raptor_code/
decoder.rs

1use alloc::vec::Vec;
2
3use crate::encodingsymbols::EncodingSymbol;
4use crate::raptor;
5
6/// A struct that represents a source block decoder that uses Raptor codes.
7pub struct SourceBlockDecoder {
8    raptor: raptor::Raptor,
9}
10
11impl SourceBlockDecoder {
12    /// Create a new decoder
13    ///
14    /// # Arguments
15    ///
16    /// * `nb_source_symbols` - Number of source symbols in the block
17    ///
18    /// # Returns
19    ///
20    /// * A new `SourceBlockDecoder` instance
21    pub fn new(nb_source_symbols: usize) -> Self {
22        SourceBlockDecoder {
23            raptor: raptor::Raptor::new(nb_source_symbols as u32),
24        }
25    }
26
27    /// Push an encoding symbol to the decoder
28    ///
29    /// # Arguments
30    ///
31    /// * `encoding_symbol` - A slice of u8 numbers representing the encoding
32    ///   symbol data
33    /// * `esi` - Encoding symbol identifier (ESI)
34    pub fn push_encoding_symbol(&mut self, encoding_symbol: &[u8], esi: u32) {
35        let encoding_symbol = EncodingSymbol::new(encoding_symbol, esi);
36        self.raptor.add_encoding_symbol(&encoding_symbol);
37    }
38
39    /// Return true when the block can be fully decoded
40    pub fn fully_specified(&self) -> bool {
41        self.raptor.fully_specified()
42    }
43
44    /// Decode the source block
45    ///
46    ///
47    /// # Parameters
48    ///
49    /// * `source_block_length`: The size of the source block in bytes.
50    /// * `encoding_symbol_size`: Size of an encoding symbol
51    ///
52    /// # Returns
53    ///
54    /// * `None` if the source block cannot be decoded
55    /// * `Some(Vec<u8>)` if the block is decoded. The vector contains the
56    ///   decoded source block data
57    pub fn decode(&mut self, source_block_length: usize) -> Option<Vec<u8>> {
58        self.raptor.decode(source_block_length)
59    }
60}
61
62/// Decodes a source block from a given set of available encoding symbols.
63///
64/// # Parameters
65///
66/// * `encoding_symbols`: A list of available encoding symbols. Missing encoding
67///   symbols should be represented as `None`.
68/// * `nb_source_symbols`: The number of source symbols in the block (k).
69/// * `source_block_length`: The size of the source block in bytes.
70///
71/// # Returns
72///
73/// A vector of bytes representing the decoded source block, or `None` if the
74/// source block cannot be decoded. The function uses the available encoding
75/// symbols to reconstruct the original source block.
76pub fn decode_source_block(
77    encoding_symbols: &[Option<Vec<u8>>],
78    nb_source_symbols: usize,
79    source_block_length: usize,
80) -> Option<Vec<u8>> {
81    let encoding_symbols = EncodingSymbol::from_option_block(encoding_symbols);
82    let mut raptor = raptor::Raptor::new(nb_source_symbols as u32);
83    raptor.add_encoding_symbols(&encoding_symbols);
84    raptor.decode(source_block_length)
85}
raptor_code/decoder.rs

raptor_code/
decoder.rs
