| //! 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<T, E = Error> = core::result::Result<T, E>; |
| 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<MZFlush> 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<Self, MZError> { |
| 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<T: Copy>(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<HuffmanOxide>, |
| 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<usize>, out_size: Option<usize>) { |
| 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::<i32>(); |
| 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<HashBuffers>, |
| |
| 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<LocalBuf>, |
| } |
| |
| 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<bool> { |
| 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<bool> { |
| 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<i32> { |
| 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[..]); |
| } |
| } |