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ruzstd 0.3.1

A decoder for the zstd compression format
Documentation 
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use super::super::blocks::sequence_section::Sequence;
use super::decodebuffer::Decodebuffer;
use crate::decoding::dictionary::Dictionary;
use crate::fse::FSETable;
use crate::huff0::HuffmanTable;

pub struct DecoderScratch {
    pub huf: HuffmanScratch,
    pub fse: FSEScratch,
    pub buffer: Decodebuffer,
    pub offset_hist: [u32; 3],

    pub literals_buffer: Vec<u8>,
    pub sequences: Vec<Sequence>,
    pub block_content_buffer: Vec<u8>,
}

impl DecoderScratch {
    pub fn new(window_size: usize) -> DecoderScratch {
        DecoderScratch {
            huf: HuffmanScratch {
                table: HuffmanTable::new(),
            },
            fse: FSEScratch {
                offsets: FSETable::new(),
                of_rle: None,
                literal_lengths: FSETable::new(),
                ll_rle: None,
                match_lengths: FSETable::new(),
                ml_rle: None,
            },
            buffer: Decodebuffer::new(window_size),
            offset_hist: [1, 4, 8],

            block_content_buffer: Vec::new(),
            literals_buffer: Vec::new(),
            sequences: Vec::new(),
        }
    }

    pub fn reset(&mut self, window_size: usize) {
        self.offset_hist = [1, 4, 8];
        self.literals_buffer.clear();
        self.sequences.clear();
        self.block_content_buffer.clear();

        self.buffer.reset(window_size);

        self.fse.literal_lengths.reset();
        self.fse.match_lengths.reset();
        self.fse.offsets.reset();
        self.fse.ll_rle = None;
        self.fse.ml_rle = None;
        self.fse.of_rle = None;

        self.huf.table.reset();
    }

    pub fn use_dict(&mut self, dict: &Dictionary) {
        self.fse = dict.fse.clone();
        self.huf = dict.huf.clone();
        self.offset_hist = dict.offset_hist;
        self.buffer.dict_content = dict.dict_content.clone();
    }

    /// parses the dictionary and set the tables
    /// it returns the dict_id for checking with the frame's dict_id
    pub fn load_dict(
        &mut self,
        raw: &[u8],
    ) -> Result<u32, super::dictionary::DictionaryDecodeError> {
        let dict = super::dictionary::Dictionary::decode_dict(raw)?;

        self.huf = dict.huf.clone();
        self.fse = dict.fse.clone();
        self.offset_hist = dict.offset_hist;
        self.buffer.dict_content = dict.dict_content.clone();
        Ok(dict.id)
    }
}

#[derive(Clone)]
pub struct HuffmanScratch {
    pub table: HuffmanTable,
}

impl HuffmanScratch {
    pub fn new() -> HuffmanScratch {
        HuffmanScratch {
            table: HuffmanTable::new(),
        }
    }
}

impl Default for HuffmanScratch {
    fn default() -> Self {
        Self::new()
    }
}

#[derive(Clone)]
pub struct FSEScratch {
    pub offsets: FSETable,
    pub of_rle: Option<u8>,
    pub literal_lengths: FSETable,
    pub ll_rle: Option<u8>,
    pub match_lengths: FSETable,
    pub ml_rle: Option<u8>,
}

impl FSEScratch {
    pub fn new() -> FSEScratch {
        FSEScratch {
            offsets: FSETable::new(),
            of_rle: None,
            literal_lengths: FSETable::new(),
            ll_rle: None,
            match_lengths: FSETable::new(),
            ml_rle: None,
        }
    }
}

impl Default for FSEScratch {
    fn default() -> Self {
        Self::new()
    }
}