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Expose max_freq option #4

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Expose max_freq option #4

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11 changes: 7 additions & 4 deletions src/lzss_huff.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -36,7 +36,9 @@ pub struct Options {
/// backfill symbol for LZSS dictionary
pub precursor: u8,
/// return error if file is larger
pub max_file_size: u64
pub max_file_size: u64,
/// updates tree when the root frequency comes to this value.
pub max_freq: usize,
}

pub const STD_OPTIONS: Options = Options {
Expand All @@ -47,7 +49,8 @@ pub const STD_OPTIONS: Options = Options {
threshold: 2,
lookahead: 60,
precursor: b' ',
max_file_size: u32::MAX as u64/4
max_file_size: u32::MAX as u64/4,
max_freq: 0x8000,
};

/// Structure to perform the LZSS stage of compression.
Expand Down Expand Up @@ -243,7 +246,7 @@ where R: Read + Seek, W: Write + Seek {
// init
let mut bytes = reader.bytes();
let mut lzss = LZSS::create(opt.clone());
let mut huff = AdaptiveHuffmanCoder::create(256 + opt.lookahead - opt.threshold);
let mut huff = AdaptiveHuffmanCoder::create(opt.max_freq, 256 + opt.lookahead - opt.threshold);
// setup dictionary
let start_pos = opt.window_size - opt.lookahead;
for i in 0..start_pos {
Expand Down Expand Up @@ -339,7 +342,7 @@ where R: Read + Seek, W: Write + Seek {
false => u32::MAX
};
// init
let mut huff = AdaptiveHuffmanDecoder::create(256 + opt.lookahead - opt.threshold);
let mut huff = AdaptiveHuffmanDecoder::create(opt.max_freq, 256 + opt.lookahead - opt.threshold);
let mut lzss= LZSS::create(opt.clone());
let start_pos = opt.window_size - opt.lookahead;
for i in 0..start_pos {
Expand Down
3 changes: 2 additions & 1 deletion src/td0.rs
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Expand Up @@ -55,7 +55,8 @@ pub const TD_V2_OPTIONS: lzss_huff::Options = lzss_huff::Options {
threshold: 2,
lookahead: 60,
precursor: b' ',
max_file_size: 3_000_000
max_file_size: 3_000_000,
max_freq: 0x8000,
};

/// Convert a TD0 image from advanced compression to normal.
Expand Down
12 changes: 6 additions & 6 deletions src/tools/adaptive_huff.rs
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Expand Up @@ -139,9 +139,9 @@ const D_CODE: [u8;256] = [
];

impl AdaptiveHuffmanTree {
pub fn create(num_symbols: usize) -> Self {
pub fn create(max_freq: usize, num_symbols: usize) -> Self {
let mut ans = Self {
max_freq: 0x8000,
max_freq,
num_symb: num_symbols,
node_count: 2*num_symbols - 1,
root: 2*num_symbols - 2,
Expand Down Expand Up @@ -292,9 +292,9 @@ impl AdaptiveHuffmanTree {
}

impl AdaptiveHuffmanCoder {
pub fn create(num_symbols: usize) -> Self {
pub fn create(max_freq: usize, num_symbols: usize) -> Self {
Self {
tree: AdaptiveHuffmanTree::create(num_symbols),
tree: AdaptiveHuffmanTree::create(max_freq, num_symbols),
bits: BitVec::new(),
ptr: 0
}
Expand Down Expand Up @@ -356,9 +356,9 @@ impl AdaptiveHuffmanCoder {
}

impl AdaptiveHuffmanDecoder {
pub fn create(num_symbols: usize) -> Self {
pub fn create(max_freq: usize, num_symbols: usize) -> Self {
Self {
tree: AdaptiveHuffmanTree::create(num_symbols),
tree: AdaptiveHuffmanTree::create(max_freq, num_symbols),
bits: BitVec::new(),
ptr: 0
}
Expand Down