[bencode] Decode lists
This commit is contained in:
parent
81017b3f90
commit
e2b2f8efca
261
src/bencode.rs
261
src/bencode.rs
@ -1,6 +1,6 @@
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use std::collections::HashMap;
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use std::collections::HashMap;
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use anyhow::{anyhow, Result};
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use anyhow::{anyhow, ensure, Result};
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/*struct FileInfo {
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/*struct FileInfo {
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length: i64,
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length: i64,
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@ -52,12 +52,15 @@ enum BencodeType {
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impl Bencode {
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impl Bencode {
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pub fn decode(input: &str) -> Result<Bencode> {
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pub fn decode(input: &str) -> Result<Bencode> {
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Self::decode_type(input.as_bytes())
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let (result, end_pos) = Self::decode_type(input.as_bytes())?;
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ensure!(end_pos == input.len() - 1,
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"Could not fully decode input. Got {} chars left to decode", input.len() - 1 - end_pos);
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Ok(result)
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}
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}
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fn decode_type(input: &[u8]) -> Result<Bencode>{
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fn decode_type(input: &[u8]) -> Result<(Bencode, usize)>{
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if input.len() == 0 {
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if input.len() == 0 {
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return Err(anyhow!("Empty string is not valid bencode"));
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return Err(anyhow!("Empty string is not valid bencode"))
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}
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}
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let char = input[0] as char;
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let char = input[0] as char;
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let type_ = match char {
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let type_ = match char {
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@ -65,33 +68,50 @@ impl Bencode {
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'l' => Ok(BencodeType::List),
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'l' => Ok(BencodeType::List),
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'd' => Ok(BencodeType::Dict),
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'd' => Ok(BencodeType::Dict),
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'0'..='9' => Ok(BencodeType::Bytes),
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'0'..='9' => Ok(BencodeType::Bytes),
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_ => Err(anyhow!("Unknown bencoding char: {char}")),
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_ => Err(anyhow!("Invalid bencoding start char: {char}")),
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}?;
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}?;
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let end_char = match type_ {
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let end_to_decode = match type_ {
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BencodeType::Integer | BencodeType::List | BencodeType::Dict=> 'e',
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BencodeType::List | BencodeType::Dict => {
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BencodeType::Bytes => ':'
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input.len()
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};
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let mut end_pos= 1;
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for &c in &input[1..] {
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if c == end_char as u8 {
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break
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}
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end_pos += 1;
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}
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let to_decode = match type_ {
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BencodeType::Integer | BencodeType::List | BencodeType::Dict=> &input[1..end_pos],
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BencodeType::Bytes => {
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let bytes_len = Self::decode_int_only(&input[0..end_pos])? as usize;
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let bytes_start= end_pos + 1;
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&input[bytes_start..bytes_start + bytes_len]
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},
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},
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BencodeType::Integer | BencodeType::Bytes => {
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let end_char = match type_ {
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BencodeType::Integer => Ok('e'),
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BencodeType::Bytes => Ok(':'),
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_ => Err(anyhow!("Should be logically impossible"))
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}?;
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let result = input.iter().position(|&x| x == end_char as u8).ok_or_else(|| anyhow!("Could not find terminating character {end_char}"))?;
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result
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}
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};
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let (to_decode, end_decoded) = match type_ {
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BencodeType::Integer => (&input[1..end_to_decode], end_to_decode),
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BencodeType::Bytes => {
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let bytes_len = Self::decode_int_only(&input[0..end_to_decode])? as usize;
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let bytes_start= end_to_decode + 1;
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let end_pos = bytes_start + bytes_len;
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(&input[bytes_start..end_pos], end_pos - 1)
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},
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BencodeType::List | BencodeType::Dict => (&input[1..end_to_decode], 0),
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};
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};
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match type_ {
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match type_ {
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BencodeType::Integer => Self::decode_int(to_decode),
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BencodeType::Integer => {
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BencodeType::List => Self::dummy(to_decode),
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let result = Self::decode_int(to_decode)?;
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BencodeType::Dict => Self::dummy(to_decode),
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Ok((result, end_decoded))
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BencodeType::Bytes => Self::decode_bytes(to_decode),
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},
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BencodeType::Bytes => {
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let result = Self::decode_bytes(to_decode)?;
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Ok((result, end_decoded))
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},
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BencodeType::List => {
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let (result, end_pos) = Self::decode_list(to_decode)?;
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Ok((result, end_pos + 1))
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},
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BencodeType::Dict => {
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let result = Self::dummy(to_decode)?;
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Ok((result, end_decoded))
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},
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}
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}
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}
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}
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@ -109,6 +129,23 @@ impl Bencode {
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Ok(Bencode::Bytes(ByteString::from_slice(input)))
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Ok(Bencode::Bytes(ByteString::from_slice(input)))
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}
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}
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fn decode_list(input: &[u8]) -> Result<(Bencode, usize)> {
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let mut result = Vec::new();
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let mut decoded_pos = 0;
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loop {
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if decoded_pos >= input.len() {
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return Err(anyhow!("Unfinished list. Could not find terminating character 'e'"))
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}
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if input[decoded_pos] == 'e' as u8 {
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break;
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}
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let (li_result, end_pos ) = Self::decode_type(&input[decoded_pos..])?;
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result.push(li_result);
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decoded_pos += end_pos + 1;
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}
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Ok((Bencode::List(result), decoded_pos))
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}
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fn dummy(_input: &[u8]) -> Result<Bencode> {
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fn dummy(_input: &[u8]) -> Result<Bencode> {
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Ok(Bencode::Integer(42))
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Ok(Bencode::Integer(42))
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}
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}
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@ -146,16 +183,172 @@ mod tests {
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assert_eq!(Bencode::decode_bytes("💩".as_bytes()).unwrap(), Bencode::Bytes(ByteString::from_str("💩")));
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assert_eq!(Bencode::decode_bytes("💩".as_bytes()).unwrap(), Bencode::Bytes(ByteString::from_str("💩")));
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}
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}
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fn test_encode_bytes(input: &str) -> String {
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format!("{}:{input}", input.len())
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}
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#[test]
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#[test]
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fn test_bytes_str() {
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fn test_bytes_str() {
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let str = "hallo";
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assert_eq!(Bencode::decode(test_encode_bytes("hallo").as_str()).unwrap(), Bencode::Bytes(ByteString::from_str("hallo")));
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assert_eq!(Bencode::decode(format!("{}:{str}", str.len()).as_str()).unwrap(), Bencode::Bytes(ByteString::from_str("hallo")));
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assert_eq!(Bencode::decode(test_encode_bytes("tschüss").as_str()).unwrap(), Bencode::Bytes(ByteString::from_str("tschüss")));
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let str = "tschüss";
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assert_eq!(Bencode::decode(test_encode_bytes("💩").as_str()).unwrap(), Bencode::Bytes(ByteString::from_str("💩")));
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assert_eq!(Bencode::decode(format!("{}:{str}", str.len()).as_str()).unwrap(), Bencode::Bytes(ByteString::from_str("tschüss")));
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assert_eq!(Bencode::decode(test_encode_bytes("hallo 💩, this is a long text").as_str()).unwrap(), Bencode::Bytes(ByteString::from_str("hallo 💩, this is a long text")));
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let str = "💩";
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}
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assert_eq!(Bencode::decode(format!("{}:{str}", str.len()).as_str()).unwrap(), Bencode::Bytes(ByteString::from_str("💩")));
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let str = "hallo 💩, this is a long text";
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#[test]
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assert_eq!(Bencode::decode(format!("{}:{str}", str.len()).as_str()).unwrap(), Bencode::Bytes(ByteString::from_str("hallo 💩, this is a long text")));
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fn test_list() {
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assert_eq!(Bencode::decode_list(
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("e").as_bytes()).unwrap(),
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(Bencode::List(Vec::new()), 0)
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);
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let str = "i42ee";
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assert_eq!(Bencode::decode_list(
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str.as_bytes()).unwrap(),
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(
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Bencode::List(vec![
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Bencode::Integer(42),
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]),
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str.len() - 1,
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)
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);
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let str = format!("{}e", test_encode_bytes("hallo"));
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assert_eq!(Bencode::decode_list(
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str.as_bytes()).unwrap(),
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(
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Bencode::List(vec![
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Bencode::Bytes(ByteString::from_str("hallo")),
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]),
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str.len() - 1,
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)
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);
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let str = format!("{}{}e", test_encode_bytes("hallo"), "i42e");
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assert_eq!(Bencode::decode_list(
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str.as_bytes()).unwrap(),
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(
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Bencode::List(vec![
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Bencode::Bytes(ByteString::from_str("hallo")),
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Bencode::Integer(42),
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]),
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str.len() - 1,
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)
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);
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let str = format!("{}{}{}{}e", "i-17e", test_encode_bytes("hallo"), "i42e", test_encode_bytes("tschüssi💩"));
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assert_eq!(Bencode::decode_list(
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str.as_bytes()).unwrap(),
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(
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Bencode::List(vec![
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Bencode::Integer(-17),
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Bencode::Bytes(ByteString::from_str("hallo")),
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Bencode::Integer(42),
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Bencode::Bytes(ByteString::from_str("tschüssi💩")),
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]),
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str.len() - 1,
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)
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);
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}
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#[test]
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fn test_multi_list() {
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assert_eq!(Bencode::decode_list(
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("lelee").as_bytes()).unwrap(),
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(Bencode::List(vec![
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Bencode::List(Vec::new()),
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Bencode::List(Vec::new()),
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]),
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4)
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);
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let str = format!("l{}{}ee", test_encode_bytes("hallo"), "i42e");
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assert_eq!(Bencode::decode_list(
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str.as_bytes()).unwrap(),
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(Bencode::List(vec![
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Bencode::List(vec![
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Bencode::Bytes(ByteString::from_str("hallo")),
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Bencode::Integer(42),
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]),
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]),
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str.len() - 1)
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);
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let str = format!("l{}{}el{}{}{}ee", test_encode_bytes("hallo"), "i42e", "i17e", test_encode_bytes("tschüss💩"), "i33e");
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assert_eq!(Bencode::decode_list(
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str.as_bytes()).unwrap(),
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(Bencode::List(vec![
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Bencode::List(vec![
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Bencode::Bytes(ByteString::from_str("hallo")),
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Bencode::Integer(42),
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]),
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Bencode::List(vec![
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Bencode::Integer(17),
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Bencode::Bytes(ByteString::from_str("tschüss💩")),
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Bencode::Integer(33),
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]),
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]),
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str.len() - 1)
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);
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}
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#[test]
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fn test_list_str() {
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assert_eq!(Bencode::decode(
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"le").unwrap(),
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Bencode::List(Vec::new())
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);
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assert_eq!(Bencode::decode(
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"li42ee").unwrap(),
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Bencode::List(vec![
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Bencode::Integer(42),
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])
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);
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assert_eq!(Bencode::decode(
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(format!("l{}e", test_encode_bytes("hallo"))).as_str()).unwrap(),
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Bencode::List(vec![
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Bencode::Bytes(ByteString::from_str("hallo")),
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])
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);
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assert_eq!(Bencode::decode(
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(format!("l{}{}e", test_encode_bytes("hallo"), "i42e")).as_str()).unwrap(),
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Bencode::List(vec![
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Bencode::Bytes(ByteString::from_str("hallo")),
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Bencode::Integer(42),
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])
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);
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assert_eq!(Bencode::decode(
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(format!("l{}{}{}{}e", "i-17e", test_encode_bytes("hallo"), "i42e", test_encode_bytes("tschüssi💩"))).as_str()).unwrap(),
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Bencode::List(vec![
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Bencode::Integer(-17),
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Bencode::Bytes(ByteString::from_str("hallo")),
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Bencode::Integer(42),
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Bencode::Bytes(ByteString::from_str("tschüssi💩")),
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])
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);
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assert_eq!(Bencode::decode("llelee").unwrap(),
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Bencode::List(vec![
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Bencode::List(Vec::new()),
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Bencode::List(Vec::new()),
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]),
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);
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let str = format!("ll{}{}ee", test_encode_bytes("hallo"), "i42e");
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assert_eq!(Bencode::decode(&str).unwrap(),
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Bencode::List(vec![
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Bencode::List(vec![
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Bencode::Bytes(ByteString::from_str("hallo")),
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Bencode::Integer(42),
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]),
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]),
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);
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let str = format!("ll{}{}el{}{}{}ee", test_encode_bytes("hallo"), "i42e", "i17e", test_encode_bytes("tschüss💩"), "i33e");
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assert_eq!(Bencode::decode(&str).unwrap(),
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Bencode::List(vec![
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Bencode::List(vec![
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Bencode::Bytes(ByteString::from_str("hallo")),
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Bencode::Integer(42),
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]),
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Bencode::List(vec![
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Bencode::Integer(17),
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Bencode::Bytes(ByteString::from_str("tschüss💩")),
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Bencode::Integer(33),
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]),
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]),
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);
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}
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}
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}
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}
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