What is it?

• A collection of 120+ RLE and related codecs optimized for all kinds of different inputs and scenarios.
• Usually the fastest run length en/decoder by far. Single Core Decompression Speeds > 34 GB/s and Compression Speeds > 28 GB/s have been observed with large files. (small files can exceed 120 GB/s decode, 60 GB/s encode)
• Written in C.
• SIMD Variants for AVX-512F, AVX2, AVX, SSE4.1, SSSE3 and SSE2 variants are available for various decoders and encoders. Automatically picked at runtime based on the extensions available on the current platform.
• Variants include: Single RLE Symbol, Short Strings of RLE Symbols, Byte Alignmed, Symbol Aligned, 8 Bit, 16 Bit, 24 Bit, 32 Bit, 48 Bit, 64 Bit, 128 Bit, Different probabilities of reoccuring symbols, ...
• OpenCL variant available for some of the decoders.
• Licensed under Two Clause BSD.

Benchmark

See Full Benchmark with Graphs, the tables below only contain a tiny selection of the 100+ codecs.

• Single-Threaded
• Running on an AMD Ryzen 9 7950X, 32 GB DDR5-6000 CL30 on Windows 11.
• Compiled with Visual Studio 2022.
• Compared to TurboRLE and MRLE (with AVX2 enabled; benchmarking results have been converted from MB/s to MiB/s) (7f6e486, April 2023)
• Contained Codecs w/ Compression / Decompression Speed vs. Ratio Pareto + Notable Entropy Highlighted

video-frame.raw (heavily quantized video frame DCTs, 88,473,600 Bytes)

Type	Ratio	Encoding Speed	Decoding Speed	Entropy Compressible To
8 Bit	19.34 %	3,319.6 MiB/s	25,830.4 MiB/s	9.50 %
8 Bit Packed	17.95 %	2,907.5 MiB/s	19,783.6 MiB/s	9.69 %
8 Bit 1LUT Short	16.93 %	2,365.1 MiB/s	11,069.1 MiB/s	9.87 %
8 Bit 3LUT	17.41 %	2,146.7 MiB/s	15,819.2 MiB/s	9.80 %
8 Bit 3LUT Short	16.49 %	2,085.6 MiB/s	8,100.4 MiB/s	9.93 %
8 Bit 7LUT	17.46 %	2,094.6 MiB/s	16,100.9 MiB/s	9.94 %
8 Bit Single	18.31 %	1,654.7 MiB/s	23,750.2 MiB/s	9.71 %
8 Bit Single Short	17.05 %	1,414.4 MiB/s	14,143.6 MiB/s	9.81 %
16 Bit 1LUT Short (Symbol)	18.23 %	3,783.5 MiB/s	13,705.5 MiB/s	9.72 %
16 Bit 1LUT Short (Byte)	18.11 %	3,745.3 MiB/s	12,951.5 MiB/s	9.90 %
16 Bit 3LUT (Byte)	17.74 %	3,708.2 MiB/s	15,577.4 MiB/s	9.82 %
16 Bit 7LUT (Byte)	17.53 %	3,526.7 MiB/s	13,249.8 MiB/s	9.96 %
16 Bit 7LUT Short Greedy (Byte)	15.37 %	691.3 MiB/s	3,075.2 MiB/s	10.59 %
24 Bit Packed (Byte)	19.19 %	6,890.9 MiB/s	21,560.0 MiB/s	9.57 %
24 Bit 3LUT (Byte)	18.52 %	5,367.1 MiB/s	18,636.5 MiB/s	9.49 %
24 Bit 7LUT (Byte)	18.44 %	5,196.5 MiB/s	17,679.4 MiB/s	9.59 %
24 Bit 7LUT Short Greedy (Byte)	15.46 %	639.3 MiB/s	3,375.4 MiB/s	10.67 %
32 Bit Packed (Byte)	19.82 %	8,946.4 MiB/s	23,569.8 MiB/s	9.46 %
32 Bit 3LUT (Byte)	19.25 %	7,149.3 MiB/s	23,580.3 MiB/s	9.34 %
32 Bit 7LUT (Byte)	19.22 %	7,066.1 MiB/s	23,033.8 MiB/s	9.45 %
32 Bit 7LUT Short Greedy (Byte)	15.09 %	663.1 MiB/s	3,298.1 MiB/s	10.59 %
48 Bit Packed (Byte)	20.84 %	10,911.9 MiB/s	26,397.7 MiB/s	9.40 %
48 Bit 3LUT (Byte)	20.41 %	9,304.9 MiB/s	25,603.9 MiB/s	9.25 %
48 Bit 3LUT Short Greedy (Byte)	15.88 %	931.3 MiB/s	6,064.8 MiB/s	10.04 %
48 Bit 7LUT (Byte)	20.42 %	9,457.1 MiB/s	25,088.5 MiB/s	9.34 %
64 Bit Packed (Symbol)	22.34 %	12,697.9 MiB/s	26,375.4 MiB/s	9.23 %
64 Bit (Byte)	23.66 %	13,514.1 MiB/s	25,773.6 MiB/s	9.63 %
64 Bit Packed (Byte)	21.63 %	13,306.5 MiB/s	26,183.1 MiB/s	9.40 %
64 Bit 3LUT (Byte)	21.30 %	11,442.9 MiB/s	27,864.0 MiB/s	9.25 %
64 Bit 3LUT Short Greedy (Byte)	15.66 %	905.2 MiB/s	6,293.0 MiB/s	9.95 %
64 Bit 7LUT (Byte)	21.32 %	11,479.3 MiB/s	26,879.6 MiB/s	9.32 %
8 Bit RLE + Huffman-esque	12.51 %	332.0 MiB/s	1,676.7 MiB/s	9.82 %
Low Entropy	19.93 %	800.2 MiB/s	2,690.6 MiB/s	9.05 %
Low Entropy Single	19.96 %	802.4 MiB/s	4,389.0 MiB/s	9.10 %
-	-	-	-	-
memcpy	100.00 %	28,667.8 MiB/s	28,590.1 MiB/s	14.03 %
trle	16.0 %	1,177.7 MiB/s	5,356.0 MiB/s	-
srle 0	17.8 %	1,182.3 MiB/s	11,214.7 MiB/s	-
srle 8	18.7 %	2,044.3 MiB/s	12,300.2 MiB/s	-
srle 16	21.3 %	1,997.0 MiB/s	15,479.0 MiB/s	-
srle 32	24.2 %	3,782.2 MiB/s	18,975.8 MiB/s	-
srle 64	27.5 %	6,581.4 MiB/s	23,128.3 MiB/s	-
mrle	19.7 %	450.3 MiB/s	3,168.4 MiB/s	-

1034.db (Checkers program "End Game Table Base", 419,225,625 Bytes)

Type	Ratio	Encoding Speed	Decoding Speed	Entropy Compressible To
8 Bit	23.02 %	2,443.8 MiB/s	21,198.0 MiB/s	12.08 %
8 Bit Packed	20.10 %	2,199.4 MiB/s	15,151.8 MiB/s	12.74 %
8 Bit 1LUT Short	18.91 %	1,767.7 MiB/s	7,905.5 MiB/s	12.46 %
8 Bit 3LUT	19.77 %	1,841.7 MiB/s	14,211.6 MiB/s	12.31 %
8 Bit 7LUT	19.75 %	1,768.7 MiB/s	14,629.5 MiB/s	12.50 %
8 Bit Single	20.59 %	1,325.0 MiB/s	18,469.7 MiB/s	12.06 %
8 Bit Single Short	18.55 %	1,157.3 MiB/s	9,756.9 MiB/s	12.09 %
16 Bit Packed (Byte)	20.65 %	3,378.7 MiB/s	15,516.6 MiB/s	12.59 %
16 Bit 3LUT (Byte)	20.20 %	2,641.6 MiB/s	15,500.6 MiB/s	12.30 %
16 Bit 7LUT (Byte)	20.14 %	2,708.0 MiB/s	13,971.5 MiB/s	12.35 %
24 Bit Packed (Byte)	22.05 %	4,233.2 MiB/s	17,670.5 MiB/s	12.34 %
24 Bit 3LUT (Byte)	21.52 %	3,448.9 MiB/s	16,464.5 MiB/s	11.96 %
32 Bit Packed (Byte)	23.44 %	5,240.1 MiB/s	17,864.4 MiB/s	12.15 %
32 Bit 3LUT (Byte)	22.86 %	4,289.1 MiB/s	20,829.1 MiB/s	11.79 %
32 Bit 7LUT (Byte)	22.89 %	4,294.6 MiB/s	20,065.2 MiB/s	11.86 %
48 Bit Packed (Byte)	25.87 %	6,516.7 MiB/s	22,210.4 MiB/s	11.95 %
48 Bit 3LUT (Byte)	25.41 %	5,712.4 MiB/s	20,904.4 MiB/s	11.66 %
64 Bit 3LUT (Symbol)	28.66 %	6,464.5 MiB/s	23,401.9 MiB/s	11.56 %
64 Bit (Byte)	31.66 %	8,034.7 MiB/s	21,153.2 MiB/s	12.16 %
64 Bit Packed (Byte)	27.29 %	7,836.3 MiB/s	22,219.0 MiB/s	11.90 %
64 Bit 3LUT (Byte)	26.90 %	6,780.3 MiB/s	23,777.1 MiB/s	11.63 %
64 Bit 7LUT (Byte)	27.05 %	6,839.2 MiB/s	22,970.8 MiB/s	11.76 %
128 Bit (Byte)	37.25 %	6,763.4 MiB/s	24,011.4 MiB/s	12.28 %
128 Bit Packed (Byte)	31.21 %	6,582.9 MiB/s	23,994.6 MiB/s	11.98 %
8 Bit RLE + Huffman-esque	16.76 %	326.5 MiB/s	1,456.9 MiB/s	12.36 %
Low Entropy	21.15 %	799.7 MiB/s	4,282.1 MiB/s	10.37 %
Low Entropy Single	21.15 %	765.9 MiB/s	4,292.2 MiB/s	10.37 %
-	-	-	-	-
memcpy	100.00 %	26,689.1 MiB/s	27,304.6 MiB/s	16.76 %
trle	17.4 %	1,112.8 MiB/s	4,097.4 MiB/s	-
srle 0	20.2 %	1,080.3 MiB/s	8,027.7 MiB/s	-
srle 8	22.0 %	1,816.5 MiB/s	8,802.3 MiB/s	-
srle 16	27.1 %	1,644.2 MiB/s	9,915.1 MiB/s	-
srle 32	32.7 %	2,870.4 MiB/s	13,289.7 MiB/s	-
srle 64	39.5 %	4,763.9 MiB/s	18,966.4 MiB/s	-
mrle	21.0 %	446.9 MiB/s	3,115.4 MiB/s	-

enwik9.bwt (Wikipedia extract enwiki9 encoded using libdivsufsort, 1,000,000,124 Bytes)

Type	Ratio	Encoding Speed	Decoding Speed	Entropy Compressible To
8 Bit	48.80 %	1,225.6 MiB/s	16,097.6 MiB/s	34.13 %
8 Bit Short	44.42 %	899.3 MiB/s	6,975.0 MiB/s	32.26 %
8 Bit Packed	44.86 %	1,038.7 MiB/s	7,514.9 MiB/s	32.95 %
8 Bit 1LUT Short	41.87 %	828.2 MiB/s	4,088.0 MiB/s	31.38 %
8 Bit 3LUT	43.29 %	775.1 MiB/s	6,116.6 MiB/s	32.27 %
8 Bit 3LUT Short	40.34 %	765.3 MiB/s	3,046.5 MiB/s	30.63 %
8 Bit 7LUT	42.98 %	720.4 MiB/s	4,845.2 MiB/s	32.42 %
16 Bit Packed (Symbol)	47.89 %	1,871.4 MiB/s	9,417.5 MiB/s	34.25 %
16 Bit 1LUT Short (Symbol)	46.43 %	1,425.4 MiB/s	5,926.8 MiB/s	33.47 %
16 Bit Packed (Byte)	46.99 %	1,975.6 MiB/s	8,322.4 MiB/s	33.96 %
16 Bit 1LUT Short (Byte)	46.15 %	1,404.6 MiB/s	5,410.5 MiB/s	33.47 %
16 Bit 3LUT (Byte)	44.91 %	1,332.9 MiB/s	5,786.9 MiB/s	33.36 %
16 Bit 7LUT (Byte)	44.17 %	1,269.3 MiB/s	4,792.9 MiB/s	33.00 %
24 Bit Packed (Byte)	49.39 %	2,846.0 MiB/s	10,096.3 MiB/s	35.00 %
24 Bit 3LUT (Byte)	47.63 %	2,154.2 MiB/s	8,316.6 MiB/s	34.23 %
24 Bit 7LUT (Byte)	47.15 %	2,021.5 MiB/s	7,081.2 MiB/s	33.86 %
32 Bit Packed (Byte)	51.63 %	3,991.3 MiB/s	12,316.8 MiB/s	35.94 %
32 Bit 3LUT (Byte)	50.02 %	3,049.7 MiB/s	11,014.7 MiB/s	35.15 %
32 Bit 7LUT (Byte)	49.72 %	2,929.3 MiB/s	9,734.1 MiB/s	34.97 %
48 Bit (Byte)	57.58 %	5,568.3 MiB/s	17,036.4 MiB/s	38.86 %
48 Bit Packed (Byte)	55.01 %	5,463.9 MiB/s	16,106.6 MiB/s	37.48 %
48 Bit 3LUT (Byte)	53.66 %	4,511.6 MiB/s	14,552.7 MiB/s	36.78 %
48 Bit 7LUT (Byte)	53.48 %	4,362.4 MiB/s	13,340.3 MiB/s	36.64 %
64 Bit Packed (Symbol)	58.87 %	6,995.2 MiB/s	17,252.6 MiB/s	39.42 %
64 Bit (Byte)	59.94 %	7,594.6 MiB/s	17,821.4 MiB/s	40.05 %
64 Bit Packed (Byte)	57.33 %	7,285.0 MiB/s	16,557.0 MiB/s	38.65 %
64 Bit 1LUT Short (Byte)	57.24 %	6,176.4 MiB/s	16,263.8 MiB/s	38.60 %
64 Bit 3LUT (Byte)	56.28 %	6,050.7 MiB/s	17,019.3 MiB/s	38.04 %
64 Bit 7LUT (Byte)	56.10 %	5,933.0 MiB/s	16,061.7 MiB/s	37.92 %
128 Bit Packed (Symbol)	64.32 %	5,640.8 MiB/s	20,237.7 MiB/s	42.35 %
128 Bit Packed (Byte)	62.94 %	5,650.8 MiB/s	20,158.4 MiB/s	41.61 %
8 Bit MMTF 128	63.49 %	1,101.2 MiB/s	1,299.9 MiB/s	29.84 %
Low Entropy	64.19 %	383.3 MiB/s	913.9 MiB/s	34.06 %
Low Entropy Single	89.22 %	561.6 MiB/s	7,491.0 MiB/s	59.50 %
Low Entropy Short	66.17 %	394.1 MiB/s	1,412.4 MiB/s	36.11 %
Low Entropy Short Single	89.65 %	576.5 MiB/s	9,841.2 MiB/s	61.05 %
Multi MTF 128 Bit (Transform)	100.00 %	1,206.2 MiB/s	1,289.8 MiB/s	33.92 %
Multi MTF 256 Bit (Transform)	100.00 %	2,012.2 MiB/s	1,966.1 MiB/s	35.65 %
Bit MMTF 8 Bit (Transform)	100.00 %	1,843.2 MiB/s	1,973.5 MiB/s	35.87 %
Bit MMTF 16 Bit (Transform)	100.00 %	2,309.8 MiB/s	2,272.9 MiB/s	38.34 %
-	-	-	-	-
memcpy	100.00 %	26,973.3 MiB/s	27,041.2 MiB/s	65.94 %
trle	42.0 %	697.6 MiB/s	2,062.9 MiB/s	-
srle 0	46.4 %	680.6 MiB/s	5,004.5 MiB/s	-
srle 8	46.9 %	858.6 MiB/s	6,095.1 MiB/s	-
srle 16	54.4 %	906.4 MiB/s	8,676.0 MiB/s	-
srle 32	61.0 %	1,766.0 MiB/s	13,019.7 MiB/s	-
srle 64	66.8 %	3,289.0 MiB/s	18,491.6 MiB/s	-
mrle	64.1 %	320.2 MiB/s	1,104.0 MiB/s	-

The 24 Bit and 48 Bit Variants allow for run length encoding of common data layouts that are usually not covered by RLE implementations:

Pixel Art Bitmap Image (PNG converted to BMP, 123,710,454 Bytes)

Type	Ratio	Encoding Speed	Decoding Speed	Entropy Compressible To
8 Bit	99.99 %	6,995.3 MiB/s	18,357.0 MiB/s	76.10 %
8 Bit 1LUT Short	99.98 %	6,974.3 MiB/s	18,023.2 MiB/s	75.63 %
8 Bit 3LUT	99.99 %	6,936.1 MiB/s	18,595.7 MiB/s	75.94 %
8 Bit Single	100.00 %	3,512.8 MiB/s	18,470.1 MiB/s	77.03 %
16 Bit Short (Byte)	99.99 %	18,127.2 MiB/s	18,953.0 MiB/s	75.56 %
16 Bit 3LUT Short (Byte)	99.99 %	17,991.9 MiB/s	19,252.9 MiB/s	75.71 %
24 Bit (Symbol)	1.84 %	24,537.1 MiB/s	33,067.5 MiB/s	1.32 %
24 Bit Short (Symbol)	2.08 %	21,904.2 MiB/s	32,713.6 MiB/s	1.52 %
24 Bit Packed (Symbol)	2.00 %	23,590.4 MiB/s	32,955.6 MiB/s	1.39 %
24 Bit 1LUT Short (Symbol)	2.08 %	19,894.5 MiB/s	32,751.7 MiB/s	1.51 %
24 Bit 3LUT (Symbol)	1.31 %	21,232.5 MiB/s	33,073.5 MiB/s	0.93 %
24 Bit 3LUT Short (Symbol)	1.53 %	19,147.7 MiB/s	32,890.5 MiB/s	1.04 %
24 Bit 7LUT (Symbol)	1.20 %	20,599.0 MiB/s	32,846.9 MiB/s	0.83 %
24 Bit 7LUT Short (Symbol)	1.41 %	18,916.5 MiB/s	31,750.2 MiB/s	0.92 %
24 Bit (Byte)	2.13 %	25,939.7 MiB/s	33,113.4 MiB/s	1.44 %
24 Bit Short (Byte)	2.17 %	23,579.9 MiB/s	32,825.6 MiB/s	1.58 %
24 Bit Packed (Byte)	2.32 %	26,738.2 MiB/s	32,812.0 MiB/s	1.51 %
24 Bit 1LUT Short (Byte)	2.17 %	21,550.6 MiB/s	32,835.9 MiB/s	1.59 %
24 Bit 1LUT Short Greedy (Byte)	2.17 %	5,534.5 MiB/s	32,679.0 MiB/s	1.59 %
24 Bit 3LUT (Byte)	1.49 %	23,408.0 MiB/s	33,010.6 MiB/s	1.03 %
24 Bit 3LUT Short (Byte)	1.63 %	21,063.2 MiB/s	32,713.6 MiB/s	1.14 %
24 Bit 3LUT Short Greedy (Byte)	1.63 %	5,403.1 MiB/s	32,578.9 MiB/s	1.14 %
24 Bit 7LUT (Byte)	1.37 %	22,589.6 MiB/s	32,629.3 MiB/s	0.98 %
24 Bit 7LUT Short (Byte)	1.52 %	20,560.6 MiB/s	31,915.9 MiB/s	0.97 %
24 Bit 7LUT Short Greedy (Byte)	1.52 %	5,436.8 MiB/s	32,009.5 MiB/s	0.97 %
32 Bit Packed (Byte)	99.99 %	16,961.2 MiB/s	19,048.9 MiB/s	75.71 %
32 Bit 7LUT Short (Byte)	99.99 %	16,887.8 MiB/s	19,240.9 MiB/s	75.79 %
48 Bit (Symbol)	2.78 %	23,645.9 MiB/s	32,870.0 MiB/s	2.12 %
48 Bit Short (Symbol)	2.79 %	21,386.8 MiB/s	32,833.3 MiB/s	2.26 %
48 Bit Packed (Symbol)	2.87 %	22,575.5 MiB/s	32,913.6 MiB/s	2.17 %
48 Bit 1LUT Short (Symbol)	3.09 %	19,362.4 MiB/s	32,750.9 MiB/s	2.41 %
48 Bit 3LUT (Symbol)	1.71 %	20,826.5 MiB/s	32,843.5 MiB/s	1.33 %
48 Bit 3LUT Short (Symbol)	1.99 %	18,834.0 MiB/s	32,717.0 MiB/s	1.47 %
48 Bit 7LUT (Symbol)	1.49 %	20,185.7 MiB/s	32,619.2 MiB/s	1.15 %
48 Bit 7LUT Short (Symbol)	1.77 %	18,184.3 MiB/s	31,846.0 MiB/s	1.26 %
48 Bit (Byte)	3.16 %	25,473.5 MiB/s	32,911.9 MiB/s	2.31 %
48 Bit Short (Byte)	3.20 %	23,439.2 MiB/s	32,689.1 MiB/s	2.48 %
48 Bit Packed (Byte)	3.35 %	25,371.9 MiB/s	32,548.7 MiB/s	2.40 %
48 Bit 1LUT Short (Byte)	3.20 %	20,935.0 MiB/s	32,603.2 MiB/s	2.48 %
48 Bit 1LUT Short Greedy (Byte)	3.20 %	9,723.8 MiB/s	32,490.3 MiB/s	2.48 %
48 Bit 3LUT (Byte)	1.98 %	22,790.5 MiB/s	32,861.4 MiB/s	1.49 %
48 Bit 3LUT Short (Byte)	2.13 %	20,273.7 MiB/s	32,717.9 MiB/s	1.62 %
48 Bit 3LUT Short Greedy (Byte)	2.13 %	8,178.3 MiB/s	32,537.9 MiB/s	1.62 %
48 Bit 7LUT (Byte)	1.76 %	21,776.5 MiB/s	32,615.9 MiB/s	1.34 %
48 Bit 7LUT Short (Byte)	1.90 %	20,145.3 MiB/s	31,847.6 MiB/s	1.35 %
48 Bit 7LUT Short Greedy (Byte)	1.90 %	7,895.9 MiB/s	31,782.1 MiB/s	1.35 %
64 Bit (Symbol)	99.99 %	14,820.8 MiB/s	19,040.6 MiB/s	75.87 %
64 Bit 7LUT (Byte)	99.99 %	14,692.8 MiB/s	19,217.2 MiB/s	75.78 %
8 Bit MMTF 128	17.70 %	5,287.0 MiB/s	2,978.1 MiB/s	12.31 %
Multi MTF 128 Bit (Transform)	100.00 %	3,474.5 MiB/s	3,482.1 MiB/s	19.94 %
Multi MTF 256 Bit (Transform)	100.00 %	5,030.6 MiB/s	5,028.6 MiB/s	27.52 %
Bit MMTF 8 Bit (Transform)	100.00 %	1,861.6 MiB/s	1,984.2 MiB/s	73.85 %
Bit MMTF 16 Bit (Transform)	100.00 %	2,340.1 MiB/s	2,293.9 MiB/s	72.48 %
-	-	-	-	-
memcpy	100.00 %	28,288.5 MiB/s	28,261.3 MiB/s	77.03 %
trle	100.0 %	420.41 MiB/s	5,473.00 MiB/s	-
srle 0	100.0 %	329.09 MiB/s	18,106.88 MiB/s	-
srle 8	100.0 %	468.74 MiB/s	17,951.84 MiB/s	-
srle 16	100.0 %	575.39 MiB/s	20,198.96 MiB/s	-
srle 32	100.0 %	1,195.77 MiB/s	18,437.51 MiB/s	-
srle 64	100.0 %	2,294.94 MiB/s	19,407.80 MiB/s	-
mrle	100.0 %	383.18 MiB/s	2,551.12 MiB/s	-

Variants

8, 16, 24, 32, 48, 64, 128 Bit (Byte Aligned + Symbol Aligned)

• Extremely Fast.
• Variants for always aligning with the symbol width or allowing byte-wide repeats even for > 8 bit symbols.
• Decoder interprets blocks of data to boil down to a highly optimized memcpy, memset, memcpy, memset (with various different byte-lengths).
• Encoder searches for repeats and their respective lengths using movemask instructions.
• Optional variant for 8 bit single symbol encoding.

8, 16, 24, 32, 48, 64, 128 Bit Packed (Byte Aligned + Symbol Aligned)

• Similar to the base variant, but keeps around the previously used RLE symbol which is usually very beneficial to the compression ratio and tries to pack lengths a bit more optimistically.
• Also Extremely Fast, whilst providing better compression ratio for many inputs
• Also has those variants for always aligning with the symbol width or allowing byte-wide repeats even for > 8 bit symbols.
• Optional variant for 8 bit single symbol encoding (only has the optimistic packing, as it already knows what the next symbol is going to be anyways).

1 Sym LUT / 3 Sym LUT / 3 Sym LUT Short / 7 Sym LUT / 7 Sym LUT Short

• Similar to the base variant, but keeps around one / three / seven of the previously used RLE symbols, usually further improving compression ratios.
• Short Variant: Packs Range & Count Bits to fit the entire RLE command into just one byte for short ranges.

1 Sym LUT Short Greedy / 3 Sym LUT Short Greedy / 7 Sym LUT Short Greedy

• Similar to n-Sym LUT Short (actually uses the exact same decoder), but tries to even compress partial occurences of a symbol if that would save space
• Only available when byte-aligned for 16, 24, 32, 48, 64 Bit Variants
• Comparably slow to en/decode

Low Entropy / Low Entropy Short

• Tries to keep symbol general symbol frequency to improve compression ratio of an entropy encoder that could go after the Run Length Encoding like ANS, Arithmetic Coding or Huffman.
• Parses the output for run-length-encodable symbols, which are specified in the header.
• Has a single-symbol variant, that only encodes the most run-length-encodable symbol (useful for some image codecs).
• Short Variant: Same as Low Entropy, but optimized for shorter strings of run-length-encodable symbols, usually faster, also has a single-symbol variant.

8 Bit RLE + MMTF (Multi Move-To-Front Transformation)

• Runs a block-wide vectorized MTF transform on the input and depending on how many bits this needs to represent a given block (if it's not entirely representable by a variant of memset) uses only the required amount of bits to encode the block.
• Performs well on a wide variety of inputs, but usually doesn't produce the best compression ratios or (de-) compression speeds, as all blocks need to be decoded and cannot simply be memcpyd if they don't contain an encodable symbol.

RLE + Huffman-esque

• Uses a separate header, that contains a huffman-esque instructions to place recent high-prevalence symbols, copy or set a specific symbol to a block.
• Usually very high compression ratios, but comparably slow to en- & decode.

Raw MMTF (Multi Move-To-Front Transformation)

• Simply runs the block-wide vectorized MTF transform on the input to improve compressability for some scenarios.
• Doesn't compress itself.

Setup

git clone https://github.com/rainerzufalldererste/hypersonic-rle-kit.git
cd hypersonic-rle-kit
git submodule update --init --recursive

On Windows

create_project.bat

Choose your preferred compiler toolset

MSBuild /p:Configuration=Release /nologo /v:m

On Linux

premake/premake5 gmake2
config=release_x64 make

How to use it?

#include "rle.h"

uint8_t *pUncompressedData; // Some Data.
uint32_t fileSize; // Some Size.

// Get Compress Bounds.
const uint32_t compressedBufferSize = rle_compress_bounds(fileSize);
uint8_t *pCompressedData = (uint8_t *)malloc(compressedBufferSize);

// Compress.
const uint32_t compressedSize = rle8_multi_compress(pUncompressedData, fileSize, pCompressedData, compressedBufferSize);

// Allocate Output Buffer.
uint8_t *pDecompressedData = (uint8_t *)malloc(fileSize + rle_decompress_additional_size());

// Decompress.
const uint32_t decompressedSize = rle8_decompress(pCompressedData, compressedSize, pDecompressedData, fileSize);

// Cleanup.
free(pCompressedData);
free(pDecompressedData);

License

Two Clause BSD