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transmission/libtransmission/block-info.h
Charles Kerr 742ae6fb00
refactor: minor naming change in block_info (#2233)
* refactor: rename method as block_info.pieceSize()

* refactor: rename method as block_info.blockSize()
2021-11-26 13:33:56 -06:00

96 lines
2.6 KiB
C++

/*
* This file Copyright (C) Mnemosyne LLC
*
* It may be used under the GNU GPL versions 2 or 3
* or any future license endorsed by Mnemosyne LLC.
*
*/
#pragma once
#ifndef __TRANSMISSION__
#error only libtransmission should #include this header.
#endif
#include "transmission.h"
#include "metainfo.h"
struct tr_block_info
{
uint64_t total_size = 0;
uint64_t piece_size = 0;
uint64_t n_pieces = 0;
tr_block_index_t n_blocks = 0;
tr_block_index_t n_blocks_in_piece = 0;
tr_block_index_t n_blocks_in_final_piece = 0;
uint32_t block_size = 0;
uint32_t final_block_size = 0;
uint32_t final_piece_size = 0;
tr_block_info() = default;
tr_block_info(uint64_t total_size_in, uint64_t piece_size_in)
{
initSizes(total_size_in, piece_size_in);
}
void initSizes(uint64_t total_size_in, uint64_t piece_size_in);
constexpr tr_piece_index_t pieceForBlock(tr_block_index_t block) const
{
return n_blocks_in_piece ? block / n_blocks_in_piece : 0;
}
constexpr uint32_t pieceSize(tr_piece_index_t piece) const
{
// how many bytes are in this piece?
return piece + 1 == n_pieces ? final_piece_size : piece_size;
}
constexpr uint32_t blockSize(tr_block_index_t block) const
{
// how many bytes are in this block?
return block + 1 == n_blocks ? final_block_size : block_size;
}
constexpr tr_piece_index_t pieceOf(uint64_t offset) const
{
// handle 0-byte files at the end of a torrent
return offset == total_size ? n_pieces - 1 : offset / piece_size;
}
constexpr tr_block_index_t blockOf(uint64_t offset) const
{
// handle 0-byte files at the end of a torrent
return offset == total_size ? n_blocks - 1 : offset / block_size;
}
constexpr uint64_t offset(tr_piece_index_t piece, uint32_t offset, uint32_t length = 0) const
{
auto ret = piece_size;
ret *= piece;
ret += offset;
ret += length;
return ret;
}
constexpr tr_block_index_t blockOf(tr_piece_index_t piece, uint32_t offset, uint32_t length = 0) const
{
return blockOf(this->offset(piece, offset, length));
}
constexpr tr_block_span_t blockSpanForPiece(tr_piece_index_t piece) const
{
if (block_size == 0)
{
return {};
}
auto const begin = blockOf(offset(piece, 0));
auto const end = 1 + blockOf(offset(piece, pieceSize(piece) - 1));
return { begin, end };
}
static uint32_t bestBlockSize(uint64_t piece_size);
};