ppmd_rust/
decoder_7.rs

1use std::io::Read;
2
3use crate::{
4    internal::ppmd7::{PPMd7, RangeDecoder},
5    Error, PPMD7_MAX_MEM_SIZE, PPMD7_MAX_ORDER, PPMD7_MIN_MEM_SIZE, PPMD7_MIN_ORDER, SYM_END,
6};
7
8/// A decoder to decompress data using PPMd7 (PPMdH) with the 7z range coder.
9pub struct Ppmd7Decoder<R: Read> {
10    ppmd: PPMd7<RangeDecoder<R>>,
11    finished: bool,
12}
13
14unsafe impl<R: Read> Send for Ppmd7Decoder<R> {}
15unsafe impl<R: Read> Sync for Ppmd7Decoder<R> {}
16
17impl<R: Read> Ppmd7Decoder<R> {
18    /// Creates a new [`Ppmd7Decoder`] which provides a reader over the uncompressed data.
19    ///
20    /// The given `order` must be between [`PPMD7_MIN_ORDER`] and [`PPMD7_MAX_ORDER`]
21    /// The given `mem_size` must be between [`PPMD7_MIN_MEM_SIZE`] and [`PPMD7_MAX_MEM_SIZE`]
22    pub fn new(reader: R, order: u32, mem_size: u32) -> crate::Result<Self> {
23        if !(PPMD7_MIN_ORDER..=PPMD7_MAX_ORDER).contains(&order)
24            || !(PPMD7_MIN_MEM_SIZE..=PPMD7_MAX_MEM_SIZE).contains(&mem_size)
25        {
26            return Err(Error::InvalidParameter);
27        }
28
29        let ppmd = PPMd7::new_decoder(reader, order, mem_size)?;
30
31        Ok(Self {
32            ppmd,
33            finished: false,
34        })
35    }
36
37    /// Returns the inner reader.
38    pub fn into_inner(self) -> R {
39        self.ppmd.into_inner()
40    }
41}
42
43impl<R: Read> Read for Ppmd7Decoder<R> {
44    fn read(&mut self, buf: &mut [u8]) -> std::io::Result<usize> {
45        if self.finished {
46            return Ok(0);
47        }
48
49        if buf.is_empty() {
50            return Ok(0);
51        }
52
53        let mut sym = 0;
54        let mut decoded = 0;
55
56        for byte in buf.iter_mut() {
57            match self.ppmd.decode_symbol() {
58                Ok(symbol) => sym = symbol,
59                Err(err) => {
60                    if err.kind() == std::io::ErrorKind::UnexpectedEof {
61                        self.finished = true;
62                        return Ok(decoded);
63                    }
64                    return Err(err);
65                }
66            }
67
68            if sym < 0 {
69                break;
70            }
71
72            *byte = sym as u8;
73            decoded += 1;
74        }
75
76        let code = self.ppmd.range_decoder_code();
77
78        if sym >= 0 {
79            return Ok(decoded);
80        }
81
82        self.finished = true;
83
84        if sym != SYM_END || code != 0 {
85            return Err(std::io::Error::new(
86                std::io::ErrorKind::InvalidData,
87                "Error during PPMd decoding",
88            ));
89        }
90
91        // END_MARKER detected
92        Ok(decoded)
93    }
94}
ppmd_rust/decoder_7.rs

ppmd_rust/
decoder_7.rs
