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[Utility & Helpers](/categories/utility) 4. / 5. sycho/codecs-base64vlq ActiveLibrary[Utility & Helpers](/categories/utility) sycho/codecs-base64vlq ====================== Codec for VLQ (variable-length quantity) Base64 algorithm 2.0.0(4y ago)01.1M↓20.9%1MITPHPPHP >=7.3 Since Feb 22Pushed 4y agoCompare [ Source](https://github.com/SychO9/codecs-base64vlq)[ Packagist](https://packagist.org/packages/sycho/codecs-base64vlq)[ Docs](https://github.com/sycho9/codecs-base64vlq)[ RSS](/packages/sycho-codecs-base64vlq/feed)WikiDiscussions main Synced 1mo ago READMEChangelogDependencies (2)Versions (5)Used By (1) axy\\codecs\\base64vlq ====================== [](#axycodecsbase64vlq) Codec for VLQ (variable-length quantity) Base64 algorithm (PHP). [![Latest Stable Version](https://camo.githubusercontent.com/188a22efdbe4b7d84f078a7869d219ff8496190b857640329d6311ca6a1941e0/68747470733a2f2f696d672e736869656c64732e696f2f7061636b61676973742f762f6178792f636f646563732d626173653634766c712e7376673f7374796c653d666c61742d737175617265)](https://packagist.org/packages/axy/codecs-base64vlq)[![Minimum PHP Version](https://camo.githubusercontent.com/b52c83f3d45755ebcb1e6863ebb202ab192aaf773424369ffdeedae107f027ef/68747470733a2f2f696d672e736869656c64732e696f2f62616467652f7068702d253345253344253230352e342d3838393242462e7376673f7374796c653d666c61742d737175617265)](https://php.net/)[![Build Status](https://camo.githubusercontent.com/db1c7747af1ebc40c0be35c584261bc10a37001d0af6e087549c3f2d93e1c532/68747470733a2f2f696d672e736869656c64732e696f2f7472617669732f61787970726f2f636f646563732d626173653634766c712f6d61737465722e7376673f7374796c653d666c61742d737175617265)](https://travis-ci.org/axypro/codecs-base64vlq)[![Coverage Status](https://camo.githubusercontent.com/7178b883340220c7f883e795fdbf01dc658fd211156542b51e17c1b35db35a20/68747470733a2f2f636f766572616c6c732e696f2f7265706f732f61787970726f2f636f646563732d626173653634766c712f62616467652e7376673f6272616e63683d6d617374657226736572766963653d676974687562)](https://coveralls.io/github/axypro/codecs-base64vlq?branch=master)[![License](https://camo.githubusercontent.com/94991f4fbfca69e856d203fdb4012b9e474e3a73465b0ccb286f9cabc2b2f2a2/68747470733a2f2f706f7365722e707567782e6f72672f6178792f636f646563732d626173653634766c712f6c6963656e7365)](LICENSE) - The library does not require any dependencies (except composer packages). - Tested on PHP 5.4+, PHP 7, HHVM (on Linux), PHP 5.5 (on Windows). - Install: `composer require axy/codecs-base64vlq`. - License: [MIT](LICENSE). ### Documentation [](#documentation) #### VQL + Base64 [](#vql--base64) Base64 allows us to represent a sequence of numbers in a text string that can be stored and transmit in text formats (JSON, XML, etc). VLQ allows us to represent an integer in a sequence numbers with little digit capacity. For example 6 bit is the limit for Base64. The resulting numbers are called "VLQ digits". Small input number is represented by fewer VLQ-digits than big number. Thus VLQ is most effective if the input sequence is contains mainly the small numbers. VLQ+Base64 allows us effectively represented a sequence of integers (dominated by a small number of) in the text format. For example, it used in [JavaScript/CSS source map](https://www.google.ru/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&sqi=2&ved=0CBwQFjAA&url=https%3A%2F%2Fdocs.google.com%2Fdocument%2Fd%2F1U1RGAehQwRypUTovF1KRlpiOFze0b-_2gc6fAH0KY0k%2Fedit&ei=abnpVKTZKeaHygPs0oK4BA&usg=AFQjCNFpOFA_dC_8cB50KJ1dXbOH7pvJnA&bvm=bv.86475890,d.bGQ). #### The Algorithm [](#the-algorithm) For example, we have a block of numbers: `[12345, -12345, 0]`. (1). VLQ only works with unsigned integers. Transfer the sign bit to the end of the integer. `12345` in binary is `11000000111001`. Added `0` (positive) to the end: `110000001110010`. For `-12345` take a positive form and add `1` (negative) to the end: `110000001110011`. Result is `[110000001110010, 110000001110011, 0]`. (2). Transform to the VLQ-sequence. For Base64 we need a block of 6-bit numbers. Most significant bit is reserved - it is "continuation". Split numbers to groups of 5 bits: `[11000 00011 10010, 11000 00011 10011, 00000]`. Output starting from the least significant bits. If the group is not the last in the current number then set the continuation bit. Result: `[110010 100011 011000 110011 100011 011000 000000]`. Or decimal `[50, 35, 24, 51, 35, 24, 0]`. These are VLQ digits. (3). Replace the numbers on the letters of the Base64-alphabet. The standard alphabet is `A..Za..z0..9+/`. Result is `yjYzjYA`. #### How to use the library [](#how-to-use-the-library) ``` use axy\codecs\base64vlq\Encoder; $encoder = new Encoder(); $encoder->encode([12345, -12345, 0]); // yjYzjYA $encoder->decode('yjYzjYA'); // [12345, 012345, 9] $encoder->decode('Variable+Length+QuantitY'); // [-10, 13, -13349, -13 ... -12797139] ``` Or default encoder can be obtained as follow: ``` $encoder = Encoder::getStandardInstance(); ``` In this case, the object creation and preliminary calculations are performed only once. #### Custom options [](#custom-options) The standard encoder uses standard options: 1. Transfer the sign bit. 2. 6-bit VLQ digits. 3. Standard alphabet: `A..Za..z0..9+/`. You can apply your settings: ``` Encoder::__construct([array|string $alphabet, int $bits, bool $signed = true]) ``` ``` /* Custom alphabet, 4 bits, no sign transfer */ $encoder = new Encoder('My Alphabet', 3, false); $encoder->encode([12345, 6789]); // phalllApplhhhy ``` Custom alphabet can be specified as a string (`My Alphabet`) or as an array (`[1 => 'A', 10 => 'B', 15 => 'C', 20 => 'D']`). #### Exceptions [](#exceptions) The error classes are located in the namespace `axy\codecs\base64vlq\Encoder\Errors`. - Error - VLQ - InvalidVLQSequence - Base64 - InvalidBase64 - InvalidBase64Input ##### InvalidVLQSequence [](#invalidvlqsequence) ``` $encoder->decode('Az'); // VLQ sequence is invalid: [0,51] ``` `z` is 51 (the continuation bit = 1). The last digit must have 0 in continuation bit. ##### InvalidBase64 [](#invalidbase64) ``` $encoder->decode('A*A'); // Base-64 string is invalid: "A*A" ``` `*` are not in the standard Base64 alphabet. ##### InvalidBase64Input [](#invalidbase64input) For the standard encoder this exception should not occur. Can occur for incorrect custom options: ``` $encoder = new Encoder('qwe', 10); $encoder->encode([10, 20, 30]); // Number 20 is not found in Base64 alphabet ``` 10 bits is 1024 variants, but the alphabet contains only 3 letter. ### Health Score 37 — LowBetter than 83% of packages Maintenance20 Infrequent updates — may be unmaintained Popularity39 Limited adoption so far Community12 Small or concentrated contributor base Maturity61 Established project with proven stability Bus Factor1 Top contributor holds 85% of commits — single point of failure How is this calculated?**Maintenance (25%)** — Last commit recency, latest release date, and issue-to-star ratio. Uses a 2-year decay window. **Popularity (30%)** — Total and monthly downloads, GitHub stars, and forks. Logarithmic scaling prevents top-heavy scores. **Community (15%)** — Contributors, dependents, forks, watchers, and maintainers. Measures real ecosystem engagement. **Maturity (30%)** — Project age, version count, PHP version support, and release stability. ### Release Activity Cadence Every ~1301 days Total 3 Last Release 1500d ago Major Versions 1.0.1 → 2.0.02022-04-09 PHP version history (2 changes)1.0.0PHP >=5.4.0 2.0.0PHP >=7.3 ### Community Maintainers ![](https://avatars.githubusercontent.com/u/3653255?v=4)[SychO](/maintainers/SychO)[@Sycho](https://github.com/Sycho) --- Top Contributors [![vasa-c](https://avatars.githubusercontent.com/u/557081?v=4)](https://github.com/vasa-c "vasa-c (17 commits)")[![SychO9](https://avatars.githubusercontent.com/u/20267363?v=4)](https://github.com/SychO9 "SychO9 (3 commits)") --- Tags base64Source mapcodecVLQVariable length quantity ### Embed Badge ![Health badge](/badges/sycho-codecs-base64vlq/health.svg) ``` [![Health](https://phpackages.com/badges/sycho-codecs-base64vlq/health.svg)](https://phpackages.com/packages/sycho-codecs-base64vlq) ``` ### Alternatives [paragonie/constant_time_encoding Constant-time Implementations of RFC 4648 Encoding (Base-64, Base-32, Base-16) 901329.7M148](/packages/paragonie-constant-time-encoding)[spomky-labs/base64url Base 64 URL Safe Encoding/Decoding PHP Library 15439.5M49](/packages/spomky-labs-base64url)[elfsundae/laravel-hashid A simple, elegant way to obfuscate your data by generating reversible, non-sequential, URL-safe identifiers. 415246.3k2](/packages/elfsundae-laravel-hashid)[axy/sourcemap Work with JavaScript/CSS Source Map 24734.1k5](/packages/axy-sourcemap)[delight-im/base64 Simple and convenient Base64 encoding and decoding for PHP 15158.1k6](/packages/delight-im-base64)[efficiently/larasset Larasset is a library for Laravel 5 which manage assets in an easy way. 684.8k](/packages/efficiently-larasset) PHPackages © 2026 [Directory](/)[Categories](/categories)[Trending](/trending)[Changelog](/changelog)[Analyze](/analyze)