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use nihav_core::demuxers::*;
struct GIFDemuxer<'a> {
src: &'a mut ByteReader<'a>,
frameno: u64,
is_87: bool,
pal: Arc<[u8; 1024]>,
}
impl<'a> GIFDemuxer<'a> {
fn new(io: &'a mut ByteReader<'a>) -> Self {
Self {
src: io,
frameno: 0,
is_87: false,
pal: Arc::new([0; 1024]),
}
}
fn skip_blocks(&mut self) -> DemuxerResult<()> {
loop {
let size = self.src.read_byte()?;
if size == 0 {
break;
}
self.src.read_skip(usize::from(size))?;
}
Ok(())
}
}
impl<'a> DemuxCore<'a> for GIFDemuxer<'a> {
fn open(&mut self, strmgr: &mut StreamManager, _seek_index: &mut SeekIndex) -> DemuxerResult<()> {
let mut magic = [0; 6];
self.src.read_buf(&mut magic)?;
validate!(&magic == b"GIF87a" || &magic == b"GIF89a");
self.is_87 = &magic == b"GIF87a";
let width = usize::from(self.src.read_u16le()?);
let height = usize::from(self.src.read_u16le()?);
validate!(width > 0 && height > 0);
let flags = self.src.read_byte()?;
let edata_size = 1 + 2 + if (flags & 0x80) != 0 { 3 << ((flags & 7) + 1) } else { 0 };
let mut edata = vec![0; edata_size];
edata[0] = flags;
self.src.read_buf(&mut edata[1..])?;
if (flags & 0x80) != 0 {
let mut npal = [0; 1024];
for (dpal, spal) in npal.chunks_exact_mut(4).zip(edata[3..].chunks_exact(3)) {
dpal[..3].copy_from_slice(spal);
}
self.pal = Arc::new(npal);
}
let mut delay = 0;
loop {
match self.src.peek_byte() {
Ok(0x2C) => break,
Ok(_) => {},
Err(_err) => return Err(DemuxerError::IOError),
};
let tag = self.src.read_byte()?;
match tag {
0x21 => {
validate!(!self.is_87);
let subtype = self.src.read_byte()?;
match subtype {
0xF9 => {
let bsize = self.src.read_byte()?;
validate!(bsize == 4);
let _flags = self.src.read_byte()?;
delay = self.src.read_u16le()?;
let _clr = self.src.read_byte()?;
self.skip_blocks()?;
},
0xFF => {
let bsize = self.src.read_byte()?;
validate!(bsize == 11);
let mut app_id = [0; 11];
self.src.read_buf(&mut app_id)?;
if &app_id == b"NETSCAPE2.0" {
let bsize = self.src.read_byte()?;
validate!(bsize == 3);
let b = self.src.read_byte()?;
validate!(b == 1);
let _nloops = self.src.read_u16le()?;
}
self.skip_blocks()?;
},
_ => {
self.skip_blocks()?;
},
};
},
0x2C => unreachable!(),
_ => return Err(DemuxerError::NotImplemented),
};
}
let vhdr = NAVideoInfo::new(width, height, false, PAL8_FORMAT);
let vci = NACodecTypeInfo::Video(vhdr);
let vinfo = NACodecInfo::new("gif", vci, Some(edata));
if strmgr.add_stream(NAStream::new(StreamType::Video, 0, vinfo, u32::from(delay.max(1)), 100, 0)).is_none() {
return Err(DemuxerError::MemoryError);
}
Ok(())
}
fn get_frame(&mut self, strmgr: &mut StreamManager) -> DemuxerResult<NAPacket> {
loop {
match self.src.read_byte()? {
0x2C => {
let mut data = vec![0; 10];
data[0] = 0x2C;
self.src.read_buf(&mut data[1..])?;
if (data[9] & 0x80) != 0 {
let cmap_size = 3 << ((data[9] & 7) + 1);
data.resize(10 + cmap_size, 0);
self.src.read_buf(&mut data[10..])?;
}
let lzw_bits = self.src.read_byte()?;
data.push(lzw_bits);
let mut tbuf = [0; 255];
loop {
let bsize = usize::from(self.src.read_byte()?);
data.push(bsize as u8);
if bsize == 0 {
break;
}
self.src.read_buf(&mut tbuf[..bsize])?;
data.extend_from_slice(&tbuf[..bsize]);
}
let stream = strmgr.get_stream(0).unwrap();
let ts = stream.make_ts(Some(self.frameno), None, None);
let mut pkt = NAPacket::new(stream, ts, self.frameno == 0, data);
pkt.add_side_data(NASideData::Palette(false, self.pal.clone()));
self.frameno += 1;
return Ok(pkt);
},
0x21 => {
self.src.read_byte()?;
self.skip_blocks()?;
},
0x3B => return Err(DemuxerError::EOF),
_ => unimplemented!(),
};
}
}
fn seek(&mut self, _time: NATimePoint, _seek_index: &SeekIndex) -> DemuxerResult<()> {
Err(DemuxerError::NotPossible)
}
fn get_duration(&self) -> u64 { 0 }
}
impl<'a> NAOptionHandler for GIFDemuxer<'a> {
fn get_supported_options(&self) -> &[NAOptionDefinition] { &[] }
fn set_options(&mut self, _options: &[NAOption]) { }
fn query_option_value(&self, _name: &str) -> Option<NAValue> { None }
}
pub struct GIFDemuxerCreator { }
impl DemuxerCreator for GIFDemuxerCreator {
fn new_demuxer<'a>(&self, br: &'a mut ByteReader<'a>) -> Box<dyn DemuxCore<'a> + 'a> {
Box::new(GIFDemuxer::new(br))
}
fn get_name(&self) -> &'static str { "gif" }
}
#[cfg(test)]
mod test {
use super::*;
use std::fs::File;
#[test]
fn test_gif_demux() {
// sample: https://samples.mplayerhq.hu/image-samples/GIF/3D.gif
let mut file = File::open("assets/Misc/3D.gif").unwrap();
let mut fr = FileReader::new_read(&mut file);
let mut br = ByteReader::new(&mut fr);
let mut dmx = GIFDemuxer::new(&mut br);
let mut sm = StreamManager::new();
let mut si = SeekIndex::new();
dmx.open(&mut sm, &mut si).unwrap();
loop {
let pktres = dmx.get_frame(&mut sm);
if let Err(e) = pktres {
if e == DemuxerError::EOF { break; }
panic!("error");
}
let pkt = pktres.unwrap();
println!("Got {}", pkt);
}
}
}
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