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README.md

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-# Антизапрет PAC-скрипт
+# Anti-Censorship Solution based on PAC-Script
+
+## Censorship in Russia vs. Right of Being Crazy w/ Information
+
+Censorship in Russia plagues the Freedoms of
+[Information](https://en.wikipedia.org/wiki/Freedom_of_information) and [Speech](https://en.wikipedia.org/wiki/Freedom_of_speech),
+slowly building analogue of [China Golden Shield](https://en.wikipedia.org/wiki/Golden_Shield_Project).  
+
+For good or bad, it blocks
+[Main Kampf](https://en.wikipedia.org/wiki/Mein_Kampf),
+[lolicon](https://en.wikipedia.org/wiki/Lolicon) (rearly distinguishing from hentai) and
+[critics of Putin](http://www.reuters.com/article/2014/03/13/us-russia-internet-idUSBREA2C21L20140313).
+
+Looking at how Russian government [distorts TV](https://therussianreader.wordpress.com/2015/11/22/russian-truckers-strike-dagestan/) and blocks Internet, I decided to write an Anti-Censorship extension for Chomium.
+
+I believe the freedom of information is a virtue and that everyone can go insane with all the sites on the Internets.
+
+## Task Technical Formulation
+
+You have a list of blocked domains.  
+Per each outcoming request you have to check whether host is a subdomain of the blocked domains.  
+If host is blocked, you have serve it via proxy.
+
+[PAC (proxy auto-config)](https://en.wikipedia.org/wiki/Proxy_auto-config) is executed on each request.  
+If it returns `PROXY address` to the browser then proxy is used, otherwise it returns `DIRECT`.
+
+## `Is_subdomain_of( host, blocked_hosts )`
+
+You have check `host belongs to subdomains of the blocked hosts` very fast.  
+This check is executed on each request. You should watch memeory consumption also.
+
+The naive solution is to keep array of blocked ips and check if the host resolves to one of the ips.  
+You may do it with `indexOf`, binary search, etc.  
+The shortcoming of every ip solution is that some providers resolve blocked hosts to wrong ips, so we eventually need list of hosts.
 
 ![Host Lookup Chart: Time-Memory, Hits-Misses](./chart/host-lookup-chart.png)