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base64

Searching the web for a C/C++ base64 implementation yields many results.

How does one chose? This project aims at collecting and comparing the different implementations available.

Feel free to improve this test or to submit new implementations!

Disclaimer

Keep in mind that some implementations were slightly modified to have a common interface for the test framework. In all cases, line breaks were omitted both for encoding and parsing. Also, although all implementations have been unit-tested, no analysis whatsoever has been made on error handling, so some slower implementation may actually be better at reporting malformed base64 strings for instance.

I do not own any of these implementations - make sure you check their respective license before using them.

Compared implementations

base64 (Alfred Klomp)

From https://github.com/aklomp/base64 A fast C99 implementation with SIMD acceleration

base64 (Tobias Locker)

From https://github.com/tobiaslocker/base64 A c++ single-header library implementing the approach of Nick Galbreath's in modp_b64

simdutf

From https://github.com/simdutf/simdutf A unicode validation and transcoding c++ library accelerated using SIMD instructions

base64 (Mat Gomes)

From https://github.com/matheusgomes28/base64pp A c++ library written for readibility and supported by a blog post https://matgomes.com/base64-encode-decode-cpp/

adp-gmbh (René Nyffenegger)

From http://www.adp-gmbh.ch/cpp/common/base64.html

lib64

From https://sourceforge.net/projects/libb64/

libcurl

From https://curl.haxx.se/libcurl/

Internet Software Consortium

From https://opensource.apple.com/source/basic_cmds/basic_cmds-55/uuencode/base64.c

Arduino-Base64

From https://github.com/adamvr/arduino-base64 from BuLogic's fork (https://github.com/BuLogics/libb64)

LihO

From stackoverflow thread at http://stackoverflow.com/questions/180947/base64-decode-snippet-in-c

Manuel Martinez

From stackoverflow thread at http://stackoverflow.com/questions/180947/base64-decode-snippet-in-c

DaedalusAlpha

From stackoverflow thread at http://stackoverflow.com/questions/180947/base64-decode-snippet-in-c

Elegant Dice

From stackoverflow thread at http://stackoverflow.com/questions/180947/base64-decode-snippet-in-c

polfosol

From stackoverflow thread at http://stackoverflow.com/questions/180947/base64-decode-snippet-in-c

omnifarious

From stackoverflow thread at http://stackoverflow.com/questions/5288076/doing-base64-encoding-and-decoding-in-openssl-c

** Note that although this implementation is in the results, it does not produce valid results - including extra '=' padding when not necessary.

user152949

From stackoverflow thread at http://stackoverflow.com/questions/180947/base64-decode-snippet-in-c

jounimalinen

From http://web.mit.edu/freebsd/head/contrib/wpa/src/utils/base64.c

test_wikibooks_org_c

From https://en.wikibooks.org/wiki/Algorithm_Implementation/Miscellaneous/Base64

test_wikibooks_org_cpp

From https://en.wikibooks.org/wiki/Algorithm_Implementation/Miscellaneous/Base64

apache

Which I think was based on Rob McCool's uuencode's implementation in 1993 https://opensource.apple.com/source/QuickTimeStreamingServer/QuickTimeStreamingServer-452/CommonUtilitiesLib/base64.c

NibbleAndAHalf

From https://github.com/superwills/NibbleAndAHalf/

Gnome

From https://github.com/GNOME/glib/blob/master/glib/gbase64.c

cppcodec

From https://github.com/tplgy/cppcodec

Conclusion

• If you want the fastest implementation, Turbo-Base64 (GPL-3.0) is the fastest. Slightly behind, and with more permissive licenses, simdutf (MIT License) and base64 (Alfred Klomp) (BSD-2 License) are both great alternatives.
• If you want a simple single-header c++ file with good performance, go for base64 (Tobias Locker)
• Some other implementations are terrible, the slower ones generally allocate memory dynamically as they convert, even though the output size is deterministic and can be preallocated;
• libb64 shows very strange performance results - I get the feeling that they are doing something neat but that I am perhaps not using their code right;
• A lot of implementations are available, everyone claims theirs is better. This test shows that unless you measure, you cannot make any claims about the performance of your code;

Keep in mind that these results were all obtained using a specific compiler and could differ on another compiler.