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Make encode_varint use a generic Writer

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Tangent 128 2017-07-30 01:43:09 -04:00
parent da81b741a3
commit cf4821599e
1 changed files with 68 additions and 54 deletions
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122
src/ebml.rs
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@ -1,4 +1,7 @@
use bytes::{BigEndian, ByteOrder, BufMut}; use bytes::{BigEndian, ByteOrder, BufMut};
use std::error::Error as ErrorTrait;
use std::fmt::{Display, Formatter, Result as FmtResult};
use std::io::{Cursor, Error as IoError, ErrorKind, Result as IoResult, Write};
pub const EBML_HEAD_ID: u64 = 0x0A45DFA3; pub const EBML_HEAD_ID: u64 = 0x0A45DFA3;
pub const VOID_ID: u64 = 0x6C; pub const VOID_ID: u64 = 0x6C;
@ -13,8 +16,21 @@ pub enum Error {
#[derive(Debug, PartialEq)] #[derive(Debug, PartialEq)]
pub enum WriteError { pub enum WriteError {
BufferTooSmall, OutOfRange
OutOfRange, }
impl Display for WriteError {
fn fmt(&self, f: &mut Formatter) -> FmtResult {
match self {
&WriteError::OutOfRange => write!(f, "EBML Varint out of range")
}
}
}
impl ErrorTrait for WriteError {
fn description(&self) -> &str {
match self {
&WriteError::OutOfRange => "EBML Varint out of range"
}
}
} }
#[derive(Debug, PartialEq)] #[derive(Debug, PartialEq)]
@ -113,12 +129,12 @@ const SMALL_FLAG: u64 = 0x80;
const EIGHT_FLAG: u64 = 0x01 << (8*7); const EIGHT_FLAG: u64 = 0x01 << (8*7);
const EIGHT_MAX: u64 = EIGHT_FLAG - 2; const EIGHT_MAX: u64 = EIGHT_FLAG - 2;
/// Tries to write an EBML varint to the buffer /// Tries to write an EBML varint
pub fn encode_varint<T: BufMut>(varint: Varint, buffer: &mut T) -> Result<usize, WriteError> { pub fn encode_varint<T: Write>(varint: Varint, output: &mut T) -> IoResult<usize> {
let (size, number) = match varint { let (size, number) = match varint {
Varint::Unknown => (1, 0xFF), Varint::Unknown => (1, 0xFF),
Varint::Value(too_big) if too_big > EIGHT_MAX => { Varint::Value(too_big) if too_big > EIGHT_MAX => {
return Err(WriteError::OutOfRange) return Err(IoError::new(ErrorKind::InvalidInput, WriteError::OutOfRange))
}, },
Varint::Value(value) => { Varint::Value(value) => {
let mut flag = SMALL_FLAG; let mut flag = SMALL_FLAG;
@ -135,12 +151,10 @@ pub fn encode_varint<T: BufMut>(varint: Varint, buffer: &mut T) -> Result<usize,
} }
}; };
if buffer.remaining_mut() < size { let mut buffer = Cursor::new([0; 8]);
Err(WriteError::BufferTooSmall) buffer.put_uint::<BigEndian>(number, size);
} else {
buffer.put_uint::<BigEndian>(number, size); return output.write_all(&buffer.get_ref()[..size]).map(|()| size);
Ok(size)
}
} }
#[derive(Debug, PartialEq)] #[derive(Debug, PartialEq)]
@ -186,7 +200,7 @@ pub trait Schema<'a> {
#[cfg(test)] #[cfg(test)]
mod tests { mod tests {
use bytes::{BytesMut, Buf}; use bytes::{BytesMut};
use ebml::*; use ebml::*;
use ebml::Error::{CorruptVarint, UnknownElementId}; use ebml::Error::{CorruptVarint, UnknownElementId};
use ebml::Varint::{Unknown, Value}; use ebml::Varint::{Unknown, Value};
@ -220,69 +234,69 @@ mod tests {
#[test] #[test]
fn encode_varints() { fn encode_varints() {
let mut buffer = BytesMut::with_capacity(10); let mut buffer = BytesMut::with_capacity(10).writer();
let mut no_space = Cursor::new([0; 0]); let mut no_space = Cursor::new([0; 0]).writer();
assert_eq!(no_space.remaining_mut(), 0); assert_eq!(no_space.get_ref().remaining_mut(), 0);
let mut six_buffer = Cursor::new([0; 6]); let mut six_buffer = Cursor::new([0; 6]).writer();
assert_eq!(six_buffer.remaining_mut(), 6); assert_eq!(six_buffer.get_ref().remaining_mut(), 6);
// 1 byte // 1 byte
assert_eq!(encode_varint(Varint::Unknown, &mut buffer), Ok(1)); assert_eq!(encode_varint(Varint::Unknown, &mut buffer).unwrap(), 1);
assert_eq!(buffer.split_to(1), &[0xFF].as_ref()); assert_eq!(buffer.get_mut().split_to(1), &[0xFF].as_ref());
assert_eq!(encode_varint(Varint::Unknown, &mut no_space), Err(WriteError::BufferTooSmall)); assert_eq!(encode_varint(Varint::Unknown, &mut no_space).unwrap_err().kind(), ErrorKind::WriteZero);
assert_eq!(encode_varint(Varint::Value(0), &mut buffer), Ok(1)); assert_eq!(encode_varint(Varint::Value(0), &mut buffer).unwrap(), 1);
assert_eq!(buffer.split_to(1), &[0x80 | 0].as_ref()); assert_eq!(buffer.get_mut().split_to(1), &[0x80 | 0].as_ref());
assert_eq!(encode_varint(Varint::Value(0), &mut no_space), Err(WriteError::BufferTooSmall)); assert_eq!(encode_varint(Varint::Value(0), &mut no_space).unwrap_err().kind(), ErrorKind::WriteZero);
assert_eq!(encode_varint(Varint::Value(1), &mut buffer), Ok(1)); assert_eq!(encode_varint(Varint::Value(1), &mut buffer).unwrap(), 1);
assert_eq!(buffer.split_to(1), &[0x80 | 1].as_ref()); assert_eq!(buffer.get_mut().split_to(1), &[0x80 | 1].as_ref());
assert_eq!(encode_varint(Varint::Value(1), &mut no_space), Err(WriteError::BufferTooSmall)); assert_eq!(encode_varint(Varint::Value(1), &mut no_space).unwrap_err().kind(), ErrorKind::WriteZero);
assert_eq!(encode_varint(Varint::Value(126), &mut buffer), Ok(1)); assert_eq!(encode_varint(Varint::Value(126), &mut buffer).unwrap(), 1);
assert_eq!(buffer.split_to(1), &[0xF0 | 126].as_ref()); assert_eq!(buffer.get_mut().split_to(1), &[0xF0 | 126].as_ref());
assert_eq!(encode_varint(Varint::Value(126), &mut no_space), Err(WriteError::BufferTooSmall)); assert_eq!(encode_varint(Varint::Value(126), &mut no_space).unwrap_err().kind(), ErrorKind::WriteZero);
// 2 bytes // 2 bytes
assert_eq!(encode_varint(Varint::Value(127), &mut buffer), Ok(2)); assert_eq!(encode_varint(Varint::Value(127), &mut buffer).unwrap(), 2);
assert_eq!(&buffer.split_to(2), &[0x40, 127].as_ref()); assert_eq!(&buffer.get_mut().split_to(2), &[0x40, 127].as_ref());
assert_eq!(encode_varint(Varint::Value(127), &mut no_space), Err(WriteError::BufferTooSmall)); assert_eq!(encode_varint(Varint::Value(127), &mut no_space).unwrap_err().kind(), ErrorKind::WriteZero);
assert_eq!(encode_varint(Varint::Value(128), &mut buffer), Ok(2)); assert_eq!(encode_varint(Varint::Value(128), &mut buffer).unwrap(), 2);
assert_eq!(&buffer.split_to(2), &[0x40, 128].as_ref()); assert_eq!(&buffer.get_mut().split_to(2), &[0x40, 128].as_ref());
assert_eq!(encode_varint(Varint::Value(128), &mut no_space), Err(WriteError::BufferTooSmall)); assert_eq!(encode_varint(Varint::Value(128), &mut no_space).unwrap_err().kind(), ErrorKind::WriteZero);
// 6 bytes // 6 bytes
assert_eq!(six_buffer.remaining_mut(), 6); assert_eq!(six_buffer.get_ref().remaining_mut(), 6);
assert_eq!(encode_varint(Varint::Value(0x03FFFFFFFFFE), &mut six_buffer), Ok(6)); assert_eq!(encode_varint(Varint::Value(0x03FFFFFFFFFE), &mut six_buffer).unwrap(), 6);
assert_eq!(six_buffer.remaining_mut(), 0); assert_eq!(six_buffer.get_ref().remaining_mut(), 0);
assert_eq!(&six_buffer.get_ref(), &[0x07, 0xFF, 0xFF, 0xFF, 0xFF, 0xFE].as_ref()); assert_eq!(&six_buffer.get_ref().get_ref(), &[0x07, 0xFF, 0xFF, 0xFF, 0xFF, 0xFE].as_ref());
six_buffer = Cursor::new([0; 6]); six_buffer = Cursor::new([0; 6]).writer();
// 7 bytes // 7 bytes
assert_eq!(encode_varint(Varint::Value(0x03FFFFFFFFFF), &mut buffer), Ok(7)); assert_eq!(encode_varint(Varint::Value(0x03FFFFFFFFFF), &mut buffer).unwrap(), 7);
assert_eq!(&buffer.split_to(7), &[0x02, 0x03, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF].as_ref()); assert_eq!(&buffer.get_mut().split_to(7), &[0x02, 0x03, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF].as_ref());
assert_eq!(encode_varint(Varint::Value(0x01000000000000), &mut buffer), Ok(7)); assert_eq!(encode_varint(Varint::Value(0x01000000000000), &mut buffer).unwrap(), 7);
assert_eq!(&buffer.split_to(7), &[0x03, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00].as_ref()); assert_eq!(&buffer.get_mut().split_to(7), &[0x03, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00].as_ref());
assert_eq!(encode_varint(Varint::Value(0x01FFFFFFFFFFFE), &mut buffer), Ok(7)); assert_eq!(encode_varint(Varint::Value(0x01FFFFFFFFFFFE), &mut buffer).unwrap(), 7);
assert_eq!(&buffer.split_to(7), &[0x03, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFE].as_ref()); assert_eq!(&buffer.get_mut().split_to(7), &[0x03, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFE].as_ref());
assert_eq!(encode_varint(Varint::Value(0x01FFFFFFFFFFFE), &mut no_space), Err(WriteError::BufferTooSmall)); assert_eq!(encode_varint(Varint::Value(0x01FFFFFFFFFFFE), &mut no_space).unwrap_err().kind(), ErrorKind::WriteZero);
assert_eq!(encode_varint(Varint::Value(0x01FFFFFFFFFFFE), &mut six_buffer), Err(WriteError::BufferTooSmall)); assert_eq!(encode_varint(Varint::Value(0x01FFFFFFFFFFFE), &mut six_buffer).unwrap_err().kind(), ErrorKind::WriteZero);
// 8 bytes // 8 bytes
assert_eq!(encode_varint(Varint::Value(0x01FFFFFFFFFFFF), &mut buffer), Ok(8)); assert_eq!(encode_varint(Varint::Value(0x01FFFFFFFFFFFF), &mut buffer).unwrap(), 8);
assert_eq!(&buffer.split_to(8), &[0x01, 0x01, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF].as_ref()); assert_eq!(&buffer.get_mut().split_to(8), &[0x01, 0x01, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF].as_ref());
assert_eq!(encode_varint(Varint::Value(0xFFFFFFFFFFFFFE), &mut buffer), Ok(8)); assert_eq!(encode_varint(Varint::Value(0xFFFFFFFFFFFFFE), &mut buffer).unwrap(), 8);
assert_eq!(&buffer.split_to(8), &[0x01, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFE].as_ref()); assert_eq!(&buffer.get_mut().split_to(8), &[0x01, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFE].as_ref());
assert_eq!(encode_varint(Varint::Value(0xFFFFFFFFFFFFFF), &mut buffer), Err(WriteError::OutOfRange)); assert_eq!(encode_varint(Varint::Value(0xFFFFFFFFFFFFFF), &mut buffer).unwrap_err().kind(), ErrorKind::InvalidInput);
assert_eq!(encode_varint(Varint::Value(u64::max_value()), &mut buffer), Err(WriteError::OutOfRange)); assert_eq!(encode_varint(Varint::Value(u64::max_value()), &mut buffer).unwrap_err().kind(), ErrorKind::InvalidInput);
} }
#[test] #[test]