Break code into modules
This commit is contained in:
parent
124536d703
commit
8411363035
|
|
@ -4,8 +4,9 @@ use std::env::args;
|
|||
use std::fs::File;
|
||||
use std::io::Read;
|
||||
use std::path::Path;
|
||||
use lab_ebml::{Schema, Webm};
|
||||
use lab_ebml::WebmElement::*;
|
||||
use lab_ebml::Schema;
|
||||
use lab_ebml::webm::Webm;
|
||||
use lab_ebml::webm::WebmElement::*;
|
||||
|
||||
pub fn main() {
|
||||
let mut args = args();
|
||||
|
|
|
|||
|
|
@ -0,0 +1,135 @@
|
|||
pub const EBML_HEAD_ID: u64 = 0x0A45DFA3;
|
||||
pub const VOID_ID: u64 = 0x6C;
|
||||
|
||||
#[derive(Debug, PartialEq)]
|
||||
pub enum Error {
|
||||
CorruptVarint,
|
||||
UnknownElementId,
|
||||
UnknownElementLength,
|
||||
CorruptPayload,
|
||||
}
|
||||
|
||||
#[derive(Debug, PartialEq)]
|
||||
pub enum Varint {
|
||||
/// a numeric value
|
||||
Value(u64),
|
||||
/// the reserved "unknown" value
|
||||
Unknown
|
||||
}
|
||||
|
||||
/// Try to parse an EBML varint at the start of the given slice.
|
||||
/// Returns an Err() if the format is corrupt.
|
||||
/// Returns Ok(None) if more bytes are needed to get a result.
|
||||
/// Returns Ok(Some((varint, size))) to return a varint value and
|
||||
/// the size of the parsed varint.
|
||||
pub fn decode_varint(bytes: &[u8]) -> Result<Option<(Varint, usize)>, Error> {
|
||||
let mut value: u64 = 0;
|
||||
let mut value_length = 1;
|
||||
let mut mask: u8 = 0x80;
|
||||
let mut unknown_marker: u64 = !0;
|
||||
|
||||
if bytes.len() == 0 {
|
||||
return Ok(None)
|
||||
}
|
||||
|
||||
// get length marker bit from first byte & parse first byte
|
||||
while mask > 0 {
|
||||
if (mask & bytes[0]) != 0 {
|
||||
value = (bytes[0] & !mask) as u64;
|
||||
unknown_marker = (mask - 1) as u64;
|
||||
break
|
||||
}
|
||||
value_length += 1;
|
||||
mask = mask >> 1;
|
||||
}
|
||||
|
||||
if mask == 0 {
|
||||
return Err(Error::CorruptVarint)
|
||||
}
|
||||
|
||||
// check we have enough data to parse
|
||||
if value_length > bytes.len() {
|
||||
return Ok(None)
|
||||
}
|
||||
|
||||
// decode remaining bytes
|
||||
for i in 1..value_length {
|
||||
value = (value << 8) + (bytes[i] as u64);
|
||||
unknown_marker = (unknown_marker << 8) + 0xFF;
|
||||
}
|
||||
|
||||
// determine result
|
||||
if value == unknown_marker {
|
||||
Ok(Some((Varint::Unknown, value_length)))
|
||||
} else {
|
||||
Ok(Some((Varint::Value(value), value_length)))
|
||||
}
|
||||
}
|
||||
|
||||
/// Try to parse an EBML element header at the start of the given slice.
|
||||
/// Returns an Err() if the format is corrupt.
|
||||
/// Returns Ok(None) if more bytes are needed to get a result.
|
||||
/// Returns Ok(Some((id, varint, size))) to return the element id,
|
||||
/// the size of the payload, and the size of the parsed header.
|
||||
pub fn decode_tag(bytes: &[u8]) -> Result<Option<(u64, Varint, usize)>, Error> {
|
||||
// parse element ID
|
||||
match decode_varint(bytes) {
|
||||
Ok(None) => Ok(None),
|
||||
Err(err) => Err(err),
|
||||
Ok(Some((Varint::Unknown, _))) => Err(Error::UnknownElementId),
|
||||
Ok(Some((Varint::Value(element_id), id_size))) => {
|
||||
// parse payload size
|
||||
match decode_varint(&bytes[id_size..]) {
|
||||
Ok(None) => Ok(None),
|
||||
Err(err) => Err(err),
|
||||
Ok(Some((element_length, length_size))) =>
|
||||
Ok(Some((
|
||||
element_id,
|
||||
element_length,
|
||||
id_size + length_size
|
||||
)))
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
#[derive(Debug, PartialEq)]
|
||||
pub struct Ebml<S, T>(pub S, pub T);
|
||||
|
||||
pub trait Schema<'a> {
|
||||
type Element: 'a;
|
||||
|
||||
fn should_unwrap(&self, element_id: u64) -> bool;
|
||||
fn decode<'b: 'a>(&self, element_id: u64, bytes: &'b[u8]) -> Result<Self::Element, Error>;
|
||||
|
||||
fn decode_element<'b: 'a>(&self, bytes: &'b[u8]) -> Result<Option<(Self::Element, usize)>, Error> {
|
||||
match decode_tag(bytes) {
|
||||
Ok(None) => Ok(None),
|
||||
Err(err) => Err(err),
|
||||
Ok(Some((element_id, payload_size_tag, tag_size))) => {
|
||||
let should_unwrap = self.should_unwrap(element_id);
|
||||
|
||||
let payload_size = match (should_unwrap, payload_size_tag) {
|
||||
(true, _) => 0,
|
||||
(false, Varint::Unknown) => return Err(Error::UnknownElementLength),
|
||||
(false, Varint::Value(size)) => size as usize
|
||||
};
|
||||
|
||||
let element_size = tag_size + payload_size;
|
||||
if element_size > bytes.len() {
|
||||
// need to read more still
|
||||
return Ok(None);
|
||||
}
|
||||
|
||||
match self.decode(element_id, &bytes[tag_size..element_size]) {
|
||||
Ok(element) => Ok(Some((element, element_size))),
|
||||
Err(error) => Err(error)
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
fn parse<T>(self, source: T) -> Ebml<Self, T> where Self: Sized {
|
||||
Ebml(self, source)
|
||||
}
|
||||
}
|
||||
|
|
@ -0,0 +1,36 @@
|
|||
use ebml::*;
|
||||
|
||||
pub struct EbmlIterator<'b, T: Schema<'b>> {
|
||||
schema: T,
|
||||
slice: &'b[u8],
|
||||
position: usize,
|
||||
}
|
||||
|
||||
impl<'b, S: Schema<'b>> IntoIterator for Ebml<S, &'b[u8]> {
|
||||
type Item = S::Element;
|
||||
type IntoIter = EbmlIterator<'b, S>;
|
||||
|
||||
fn into_iter(self) -> EbmlIterator<'b, S>
|
||||
{
|
||||
EbmlIterator {
|
||||
schema: self.0,
|
||||
slice: self.1,
|
||||
position: 0
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
impl<'b, T: Schema<'b>> Iterator for EbmlIterator<'b, T> {
|
||||
type Item = T::Element;
|
||||
|
||||
fn next(&mut self) -> Option<T::Element> {
|
||||
match self.schema.decode_element(&self.slice[self.position..]) {
|
||||
Err(_) => None,
|
||||
Ok(None) => None,
|
||||
Ok(Some((element, element_size))) => {
|
||||
self.position += element_size;
|
||||
Some(element)
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
221
src/lib.rs
221
src/lib.rs
|
|
@ -1,224 +1,11 @@
|
|||
|
||||
extern crate futures;
|
||||
|
||||
#[derive(Debug, PartialEq)]
|
||||
pub enum Error {
|
||||
CorruptVarint,
|
||||
UnknownElementId,
|
||||
UnknownElementLength,
|
||||
CorruptPayload,
|
||||
}
|
||||
pub mod ebml;
|
||||
mod iterator;
|
||||
pub mod webm;
|
||||
|
||||
#[derive(Debug, PartialEq)]
|
||||
pub enum Varint {
|
||||
/// a numeric value
|
||||
Value(u64),
|
||||
/// the reserved "unknown" value
|
||||
Unknown
|
||||
}
|
||||
|
||||
/// Try to parse an EBML varint at the start of the given slice.
|
||||
/// Returns an Err() if the format is corrupt.
|
||||
/// Returns Ok(None) if more bytes are needed to get a result.
|
||||
/// Returns Ok(Some((varint, size))) to return a varint value and
|
||||
/// the size of the parsed varint.
|
||||
pub fn decode_varint(bytes: &[u8]) -> Result<Option<(Varint, usize)>, Error> {
|
||||
let mut value: u64 = 0;
|
||||
let mut value_length = 1;
|
||||
let mut mask: u8 = 0x80;
|
||||
let mut unknown_marker: u64 = !0;
|
||||
|
||||
if bytes.len() == 0 {
|
||||
return Ok(None)
|
||||
}
|
||||
|
||||
// get length marker bit from first byte & parse first byte
|
||||
while mask > 0 {
|
||||
if (mask & bytes[0]) != 0 {
|
||||
value = (bytes[0] & !mask) as u64;
|
||||
unknown_marker = (mask - 1) as u64;
|
||||
break
|
||||
}
|
||||
value_length += 1;
|
||||
mask = mask >> 1;
|
||||
}
|
||||
|
||||
if mask == 0 {
|
||||
return Err(Error::CorruptVarint)
|
||||
}
|
||||
|
||||
// check we have enough data to parse
|
||||
if value_length > bytes.len() {
|
||||
return Ok(None)
|
||||
}
|
||||
|
||||
// decode remaining bytes
|
||||
for i in 1..value_length {
|
||||
value = (value << 8) + (bytes[i] as u64);
|
||||
unknown_marker = (unknown_marker << 8) + 0xFF;
|
||||
}
|
||||
|
||||
// determine result
|
||||
if value == unknown_marker {
|
||||
Ok(Some((Varint::Unknown, value_length)))
|
||||
} else {
|
||||
Ok(Some((Varint::Value(value), value_length)))
|
||||
}
|
||||
}
|
||||
|
||||
/// Try to parse an EBML element header at the start of the given slice.
|
||||
/// Returns an Err() if the format is corrupt.
|
||||
/// Returns Ok(None) if more bytes are needed to get a result.
|
||||
/// Returns Ok(Some((id, varint, size))) to return the element id,
|
||||
/// the size of the payload, and the size of the parsed header.
|
||||
pub fn decode_tag(bytes: &[u8]) -> Result<Option<(u64, Varint, usize)>, Error> {
|
||||
// parse element ID
|
||||
match decode_varint(bytes) {
|
||||
Ok(None) => Ok(None),
|
||||
Err(err) => Err(err),
|
||||
Ok(Some((Varint::Unknown, _))) => Err(Error::UnknownElementId),
|
||||
Ok(Some((Varint::Value(element_id), id_size))) => {
|
||||
// parse payload size
|
||||
match decode_varint(&bytes[id_size..]) {
|
||||
Ok(None) => Ok(None),
|
||||
Err(err) => Err(err),
|
||||
Ok(Some((element_length, length_size))) =>
|
||||
Ok(Some((
|
||||
element_id,
|
||||
element_length,
|
||||
id_size + length_size
|
||||
)))
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
pub trait Schema<'a> {
|
||||
type Element: 'a;
|
||||
|
||||
fn should_unwrap(&self, element_id: u64) -> bool;
|
||||
fn decode<'b: 'a>(&self, element_id: u64, bytes: &'b[u8]) -> Result<Self::Element, Error>;
|
||||
|
||||
fn decode_element<'b: 'a>(&self, bytes: &'b[u8]) -> Result<Option<(Self::Element, usize)>, Error> {
|
||||
match decode_tag(bytes) {
|
||||
Ok(None) => Ok(None),
|
||||
Err(err) => Err(err),
|
||||
Ok(Some((element_id, payload_size_tag, tag_size))) => {
|
||||
let should_unwrap = self.should_unwrap(element_id);
|
||||
|
||||
let payload_size = match (should_unwrap, payload_size_tag) {
|
||||
(true, _) => 0,
|
||||
(false, Varint::Unknown) => return Err(Error::UnknownElementLength),
|
||||
(false, Varint::Value(size)) => size as usize
|
||||
};
|
||||
|
||||
let element_size = tag_size + payload_size;
|
||||
if element_size > bytes.len() {
|
||||
// need to read more still
|
||||
return Ok(None);
|
||||
}
|
||||
|
||||
match self.decode(element_id, &bytes[tag_size..element_size]) {
|
||||
Ok(element) => Ok(Some((element, element_size))),
|
||||
Err(error) => Err(error)
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
fn parse<T>(self, source: T) -> Ebml<Self, T> where Self: Sized {
|
||||
Ebml(self, source)
|
||||
}
|
||||
|
||||
}
|
||||
|
||||
pub const EBML_HEAD_ID: u64 = 0x0A45DFA3;
|
||||
pub const VOID_ID: u64 = 0x6C;
|
||||
|
||||
#[derive(Debug, PartialEq)]
|
||||
pub struct Ebml<S, T>(S, T);
|
||||
|
||||
impl<'b, S: Schema<'b>> IntoIterator for Ebml<S, &'b[u8]> {
|
||||
type Item = S::Element;
|
||||
type IntoIter = EbmlIterator<'b, S>;
|
||||
|
||||
fn into_iter(self) -> EbmlIterator<'b, S>
|
||||
{
|
||||
EbmlIterator {
|
||||
schema: self.0,
|
||||
slice: self.1,
|
||||
position: 0
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
const SEGMENT_ID: u64 = 0x08538067;
|
||||
const SEEK_HEAD_ID: u64 = 0x014D9B74;
|
||||
const SEGMENT_INFO_ID: u64 = 0x0549A966;
|
||||
const CUES_ID: u64 = 0x0C53BB6B;
|
||||
const TRACKS_ID: u64 = 0x0654AE6B;
|
||||
const CLUSTER_ID: u64 = 0x0F43B675;
|
||||
pub struct Webm;
|
||||
|
||||
#[derive(Debug, PartialEq)]
|
||||
pub enum WebmElement<'b> {
|
||||
EbmlHead,
|
||||
Void,
|
||||
Segment,
|
||||
SeekHead,
|
||||
Info,
|
||||
Cues,
|
||||
Tracks(&'b[u8]),
|
||||
Cluster(&'b[u8]),
|
||||
Unknown(u64)
|
||||
}
|
||||
|
||||
impl<'a> Schema<'a> for Webm {
|
||||
type Element = WebmElement<'a>;
|
||||
|
||||
fn should_unwrap(&self, element_id: u64) -> bool {
|
||||
match element_id {
|
||||
// Segment
|
||||
SEGMENT_ID => true,
|
||||
_ => false
|
||||
}
|
||||
}
|
||||
|
||||
fn decode<'b: 'a>(&self, element_id: u64, bytes: &'b[u8]) -> Result<WebmElement<'b>, Error> {
|
||||
match element_id {
|
||||
EBML_HEAD_ID => Ok(WebmElement::EbmlHead),
|
||||
VOID_ID => Ok(WebmElement::Void),
|
||||
SEGMENT_ID => Ok(WebmElement::Segment),
|
||||
SEEK_HEAD_ID => Ok(WebmElement::SeekHead),
|
||||
SEGMENT_INFO_ID => Ok(WebmElement::Info),
|
||||
CUES_ID => Ok(WebmElement::Cues),
|
||||
TRACKS_ID => Ok(WebmElement::Tracks(bytes)),
|
||||
CLUSTER_ID => Ok(WebmElement::Cluster(bytes)),
|
||||
_ => Ok(WebmElement::Unknown(element_id))
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
pub struct EbmlIterator<'b, T: Schema<'b>> {
|
||||
schema: T,
|
||||
slice: &'b[u8],
|
||||
position: usize,
|
||||
}
|
||||
|
||||
impl<'b, T: Schema<'b>> Iterator for EbmlIterator<'b, T> {
|
||||
type Item = T::Element;
|
||||
|
||||
fn next(&mut self) -> Option<T::Element> {
|
||||
match self.schema.decode_element(&self.slice[self.position..]) {
|
||||
Err(_) => None,
|
||||
Ok(None) => None,
|
||||
Ok(Some((element, element_size))) => {
|
||||
self.position += element_size;
|
||||
Some(element)
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
pub use ebml::{Error, Schema};
|
||||
|
||||
#[cfg(test)]
|
||||
mod tests {
|
||||
|
|
|
|||
|
|
@ -0,0 +1,48 @@
|
|||
use ebml::*;
|
||||
|
||||
const SEGMENT_ID: u64 = 0x08538067;
|
||||
const SEEK_HEAD_ID: u64 = 0x014D9B74;
|
||||
const SEGMENT_INFO_ID: u64 = 0x0549A966;
|
||||
const CUES_ID: u64 = 0x0C53BB6B;
|
||||
const TRACKS_ID: u64 = 0x0654AE6B;
|
||||
const CLUSTER_ID: u64 = 0x0F43B675;
|
||||
pub struct Webm;
|
||||
|
||||
#[derive(Debug, PartialEq)]
|
||||
pub enum WebmElement<'b> {
|
||||
EbmlHead,
|
||||
Void,
|
||||
Segment,
|
||||
SeekHead,
|
||||
Info,
|
||||
Cues,
|
||||
Tracks(&'b[u8]),
|
||||
Cluster(&'b[u8]),
|
||||
Unknown(u64)
|
||||
}
|
||||
|
||||
impl<'a> Schema<'a> for Webm {
|
||||
type Element = WebmElement<'a>;
|
||||
|
||||
fn should_unwrap(&self, element_id: u64) -> bool {
|
||||
match element_id {
|
||||
// Segment
|
||||
SEGMENT_ID => true,
|
||||
_ => false
|
||||
}
|
||||
}
|
||||
|
||||
fn decode<'b: 'a>(&self, element_id: u64, bytes: &'b[u8]) -> Result<WebmElement<'b>, Error> {
|
||||
match element_id {
|
||||
EBML_HEAD_ID => Ok(WebmElement::EbmlHead),
|
||||
VOID_ID => Ok(WebmElement::Void),
|
||||
SEGMENT_ID => Ok(WebmElement::Segment),
|
||||
SEEK_HEAD_ID => Ok(WebmElement::SeekHead),
|
||||
SEGMENT_INFO_ID => Ok(WebmElement::Info),
|
||||
CUES_ID => Ok(WebmElement::Cues),
|
||||
TRACKS_ID => Ok(WebmElement::Tracks(bytes)),
|
||||
CLUSTER_ID => Ok(WebmElement::Cluster(bytes)),
|
||||
_ => Ok(WebmElement::Unknown(element_id))
|
||||
}
|
||||
}
|
||||
}
|
||||
Loading…
Reference in New Issue