87 lines
2.4 KiB
Rust
87 lines
2.4 KiB
Rust
use std::io::Cursor;
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use std::sync::Arc;
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use webm::*;
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#[derive(Clone)]
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pub enum Chunk<B: AsRef<[u8]> = Vec<u8>> {
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Headers {
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bytes: Arc<B>
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},
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ClusterHead {
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keyframe: bool,
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start: u64,
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end: u64,
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// space for a Cluster tag and a Timecode tag
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bytes: [u8;16],
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bytes_used: u8
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},
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ClusterBody {
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bytes: Arc<B>
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}
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}
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impl<B: AsRef<[u8]>> Chunk<B> {
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pub fn new_cluster_head(timecode: u64) -> Chunk {
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let mut chunk = Chunk::ClusterHead {
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keyframe: false,
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start: 0,
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end: 0,
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bytes: [0;16],
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bytes_used: 0
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};
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chunk.update_timecode(timecode);
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chunk
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}
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pub fn update_timecode(&mut self, timecode: u64) {
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if let &mut Chunk::ClusterHead {ref mut start, ref mut end, ref mut bytes, ref mut bytes_used, ..} = self {
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let delta = *end - *start;
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*start = timecode;
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*end = *start + delta;
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let mut cursor = Cursor::new(bytes as &mut [u8]);
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// buffer is sized so these should never fail
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encode_webm_element(&WebmElement::Cluster, &mut cursor).unwrap();
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encode_webm_element(&WebmElement::Timecode(timecode), &mut cursor).unwrap();
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*bytes_used = cursor.position() as u8;
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}
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}
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pub fn extend_timespan(&mut self, timecode: u64) {
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if let &mut Chunk::ClusterHead {start, ref mut end, ..} = self {
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if timecode > start {
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*end = timecode;
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}
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}
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}
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pub fn mark_keyframe(&mut self, new_keyframe: bool) {
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if let &mut Chunk::ClusterHead {ref mut keyframe, ..} = self {
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*keyframe = new_keyframe;
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}
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}
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}
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impl<B: AsRef<[u8]>> AsRef<[u8]> for Chunk<B> {
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fn as_ref(&self) -> &[u8] {
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match self {
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&Chunk::Headers {ref bytes, ..} => bytes.as_ref().as_ref(),
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&Chunk::ClusterHead {ref bytes, bytes_used, ..} => bytes[..bytes_used as usize].as_ref(),
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&Chunk::ClusterBody {ref bytes, ..} => bytes.as_ref().as_ref()
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}
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}
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}
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#[cfg(test)]
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mod tests {
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use chunk::*;
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#[test]
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fn enough_space_for_header() {
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let mut chunk: Chunk = Chunk::ClusterHead {
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keyframe: false,
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start: 0,
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end: 0,
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bytes: [0;16]
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};
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chunk.update_timecode(u64::max_value());
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}
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}
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