diff options
Diffstat (limited to 'vendor/miniz_oxide/src/deflate/core.rs')
| -rw-r--r-- | vendor/miniz_oxide/src/deflate/core.rs | 2462 |
1 files changed, 2462 insertions, 0 deletions
diff --git a/vendor/miniz_oxide/src/deflate/core.rs b/vendor/miniz_oxide/src/deflate/core.rs new file mode 100644 index 0000000..d2db260 --- /dev/null +++ b/vendor/miniz_oxide/src/deflate/core.rs @@ -0,0 +1,2462 @@ +//! 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[..]); + } +} |