//! Streaming compression functionality. use alloc::boxed::Box; use core::convert::TryInto; use core::{cmp, mem}; use super::super::*; use super::deflate_flags::*; use super::CompressionLevel; use crate::deflate::buffer::{ update_hash, HashBuffers, LocalBuf, LZ_CODE_BUF_SIZE, LZ_DICT_FULL_SIZE, LZ_HASH_BITS, LZ_HASH_SHIFT, LZ_HASH_SIZE, OUT_BUF_SIZE, }; use crate::shared::{update_adler32, HUFFMAN_LENGTH_ORDER, MZ_ADLER32_INIT}; use crate::DataFormat; // Currently not bubbled up outside this module, so can fill in with more // context eventually if needed. type Result = core::result::Result; struct Error {} const MAX_PROBES_MASK: i32 = 0xFFF; const MAX_SUPPORTED_HUFF_CODESIZE: usize = 32; /// Length code for length values. #[rustfmt::skip] const LEN_SYM: [u16; 256] = [ 257, 258, 259, 260, 261, 262, 263, 264, 265, 265, 266, 266, 267, 267, 268, 268, 269, 269, 269, 269, 270, 270, 270, 270, 271, 271, 271, 271, 272, 272, 272, 272, 273, 273, 273, 273, 273, 273, 273, 273, 274, 274, 274, 274, 274, 274, 274, 274, 275, 275, 275, 275, 275, 275, 275, 275, 276, 276, 276, 276, 276, 276, 276, 276, 277, 277, 277, 277, 277, 277, 277, 277, 277, 277, 277, 277, 277, 277, 277, 277, 278, 278, 278, 278, 278, 278, 278, 278, 278, 278, 278, 278, 278, 278, 278, 278, 279, 279, 279, 279, 279, 279, 279, 279, 279, 279, 279, 279, 279, 279, 279, 279, 280, 280, 280, 280, 280, 280, 280, 280, 280, 280, 280, 280, 280, 280, 280, 280, 281, 281, 281, 281, 281, 281, 281, 281, 281, 281, 281, 281, 281, 281, 281, 281, 281, 281, 281, 281, 281, 281, 281, 281, 281, 281, 281, 281, 281, 281, 281, 281, 282, 282, 282, 282, 282, 282, 282, 282, 282, 282, 282, 282, 282, 282, 282, 282, 282, 282, 282, 282, 282, 282, 282, 282, 282, 282, 282, 282, 282, 282, 282, 282, 283, 283, 283, 283, 283, 283, 283, 283, 283, 283, 283, 283, 283, 283, 283, 283, 283, 283, 283, 283, 283, 283, 283, 283, 283, 283, 283, 283, 283, 283, 283, 283, 284, 284, 284, 284, 284, 284, 284, 284, 284, 284, 284, 284, 284, 284, 284, 284, 284, 284, 284, 284, 284, 284, 284, 284, 284, 284, 284, 284, 284, 284, 284, 285 ]; /// Number of extra bits for length values. #[rustfmt::skip] const LEN_EXTRA: [u8; 256] = [ 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 0 ]; /// Distance codes for distances smaller than 512. #[rustfmt::skip] const SMALL_DIST_SYM: [u8; 512] = [ 0, 1, 2, 3, 4, 4, 5, 5, 6, 6, 6, 6, 7, 7, 7, 7, 8, 8, 8, 8, 8, 8, 8, 8, 9, 9, 9, 9, 9, 9, 9, 9, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17 ]; /// Number of extra bits for distances smaller than 512. #[rustfmt::skip] const SMALL_DIST_EXTRA: [u8; 512] = [ 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7 ]; /// Base values to calculate distances above 512. #[rustfmt::skip] const LARGE_DIST_SYM: [u8; 128] = [ 0, 0, 18, 19, 20, 20, 21, 21, 22, 22, 22, 22, 23, 23, 23, 23, 24, 24, 24, 24, 24, 24, 24, 24, 25, 25, 25, 25, 25, 25, 25, 25, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29 ]; /// Number of extra bits distances above 512. #[rustfmt::skip] const LARGE_DIST_EXTRA: [u8; 128] = [ 0, 0, 8, 8, 9, 9, 9, 9, 10, 10, 10, 10, 10, 10, 10, 10, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13 ]; #[rustfmt::skip] const BITMASKS: [u32; 17] = [ 0x0000, 0x0001, 0x0003, 0x0007, 0x000F, 0x001F, 0x003F, 0x007F, 0x00FF, 0x01FF, 0x03FF, 0x07FF, 0x0FFF, 0x1FFF, 0x3FFF, 0x7FFF, 0xFFFF ]; /// The maximum number of checks for matches in the hash table the compressor will make for each /// compression level. const NUM_PROBES: [u32; 11] = [0, 1, 6, 32, 16, 32, 128, 256, 512, 768, 1500]; #[derive(Copy, Clone)] struct SymFreq { key: u16, sym_index: u16, } pub mod deflate_flags { /// Whether to use a zlib wrapper. pub const TDEFL_WRITE_ZLIB_HEADER: u32 = 0x0000_1000; /// Should we compute the adler32 checksum. pub const TDEFL_COMPUTE_ADLER32: u32 = 0x0000_2000; /// Should we use greedy parsing (as opposed to lazy parsing where look ahead one or more /// bytes to check for better matches.) pub const TDEFL_GREEDY_PARSING_FLAG: u32 = 0x0000_4000; /// Used in miniz to skip zero-initializing hash and dict. We don't do this here, so /// this flag is ignored. pub const TDEFL_NONDETERMINISTIC_PARSING_FLAG: u32 = 0x0000_8000; /// Only look for matches with a distance of 0. pub const TDEFL_RLE_MATCHES: u32 = 0x0001_0000; /// Only use matches that are at least 6 bytes long. pub const TDEFL_FILTER_MATCHES: u32 = 0x0002_0000; /// Force the compressor to only output static blocks. (Blocks using the default huffman codes /// specified in the deflate specification.) pub const TDEFL_FORCE_ALL_STATIC_BLOCKS: u32 = 0x0004_0000; /// Force the compressor to only output raw/uncompressed blocks. pub const TDEFL_FORCE_ALL_RAW_BLOCKS: u32 = 0x0008_0000; } /// Strategy setting for compression. /// /// The non-default settings offer some special-case compression variants. #[repr(i32)] #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)] pub enum CompressionStrategy { /// Don't use any of the special strategies. Default = 0, /// Only use matches that are at least 5 bytes long. Filtered = 1, /// Don't look for matches, only huffman encode the literals. HuffmanOnly = 2, /// Only look for matches with a distance of 1, i.e do run-length encoding only. RLE = 3, /// Only use static/fixed blocks. (Blocks using the default huffman codes /// specified in the deflate specification.) Fixed = 4, } /// A list of deflate flush types. #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)] pub enum TDEFLFlush { /// Normal operation. /// /// Compress as much as there is space for, and then return waiting for more input. None = 0, /// Try to flush all the current data and output an empty raw block. Sync = 2, /// Same as [`Sync`][Self::Sync], but reset the dictionary so that the following data does not /// depend on previous data. Full = 3, /// Try to flush everything and end the deflate stream. /// /// On success this will yield a [`TDEFLStatus::Done`] return status. Finish = 4, } impl From for TDEFLFlush { fn from(flush: MZFlush) -> Self { match flush { MZFlush::None => TDEFLFlush::None, MZFlush::Sync => TDEFLFlush::Sync, MZFlush::Full => TDEFLFlush::Full, MZFlush::Finish => TDEFLFlush::Finish, _ => TDEFLFlush::None, // TODO: ??? What to do ??? } } } impl TDEFLFlush { pub fn new(flush: i32) -> Result { match flush { 0 => Ok(TDEFLFlush::None), 2 => Ok(TDEFLFlush::Sync), 3 => Ok(TDEFLFlush::Full), 4 => Ok(TDEFLFlush::Finish), _ => Err(MZError::Param), } } } /// Return status of compression. #[repr(i32)] #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)] pub enum TDEFLStatus { /// Usage error. /// /// This indicates that either the [`CompressorOxide`] experienced a previous error, or the /// stream has already been [`TDEFLFlush::Finish`]'d. BadParam = -2, /// Error putting data into output buffer. /// /// This usually indicates a too-small buffer. PutBufFailed = -1, /// Compression succeeded normally. Okay = 0, /// Compression succeeded and the deflate stream was ended. /// /// This is the result of calling compression with [`TDEFLFlush::Finish`]. Done = 1, } const MAX_HUFF_SYMBOLS: usize = 288; /// Size of hash chain for fast compression mode. const LEVEL1_HASH_SIZE_MASK: u32 = 4095; /// The number of huffman tables used by the compressor. /// Literal/length, Distances and Length of the huffman codes for the other two tables. const MAX_HUFF_TABLES: usize = 3; /// Literal/length codes const MAX_HUFF_SYMBOLS_0: usize = 288; /// Distance codes. const MAX_HUFF_SYMBOLS_1: usize = 32; /// Huffman length values. const MAX_HUFF_SYMBOLS_2: usize = 19; /// Size of the chained hash table. pub(crate) const LZ_DICT_SIZE: usize = 32_768; /// Mask used when stepping through the hash chains. const LZ_DICT_SIZE_MASK: usize = (LZ_DICT_SIZE as u32 - 1) as usize; /// The minimum length of a match. const MIN_MATCH_LEN: u8 = 3; /// The maximum length of a match. pub(crate) const MAX_MATCH_LEN: usize = 258; const DEFAULT_FLAGS: u32 = NUM_PROBES[4] | TDEFL_WRITE_ZLIB_HEADER; mod zlib { const DEFAULT_CM: u8 = 8; const DEFAULT_CINFO: u8 = 7 << 4; const _DEFAULT_FDICT: u8 = 0; const DEFAULT_CMF: u8 = DEFAULT_CM | DEFAULT_CINFO; /// The 16-bit value consisting of CMF and FLG must be divisible by this to be valid. const FCHECK_DIVISOR: u8 = 31; /// Generate FCHECK from CMF and FLG (without FCKECH )so that they are correct according to the /// specification, i.e (CMF*256 + FCHK) % 31 = 0. /// Returns flg with the FCHKECK bits added (any existing FCHECK bits are ignored). fn add_fcheck(cmf: u8, flg: u8) -> u8 { let rem = ((usize::from(cmf) * 256) + usize::from(flg)) % usize::from(FCHECK_DIVISOR); // Clear existing FCHECK if any let flg = flg & 0b11100000; // Casting is safe as rem can't overflow since it is a value mod 31 // We can simply add the value to flg as (31 - rem) will never be above 2^5 flg + (FCHECK_DIVISOR - rem as u8) } fn zlib_level_from_flags(flags: u32) -> u8 { use super::NUM_PROBES; let num_probes = flags & (super::MAX_PROBES_MASK as u32); if flags & super::TDEFL_GREEDY_PARSING_FLAG != 0 { if num_probes <= 1 { 0 } else { 1 } } else if num_probes >= NUM_PROBES[9] { 3 } else { 2 } } /// Get the zlib header for the level using the default window size and no /// dictionary. fn header_from_level(level: u8) -> [u8; 2] { let cmf = DEFAULT_CMF; [cmf, add_fcheck(cmf, (level as u8) << 6)] } /// Create a zlib header from the given compression flags. /// Only level is considered. pub fn header_from_flags(flags: u32) -> [u8; 2] { let level = zlib_level_from_flags(flags); header_from_level(level) } #[cfg(test)] mod test { #[test] fn zlib() { use super::super::*; use super::*; let test_level = |level, expected| { let flags = create_comp_flags_from_zip_params( level, MZ_DEFAULT_WINDOW_BITS, CompressionStrategy::Default as i32, ); assert_eq!(zlib_level_from_flags(flags), expected); }; assert_eq!(zlib_level_from_flags(DEFAULT_FLAGS), 2); test_level(0, 0); test_level(1, 0); test_level(2, 1); test_level(3, 1); for i in 4..=8 { test_level(i, 2) } test_level(9, 3); test_level(10, 3); } #[test] fn test_header() { let header = super::header_from_level(3); assert_eq!( ((usize::from(header[0]) * 256) + usize::from(header[1])) % 31, 0 ); } } } fn memset(slice: &mut [T], val: T) { for x in slice { *x = val } } #[cfg(test)] #[inline] fn write_u16_le(val: u16, slice: &mut [u8], pos: usize) { slice[pos] = val as u8; slice[pos + 1] = (val >> 8) as u8; } // Read the two bytes starting at pos and interpret them as an u16. #[inline] const fn read_u16_le(slice: &[u8], pos: usize) -> u16 { // The compiler is smart enough to optimize this into an unaligned load. slice[pos] as u16 | ((slice[pos + 1] as u16) << 8) } /// Main compression struct. pub struct CompressorOxide { lz: LZOxide, params: ParamsOxide, huff: Box, dict: DictOxide, } impl CompressorOxide { /// Create a new `CompressorOxide` with the given flags. /// /// # Notes /// This function may be changed to take different parameters in the future. pub fn new(flags: u32) -> Self { CompressorOxide { lz: LZOxide::new(), params: ParamsOxide::new(flags), /// Put HuffmanOxide on the heap with default trick to avoid /// excessive stack copies. huff: Box::default(), dict: DictOxide::new(flags), } } /// Get the adler32 checksum of the currently encoded data. pub const fn adler32(&self) -> u32 { self.params.adler32 } /// Get the return status of the previous [`compress`](fn.compress.html) /// call with this compressor. pub const fn prev_return_status(&self) -> TDEFLStatus { self.params.prev_return_status } /// Get the raw compressor flags. /// /// # Notes /// This function may be deprecated or changed in the future to use more rust-style flags. pub const fn flags(&self) -> i32 { self.params.flags as i32 } /// Returns whether the compressor is wrapping the data in a zlib format or not. pub fn data_format(&self) -> DataFormat { if (self.params.flags & TDEFL_WRITE_ZLIB_HEADER) != 0 { DataFormat::Zlib } else { DataFormat::Raw } } /// Reset the state of the compressor, keeping the same parameters. /// /// This avoids re-allocating data. pub fn reset(&mut self) { // LZ buf and huffman has no settings or dynamic memory // that needs to be saved, so we simply replace them. self.lz = LZOxide::new(); self.params.reset(); *self.huff = HuffmanOxide::default(); self.dict.reset(); } /// Set the compression level of the compressor. /// /// Using this to change level after compression has started is supported. /// # Notes /// The compression strategy will be reset to the default one when this is called. pub fn set_compression_level(&mut self, level: CompressionLevel) { let format = self.data_format(); self.set_format_and_level(format, level as u8); } /// Set the compression level of the compressor using an integer value. /// /// Using this to change level after compression has started is supported. /// # Notes /// The compression strategy will be reset to the default one when this is called. pub fn set_compression_level_raw(&mut self, level: u8) { let format = self.data_format(); self.set_format_and_level(format, level); } /// Update the compression settings of the compressor. /// /// Changing the `DataFormat` after compression has started will result in /// a corrupted stream. /// /// # Notes /// This function mainly intended for setting the initial settings after e.g creating with /// `default` or after calling `CompressorOxide::reset()`, and behaviour may be changed /// to disallow calling it after starting compression in the future. pub fn set_format_and_level(&mut self, data_format: DataFormat, level: u8) { let flags = create_comp_flags_from_zip_params( level.into(), data_format.to_window_bits(), CompressionStrategy::Default as i32, ); self.params.update_flags(flags); self.dict.update_flags(flags); } } impl Default for CompressorOxide { /// Initialize the compressor with a level of 4, zlib wrapper and /// the default strategy. fn default() -> Self { CompressorOxide { lz: LZOxide::new(), params: ParamsOxide::new(DEFAULT_FLAGS), /// Put HuffmanOxide on the heap with default trick to avoid /// excessive stack copies. huff: Box::default(), dict: DictOxide::new(DEFAULT_FLAGS), } } } /// Callback function and user used in `compress_to_output`. pub struct CallbackFunc<'a> { pub put_buf_func: &'a mut dyn FnMut(&[u8]) -> bool, } impl<'a> CallbackFunc<'a> { fn flush_output( &mut self, saved_output: SavedOutputBufferOxide, params: &mut ParamsOxide, ) -> i32 { // TODO: As this could be unsafe since // we can't verify the function pointer // this whole function should maybe be unsafe as well. let call_success = (self.put_buf_func)(¶ms.local_buf.b[0..saved_output.pos as usize]); if !call_success { params.prev_return_status = TDEFLStatus::PutBufFailed; return params.prev_return_status as i32; } params.flush_remaining as i32 } } struct CallbackBuf<'a> { pub out_buf: &'a mut [u8], } impl<'a> CallbackBuf<'a> { fn flush_output( &mut self, saved_output: SavedOutputBufferOxide, params: &mut ParamsOxide, ) -> i32 { if saved_output.local { let n = cmp::min( saved_output.pos as usize, self.out_buf.len() - params.out_buf_ofs, ); (&mut self.out_buf[params.out_buf_ofs..params.out_buf_ofs + n]) .copy_from_slice(¶ms.local_buf.b[..n]); params.out_buf_ofs += n; if saved_output.pos != n { params.flush_ofs = n as u32; params.flush_remaining = (saved_output.pos - n) as u32; } } else { params.out_buf_ofs += saved_output.pos; } params.flush_remaining as i32 } } enum CallbackOut<'a> { Func(CallbackFunc<'a>), Buf(CallbackBuf<'a>), } impl<'a> CallbackOut<'a> { fn new_output_buffer<'b>( &'b mut self, local_buf: &'b mut [u8], out_buf_ofs: usize, ) -> OutputBufferOxide<'b> { let is_local; let buf_len = OUT_BUF_SIZE - 16; let chosen_buffer = match *self { CallbackOut::Buf(ref mut cb) if cb.out_buf.len() - out_buf_ofs >= OUT_BUF_SIZE => { is_local = false; &mut cb.out_buf[out_buf_ofs..out_buf_ofs + buf_len] } _ => { is_local = true; &mut local_buf[..buf_len] } }; OutputBufferOxide { inner: chosen_buffer, inner_pos: 0, local: is_local, bit_buffer: 0, bits_in: 0, } } } struct CallbackOxide<'a> { in_buf: Option<&'a [u8]>, in_buf_size: Option<&'a mut usize>, out_buf_size: Option<&'a mut usize>, out: CallbackOut<'a>, } impl<'a> CallbackOxide<'a> { fn new_callback_buf(in_buf: &'a [u8], out_buf: &'a mut [u8]) -> Self { CallbackOxide { in_buf: Some(in_buf), in_buf_size: None, out_buf_size: None, out: CallbackOut::Buf(CallbackBuf { out_buf }), } } fn new_callback_func(in_buf: &'a [u8], callback_func: CallbackFunc<'a>) -> Self { CallbackOxide { in_buf: Some(in_buf), in_buf_size: None, out_buf_size: None, out: CallbackOut::Func(callback_func), } } fn update_size(&mut self, in_size: Option, out_size: Option) { if let (Some(in_size), Some(size)) = (in_size, self.in_buf_size.as_mut()) { **size = in_size; } if let (Some(out_size), Some(size)) = (out_size, self.out_buf_size.as_mut()) { **size = out_size } } fn flush_output( &mut self, saved_output: SavedOutputBufferOxide, params: &mut ParamsOxide, ) -> i32 { if saved_output.pos == 0 { return params.flush_remaining as i32; } self.update_size(Some(params.src_pos), None); match self.out { CallbackOut::Func(ref mut cf) => cf.flush_output(saved_output, params), CallbackOut::Buf(ref mut cb) => cb.flush_output(saved_output, params), } } } struct OutputBufferOxide<'a> { pub inner: &'a mut [u8], pub inner_pos: usize, pub local: bool, pub bit_buffer: u32, pub bits_in: u32, } impl<'a> OutputBufferOxide<'a> { fn put_bits(&mut self, bits: u32, len: u32) { assert!(bits <= ((1u32 << len) - 1u32)); self.bit_buffer |= bits << self.bits_in; self.bits_in += len; while self.bits_in >= 8 { self.inner[self.inner_pos] = self.bit_buffer as u8; self.inner_pos += 1; self.bit_buffer >>= 8; self.bits_in -= 8; } } const fn save(&self) -> SavedOutputBufferOxide { SavedOutputBufferOxide { pos: self.inner_pos, bit_buffer: self.bit_buffer, bits_in: self.bits_in, local: self.local, } } fn load(&mut self, saved: SavedOutputBufferOxide) { self.inner_pos = saved.pos; self.bit_buffer = saved.bit_buffer; self.bits_in = saved.bits_in; self.local = saved.local; } fn pad_to_bytes(&mut self) { if self.bits_in != 0 { let len = 8 - self.bits_in; self.put_bits(0, len); } } } struct SavedOutputBufferOxide { pub pos: usize, pub bit_buffer: u32, pub bits_in: u32, pub local: bool, } struct BitBuffer { pub bit_buffer: u64, pub bits_in: u32, } impl BitBuffer { fn put_fast(&mut self, bits: u64, len: u32) { self.bit_buffer |= bits << self.bits_in; self.bits_in += len; } fn flush(&mut self, output: &mut OutputBufferOxide) -> Result<()> { let pos = output.inner_pos; { // isolation to please borrow checker let inner = &mut output.inner[pos..pos + 8]; let bytes = u64::to_le_bytes(self.bit_buffer); inner.copy_from_slice(&bytes); } match output.inner_pos.checked_add((self.bits_in >> 3) as usize) { Some(n) if n <= output.inner.len() => output.inner_pos = n, _ => return Err(Error {}), } self.bit_buffer >>= self.bits_in & !7; self.bits_in &= 7; Ok(()) } } /// A struct containing data about huffman codes and symbol frequencies. /// /// NOTE: Only the literal/lengths have enough symbols to actually use /// the full array. It's unclear why it's defined like this in miniz, /// it could be for cache/alignment reasons. struct HuffmanOxide { /// Number of occurrences of each symbol. pub count: [[u16; MAX_HUFF_SYMBOLS]; MAX_HUFF_TABLES], /// The bits of the huffman code assigned to the symbol pub codes: [[u16; MAX_HUFF_SYMBOLS]; MAX_HUFF_TABLES], /// The length of the huffman code assigned to the symbol. pub code_sizes: [[u8; MAX_HUFF_SYMBOLS]; MAX_HUFF_TABLES], } /// Tables used for literal/lengths in `HuffmanOxide`. const LITLEN_TABLE: usize = 0; /// Tables for distances. const DIST_TABLE: usize = 1; /// Tables for the run-length encoded huffman lengths for literals/lengths/distances. const HUFF_CODES_TABLE: usize = 2; /// Status of RLE encoding of huffman code lengths. struct Rle { pub z_count: u32, pub repeat_count: u32, pub prev_code_size: u8, } impl Rle { fn prev_code_size( &mut self, packed_code_sizes: &mut [u8], packed_pos: &mut usize, h: &mut HuffmanOxide, ) -> Result<()> { let mut write = |buf| write(buf, packed_code_sizes, packed_pos); let counts = &mut h.count[HUFF_CODES_TABLE]; if self.repeat_count != 0 { if self.repeat_count < 3 { counts[self.prev_code_size as usize] = counts[self.prev_code_size as usize].wrapping_add(self.repeat_count as u16); let code = self.prev_code_size; write(&[code, code, code][..self.repeat_count as usize])?; } else { counts[16] = counts[16].wrapping_add(1); write(&[16, (self.repeat_count - 3) as u8][..])?; } self.repeat_count = 0; } Ok(()) } fn zero_code_size( &mut self, packed_code_sizes: &mut [u8], packed_pos: &mut usize, h: &mut HuffmanOxide, ) -> Result<()> { let mut write = |buf| write(buf, packed_code_sizes, packed_pos); let counts = &mut h.count[HUFF_CODES_TABLE]; if self.z_count != 0 { if self.z_count < 3 { counts[0] = counts[0].wrapping_add(self.z_count as u16); write(&[0, 0, 0][..self.z_count as usize])?; } else if self.z_count <= 10 { counts[17] = counts[17].wrapping_add(1); write(&[17, (self.z_count - 3) as u8][..])?; } else { counts[18] = counts[18].wrapping_add(1); write(&[18, (self.z_count - 11) as u8][..])?; } self.z_count = 0; } Ok(()) } } fn write(src: &[u8], dst: &mut [u8], dst_pos: &mut usize) -> Result<()> { match dst.get_mut(*dst_pos..*dst_pos + src.len()) { Some(s) => s.copy_from_slice(src), None => return Err(Error {}), } *dst_pos += src.len(); Ok(()) } impl Default for HuffmanOxide { fn default() -> Self { HuffmanOxide { count: [[0; MAX_HUFF_SYMBOLS]; MAX_HUFF_TABLES], codes: [[0; MAX_HUFF_SYMBOLS]; MAX_HUFF_TABLES], code_sizes: [[0; MAX_HUFF_SYMBOLS]; MAX_HUFF_TABLES], } } } impl HuffmanOxide { fn radix_sort_symbols<'a>( symbols0: &'a mut [SymFreq], symbols1: &'a mut [SymFreq], ) -> &'a mut [SymFreq] { let mut hist = [[0; 256]; 2]; for freq in symbols0.iter() { hist[0][(freq.key & 0xFF) as usize] += 1; hist[1][((freq.key >> 8) & 0xFF) as usize] += 1; } let mut n_passes = 2; if symbols0.len() == hist[1][0] { n_passes -= 1; } let mut current_symbols = symbols0; let mut new_symbols = symbols1; for (pass, hist_item) in hist.iter().enumerate().take(n_passes) { let mut offsets = [0; 256]; let mut offset = 0; for i in 0..256 { offsets[i] = offset; offset += hist_item[i]; } for sym in current_symbols.iter() { let j = ((sym.key >> (pass * 8)) & 0xFF) as usize; new_symbols[offsets[j]] = *sym; offsets[j] += 1; } mem::swap(&mut current_symbols, &mut new_symbols); } current_symbols } fn calculate_minimum_redundancy(symbols: &mut [SymFreq]) { match symbols.len() { 0 => (), 1 => symbols[0].key = 1, n => { symbols[0].key += symbols[1].key; let mut root = 0; let mut leaf = 2; for next in 1..n - 1 { if (leaf >= n) || (symbols[root].key < symbols[leaf].key) { symbols[next].key = symbols[root].key; symbols[root].key = next as u16; root += 1; } else { symbols[next].key = symbols[leaf].key; leaf += 1; } if (leaf >= n) || (root < next && symbols[root].key < symbols[leaf].key) { symbols[next].key = symbols[next].key.wrapping_add(symbols[root].key); symbols[root].key = next as u16; root += 1; } else { symbols[next].key = symbols[next].key.wrapping_add(symbols[leaf].key); leaf += 1; } } symbols[n - 2].key = 0; for next in (0..n - 2).rev() { symbols[next].key = symbols[symbols[next].key as usize].key + 1; } let mut avbl = 1; let mut used = 0; let mut dpth = 0; let mut root = (n - 2) as i32; let mut next = (n - 1) as i32; while avbl > 0 { while (root >= 0) && (symbols[root as usize].key == dpth) { used += 1; root -= 1; } while avbl > used { symbols[next as usize].key = dpth; next -= 1; avbl -= 1; } avbl = 2 * used; dpth += 1; used = 0; } } } } fn enforce_max_code_size(num_codes: &mut [i32], code_list_len: usize, max_code_size: usize) { if code_list_len <= 1 { return; } num_codes[max_code_size] += num_codes[max_code_size + 1..].iter().sum::(); let total = num_codes[1..=max_code_size] .iter() .rev() .enumerate() .fold(0u32, |total, (i, &x)| total + ((x as u32) << i)); for _ in (1 << max_code_size)..total { num_codes[max_code_size] -= 1; for i in (1..max_code_size).rev() { if num_codes[i] != 0 { num_codes[i] -= 1; num_codes[i + 1] += 2; break; } } } } fn optimize_table( &mut self, table_num: usize, table_len: usize, code_size_limit: usize, static_table: bool, ) { let mut num_codes = [0i32; MAX_SUPPORTED_HUFF_CODESIZE + 1]; let mut next_code = [0u32; MAX_SUPPORTED_HUFF_CODESIZE + 1]; if static_table { for &code_size in &self.code_sizes[table_num][..table_len] { num_codes[code_size as usize] += 1; } } else { let mut symbols0 = [SymFreq { key: 0, sym_index: 0, }; MAX_HUFF_SYMBOLS]; let mut symbols1 = [SymFreq { key: 0, sym_index: 0, }; MAX_HUFF_SYMBOLS]; let mut num_used_symbols = 0; for i in 0..table_len { if self.count[table_num][i] != 0 { symbols0[num_used_symbols] = SymFreq { key: self.count[table_num][i], sym_index: i as u16, }; num_used_symbols += 1; } } let symbols = Self::radix_sort_symbols( &mut symbols0[..num_used_symbols], &mut symbols1[..num_used_symbols], ); Self::calculate_minimum_redundancy(symbols); for symbol in symbols.iter() { num_codes[symbol.key as usize] += 1; } Self::enforce_max_code_size(&mut num_codes, num_used_symbols, code_size_limit); memset(&mut self.code_sizes[table_num][..], 0); memset(&mut self.codes[table_num][..], 0); let mut last = num_used_symbols; for (i, &num_item) in num_codes .iter() .enumerate() .take(code_size_limit + 1) .skip(1) { let first = last - num_item as usize; for symbol in &symbols[first..last] { self.code_sizes[table_num][symbol.sym_index as usize] = i as u8; } last = first; } } let mut j = 0; next_code[1] = 0; for i in 2..=code_size_limit { j = (j + num_codes[i - 1]) << 1; next_code[i] = j as u32; } for (&code_size, huff_code) in self.code_sizes[table_num] .iter() .take(table_len) .zip(self.codes[table_num].iter_mut().take(table_len)) { if code_size == 0 { continue; } let mut code = next_code[code_size as usize]; next_code[code_size as usize] += 1; let mut rev_code = 0; for _ in 0..code_size { rev_code = (rev_code << 1) | (code & 1); code >>= 1; } *huff_code = rev_code as u16; } } fn start_static_block(&mut self, output: &mut OutputBufferOxide) { memset(&mut self.code_sizes[LITLEN_TABLE][0..144], 8); memset(&mut self.code_sizes[LITLEN_TABLE][144..256], 9); memset(&mut self.code_sizes[LITLEN_TABLE][256..280], 7); memset(&mut self.code_sizes[LITLEN_TABLE][280..288], 8); memset(&mut self.code_sizes[DIST_TABLE][..32], 5); self.optimize_table(LITLEN_TABLE, 288, 15, true); self.optimize_table(DIST_TABLE, 32, 15, true); output.put_bits(0b01, 2) } fn start_dynamic_block(&mut self, output: &mut OutputBufferOxide) -> Result<()> { // There will always be one, and only one end of block code. self.count[0][256] = 1; self.optimize_table(0, MAX_HUFF_SYMBOLS_0, 15, false); self.optimize_table(1, MAX_HUFF_SYMBOLS_1, 15, false); let num_lit_codes = 286 - &self.code_sizes[0][257..286] .iter() .rev() .take_while(|&x| *x == 0) .count(); let num_dist_codes = 30 - &self.code_sizes[1][1..30] .iter() .rev() .take_while(|&x| *x == 0) .count(); let mut code_sizes_to_pack = [0u8; MAX_HUFF_SYMBOLS_0 + MAX_HUFF_SYMBOLS_1]; let mut packed_code_sizes = [0u8; MAX_HUFF_SYMBOLS_0 + MAX_HUFF_SYMBOLS_1]; let total_code_sizes_to_pack = num_lit_codes + num_dist_codes; code_sizes_to_pack[..num_lit_codes].copy_from_slice(&self.code_sizes[0][..num_lit_codes]); code_sizes_to_pack[num_lit_codes..total_code_sizes_to_pack] .copy_from_slice(&self.code_sizes[1][..num_dist_codes]); let mut rle = Rle { z_count: 0, repeat_count: 0, prev_code_size: 0xFF, }; memset(&mut self.count[HUFF_CODES_TABLE][..MAX_HUFF_SYMBOLS_2], 0); let mut packed_pos = 0; for &code_size in &code_sizes_to_pack[..total_code_sizes_to_pack] { if code_size == 0 { rle.prev_code_size(&mut packed_code_sizes, &mut packed_pos, self)?; rle.z_count += 1; if rle.z_count == 138 { rle.zero_code_size(&mut packed_code_sizes, &mut packed_pos, self)?; } } else { rle.zero_code_size(&mut packed_code_sizes, &mut packed_pos, self)?; if code_size != rle.prev_code_size { rle.prev_code_size(&mut packed_code_sizes, &mut packed_pos, self)?; self.count[HUFF_CODES_TABLE][code_size as usize] = self.count[HUFF_CODES_TABLE][code_size as usize].wrapping_add(1); write(&[code_size], &mut packed_code_sizes, &mut packed_pos)?; } else { rle.repeat_count += 1; if rle.repeat_count == 6 { rle.prev_code_size(&mut packed_code_sizes, &mut packed_pos, self)?; } } } rle.prev_code_size = code_size; } if rle.repeat_count != 0 { rle.prev_code_size(&mut packed_code_sizes, &mut packed_pos, self)?; } else { rle.zero_code_size(&mut packed_code_sizes, &mut packed_pos, self)?; } self.optimize_table(2, MAX_HUFF_SYMBOLS_2, 7, false); output.put_bits(2, 2); output.put_bits((num_lit_codes - 257) as u32, 5); output.put_bits((num_dist_codes - 1) as u32, 5); let mut num_bit_lengths = 18 - HUFFMAN_LENGTH_ORDER .iter() .rev() .take_while(|&swizzle| self.code_sizes[HUFF_CODES_TABLE][*swizzle as usize] == 0) .count(); num_bit_lengths = cmp::max(4, num_bit_lengths + 1); output.put_bits(num_bit_lengths as u32 - 4, 4); for &swizzle in &HUFFMAN_LENGTH_ORDER[..num_bit_lengths] { output.put_bits( u32::from(self.code_sizes[HUFF_CODES_TABLE][swizzle as usize]), 3, ); } let mut packed_code_size_index = 0; while packed_code_size_index < packed_pos { let code = packed_code_sizes[packed_code_size_index] as usize; packed_code_size_index += 1; assert!(code < MAX_HUFF_SYMBOLS_2); output.put_bits( u32::from(self.codes[HUFF_CODES_TABLE][code]), u32::from(self.code_sizes[HUFF_CODES_TABLE][code]), ); if code >= 16 { output.put_bits( u32::from(packed_code_sizes[packed_code_size_index]), [2, 3, 7][code - 16], ); packed_code_size_index += 1; } } Ok(()) } } struct DictOxide { /// The maximum number of checks in the hash chain, for the initial, /// and the lazy match respectively. pub max_probes: [u32; 2], /// Buffer of input data. /// Padded with 1 byte to simplify matching code in `compress_fast`. pub b: Box, pub code_buf_dict_pos: usize, pub lookahead_size: usize, pub lookahead_pos: usize, pub size: usize, } const fn probes_from_flags(flags: u32) -> [u32; 2] { [ 1 + ((flags & 0xFFF) + 2) / 3, 1 + (((flags & 0xFFF) >> 2) + 2) / 3, ] } impl DictOxide { fn new(flags: u32) -> Self { DictOxide { max_probes: probes_from_flags(flags), b: Box::default(), code_buf_dict_pos: 0, lookahead_size: 0, lookahead_pos: 0, size: 0, } } fn update_flags(&mut self, flags: u32) { self.max_probes = probes_from_flags(flags); } fn reset(&mut self) { self.b.reset(); self.code_buf_dict_pos = 0; self.lookahead_size = 0; self.lookahead_pos = 0; self.size = 0; } /// Do an unaligned read of the data at `pos` in the dictionary and treat it as if it was of /// type T. #[inline] fn read_unaligned_u32(&self, pos: usize) -> u32 { // Masking the value here helps avoid bounds checks. let pos = (pos & LZ_DICT_SIZE_MASK) as usize; let end = pos + 4; // Somehow this assertion makes things faster. assert!(end < LZ_DICT_FULL_SIZE); let bytes: [u8; 4] = self.b.dict[pos..end].try_into().unwrap(); u32::from_le_bytes(bytes) } /// Do an unaligned read of the data at `pos` in the dictionary and treat it as if it was of /// type T. #[inline] fn read_unaligned_u64(&self, pos: usize) -> u64 { let pos = pos as usize; let bytes: [u8; 8] = self.b.dict[pos..pos + 8].try_into().unwrap(); u64::from_le_bytes(bytes) } /// Do an unaligned read of the data at `pos` in the dictionary and treat it as if it was of /// type T. #[inline] fn read_as_u16(&self, pos: usize) -> u16 { read_u16_le(&self.b.dict[..], pos) } /// Try to find a match for the data at lookahead_pos in the dictionary that is /// longer than `match_len`. /// Returns a tuple containing (match_distance, match_length). Will be equal to the input /// values if no better matches were found. fn find_match( &self, lookahead_pos: usize, max_dist: usize, max_match_len: u32, mut match_dist: u32, mut match_len: u32, ) -> (u32, u32) { // Clamp the match len and max_match_len to be valid. (It should be when this is called, but // do it for now just in case for safety reasons.) // This should normally end up as at worst conditional moves, // so it shouldn't slow us down much. // TODO: Statically verify these so we don't need to do this. let max_match_len = cmp::min(MAX_MATCH_LEN as u32, max_match_len); match_len = cmp::max(match_len, 1); let pos = lookahead_pos as usize & LZ_DICT_SIZE_MASK; let mut probe_pos = pos; // Number of probes into the hash chains. let mut num_probes_left = self.max_probes[(match_len >= 32) as usize]; // If we already have a match of the full length don't bother searching for another one. if max_match_len <= match_len { return (match_dist, match_len); } // Read the last byte of the current match, and the next one, used to compare matches. let mut c01: u16 = self.read_as_u16(pos as usize + match_len as usize - 1); // Read the two bytes at the end position of the current match. let s01: u16 = self.read_as_u16(pos as usize); 'outer: loop { let mut dist; 'found: loop { num_probes_left -= 1; if num_probes_left == 0 { // We have done as many probes in the hash chain as the current compression // settings allow, so return the best match we found, if any. return (match_dist, match_len); } for _ in 0..3 { let next_probe_pos = self.b.next[probe_pos as usize] as usize; dist = (lookahead_pos - next_probe_pos) & 0xFFFF; if next_probe_pos == 0 || dist > max_dist { // We reached the end of the hash chain, or the next value is further away // than the maximum allowed distance, so return the best match we found, if // any. return (match_dist, match_len); } // Mask the position value to get the position in the hash chain of the next // position to match against. probe_pos = next_probe_pos & LZ_DICT_SIZE_MASK; if self.read_as_u16((probe_pos + match_len as usize - 1) as usize) == c01 { break 'found; } } } if dist == 0 { // We've looked through the whole match range, so return the best match we // found. return (match_dist, match_len); } // Check if the two first bytes match. if self.read_as_u16(probe_pos as usize) != s01 { continue; } let mut p = pos + 2; let mut q = probe_pos + 2; // The first two bytes matched, so check the full length of the match. for _ in 0..32 { let p_data: u64 = self.read_unaligned_u64(p); let q_data: u64 = self.read_unaligned_u64(q); // Compare of 8 bytes at a time by using unaligned loads of 64-bit integers. let xor_data = p_data ^ q_data; if xor_data == 0 { p += 8; q += 8; } else { // If not all of the last 8 bytes matched, check how may of them did. let trailing = xor_data.trailing_zeros(); let probe_len = p - pos + (trailing as usize >> 3); if probe_len > match_len as usize { match_dist = dist as u32; match_len = cmp::min(max_match_len, probe_len as u32); if match_len == max_match_len { // We found a match that had the maximum allowed length, // so there is now point searching further. return (match_dist, match_len); } // We found a better match, so save the last two bytes for further match // comparisons. c01 = self.read_as_u16(pos + match_len as usize - 1) } continue 'outer; } } return (dist as u32, cmp::min(max_match_len, MAX_MATCH_LEN as u32)); } } } struct ParamsOxide { pub flags: u32, pub greedy_parsing: bool, pub block_index: u32, pub saved_match_dist: u32, pub saved_match_len: u32, pub saved_lit: u8, pub flush: TDEFLFlush, pub flush_ofs: u32, pub flush_remaining: u32, pub finished: bool, pub adler32: u32, pub src_pos: usize, pub out_buf_ofs: usize, pub prev_return_status: TDEFLStatus, pub saved_bit_buffer: u32, pub saved_bits_in: u32, pub local_buf: Box, } impl ParamsOxide { fn new(flags: u32) -> Self { ParamsOxide { flags, greedy_parsing: flags & TDEFL_GREEDY_PARSING_FLAG != 0, block_index: 0, saved_match_dist: 0, saved_match_len: 0, saved_lit: 0, flush: TDEFLFlush::None, flush_ofs: 0, flush_remaining: 0, finished: false, adler32: MZ_ADLER32_INIT, src_pos: 0, out_buf_ofs: 0, prev_return_status: TDEFLStatus::Okay, saved_bit_buffer: 0, saved_bits_in: 0, local_buf: Box::default(), } } fn update_flags(&mut self, flags: u32) { self.flags = flags; self.greedy_parsing = self.flags & TDEFL_GREEDY_PARSING_FLAG != 0; } /// Reset state, saving settings. fn reset(&mut self) { self.block_index = 0; self.saved_match_len = 0; self.saved_match_dist = 0; self.saved_lit = 0; self.flush = TDEFLFlush::None; self.flush_ofs = 0; self.flush_remaining = 0; self.finished = false; self.adler32 = MZ_ADLER32_INIT; self.src_pos = 0; self.out_buf_ofs = 0; self.prev_return_status = TDEFLStatus::Okay; self.saved_bit_buffer = 0; self.saved_bits_in = 0; self.local_buf.b = [0; OUT_BUF_SIZE]; } } struct LZOxide { pub codes: [u8; LZ_CODE_BUF_SIZE], pub code_position: usize, pub flag_position: usize, // The total number of bytes in the current block. // (Could maybe use usize, but it's not possible to exceed a block size of ) pub total_bytes: u32, pub num_flags_left: u32, } impl LZOxide { const fn new() -> Self { LZOxide { codes: [0; LZ_CODE_BUF_SIZE], code_position: 1, flag_position: 0, total_bytes: 0, num_flags_left: 8, } } fn write_code(&mut self, val: u8) { self.codes[self.code_position] = val; self.code_position += 1; } fn init_flag(&mut self) { if self.num_flags_left == 8 { *self.get_flag() = 0; self.code_position -= 1; } else { *self.get_flag() >>= self.num_flags_left; } } fn get_flag(&mut self) -> &mut u8 { &mut self.codes[self.flag_position] } fn plant_flag(&mut self) { self.flag_position = self.code_position; self.code_position += 1; } fn consume_flag(&mut self) { self.num_flags_left -= 1; if self.num_flags_left == 0 { self.num_flags_left = 8; self.plant_flag(); } } } fn compress_lz_codes( huff: &HuffmanOxide, output: &mut OutputBufferOxide, lz_code_buf: &[u8], ) -> Result { let mut flags = 1; let mut bb = BitBuffer { bit_buffer: u64::from(output.bit_buffer), bits_in: output.bits_in, }; let mut i: usize = 0; while i < lz_code_buf.len() { if flags == 1 { flags = u32::from(lz_code_buf[i]) | 0x100; i += 1; } // The lz code was a length code if flags & 1 == 1 { flags >>= 1; let sym; let num_extra_bits; let match_len = lz_code_buf[i] as usize; let match_dist = read_u16_le(lz_code_buf, i + 1); i += 3; debug_assert!(huff.code_sizes[0][LEN_SYM[match_len] as usize] != 0); bb.put_fast( u64::from(huff.codes[0][LEN_SYM[match_len] as usize]), u32::from(huff.code_sizes[0][LEN_SYM[match_len] as usize]), ); bb.put_fast( match_len as u64 & u64::from(BITMASKS[LEN_EXTRA[match_len] as usize]), u32::from(LEN_EXTRA[match_len]), ); if match_dist < 512 { sym = SMALL_DIST_SYM[match_dist as usize] as usize; num_extra_bits = SMALL_DIST_EXTRA[match_dist as usize] as usize; } else { sym = LARGE_DIST_SYM[(match_dist >> 8) as usize] as usize; num_extra_bits = LARGE_DIST_EXTRA[(match_dist >> 8) as usize] as usize; } debug_assert!(huff.code_sizes[1][sym] != 0); bb.put_fast( u64::from(huff.codes[1][sym]), u32::from(huff.code_sizes[1][sym]), ); bb.put_fast( u64::from(match_dist) & u64::from(BITMASKS[num_extra_bits as usize]), num_extra_bits as u32, ); } else { // The lz code was a literal for _ in 0..3 { flags >>= 1; let lit = lz_code_buf[i]; i += 1; debug_assert!(huff.code_sizes[0][lit as usize] != 0); bb.put_fast( u64::from(huff.codes[0][lit as usize]), u32::from(huff.code_sizes[0][lit as usize]), ); if flags & 1 == 1 || i >= lz_code_buf.len() { break; } } } bb.flush(output)?; } output.bits_in = 0; output.bit_buffer = 0; while bb.bits_in != 0 { let n = cmp::min(bb.bits_in, 16); output.put_bits(bb.bit_buffer as u32 & BITMASKS[n as usize], n); bb.bit_buffer >>= n; bb.bits_in -= n; } // Output the end of block symbol. output.put_bits( u32::from(huff.codes[0][256]), u32::from(huff.code_sizes[0][256]), ); Ok(true) } fn compress_block( huff: &mut HuffmanOxide, output: &mut OutputBufferOxide, lz: &LZOxide, static_block: bool, ) -> Result { if static_block { huff.start_static_block(output); } else { huff.start_dynamic_block(output)?; } compress_lz_codes(huff, output, &lz.codes[..lz.code_position]) } fn flush_block( d: &mut CompressorOxide, callback: &mut CallbackOxide, flush: TDEFLFlush, ) -> Result { let mut saved_buffer; { let mut output = callback .out .new_output_buffer(&mut d.params.local_buf.b, d.params.out_buf_ofs); output.bit_buffer = d.params.saved_bit_buffer; output.bits_in = d.params.saved_bits_in; let use_raw_block = (d.params.flags & TDEFL_FORCE_ALL_RAW_BLOCKS != 0) && (d.dict.lookahead_pos - d.dict.code_buf_dict_pos) <= d.dict.size; assert!(d.params.flush_remaining == 0); d.params.flush_ofs = 0; d.params.flush_remaining = 0; d.lz.init_flag(); // If we are at the start of the stream, write the zlib header if requested. if d.params.flags & TDEFL_WRITE_ZLIB_HEADER != 0 && d.params.block_index == 0 { let header = zlib::header_from_flags(d.params.flags as u32); output.put_bits(header[0].into(), 8); output.put_bits(header[1].into(), 8); } // Output the block header. output.put_bits((flush == TDEFLFlush::Finish) as u32, 1); saved_buffer = output.save(); let comp_success = if !use_raw_block { let use_static = (d.params.flags & TDEFL_FORCE_ALL_STATIC_BLOCKS != 0) || (d.lz.total_bytes < 48); compress_block(&mut d.huff, &mut output, &d.lz, use_static)? } else { false }; // If we failed to compress anything and the output would take up more space than the output // data, output a stored block instead, which has at most 5 bytes of overhead. // We only use some simple heuristics for now. // A stored block will have an overhead of at least 4 bytes containing the block length // but usually more due to the length parameters having to start at a byte boundary and thus // requiring up to 5 bytes of padding. // As a static block will have an overhead of at most 1 bit per byte // (as literals are either 8 or 9 bytes), a raw block will // never take up less space if the number of input bytes are less than 32. let expanded = (d.lz.total_bytes > 32) && (output.inner_pos - saved_buffer.pos + 1 >= (d.lz.total_bytes as usize)) && (d.dict.lookahead_pos - d.dict.code_buf_dict_pos <= d.dict.size); if use_raw_block || expanded { output.load(saved_buffer); // Block header. output.put_bits(0, 2); // Block length has to start on a byte boundary, s opad. output.pad_to_bytes(); // Block length and ones complement of block length. output.put_bits(d.lz.total_bytes & 0xFFFF, 16); output.put_bits(!d.lz.total_bytes & 0xFFFF, 16); // Write the actual bytes. for i in 0..d.lz.total_bytes { let pos = (d.dict.code_buf_dict_pos + i as usize) & LZ_DICT_SIZE_MASK; output.put_bits(u32::from(d.dict.b.dict[pos as usize]), 8); } } else if !comp_success { output.load(saved_buffer); compress_block(&mut d.huff, &mut output, &d.lz, true)?; } if flush != TDEFLFlush::None { if flush == TDEFLFlush::Finish { output.pad_to_bytes(); if d.params.flags & TDEFL_WRITE_ZLIB_HEADER != 0 { let mut adler = d.params.adler32; for _ in 0..4 { output.put_bits((adler >> 24) & 0xFF, 8); adler <<= 8; } } } else { // Sync or Full flush. // Output an empty raw block. output.put_bits(0, 3); output.pad_to_bytes(); output.put_bits(0, 16); output.put_bits(0xFFFF, 16); } } memset(&mut d.huff.count[0][..MAX_HUFF_SYMBOLS_0], 0); memset(&mut d.huff.count[1][..MAX_HUFF_SYMBOLS_1], 0); d.lz.code_position = 1; d.lz.flag_position = 0; d.lz.num_flags_left = 8; d.dict.code_buf_dict_pos += d.lz.total_bytes as usize; d.lz.total_bytes = 0; d.params.block_index += 1; saved_buffer = output.save(); d.params.saved_bit_buffer = saved_buffer.bit_buffer; d.params.saved_bits_in = saved_buffer.bits_in; } Ok(callback.flush_output(saved_buffer, &mut d.params)) } fn record_literal(h: &mut HuffmanOxide, lz: &mut LZOxide, lit: u8) { lz.total_bytes += 1; lz.write_code(lit); *lz.get_flag() >>= 1; lz.consume_flag(); h.count[0][lit as usize] += 1; } fn record_match(h: &mut HuffmanOxide, lz: &mut LZOxide, mut match_len: u32, mut match_dist: u32) { assert!(match_len >= MIN_MATCH_LEN.into()); assert!(match_dist >= 1); assert!(match_dist as usize <= LZ_DICT_SIZE); lz.total_bytes += match_len; match_dist -= 1; match_len -= u32::from(MIN_MATCH_LEN); lz.write_code(match_len as u8); lz.write_code(match_dist as u8); lz.write_code((match_dist >> 8) as u8); *lz.get_flag() >>= 1; *lz.get_flag() |= 0x80; lz.consume_flag(); let symbol = if match_dist < 512 { SMALL_DIST_SYM[match_dist as usize] } else { LARGE_DIST_SYM[((match_dist >> 8) & 127) as usize] } as usize; h.count[1][symbol] += 1; h.count[0][LEN_SYM[match_len as usize] as usize] += 1; } fn compress_normal(d: &mut CompressorOxide, callback: &mut CallbackOxide) -> bool { let mut src_pos = d.params.src_pos; let in_buf = match callback.in_buf { None => return true, Some(in_buf) => in_buf, }; let mut lookahead_size = d.dict.lookahead_size; let mut lookahead_pos = d.dict.lookahead_pos; let mut saved_lit = d.params.saved_lit; let mut saved_match_dist = d.params.saved_match_dist; let mut saved_match_len = d.params.saved_match_len; while src_pos < in_buf.len() || (d.params.flush != TDEFLFlush::None && lookahead_size != 0) { let src_buf_left = in_buf.len() - src_pos; let num_bytes_to_process = cmp::min(src_buf_left, MAX_MATCH_LEN - lookahead_size as usize); if lookahead_size + d.dict.size >= usize::from(MIN_MATCH_LEN) - 1 && num_bytes_to_process > 0 { let dictb = &mut d.dict.b; let mut dst_pos = (lookahead_pos + lookahead_size as usize) & LZ_DICT_SIZE_MASK; let mut ins_pos = lookahead_pos + lookahead_size as usize - 2; // Start the hash value from the first two bytes let mut hash = update_hash( u16::from(dictb.dict[(ins_pos & LZ_DICT_SIZE_MASK) as usize]), dictb.dict[((ins_pos + 1) & LZ_DICT_SIZE_MASK) as usize], ); lookahead_size += num_bytes_to_process; for &c in &in_buf[src_pos..src_pos + num_bytes_to_process] { // Add byte to input buffer. dictb.dict[dst_pos as usize] = c; if (dst_pos as usize) < MAX_MATCH_LEN - 1 { dictb.dict[LZ_DICT_SIZE + dst_pos as usize] = c; } // Generate hash from the current byte, hash = update_hash(hash, c); dictb.next[(ins_pos & LZ_DICT_SIZE_MASK) as usize] = dictb.hash[hash as usize]; // and insert it into the hash chain. dictb.hash[hash as usize] = ins_pos as u16; dst_pos = (dst_pos + 1) & LZ_DICT_SIZE_MASK; ins_pos += 1; } src_pos += num_bytes_to_process; } else { let dictb = &mut d.dict.b; for &c in &in_buf[src_pos..src_pos + num_bytes_to_process] { let dst_pos = (lookahead_pos + lookahead_size) & LZ_DICT_SIZE_MASK; dictb.dict[dst_pos as usize] = c; if (dst_pos as usize) < MAX_MATCH_LEN - 1 { dictb.dict[LZ_DICT_SIZE + dst_pos as usize] = c; } lookahead_size += 1; if lookahead_size + d.dict.size >= MIN_MATCH_LEN.into() { let ins_pos = lookahead_pos + lookahead_size - 3; let hash = ((u32::from(dictb.dict[(ins_pos & LZ_DICT_SIZE_MASK) as usize]) << (LZ_HASH_SHIFT * 2)) ^ ((u32::from(dictb.dict[((ins_pos + 1) & LZ_DICT_SIZE_MASK) as usize]) << LZ_HASH_SHIFT) ^ u32::from(c))) & (LZ_HASH_SIZE as u32 - 1); dictb.next[(ins_pos & LZ_DICT_SIZE_MASK) as usize] = dictb.hash[hash as usize]; dictb.hash[hash as usize] = ins_pos as u16; } } src_pos += num_bytes_to_process; } d.dict.size = cmp::min(LZ_DICT_SIZE - lookahead_size, d.dict.size); if d.params.flush == TDEFLFlush::None && (lookahead_size as usize) < MAX_MATCH_LEN { break; } let mut len_to_move = 1; let mut cur_match_dist = 0; let mut cur_match_len = if saved_match_len != 0 { saved_match_len } else { u32::from(MIN_MATCH_LEN) - 1 }; let cur_pos = lookahead_pos & LZ_DICT_SIZE_MASK; if d.params.flags & (TDEFL_RLE_MATCHES | TDEFL_FORCE_ALL_RAW_BLOCKS) != 0 { // If TDEFL_RLE_MATCHES is set, we only look for repeating sequences of the current byte. if d.dict.size != 0 && d.params.flags & TDEFL_FORCE_ALL_RAW_BLOCKS == 0 { let c = d.dict.b.dict[((cur_pos.wrapping_sub(1)) & LZ_DICT_SIZE_MASK) as usize]; cur_match_len = d.dict.b.dict[cur_pos as usize..(cur_pos + lookahead_size) as usize] .iter() .take_while(|&x| *x == c) .count() as u32; if cur_match_len < MIN_MATCH_LEN.into() { cur_match_len = 0 } else { cur_match_dist = 1 } } } else { // Try to find a match for the bytes at the current position. let dist_len = d.dict.find_match( lookahead_pos, d.dict.size, lookahead_size as u32, cur_match_dist, cur_match_len, ); cur_match_dist = dist_len.0; cur_match_len = dist_len.1; } let far_and_small = cur_match_len == MIN_MATCH_LEN.into() && cur_match_dist >= 8 * 1024; let filter_small = d.params.flags & TDEFL_FILTER_MATCHES != 0 && cur_match_len <= 5; if far_and_small || filter_small || cur_pos == cur_match_dist as usize { cur_match_dist = 0; cur_match_len = 0; } if saved_match_len != 0 { if cur_match_len > saved_match_len { record_literal(&mut d.huff, &mut d.lz, saved_lit); if cur_match_len >= 128 { record_match(&mut d.huff, &mut d.lz, cur_match_len, cur_match_dist); saved_match_len = 0; len_to_move = cur_match_len as usize; } else { saved_lit = d.dict.b.dict[cur_pos as usize]; saved_match_dist = cur_match_dist; saved_match_len = cur_match_len; } } else { record_match(&mut d.huff, &mut d.lz, saved_match_len, saved_match_dist); len_to_move = (saved_match_len - 1) as usize; saved_match_len = 0; } } else if cur_match_dist == 0 { record_literal( &mut d.huff, &mut d.lz, d.dict.b.dict[cmp::min(cur_pos as usize, d.dict.b.dict.len() - 1)], ); } else if d.params.greedy_parsing || (d.params.flags & TDEFL_RLE_MATCHES != 0) || cur_match_len >= 128 { // If we are using lazy matching, check for matches at the next byte if the current // match was shorter than 128 bytes. record_match(&mut d.huff, &mut d.lz, cur_match_len, cur_match_dist); len_to_move = cur_match_len as usize; } else { saved_lit = d.dict.b.dict[cmp::min(cur_pos as usize, d.dict.b.dict.len() - 1)]; saved_match_dist = cur_match_dist; saved_match_len = cur_match_len; } lookahead_pos += len_to_move; assert!(lookahead_size >= len_to_move); lookahead_size -= len_to_move; d.dict.size = cmp::min(d.dict.size + len_to_move, LZ_DICT_SIZE); let lz_buf_tight = d.lz.code_position > LZ_CODE_BUF_SIZE - 8; let raw = d.params.flags & TDEFL_FORCE_ALL_RAW_BLOCKS != 0; let fat = ((d.lz.code_position * 115) >> 7) >= d.lz.total_bytes as usize; let fat_or_raw = (d.lz.total_bytes > 31 * 1024) && (fat || raw); if lz_buf_tight || fat_or_raw { d.params.src_pos = src_pos; // These values are used in flush_block, so we need to write them back here. d.dict.lookahead_size = lookahead_size; d.dict.lookahead_pos = lookahead_pos; let n = flush_block(d, callback, TDEFLFlush::None) .unwrap_or(TDEFLStatus::PutBufFailed as i32); if n != 0 { d.params.saved_lit = saved_lit; d.params.saved_match_dist = saved_match_dist; d.params.saved_match_len = saved_match_len; return n > 0; } } } d.params.src_pos = src_pos; d.dict.lookahead_size = lookahead_size; d.dict.lookahead_pos = lookahead_pos; d.params.saved_lit = saved_lit; d.params.saved_match_dist = saved_match_dist; d.params.saved_match_len = saved_match_len; true } const COMP_FAST_LOOKAHEAD_SIZE: usize = 4096; fn compress_fast(d: &mut CompressorOxide, callback: &mut CallbackOxide) -> bool { let mut src_pos = d.params.src_pos; let mut lookahead_size = d.dict.lookahead_size; let mut lookahead_pos = d.dict.lookahead_pos; let mut cur_pos = lookahead_pos & LZ_DICT_SIZE_MASK; let in_buf = match callback.in_buf { None => return true, Some(in_buf) => in_buf, }; debug_assert!(d.lz.code_position < LZ_CODE_BUF_SIZE - 2); while src_pos < in_buf.len() || (d.params.flush != TDEFLFlush::None && lookahead_size > 0) { let mut dst_pos = ((lookahead_pos + lookahead_size) & LZ_DICT_SIZE_MASK) as usize; let mut num_bytes_to_process = cmp::min( in_buf.len() - src_pos, (COMP_FAST_LOOKAHEAD_SIZE - lookahead_size) as usize, ); lookahead_size += num_bytes_to_process; while num_bytes_to_process != 0 { let n = cmp::min(LZ_DICT_SIZE - dst_pos, num_bytes_to_process); d.dict.b.dict[dst_pos..dst_pos + n].copy_from_slice(&in_buf[src_pos..src_pos + n]); if dst_pos < MAX_MATCH_LEN - 1 { let m = cmp::min(n, MAX_MATCH_LEN - 1 - dst_pos); d.dict.b.dict[dst_pos + LZ_DICT_SIZE..dst_pos + LZ_DICT_SIZE + m] .copy_from_slice(&in_buf[src_pos..src_pos + m]); } src_pos += n; dst_pos = (dst_pos + n) & LZ_DICT_SIZE_MASK as usize; num_bytes_to_process -= n; } d.dict.size = cmp::min(LZ_DICT_SIZE - lookahead_size, d.dict.size); if d.params.flush == TDEFLFlush::None && lookahead_size < COMP_FAST_LOOKAHEAD_SIZE { break; } while lookahead_size >= 4 { let mut cur_match_len = 1; let first_trigram = d.dict.read_unaligned_u32(cur_pos) & 0xFF_FFFF; let hash = (first_trigram ^ (first_trigram >> (24 - (LZ_HASH_BITS - 8)))) & LEVEL1_HASH_SIZE_MASK; let mut probe_pos = usize::from(d.dict.b.hash[hash as usize]); d.dict.b.hash[hash as usize] = lookahead_pos as u16; let mut cur_match_dist = (lookahead_pos - probe_pos as usize) as u16; if cur_match_dist as usize <= d.dict.size { probe_pos &= LZ_DICT_SIZE_MASK; let trigram = d.dict.read_unaligned_u32(probe_pos) & 0xFF_FFFF; if first_trigram == trigram { // Trigram was tested, so we can start with "+ 3" displacement. let mut p = cur_pos + 3; let mut q = probe_pos + 3; cur_match_len = (|| { for _ in 0..32 { let p_data: u64 = d.dict.read_unaligned_u64(p); let q_data: u64 = d.dict.read_unaligned_u64(q); let xor_data = p_data ^ q_data; if xor_data == 0 { p += 8; q += 8; } else { let trailing = xor_data.trailing_zeros(); return p as u32 - cur_pos as u32 + (trailing >> 3); } } if cur_match_dist == 0 { 0 } else { MAX_MATCH_LEN as u32 } })(); if cur_match_len < MIN_MATCH_LEN.into() || (cur_match_len == MIN_MATCH_LEN.into() && cur_match_dist >= 8 * 1024) { let lit = first_trigram as u8; cur_match_len = 1; d.lz.write_code(lit); *d.lz.get_flag() >>= 1; d.huff.count[0][lit as usize] += 1; } else { // Limit the match to the length of the lookahead so we don't create a match // that ends after the end of the input data. cur_match_len = cmp::min(cur_match_len, lookahead_size as u32); debug_assert!(cur_match_len >= MIN_MATCH_LEN.into()); debug_assert!(cur_match_dist >= 1); debug_assert!(cur_match_dist as usize <= LZ_DICT_SIZE); cur_match_dist -= 1; d.lz.write_code((cur_match_len - u32::from(MIN_MATCH_LEN)) as u8); d.lz.write_code(cur_match_dist as u8); d.lz.write_code((cur_match_dist >> 8) as u8); *d.lz.get_flag() >>= 1; *d.lz.get_flag() |= 0x80; if cur_match_dist < 512 { d.huff.count[1][SMALL_DIST_SYM[cur_match_dist as usize] as usize] += 1; } else { d.huff.count[1] [LARGE_DIST_SYM[(cur_match_dist >> 8) as usize] as usize] += 1; } d.huff.count[0][LEN_SYM[(cur_match_len - u32::from(MIN_MATCH_LEN)) as usize] as usize] += 1; } } else { d.lz.write_code(first_trigram as u8); *d.lz.get_flag() >>= 1; d.huff.count[0][first_trigram as u8 as usize] += 1; } d.lz.consume_flag(); d.lz.total_bytes += cur_match_len; lookahead_pos += cur_match_len as usize; d.dict.size = cmp::min(d.dict.size + cur_match_len as usize, LZ_DICT_SIZE); cur_pos = (cur_pos + cur_match_len as usize) & LZ_DICT_SIZE_MASK; lookahead_size -= cur_match_len as usize; if d.lz.code_position > LZ_CODE_BUF_SIZE - 8 { // These values are used in flush_block, so we need to write them back here. d.dict.lookahead_size = lookahead_size; d.dict.lookahead_pos = lookahead_pos; let n = match flush_block(d, callback, TDEFLFlush::None) { Err(_) => { d.params.src_pos = src_pos; d.params.prev_return_status = TDEFLStatus::PutBufFailed; return false; } Ok(status) => status, }; if n != 0 { d.params.src_pos = src_pos; return n > 0; } debug_assert!(d.lz.code_position < LZ_CODE_BUF_SIZE - 2); lookahead_size = d.dict.lookahead_size; lookahead_pos = d.dict.lookahead_pos; } } } while lookahead_size != 0 { let lit = d.dict.b.dict[cur_pos as usize]; d.lz.total_bytes += 1; d.lz.write_code(lit); *d.lz.get_flag() >>= 1; d.lz.consume_flag(); d.huff.count[0][lit as usize] += 1; lookahead_pos += 1; d.dict.size = cmp::min(d.dict.size + 1, LZ_DICT_SIZE); cur_pos = (cur_pos + 1) & LZ_DICT_SIZE_MASK; lookahead_size -= 1; if d.lz.code_position > LZ_CODE_BUF_SIZE - 8 { // These values are used in flush_block, so we need to write them back here. d.dict.lookahead_size = lookahead_size; d.dict.lookahead_pos = lookahead_pos; let n = match flush_block(d, callback, TDEFLFlush::None) { Err(_) => { d.params.prev_return_status = TDEFLStatus::PutBufFailed; d.params.src_pos = src_pos; return false; } Ok(status) => status, }; if n != 0 { d.params.src_pos = src_pos; return n > 0; } lookahead_size = d.dict.lookahead_size; lookahead_pos = d.dict.lookahead_pos; } } } d.params.src_pos = src_pos; d.dict.lookahead_size = lookahead_size; d.dict.lookahead_pos = lookahead_pos; true } fn flush_output_buffer(c: &mut CallbackOxide, p: &mut ParamsOxide) -> (TDEFLStatus, usize, usize) { let mut res = (TDEFLStatus::Okay, p.src_pos, 0); if let CallbackOut::Buf(ref mut cb) = c.out { let n = cmp::min(cb.out_buf.len() - p.out_buf_ofs, p.flush_remaining as usize); if n != 0 { (&mut cb.out_buf[p.out_buf_ofs..p.out_buf_ofs + n]) .copy_from_slice(&p.local_buf.b[p.flush_ofs as usize..p.flush_ofs as usize + n]); } p.flush_ofs += n as u32; p.flush_remaining -= n as u32; p.out_buf_ofs += n; res.2 = p.out_buf_ofs; } if p.finished && p.flush_remaining == 0 { res.0 = TDEFLStatus::Done } res } /// Main compression function. Tries to compress as much as possible from `in_buf` and /// puts compressed output into `out_buf`. /// /// The value of `flush` determines if the compressor should attempt to flush all output /// and alternatively try to finish the stream. /// /// Use [`TDEFLFlush::Finish`] on the final call to signal that the stream is finishing. /// /// Note that this function does not keep track of whether a flush marker has been output, so /// if called using [`TDEFLFlush::Sync`], the caller needs to ensure there is enough space in the /// output buffer if they want to avoid repeated flush markers. /// See #105 for details. /// /// # Returns /// Returns a tuple containing the current status of the compressor, the current position /// in the input buffer and the current position in the output buffer. pub fn compress( d: &mut CompressorOxide, in_buf: &[u8], out_buf: &mut [u8], flush: TDEFLFlush, ) -> (TDEFLStatus, usize, usize) { compress_inner( d, &mut CallbackOxide::new_callback_buf(in_buf, out_buf), flush, ) } /// Main compression function. Callbacks output. /// /// # Returns /// Returns a tuple containing the current status of the compressor, the current position /// in the input buffer. /// /// The caller is responsible for ensuring the `CallbackFunc` struct will not cause undefined /// behaviour. pub fn compress_to_output( d: &mut CompressorOxide, in_buf: &[u8], flush: TDEFLFlush, mut callback_func: impl FnMut(&[u8]) -> bool, ) -> (TDEFLStatus, usize) { let res = compress_inner( d, &mut CallbackOxide::new_callback_func( in_buf, CallbackFunc { put_buf_func: &mut callback_func, }, ), flush, ); (res.0, res.1) } fn compress_inner( d: &mut CompressorOxide, callback: &mut CallbackOxide, flush: TDEFLFlush, ) -> (TDEFLStatus, usize, usize) { d.params.out_buf_ofs = 0; d.params.src_pos = 0; let prev_ok = d.params.prev_return_status == TDEFLStatus::Okay; let flush_finish_once = d.params.flush != TDEFLFlush::Finish || flush == TDEFLFlush::Finish; d.params.flush = flush; if !prev_ok || !flush_finish_once { d.params.prev_return_status = TDEFLStatus::BadParam; return (d.params.prev_return_status, 0, 0); } if d.params.flush_remaining != 0 || d.params.finished { let res = flush_output_buffer(callback, &mut d.params); d.params.prev_return_status = res.0; return res; } let one_probe = d.params.flags & MAX_PROBES_MASK as u32 == 1; let greedy = d.params.flags & TDEFL_GREEDY_PARSING_FLAG != 0; let filter_or_rle_or_raw = d.params.flags & (TDEFL_FILTER_MATCHES | TDEFL_FORCE_ALL_RAW_BLOCKS | TDEFL_RLE_MATCHES) != 0; let compress_success = if one_probe && greedy && !filter_or_rle_or_raw { compress_fast(d, callback) } else { compress_normal(d, callback) }; if !compress_success { return ( d.params.prev_return_status, d.params.src_pos, d.params.out_buf_ofs, ); } if let Some(in_buf) = callback.in_buf { if d.params.flags & (TDEFL_WRITE_ZLIB_HEADER | TDEFL_COMPUTE_ADLER32) != 0 { d.params.adler32 = update_adler32(d.params.adler32, &in_buf[..d.params.src_pos]); } } let flush_none = d.params.flush == TDEFLFlush::None; let in_left = callback.in_buf.map_or(0, |buf| buf.len()) - d.params.src_pos; let remaining = in_left != 0 || d.params.flush_remaining != 0; if !flush_none && d.dict.lookahead_size == 0 && !remaining { let flush = d.params.flush; match flush_block(d, callback, flush) { Err(_) => { d.params.prev_return_status = TDEFLStatus::PutBufFailed; return ( d.params.prev_return_status, d.params.src_pos, d.params.out_buf_ofs, ); } Ok(x) if x < 0 => { return ( d.params.prev_return_status, d.params.src_pos, d.params.out_buf_ofs, ) } _ => { d.params.finished = d.params.flush == TDEFLFlush::Finish; if d.params.flush == TDEFLFlush::Full { memset(&mut d.dict.b.hash[..], 0); memset(&mut d.dict.b.next[..], 0); d.dict.size = 0; } } } } let res = flush_output_buffer(callback, &mut d.params); d.params.prev_return_status = res.0; res } /// Create a set of compression flags using parameters used by zlib and other compressors. /// Mainly intended for use with transition from c libraries as it deals with raw integers. /// /// # Parameters /// `level` determines compression level. Clamped to maximum of 10. Negative values result in /// `CompressionLevel::DefaultLevel`. /// `window_bits`: Above 0, wraps the stream in a zlib wrapper, 0 or negative for a raw deflate /// stream. /// `strategy`: Sets the strategy if this conforms to any of the values in `CompressionStrategy`. /// /// # Notes /// This function may be removed or moved to the `miniz_oxide_c_api` in the future. pub fn create_comp_flags_from_zip_params(level: i32, window_bits: i32, strategy: i32) -> u32 { let num_probes = (if level >= 0 { cmp::min(10, level) } else { CompressionLevel::DefaultLevel as i32 }) as usize; let greedy = if level <= 3 { TDEFL_GREEDY_PARSING_FLAG } else { 0 }; let mut comp_flags = NUM_PROBES[num_probes] | greedy; if window_bits > 0 { comp_flags |= TDEFL_WRITE_ZLIB_HEADER; } if level == 0 { comp_flags |= TDEFL_FORCE_ALL_RAW_BLOCKS; } else if strategy == CompressionStrategy::Filtered as i32 { comp_flags |= TDEFL_FILTER_MATCHES; } else if strategy == CompressionStrategy::HuffmanOnly as i32 { comp_flags &= !MAX_PROBES_MASK as u32; } else if strategy == CompressionStrategy::Fixed as i32 { comp_flags |= TDEFL_FORCE_ALL_STATIC_BLOCKS; } else if strategy == CompressionStrategy::RLE as i32 { comp_flags |= TDEFL_RLE_MATCHES; } comp_flags } #[cfg(test)] mod test { use super::{ compress_to_output, create_comp_flags_from_zip_params, read_u16_le, write_u16_le, CompressionStrategy, CompressorOxide, TDEFLFlush, TDEFLStatus, DEFAULT_FLAGS, MZ_DEFAULT_WINDOW_BITS, }; use crate::inflate::decompress_to_vec; use alloc::vec; #[test] fn u16_to_slice() { let mut slice = [0, 0]; write_u16_le(2000, &mut slice, 0); assert_eq!(slice, [208, 7]); } #[test] fn u16_from_slice() { let mut slice = [208, 7]; assert_eq!(read_u16_le(&mut slice, 0), 2000); } #[test] fn compress_output() { assert_eq!( DEFAULT_FLAGS, create_comp_flags_from_zip_params( 4, MZ_DEFAULT_WINDOW_BITS, CompressionStrategy::Default as i32 ) ); let slice = [ 1, 2, 3, 4, 1, 2, 3, 1, 2, 3, 1, 2, 6, 1, 2, 3, 1, 2, 3, 2, 3, 1, 2, 3, ]; let mut encoded = vec![]; let flags = create_comp_flags_from_zip_params(6, 0, 0); let mut d = CompressorOxide::new(flags); let (status, in_consumed) = compress_to_output(&mut d, &slice, TDEFLFlush::Finish, |out: &[u8]| { encoded.extend_from_slice(out); true }); assert_eq!(status, TDEFLStatus::Done); assert_eq!(in_consumed, slice.len()); let decoded = decompress_to_vec(&encoded[..]).unwrap(); assert_eq!(&decoded[..], &slice[..]); } #[test] /// Check fast compress mode fn compress_fast() { let slice = [ 1, 2, 3, 4, 1, 2, 3, 1, 2, 3, 1, 2, 6, 1, 2, 3, 1, 2, 3, 2, 3, 1, 2, 3, ]; let mut encoded = vec![]; let flags = create_comp_flags_from_zip_params(1, 0, 0); let mut d = CompressorOxide::new(flags); let (status, in_consumed) = compress_to_output(&mut d, &slice, TDEFLFlush::Finish, |out: &[u8]| { encoded.extend_from_slice(out); true }); assert_eq!(status, TDEFLStatus::Done); assert_eq!(in_consumed, slice.len()); // Needs to be altered if algorithm improves. assert_eq!( &encoded[..], [99, 100, 98, 102, 1, 98, 48, 98, 3, 147, 204, 76, 204, 140, 76, 204, 0] ); let decoded = decompress_to_vec(&encoded[..]).unwrap(); assert_eq!(&decoded[..], &slice[..]); } }