Eric  Bukenya

Eric Bukenya

1649602800

LZ4: Extremely Fast Compression algorithm For C

LZ4 - Extremely fast compression

LZ4 is lossless compression algorithm, providing compression speed > 500 MB/s per core, scalable with multi-cores CPU. It features an extremely fast decoder, with speed in multiple GB/s per core, typically reaching RAM speed limits on multi-core systems.

Speed can be tuned dynamically, selecting an "acceleration" factor which trades compression ratio for faster speed. On the other end, a high compression derivative, LZ4_HC, is also provided, trading CPU time for improved compression ratio. All versions feature the same decompression speed.

LZ4 is also compatible with dictionary compression, both at API and CLI levels. It can ingest any input file as dictionary, though only the final 64KB are used. This capability can be combined with the Zstandard Dictionary Builder, in order to drastically improve compression performance on small files.

LZ4 library is provided as open-source software using BSD 2-Clause license.

BranchStatus
dev[![Build Status][travisDevBadge]][travisLink] [![Build status][AppveyorDevBadge]][AppveyorLink]

Benchmarks

The benchmark uses lzbench, from @inikep compiled with GCC v8.2.0 on Linux 64-bits (Ubuntu 4.18.0-17). The reference system uses a Core i7-9700K CPU @ 4.9GHz (w/ turbo boost). Benchmark evaluates the compression of reference Silesia Corpus in single-thread mode.

CompressorRatioCompressionDecompression
memcpy1.00013700 MB/s13700 MB/s
LZ4 default (v1.9.0)2.101780 MB/s4970 MB/s
LZO 2.092.108670 MB/s860 MB/s
QuickLZ 1.5.02.238575 MB/s780 MB/s
Snappy 1.1.42.091565 MB/s1950 MB/s
[Zstandard] 1.4.0 -12.883515 MB/s1380 MB/s
LZF v3.62.073415 MB/s910 MB/s
[zlib] deflate 1.2.11 -12.730100 MB/s415 MB/s
LZ4 HC -9 (v1.9.0)2.72141 MB/s4900 MB/s
[zlib] deflate 1.2.11 -63.09936 MB/s445 MB/s

LZ4 is also compatible and optimized for x32 mode, for which it provides additional speed performance.

Installation

make
make install     # this command may require root permissions

LZ4's Makefile supports standard Makefile conventions, including staged installs, redirection, or command redefinition. It is compatible with parallel builds (-j#).

Building LZ4 - Using vcpkg

You can download and install LZ4 using the vcpkg dependency manager:

git clone https://github.com/Microsoft/vcpkg.git
cd vcpkg
./bootstrap-vcpkg.sh
./vcpkg integrate install
vcpkg install lz4

The LZ4 port in vcpkg is kept up to date by Microsoft team members and community contributors. If the version is out of date, please create an issue or pull request on the vcpkg repository.

Documentation

The raw LZ4 block compression format is detailed within lz4_Block_format.

Arbitrarily long files or data streams are compressed using multiple blocks, for streaming requirements. These blocks are organized into a frame, defined into lz4_Frame_format. Interoperable versions of LZ4 must also respect the frame format.

Other source versions

Beyond the C reference source, many contributors have created versions of lz4 in multiple languages (Java, C#, Python, Perl, Ruby, etc.). A list of known source ports is maintained on the LZ4 Homepage.


Author: lz4
Source Code: https://github.com/lz4/lz4
License: View license
#c #algorithm 

What is GEEK

Buddha Community

LZ4: Extremely Fast Compression algorithm For C
Eric  Bukenya

Eric Bukenya

1649602800

LZ4: Extremely Fast Compression algorithm For C

LZ4 - Extremely fast compression

LZ4 is lossless compression algorithm, providing compression speed > 500 MB/s per core, scalable with multi-cores CPU. It features an extremely fast decoder, with speed in multiple GB/s per core, typically reaching RAM speed limits on multi-core systems.

Speed can be tuned dynamically, selecting an "acceleration" factor which trades compression ratio for faster speed. On the other end, a high compression derivative, LZ4_HC, is also provided, trading CPU time for improved compression ratio. All versions feature the same decompression speed.

LZ4 is also compatible with dictionary compression, both at API and CLI levels. It can ingest any input file as dictionary, though only the final 64KB are used. This capability can be combined with the Zstandard Dictionary Builder, in order to drastically improve compression performance on small files.

LZ4 library is provided as open-source software using BSD 2-Clause license.

BranchStatus
dev[![Build Status][travisDevBadge]][travisLink] [![Build status][AppveyorDevBadge]][AppveyorLink]

Benchmarks

The benchmark uses lzbench, from @inikep compiled with GCC v8.2.0 on Linux 64-bits (Ubuntu 4.18.0-17). The reference system uses a Core i7-9700K CPU @ 4.9GHz (w/ turbo boost). Benchmark evaluates the compression of reference Silesia Corpus in single-thread mode.

CompressorRatioCompressionDecompression
memcpy1.00013700 MB/s13700 MB/s
LZ4 default (v1.9.0)2.101780 MB/s4970 MB/s
LZO 2.092.108670 MB/s860 MB/s
QuickLZ 1.5.02.238575 MB/s780 MB/s
Snappy 1.1.42.091565 MB/s1950 MB/s
[Zstandard] 1.4.0 -12.883515 MB/s1380 MB/s
LZF v3.62.073415 MB/s910 MB/s
[zlib] deflate 1.2.11 -12.730100 MB/s415 MB/s
LZ4 HC -9 (v1.9.0)2.72141 MB/s4900 MB/s
[zlib] deflate 1.2.11 -63.09936 MB/s445 MB/s

LZ4 is also compatible and optimized for x32 mode, for which it provides additional speed performance.

Installation

make
make install     # this command may require root permissions

LZ4's Makefile supports standard Makefile conventions, including staged installs, redirection, or command redefinition. It is compatible with parallel builds (-j#).

Building LZ4 - Using vcpkg

You can download and install LZ4 using the vcpkg dependency manager:

git clone https://github.com/Microsoft/vcpkg.git
cd vcpkg
./bootstrap-vcpkg.sh
./vcpkg integrate install
vcpkg install lz4

The LZ4 port in vcpkg is kept up to date by Microsoft team members and community contributors. If the version is out of date, please create an issue or pull request on the vcpkg repository.

Documentation

The raw LZ4 block compression format is detailed within lz4_Block_format.

Arbitrarily long files or data streams are compressed using multiple blocks, for streaming requirements. These blocks are organized into a frame, defined into lz4_Frame_format. Interoperable versions of LZ4 must also respect the frame format.

Other source versions

Beyond the C reference source, many contributors have created versions of lz4 in multiple languages (Java, C#, Python, Perl, Ruby, etc.). A list of known source ports is maintained on the LZ4 Homepage.


Author: lz4
Source Code: https://github.com/lz4/lz4
License: View license
#c #algorithm 

Tamale  Moses

Tamale Moses

1624240146

How to Run C/C++ in Sublime Text?

C and C++ are the most powerful programming language in the world. Most of the super fast and complex libraries and algorithms are written in C or C++. Most powerful Kernel programs are also written in C. So, there is no way to skip it.

In programming competitions, most programmers prefer to write code in C or C++. Tourist is considered the worlds top programming contestant of all ages who write code in C++.

During programming competitions, programmers prefer to use a lightweight editor to focus on coding and algorithm designing. VimSublime Text, and Notepad++ are the most common editors for us. Apart from the competition, many software developers and professionals love to use Sublime Text just because of its flexibility.

I have discussed the steps we need to complete in this blog post before running a C/C++ code in Sublime Text. We will take the inputs from an input file and print outputs to an output file without using freopen file related functions in C/C++.

#cpp #c #c-programming #sublimetext #c++ #c/c++

Dicey Issues in C/C++

If you are familiar with C/C++then you must have come across some unusual things and if you haven’t, then you are about to. The below codes are checked twice before adding, so feel free to share this article with your friends. The following displays some of the issues:

  1. Using multiple variables in the print function
  2. Comparing Signed integer with unsigned integer
  3. Putting a semicolon at the end of the loop statement
  4. C preprocessor doesn’t need a semicolon
  5. Size of the string matters
  6. Macros and equations aren’t good friends
  7. Never compare Floating data type with double data type
  8. Arrays have a boundary
  9. Character constants are different from string literals
  10. Difference between single(=) and double(==) equal signs.

The below code generates no error since a print function can take any number of inputs but creates a mismatch with the variables. The print function is used to display characters, strings, integers, float, octal, and hexadecimal values onto the output screen. The format specifier is used to display the value of a variable.

  1. %d indicates Integer Format Specifier
  2. %f indicates Float Format Specifier
  3. %c indicates Character Format Specifier
  4. %s indicates String Format Specifier
  5. %u indicates Unsigned Integer Format Specifier
  6. %ld indicates Long Int Format Specifier

Image for post


A signed integer is a 32-bit datum that encodes an integer in the range [-2147483648 to 2147483647]. An unsigned integer is a 32-bit datum that encodes a non-negative integer in the range [0 to 4294967295]. The signed integer is represented in twos-complement notation. In the below code the signed integer will be converted to the maximum unsigned integer then compared with the unsigned integer.

Image for post

#problems-with-c #dicey-issues-in-c #c-programming #c++ #c #cplusplus

Ari  Bogisich

Ari Bogisich

1590587580

Loops in C++ | For, While, and Do While Loops in C++

In this Video We are going to see how to use Loops in C++. We will see How to use For, While, and Do While Loops in C++.
C++ is general purpose, compiled, object-oriented programming language and its concepts served as the basis for several other languages such as Java, Python, Ruby, Perl etc.

#c #c# #c++ #programming-c

Ari  Bogisich

Ari Bogisich

1589816580

Using isdigit() in C/C++

In this article, we’ll take a look at using the isdigit() function in C/C++. This is a very simple way to check if any value is a digit or not. Let’s look at how to use this function, using some simple examples.

#c programming #c++ #c #c#