uchardet

uchardet is an encoding detector library, which takes a sequence of bytes in an unknown character encoding without any additional information, and attempts to determine the encoding of the text. Returned encoding names are iconv-compatible.

uchardet started as a C language binding of the original C++ implementation of the universal charset detection library by Mozilla. It can now detect more charsets, and more reliably than the original implementation.

Supported Languages/Encodings

• International (Unicode)
  • UTF-8
  • UTF-16BE / UTF-16LE
  • UTF-32BE / UTF-32LE / X-ISO-10646-UCS-4-34121 / X-ISO-10646-UCS-4-21431
• Arabic
  • ISO-8859-6
  • WINDOWS-1256
• Bulgarian
  • ISO-8859-5
  • WINDOWS-1251
• Chinese
  • ISO-2022-CN
  • BIG5
  • EUC-TW
  • GB18030
  • HZ-GB-2312
• Croatian:
  • ISO-8859-2
  • ISO-8859-13
  • ISO-8859-16
  • Windows-1250
  • IBM852
  • MAC-CENTRALEUROPE
• Czech
  • Windows-1250
  • ISO-8859-2
  • IBM852
  • MAC-CENTRALEUROPE
• Danish
  • IBM865
  • ISO-8859-1
  • ISO-8859-15
  • WINDOWS-1252
• English
  • ASCII
• Esperanto
  • ISO-8859-3
• Estonian
  • ISO-8859-4
  • ISO-8859-13
  • ISO-8859-13
  • Windows-1252
  • Windows-1257
• Finnish
  • ISO-8859-1
  • ISO-8859-4
  • ISO-8859-9
  • ISO-8859-13
  • ISO-8859-15
  • WINDOWS-1252
• French
  • ISO-8859-1
  • ISO-8859-15
  • WINDOWS-1252
• German
  • ISO-8859-1
  • WINDOWS-1252
• Greek
  • ISO-8859-7
  • WINDOWS-1253
• Hebrew
  • ISO-8859-8
  • WINDOWS-1255
• Hungarian:
  • ISO-8859-2
  • WINDOWS-1250
• Irish Gaelic
  • ISO-8859-1
  • ISO-8859-9
  • ISO-8859-15
  • WINDOWS-1252
• Italian
  • ISO-8859-1
  • ISO-8859-3
  • ISO-8859-9
  • ISO-8859-15
  • WINDOWS-1252
• Japanese
  • ISO-2022-JP
  • SHIFT_JIS
  • EUC-JP
• Korean
  • ISO-2022-KR
  • EUC-KR / UHC
• Lithuanian
  • ISO-8859-4
  • ISO-8859-10
  • ISO-8859-13
• Latvian
  • ISO-8859-4
  • ISO-8859-10
  • ISO-8859-13
• Maltese
  • ISO-8859-3
• Norwegian
  • IBM865
  • ISO-8859-1
  • ISO-8859-15
  • WINDOWS-1252
• Polish:
  • ISO-8859-2
  • ISO-8859-13
  • ISO-8859-16
  • Windows-1250
  • IBM852
  • MAC-CENTRALEUROPE
• Portuguese
  • ISO-8859-1
  • ISO-8859-9
  • ISO-8859-15
  • WINDOWS-1252
• Romanian:
  • ISO-8859-2
  • ISO-8859-16
  • Windows-1250
  • IBM852
• Russian
  • ISO-8859-5
  • KOI8-R
  • WINDOWS-1251
  • MAC-CYRILLIC
  • IBM866
  • IBM855
• Slovak
  • Windows-1250
  • ISO-8859-2
  • IBM852
  • MAC-CENTRALEUROPE
• Slovene
  • ISO-8859-2
  • ISO-8859-16
  • Windows-1250
  • IBM852
  • MAC-CENTRALEUROPE
• Spanish
  • ISO-8859-1
  • ISO-8859-15
  • WINDOWS-1252
• Swedish
  • ISO-8859-1
  • ISO-8859-4
  • ISO-8859-9
  • ISO-8859-15
  • WINDOWS-1252
• Thai
  • TIS-620
  • ISO-8859-11
• Turkish:
  • ISO-8859-3
  • ISO-8859-9
• Vietnamese:
  • VISCII
  • Windows-1258
• Others
  • WINDOWS-1252

Installation

Debian/Ubuntu/Mint

apt-get install uchardet libuchardet-dev

Mageia

urpmi libuchardet libuchardet-devel

Fedora

dnf install uchardet uchardet-devel

Gentoo

emerge uchardet

Mac

brew install uchardet

or

port install uchardet

Windows

Binary packages are provided in Fedora and Msys2 repositories. There may exist other pre-built packages but I am not aware of them. Nevertheless the library is very easily and quickly compilable under Windows as well, so finding a binary package is not necessary. Some did it successfully with the CMake Windows installer and MinGW. It should be possible to use MinGW-w64 instead of MinGW, in particular to build both 32 and 64-bit DLL libraries).

Note also that it is very easily cross-buildable (for instance from a GNU/Linux machine; crossroad may help, this is what we use in our CI).

Build from source

Releases are available from: https://www.freedesktop.org/software/uchardet/releases/

If you prefer a development version, clone the git repository:

git clone https://gitlab.freedesktop.org/uchardet/uchardet.git

The source can be browsed at: https://gitlab.freedesktop.org/uchardet/uchardet

cmake .
make
make install

Build with flatpak-builder

Here is a working "module" section to include in your Flatpak's json manifest:

"modules": [
    {
        "name": "uchardet",
        "buildsystem": "cmake",
        "builddir": true,
        "config-opts": [ "-DCMAKE_INSTALL_LIBDIR=lib" ],
        "sources": [
            {
                ...
            }
        ]
    }
]

Build with CMake exported targets

uchardet installs a standard pkg-config file which will make it easily discoverable by any modern build system. Nevertheless if your project also uses CMake and you want to discover uchardet installation using CMake exported targets, you may find and link uchardet with:

project(sample LANGUAGES C)
find_package ( uchardet )
if (uchardet_FOUND)
  add_executable( sample sample.c )
  target_link_libraries ( sample PRIVATE uchardet::libuchardet )
endif ()

Note though that we recommend the library discovery with pkg-config because it is standard and generic. Therefore it will always work, even if we decided to change our own build system (which is not planned right now, but may always happen). This is why we advise to use standard pkg-config discovery.

Some more CMake specificities may be found in the commit message which implemented such support.

Usage

Command Line

uchardet Command Line Tool
Version 0.0.8

Authors: BYVoid, Jehan
Bug Report: https://gitlab.freedesktop.org/uchardet/uchardet/-/issues

Usage:
 uchardet [Options] [File]...

Options:
 -v, --version         Print version and build information.
 -h, --help            Print this help.

Library

See uchardet.h

History

As said in introduction, this was initially a project of Mozilla to allow better detection of page encodings, and it used to be part of Firefox. If not mistaken, this is not the case anymore (probably because nowadays most websites better announce their encoding, and also UTF-8 is much more widely spread).

Techniques used by universalchardet are described at https://www-archive.mozilla.org/projects/intl/universalcharsetdetection

It is to be noted that a lot has changed since the original code, yet the base concept is still around, basing detection not just on encoding rules, but importantly on analysis of character statistics in languages.

Original code of universalchardet by Mozilla can still be retrieved from the Wayback machine.

Mozilla code was extracted and packaged into a standalone library under the name uchardet by BYVoid in 2011, in a personal repository. Starting 2015, I (i.e. Jehan) started contributing, "standardized" the output to be iconv-compatible, added various encoding/language support and streamlined generation of sources for new support of encoding/languages by using texts from Wikipedia as statistics source on languages through Python scripts. Then I soon became co-maintainer. In 2016, uchardet became a freedesktop project.

Related Projects

Some of these are bindings of uchardet, others are forks of the same initial code, which has diverged over time, others are native port in other languages. This list is not exhaustive and only meant as point of interest. We don't follow the status for these projects.

• R-uchardet R binding on CRAN
• python-chardet Python port
• ruby-rchardet Ruby port
• juniversalchardet Java port of universalchardet
• jchardet Java port of chardet
• nuniversalchardet C# port of universalchardet
• nchardet C# port of chardet
• uchardet-enhanced A fork of mozilla universalchardet
• rust-uchardet Rust language binding of uchardet
• libchardet Another C/C++ API wrapping Mozilla code.

Used by

• mpv for subtitle detection
• Tepl
• Nextcloud IOS app
• Codelite
• QtAV
• …

Licenses

• Mozilla Public License Version 1.1
• GNU General Public License, version 2.0 or later.
• GNU Lesser General Public License, version 2.1 or later.

See the file COPYING for the complete text of these 3 licenses.

Code of Conduct

The uchardet project is hosted by freedesktop.org and as such follows its code of conduct. In other words, it means we will treat anyone with respect and expect anyone to do the same.

Please read freedesktop.org Code of Conduct.

In case of any problem regarding abusive behavior in uchardet project, please contact the maintainer (Jehan) or create a bug report (possibly private if needed).