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use std::cmp;
use std::convert::Into;
use std::collections::hash_map::HashMap;
use std::io::{self, Read};
use std::mem::transmute;
use byteorder::{ReadBytesExt, BigEndian};
use rustc_serialize::Decodable;
use rustc_decoder::CborDecoder;
use {
Cbor, CborUnsigned, CborSigned, CborFloat, CborBytes, CborTag, Type,
CborResult, CborError, ReadError,
};
pub struct Decoder<R> {
rdr: CborReader<R>,
}
impl<R: io::Read> Decoder<R> {
pub fn from_reader(rdr: R) -> Decoder<io::BufReader<R>> {
Decoder { rdr: CborReader::new(io::BufReader::new(rdr)) }
}
}
fn is_indefinite(first: u8) -> bool {
(first & 0b000_11111) == 0b000_11111
}
impl<R: io::Read> Decoder<R> {
pub fn decode<D: Decodable>(&mut self) -> DecodedItems<R, D> {
DecodedItems {
it: self.items(),
_phantom: ::std::marker::PhantomData,
}
}
pub fn items(&mut self) -> Items<R> {
Items { dec: self }
}
fn read_data_item(&mut self, first: Option<u8>) -> CborResult<Cbor> {
let first = match first {
Some(first) => first,
None => try!(self.rdr.read_u8()),
};
match (first & 0b111_00000) >> 5 {
0 => self.read_uint(first).map(Cbor::Unsigned),
1 => self.read_int(first).map(Cbor::Signed),
2 => self.read_bytes(first),
3 => self.read_string(first),
4 => self.read_array(first),
5 => self.read_map(first),
6 => self.read_tag(first),
7 => match first & 0b000_11111 {
v @ 0...23 => self.read_simple_value(v),
24 => {
let b = try!(self.rdr.read_u8());
self.read_simple_value(b)
}
25...27 => self.read_float(first).map(Cbor::Float),
v @ 28...30 =>
Err(self.errat(
ReadError::Unassigned { major: 7, add: v })),
31 => Ok(Cbor::Break),
_ => unreachable!(),
},
_ => unreachable!(),
}
}
fn read_simple_value(&mut self, val: u8) -> CborResult<Cbor> {
Ok(match val {
v @ 0...19 =>
return Err(self.errat(
ReadError::Unassigned { major: 7, add: v })),
20 => Cbor::Bool(false),
21 => Cbor::Bool(true),
22 => Cbor::Null,
23 => Cbor::Undefined,
v @ 24...31 =>
return Err(self.errat(
ReadError::Reserved { major: 7, add: v })),
v =>
return Err(self.errat(
ReadError::Unassigned { major: 7, add: v })),
})
}
fn read_float(&mut self, first: u8) -> CborResult<CborFloat> {
Ok(match first & 0b000_11111 {
25 => {
let n = try!(self.rdr.read_u16::<BigEndian>());
CborFloat::Float16(unsafe { transmute(n as u32) })
}
26 => CborFloat::Float32(try!(self.rdr.read_f32::<BigEndian>())),
27 => CborFloat::Float64(try!(self.rdr.read_f64::<BigEndian>())),
v => return Err(self.errat(
ReadError::InvalidAddValue { ty: Type::Float, val: v })),
})
}
fn read_tag(&mut self, first: u8) -> CborResult<Cbor> {
let tag = self.read_uint(first)?;
let tag = try!(tag.to_u64().map_err(|err| self.errat(err)));
let data = try!(self.read_data_item(None));
Ok(Cbor::Tag(CborTag { tag: tag, data: Box::new(data) }))
}
fn read_map_key(&mut self, first: Option<u8>) -> CborResult<String> {
let at = self.rdr.bytes_read;
match self.read_data_item(first)? {
Cbor::Unicode(s) => Ok(s),
Cbor::Bytes(CborBytes(bytes)) => {
match String::from_utf8(bytes) {
Ok(s) => Ok(s),
Err(err) => return Err(CborError::AtOffset {
kind: ReadError::Other(err.to_string()),
offset: at,
}),
}
}
v => return Err(CborError::AtOffset {
kind: ReadError::mismatch(Type::Unicode, &v),
offset: at,
}),
}
}
fn read_map(&mut self, first: u8) -> CborResult<Cbor> {
let mut map: HashMap<String,Cbor>;
if is_indefinite(first) {
map = HashMap::new();
loop {
let first = self.rdr.read_u8()?;
if 0xff == first {
break;
}
let key = self.read_map_key(Some(first))?;
let val = self.read_data_item(None)?;
map.insert(key, val);
}
}else {
let len = try!(self.read_len(first));
map = HashMap::with_capacity(len);
for _ in 0..len {
let key = self.read_map_key(None)?;
let val = try!(self.read_data_item(None));
map.insert(key, val);
}
}
Ok(Cbor::Map(map))
}
fn read_array(&mut self, first: u8) -> CborResult<Cbor> {
let mut array: Vec<Cbor>;
if is_indefinite(first) {
array = vec![];
loop {
let v = self.read_data_item(None)?;
if Cbor::Break == v {
break
}
array.push(v)
}
} else {
let len = self.read_len(first)?;
array = Vec::with_capacity(cmp::min(100000, len));
for _ in 0..len {
let v = self.read_data_item(None)?;
array.push(v);
}
}
Ok(Cbor::Array(array))
}
fn read_string(&mut self, first: u8) -> CborResult<Cbor> {
if is_indefinite(first) {
let mut chunks: Vec<String> = vec![];
loop {
let at = self.rdr.bytes_read;
match self.read_data_item(None)? {
Cbor::Unicode(u) => chunks.push(u),
Cbor::Break => return Ok(Cbor::Unicode(chunks.concat())),
other => return Err(CborError::AtOffset {
kind: ReadError::mismatch(Type::Unicode, &other),
offset: at
})
}
}
} else {
let len = try!(self.read_len(first));
let mut buf: Vec<u8> = vec_from_elem(len, 0u8);
try!(self.rdr.read_full(&mut buf));
String::from_utf8(buf)
.map(Cbor::Unicode)
.map_err(|err| self.errstr(err.utf8_error().to_string()))
}
}
fn read_bytes(&mut self, first: u8) -> CborResult<Cbor> {
if is_indefinite(first) {
let mut chunks: Vec<Vec<u8>> = vec![];
loop {
let at = self.rdr.bytes_read;
match self.read_data_item(None)? {
Cbor::Bytes(b) => chunks.push(b.to_vec()),
Cbor::Break => return Ok(Cbor::Bytes(CborBytes(chunks.concat()))),
other => return Err(CborError::AtOffset {
kind: ReadError::mismatch(Type::Bytes, &other),
offset: at,
})
}
}
} else {
let len = try!(self.read_len(first));
let mut buf = vec_from_elem(len, 0u8);
try!(self.rdr.read_full(&mut buf));
Ok(Cbor::Bytes(CborBytes(buf)))
}
}
fn read_len(&mut self, first: u8) -> CborResult<usize> {
self.read_uint(first)
.and_then(|v| v.to_usize().map_err(|err| self.errat(err)))
}
fn read_uint(&mut self, first: u8) -> CborResult<CborUnsigned> {
Ok(match first & 0b000_11111 {
n @ 0...23 => CborUnsigned::UInt8(n),
24 => CborUnsigned::UInt8(try!(self.rdr.read_u8())),
25 => CborUnsigned::UInt16(try!(self.rdr.read_u16::<BigEndian>())),
26 => CborUnsigned::UInt32(try!(self.rdr.read_u32::<BigEndian>())),
27 => CborUnsigned::UInt64(try!(self.rdr.read_u64::<BigEndian>())),
v => return Err(self.errat(
ReadError::InvalidAddValue { ty: Type::UInt, val: v })),
})
}
fn read_int(&mut self, first: u8) -> CborResult<CborSigned> {
Ok(match first & 0b000_11111 {
n @ 0...23 => CborSigned::Int8(-1 - (n as i8)),
24 => {
let n = try!(self.rdr.read_u8());
if n > ::std::i8::MAX as u8 {
CborSigned::Int16(-1 - (n as i16))
} else {
CborSigned::Int8(-1 - (n as i8))
}
}
25 => {
let n = try!(self.rdr.read_u16::<BigEndian>());
if n > ::std::i16::MAX as u16 {
CborSigned::Int32(-1 - (n as i32))
} else {
CborSigned::Int16(-1 - (n as i16))
}
}
26 => {
let n = try!(self.rdr.read_u32::<BigEndian>());
if n > ::std::i32::MAX as u32 {
CborSigned::Int64(-1 - (n as i64))
} else {
CborSigned::Int32(-1 - (n as i32))
}
}
27 => {
let n = try!(self.rdr.read_u64::<BigEndian>());
if n > ::std::i64::MAX as u64 {
return Err(self.errstr(format!(
"Negative integer out of range: {:?}", n)));
}
CborSigned::Int64(-1 - (n as i64))
}
v => return Err(self.errat(
ReadError::InvalidAddValue { ty: Type::Int, val: v })),
})
}
}
impl Decoder<io::Cursor<Vec<u8>>> {
pub fn from_bytes<T>(bytes: T) -> Decoder<io::Cursor<Vec<u8>>>
where T: Into<Vec<u8>> {
Decoder { rdr: CborReader::new(io::Cursor::new(bytes.into())) }
}
}
impl<R: io::Read> Decoder<R> {
fn errat(&self, err: ReadError) -> CborError {
CborError::AtOffset { kind: err, offset: self.rdr.last_offset }
}
fn errstr(&self, s: String) -> CborError {
self.errat(ReadError::Other(s))
}
}
pub struct DecodedItems<'a, R: 'a, D> {
it: Items<'a, R>,
_phantom: ::std::marker::PhantomData<D>,
}
impl<'a, R: io::Read, D: Decodable> Iterator for DecodedItems<'a, R, D> {
type Item = CborResult<D>;
fn next(&mut self) -> Option<CborResult<D>> {
self.it.next().map(|result| {
result.and_then(|v| Decodable::decode(&mut CborDecoder::new(v)))
})
}
}
pub struct Items<'a, R: 'a> {
dec: &'a mut Decoder<R>,
}
impl<'a, R: io::Read> Iterator for Items<'a, R> {
type Item = CborResult<Cbor>;
fn next(&mut self) -> Option<CborResult<Cbor>> {
let first = match self.dec.rdr.read_u8().map_err(CborError::from) {
Ok(v) => v,
Err(ref err) if err.is_eof() => return None,
Err(err) => return Some(Err(err)),
};
Some(self.dec.read_data_item(Some(first)))
}
}
struct CborReader<R> {
rdr: R,
last_offset: usize,
bytes_read: usize,
}
impl<R: io::Read> io::Read for CborReader<R> {
fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
let n = try!(self.rdr.read(buf));
self.last_offset = self.bytes_read;
self.bytes_read += n;
Ok(n)
}
}
impl<R: io::Read> CborReader<R> {
fn new(rdr: R) -> CborReader<R> {
CborReader {
rdr: rdr,
last_offset: 0,
bytes_read: 0,
}
}
fn read_full(&mut self, buf: &mut [u8]) -> CborResult<()> {
let mut nread = 0usize;
while nread < buf.len() {
match try!(self.read(&mut buf[nread..])) {
0 => return Err(CborError::UnexpectedEOF),
n => nread += n,
}
}
Ok(())
}
}
fn vec_from_elem<T: Copy>(len: usize, v: T) -> Vec<T> {
let mut xs = Vec::with_capacity(len);
unsafe { xs.set_len(len); }
for x in &mut xs { *x = v; }
xs
}