CODEWITHSUNDEEP
objective-cxcodemacosencodingmime-types
Paolo Sangregorio
Paolo Sangregorio

Reputation: 273

How can i determine if a file is binary or text?

I'm writing an application where i need to determine if the files provided from the user are text or not because i'm performing a search within them.

I'm not basing on the extension, cause i want to search also in source code files for example, or any other file that have a textual content (even for not well known extensions).

Is there a way to determine if a file is text or not?

Upvotes: 1

Views: 1207

Answers (4)

Andrew_STOP_RU_WAR_IN_UA
Andrew_STOP_RU_WAR_IN_UA

Reputation: 11426

try the following way:

func isBinary(_ path: String) -> Bool? {
    if FileManager.default.fileExists(atPath: path) == false {
        return nil
    }

    return ( try? String(contentsOfFile: path) ) == nil
}
  1. if file does not exist - it's return nil
  2. if file exist it's return it is binary or text

problem of this code is that it's will not work with large files (checking will be long)

Upvotes: -1

Paolo Sangregorio
Paolo Sangregorio

Reputation: 273

Thanks everyone for the solutions provided! I just found a framework that seems to do the job quite well!

I leave here a link for reference: https://github.com/aidansteele/MagicKit

Upvotes: 1

weston
weston

Reputation: 54781

You would need to open and read the data.

For ASCII text files, this means checking the characters are in the printable range.

For UTF text files, you may need to read the BOM (Byte Order Mark) first to determine encoding before reading the rest of the file.

Read more here: http://en.wikipedia.org/wiki/Text_file

Upvotes: 1

Ahmet Karakaya
Ahmet Karakaya

Reputation: 10139

There is no way to be certain. But note that most of the control characters would not appear in an ASCII file. You can make a pretty good guess by making a subset of most of the ASCII control characters. Then count the number of characters in the file that are in the subset, the count should be zero for an ASCII file. But in the final analysis you must prove a negative, which is a troublesome thing to do.

Upvotes: 0

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