What are the characters shown on a file after forcefully changing the extension?

user_15315918 0
Viewed 28

Recently I changed the extension of an .apk file to .txt and despite this, I was able to open it on Notepad with some random characters, that weren't available on the keyboard in the file.

org/antlr/runtime/ANTLRFileStream.class…TmOÓP=w[×QËÀ)ê|A…ÑETÔ¢NP¢™ãË—º•Q3ZÓcüþ¿j",£ß4ñGÏmÇñ˽Ïs{žçœçeûùëóW ±¨á0F5d0ÖA˔‹LÈã’ŠËR˜PqEƒ†Iy\•ØkÒºÞÁЂ´¦TL«˜H­95{ÙÚ°2K/­×–Y³Üªù(ð·:%œv\'¸!Гû÷óðª@¢èUܵä¸öòæÆÛ_±^ÔÂt^Ùª­Z¾#ýæc"XwêKž_5-7¨ù¦¿éΆmÞZ^Y*ÍS “ÛÖ¹µ¹7eûUàxn]%µ‘Ð^TÊvË^…kžUˆ;u_àTw<sÁ}µDL%ÛªØ>ùÄš@º…Rø˜¨;o)\,0ǚԞ݇ؓ‡àΪ<ò6ýr³¥GsÃ횪EOÌ_…É =è•Ç¬Ž#8ª£½ú^fùõ˜Ž›¸%pü IT{`Á2þ¶<Š:î`NÇ<î긇A˜èÿïˆ8Ç0Q¥»¨#- Ze7srRÉšíVƒõÐ]0rí&tÀ”O´‡[Y±K ö¬H›¯Ü %÷¬8Ì) r+åšW·ÑÏF†¿,bd—i%h³­ˆá8½YÄiª‘

Not just this, but while converting many other extensions like .jar,.xapk, etc. would show me these characters.

Can anyone please explain, what factors are these characters based on, and how does the OS decides or try what characters to show in an unsupported file exactly.

Is there a way to get the original content through this data?

operating-system executable-jar
1 Answers

Lets say you created a text editor, which can write and save text files as well as open text files. you also defined the encoding that will be used to save text in binary files(all files when saved are binary). So your encoding looks something as following:

Your encoding                               Emacs encoding    

TEXT       BINARY                          TEXT       BINARY
A          01000001                         ă         01000001    
B          01000010                         Ћ         01000010         
...                                         ...
Z          01011010                         Ϡ         01011010

lets say you create a file with 'ABZ' as its contents. this file when saved contains value 010000010100001001011010. When you open this file with your text editor, the editor finds 010000010100001001011010 as file contents and using above encoding it knows that its 'ABZ' hence it prints 'ABZ' on the screen.

Now lets say you open same file using emacs, since emacs uses its own encoding it displays "ăЋϠ", There is nothing wrong with emacs. it just doesn't know that data was written using your custom encoding.

So the point is that every file is written in a specific format, for example APK format can only be correctly understood by Android system. when you try to open the APK file in a text editor it just tries to make sense of binary data in the same way as emacs does in above example.

Is there a way to get the original content through this data?

If you know the originally encoding using which data was written, then you can read the contents of file using same encoding.

user_44130980
Related