diff options
Diffstat (limited to 'vendor/miniz_oxide/src/deflate/mod.rs')
-rw-r--r-- | vendor/miniz_oxide/src/deflate/mod.rs | 227 |
1 files changed, 227 insertions, 0 deletions
diff --git a/vendor/miniz_oxide/src/deflate/mod.rs b/vendor/miniz_oxide/src/deflate/mod.rs new file mode 100644 index 0000000..471b94b --- /dev/null +++ b/vendor/miniz_oxide/src/deflate/mod.rs @@ -0,0 +1,227 @@ +//! This module contains functionality for compression. + +use crate::alloc::vec; +use crate::alloc::vec::Vec; + +mod buffer; +pub mod core; +pub mod stream; +use self::core::*; + +/// How much processing the compressor should do to compress the data. +/// `NoCompression` and `Bestspeed` have special meanings, the other levels determine the number +/// of checks for matches in the hash chains and whether to use lazy or greedy parsing. +#[repr(i32)] +#[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)] +pub enum CompressionLevel { + /// Don't do any compression, only output uncompressed blocks. + NoCompression = 0, + /// Fast compression. Uses a special compression routine that is optimized for speed. + BestSpeed = 1, + /// Slow/high compression. Do a lot of checks to try to find good matches. + BestCompression = 9, + /// Even more checks, can be very slow. + UberCompression = 10, + /// Default compromise between speed and compression. + DefaultLevel = 6, + /// Use the default compression level. + DefaultCompression = -1, +} + +// Missing safe rust analogue (this and mem-to-mem are quite similar) +/* +fn tdefl_compress( + d: Option<&mut CompressorOxide>, + in_buf: *const c_void, + in_size: Option<&mut usize>, + out_buf: *mut c_void, + out_size: Option<&mut usize>, + flush: TDEFLFlush, +) -> TDEFLStatus { + let res = match d { + None => { + in_size.map(|size| *size = 0); + out_size.map(|size| *size = 0); + (TDEFLStatus::BadParam, 0, 0) + }, + Some(compressor) => { + let callback_res = CallbackOxide::new( + compressor.callback_func.clone(), + in_buf, + in_size, + out_buf, + out_size, + ); + + if let Ok(mut callback) = callback_res { + let res = compress(compressor, &mut callback, flush); + callback.update_size(Some(res.1), Some(res.2)); + res + } else { + (TDEFLStatus::BadParam, 0, 0) + } + } + }; + res.0 +}*/ + +// Missing safe rust analogue +/* +fn tdefl_init( + d: Option<&mut CompressorOxide>, + put_buf_func: PutBufFuncPtr, + put_buf_user: *mut c_void, + flags: c_int, +) -> TDEFLStatus { + if let Some(d) = d { + *d = CompressorOxide::new( + put_buf_func.map(|func| + CallbackFunc { put_buf_func: func, put_buf_user: put_buf_user } + ), + flags as u32, + ); + TDEFLStatus::Okay + } else { + TDEFLStatus::BadParam + } +}*/ + +// Missing safe rust analogue (though maybe best served by flate2 front-end instead) +/* +fn tdefl_compress_mem_to_output( + buf: *const c_void, + buf_len: usize, + put_buf_func: PutBufFuncPtr, + put_buf_user: *mut c_void, + flags: c_int, +) -> bool*/ + +// Missing safe Rust analogue +/* +fn tdefl_compress_mem_to_mem( + out_buf: *mut c_void, + out_buf_len: usize, + src_buf: *const c_void, + src_buf_len: usize, + flags: c_int, +) -> usize*/ + +/// Compress the input data to a vector, using the specified compression level (0-10). +pub fn compress_to_vec(input: &[u8], level: u8) -> Vec<u8> { + compress_to_vec_inner(input, level, 0, 0) +} + +/// Compress the input data to a vector, using the specified compression level (0-10), and with a +/// zlib wrapper. +pub fn compress_to_vec_zlib(input: &[u8], level: u8) -> Vec<u8> { + compress_to_vec_inner(input, level, 1, 0) +} + +/// Simple function to compress data to a vec. +fn compress_to_vec_inner(input: &[u8], level: u8, window_bits: i32, strategy: i32) -> Vec<u8> { + // The comp flags function sets the zlib flag if the window_bits parameter is > 0. + let flags = create_comp_flags_from_zip_params(level.into(), window_bits, strategy); + let mut compressor = CompressorOxide::new(flags); + let mut output = vec![0; ::core::cmp::max(input.len() / 2, 2)]; + + let mut in_pos = 0; + let mut out_pos = 0; + loop { + let (status, bytes_in, bytes_out) = compress( + &mut compressor, + &input[in_pos..], + &mut output[out_pos..], + TDEFLFlush::Finish, + ); + + out_pos += bytes_out; + in_pos += bytes_in; + + match status { + TDEFLStatus::Done => { + output.truncate(out_pos); + break; + } + TDEFLStatus::Okay => { + // We need more space, so resize the vector. + if output.len().saturating_sub(out_pos) < 30 { + output.resize(output.len() * 2, 0) + } + } + // Not supposed to happen unless there is a bug. + _ => panic!("Bug! Unexpectedly failed to compress!"), + } + } + + output +} + +#[cfg(test)] +mod test { + use super::{compress_to_vec, compress_to_vec_inner, CompressionStrategy}; + use crate::inflate::decompress_to_vec; + use alloc::vec; + + /// Test deflate example. + /// + /// Check if the encoder produces the same code as the example given by Mark Adler here: + /// https://stackoverflow.com/questions/17398931/deflate-encoding-with-static-huffman-codes/17415203 + #[test] + fn compress_small() { + let test_data = b"Deflate late"; + let check = [ + 0x73, 0x49, 0x4d, 0xcb, 0x49, 0x2c, 0x49, 0x55, 0x00, 0x11, 0x00, + ]; + + let res = compress_to_vec(test_data, 1); + assert_eq!(&check[..], res.as_slice()); + + let res = compress_to_vec(test_data, 9); + assert_eq!(&check[..], res.as_slice()); + } + + #[test] + fn compress_huff_only() { + let test_data = b"Deflate late"; + + let res = compress_to_vec_inner(test_data, 1, 0, CompressionStrategy::HuffmanOnly as i32); + let d = decompress_to_vec(res.as_slice()).expect("Failed to decompress!"); + assert_eq!(test_data, d.as_slice()); + } + + /// Test that a raw block compresses fine. + #[test] + fn compress_raw() { + let text = b"Hello, zlib!"; + let encoded = { + let len = text.len(); + let notlen = !len; + let mut encoded = vec![ + 1, + len as u8, + (len >> 8) as u8, + notlen as u8, + (notlen >> 8) as u8, + ]; + encoded.extend_from_slice(&text[..]); + encoded + }; + + let res = compress_to_vec(text, 0); + assert_eq!(encoded, res.as_slice()); + } + + #[test] + fn short() { + let test_data = [10, 10, 10, 10, 10, 55]; + let c = compress_to_vec(&test_data, 9); + + let d = decompress_to_vec(c.as_slice()).expect("Failed to decompress!"); + assert_eq!(&test_data, d.as_slice()); + // Check that a static block is used here, rather than a raw block + // , so the data is actually compressed. + // (The optimal compressed length would be 5, but neither miniz nor zlib manages that either + // as neither checks matches against the byte at index 0.) + assert!(c.len() <= 6); + } +} |