodiscard]] TR_CONSTEXPR20 bool is_edge_piece(tr_piece_index_t piece) const
{
return std::binary_search(std::begin(edge_pieces_), std::end(edge_pieces_), piece);
}
private:
void reset(tr_block_info const& block_info, uint64_t const* file_sizes, size_t n_files);
using byte_span_t = index_span_t<uint64_t>;
std::vector<byte_span_t> file_bytes_;
std::vector<piece_span_t> file_pieces_;
std::vector<tr_piece_index_t> edge_pieces_;
template<typename T>
struct CompareToSpan
{
using span_t = index_span_t<T>;
[[nodiscard]] constexpr int compare(T item, span_t span) const // <=>
{
if (include_empty_span && span.begin == span.end)
{
return tr_compare_3way(item, span.begin);
}
if (item < span.begin)
{
return -1;
}
if (item >= span.end)
{
return 1;
}
return 0;
}
[[nodiscard]] constexpr bool operator()(T item, span_t span) const // <
{
return compare(item, span) < 0;
}
[[nodiscard]] constexpr int compare(span_t span, T item) const // <=>
{
return -compare(item, span);
}
[[nodiscard]] constexpr bool operator()(span_t span, T item) const // <
{
return compare(span, item) < 0;
}
bool const include_empty_span;
};
};
class tr_file_priorities
{
public:
TR_CONSTEXPR20 explicit tr_file_priorities(tr_file_piece_map const* fpm) noexcept
: fpm_{ fpm }
{
}
void reset(tr_file_piece_map const*);
void set(tr_file_index_t file, tr_priority_t priority);
void set(tr_file_index_t const* files, size_t n, tr_priority_t priority);
[[nodiscard]] tr_priority_t file_priority(tr_file_index_t file) const;
[[nodiscard]] tr_priority_t piece_priority(tr_piece_index_t piece) const;
private:
tr_file_piece_map const* fpm_;
std::vector<tr_priority_t> priorities_;
};
class tr_files_wanted
{
public:
explicit tr_files_wanted(tr_file_piece_map const* fpm)
: wanted_{ std::size(*fpm) }
{
reset(fpm);
}
void reset(tr_file_piece_map const* fpm);
void set(tr_file_index_t file, bool wanted);
void set(tr_file_index_t const* files, size_t n, bool wanted);
[[nodiscard]] TR_CONSTEXPR20 bool file_wanted(tr_file_index_t file) const
{
return wanted_.test(file);
}
[[nodiscard]] bool piece_wanted(tr_piece_index_t piece) const;
private:
tr_file_piece_map const* fpm_;
tr_bitfield wanted_;
};