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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,144 @@ | ||
| // byte-encoding of objects used in BitTorrent protocol | ||
|
|
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| import std::value::{ Value } | ||
| import std::buffer::{ Buffer } | ||
| import std::sv::{ SV } | ||
| import std::span::{ Location, Span } | ||
| import std::vector::{ Vector } | ||
| import std::compact_map::{ Map } | ||
|
|
||
| struct Parser { | ||
| input: SV | ||
| loc: Location | ||
| } | ||
|
|
||
| def Parser::new(input: Buffer): Parser { | ||
| return Parser( | ||
| input: input.sv(), | ||
| loc: Location( | ||
| filename: "<bencoded string>", | ||
| line: 1, | ||
| col: 1, | ||
| index: 0, | ||
| ) | ||
| ) | ||
| } | ||
|
|
||
| def Parser::cur(&this): char => .input.data[.loc.index] as char | ||
|
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| def Parser::parse(&this): &Value { | ||
| let start = .loc | ||
| let val = match .cur() { | ||
| 'i' => .parse_int() | ||
| 'l' => .parse_list() | ||
| 'd' => .parse_dict() | ||
| else => .parse_string() | ||
| } | ||
| val.span = Span(start, .loc) | ||
| return val | ||
| } | ||
|
|
||
| def Parser::inc(&this) => .loc.index += 1 | ||
|
|
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| def Parser::parse_int_internal(&this): i64 { | ||
| let scale = 1i64 | ||
| if .cur() == '-' { | ||
| scale = -1 | ||
| .inc() | ||
| } | ||
| let num = 0i64 | ||
| while .cur().is_digit() { | ||
| num *= 10 | ||
| num += .cur() as i64 - '0' as i64 | ||
| .inc() | ||
| } | ||
| return num * scale | ||
| } | ||
|
|
||
| def Parser::parse_list(&this): &Value { | ||
| let val = Value::new(List) | ||
| val.u.as_list = Vector<&Value>::new() | ||
| .inc() // skip 'l' | ||
| while .cur() != 'e' { | ||
| val.u.as_list.push(.parse()) | ||
| } | ||
| .inc() // skip 'e' | ||
| return val | ||
| } | ||
|
|
||
| def Parser::parse_dict(&this): &Value { | ||
| let val = Value::new(Dictionary) | ||
| val.u.as_dict = Map<str, &Value>::new() | ||
| .inc() // skip 'l' | ||
| while .cur() != 'e' { | ||
| let key = .parse_string_internal() | ||
| let value = .parse() | ||
| val.u.as_dict.insert(key.str(), value) | ||
| } | ||
| .inc() // skip 'e' | ||
| return val | ||
| } | ||
|
|
||
| def Parser::parse_string_internal(&this): Buffer { | ||
| let len = .parse_int_internal() as u32 | ||
| .inc() // skip ':' | ||
| let s = .input.slice(.loc.index, .loc.index + len) | ||
|
|
||
| for let i = 0; i < len; i++ { | ||
| .inc() | ||
| } | ||
| return Buffer::from_sv(s) | ||
| } | ||
|
|
||
| def Parser::parse_string(&this): &Value { | ||
| let val = Value::new(String) | ||
| val.u.as_str = .parse_string_internal() | ||
| return val | ||
| } | ||
|
|
||
| def Parser::parse_int(&this): &Value { | ||
| let val = Value::new(Integer) | ||
| .inc() // skip 'i' | ||
| let num = .parse_int_internal() | ||
| .inc() // skip 'e' | ||
| val.u.as_int = num | ||
| return val | ||
| } | ||
|
|
||
| def parse(input: Buffer): &Value { | ||
| let parser = Parser::new(input) | ||
| return parser.parse() | ||
| } | ||
|
|
||
| def serialize_into(val: &Value, sb: &Buffer) { | ||
| match val.type { | ||
| String => { | ||
| let s = val.u.as_str | ||
| sb.putsf(`{s.size}:`) | ||
| sb.putb(&s) | ||
| } | ||
| Integer => sb.putsf(`i{val.u.as_int}e`) | ||
| List => { | ||
| sb.puts("l") | ||
| for val : val.u.as_list.iter() { | ||
| serialize_into(val, sb) | ||
| } | ||
| sb.puts("e") | ||
| } | ||
| Dictionary => { | ||
| sb.puts("d") | ||
| for it : val.u.as_dict.iter() { | ||
| sb.putsf(`{it.key.len()}:{it.key}`) | ||
| serialize_into(it.value, sb) | ||
| } | ||
| sb.puts("e") | ||
| } | ||
| else => panic(`Unsupported Value type {val.type} in Bencode::serialize_into()`) | ||
| } | ||
| } | ||
|
|
||
| def serialize(val: &Value): Buffer { | ||
| let sb = Buffer::make() | ||
| serialize_into(val, &sb) | ||
| return sb | ||
| } |