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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,167 @@ | ||
| use std::collections::HashSet; | ||
|
|
||
| use crate::metainfo::Info; | ||
|
|
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| use super::bitfield::Bitfield; | ||
|
|
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| pub const BLOCK_SIZE: u32 = 2 << 13; // 16KB | ||
|
|
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| #[derive(Debug)] | ||
| pub struct Block { | ||
| begin: u32, | ||
| length: u32, | ||
| data: Vec<u8>, | ||
| requested: bool, | ||
| } | ||
|
|
||
| #[derive(Debug)] | ||
| pub struct Piece { | ||
| index: usize, | ||
| blocks: Vec<Block>, | ||
| hash: Vec<u8>, | ||
| completed: bool, | ||
| peers: HashSet<Vec<u8>>, | ||
| } | ||
|
|
||
| #[derive(Debug)] | ||
| pub struct Pieces { | ||
| pieces: Vec<Piece>, | ||
| any_complete: bool, | ||
| } | ||
|
|
||
| impl Pieces { | ||
| pub fn new(info_dict: &Info) -> Self { | ||
| let (piece_hashes, piece_length, file_size) = match info_dict { | ||
| Info::SingleFile(info) => ( | ||
| info.base_info.pieces.clone(), | ||
| info.base_info.piece_length, | ||
| info.length, | ||
| ), | ||
| Info::MultiFile(info) => ( | ||
| info.base_info.pieces.clone(), | ||
| info.base_info.piece_length, | ||
| info.files.iter().map(|f| f.length).sum(), | ||
| ), | ||
| }; | ||
|
|
||
| assert!( | ||
| piece_length as u32 % BLOCK_SIZE == 0, | ||
| "piece length must be a multiple of the block size" | ||
| ); | ||
|
|
||
| let mut remaining_size = file_size as u32; | ||
| let mut pieces = Vec::new(); | ||
| for (i, hash) in piece_hashes.iter().enumerate() { | ||
| let mut blocks = Vec::new(); | ||
| let mut offset: u32 = 0; | ||
| while offset < (piece_length as u32).min(remaining_size) { | ||
| let length = if remaining_size < BLOCK_SIZE { | ||
| remaining_size | ||
| } else { | ||
| BLOCK_SIZE | ||
| }; | ||
| let block = Block { | ||
| begin: offset, | ||
| length, | ||
| data: Vec::new(), | ||
| requested: false, | ||
| }; | ||
| blocks.push(block); | ||
|
|
||
| remaining_size -= length; | ||
| offset += length; | ||
| } | ||
|
|
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| let piece = Piece { | ||
| index: i, | ||
| blocks, | ||
| hash: hash.to_vec(), | ||
| completed: false, | ||
| peers: HashSet::new(), | ||
| }; | ||
| pieces.push(piece); | ||
| } | ||
|
|
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| Self { | ||
| pieces, | ||
| any_complete: false, | ||
| } | ||
| } | ||
|
|
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| pub fn len(&self) -> usize { | ||
| self.pieces.len() | ||
| } | ||
|
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||
| pub fn to_bitfield(&self) -> Bitfield { | ||
| let mut bitfield = Bitfield::new(self.len()); | ||
| for piece in &self.pieces { | ||
| bitfield.set(piece.index, piece.completed).unwrap(); | ||
| } | ||
| bitfield | ||
| } | ||
|
|
||
| fn get_rarest_noncompleted_piece(&self) -> &Piece { | ||
| self.pieces | ||
| .iter() | ||
| .filter(|p| !p.completed && p.blocks.iter().any(|b| !b.requested)) | ||
| .min_by_key(|p| p.peers.len()) | ||
| .unwrap() | ||
| } | ||
|
|
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| pub fn set_requested(&mut self, index: usize, begin: u32) { | ||
| let piece = &mut self.pieces[index]; | ||
|
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| let block_bucket: usize = begin.div_ceil(BLOCK_SIZE).try_into().unwrap(); | ||
| let block = &mut piece.blocks[block_bucket]; | ||
| block.requested = true; | ||
| } | ||
|
|
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| pub fn set_block(&mut self, index: usize, begin: u32, data: Vec<u8>) { | ||
| let piece = &mut self.pieces[index]; | ||
|
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| let block_bucket: usize = begin.div_ceil(BLOCK_SIZE).try_into().unwrap(); | ||
| let block = &mut piece.blocks[block_bucket]; | ||
| block.data = data; | ||
| } | ||
|
|
||
| pub fn add_peer_count(&mut self, peer_id: &Vec<u8>, bitfield: &Bitfield) { | ||
| for (i, bit) in bitfield.iter().enumerate() { | ||
| if *bit { | ||
| self.pieces[i].peers.insert(peer_id.clone()); | ||
| } | ||
| } | ||
| } | ||
|
|
||
| pub fn add_peer_have(&mut self, peer_id: &Vec<u8>, i: usize) { | ||
| self.pieces[i].peers.insert(peer_id.clone()); | ||
| } | ||
|
|
||
| pub fn remove_peer_count(&mut self, peer_id: &Vec<u8>, bitfield: &Bitfield) { | ||
| for (i, bit) in bitfield.iter().enumerate() { | ||
| if *bit { | ||
| self.pieces[i].peers.remove(peer_id); | ||
| } | ||
| } | ||
| } | ||
|
|
||
| pub fn get_block_to_download(&mut self) -> (usize, u32, u32) { | ||
| let piece = if !self.any_complete { | ||
| let pieces = self | ||
| .pieces | ||
| .iter() | ||
| .filter(|p| !p.completed && p.blocks.iter().any(|b| !b.requested)) | ||
| .collect::<Vec<&Piece>>(); | ||
| pieces[rand::random::<usize>() % pieces.len()] | ||
| } else { | ||
| self.get_rarest_noncompleted_piece() | ||
| }; | ||
|
|
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| let block = piece | ||
| .blocks | ||
| .iter() | ||
| .find(|b| !b.requested && b.data.is_empty()) | ||
| .unwrap(); | ||
|
|
||
| (piece.index, block.begin, block.length) | ||
| } | ||
| } |
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