Identical Files Finder - my new app on Google Play - Identical Files Finder

Unforgiven said:

Good luck with the app. <img src='styles/smilies/google/smilie.png' class='mceSmilie' alt='' title='Smile ' />

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Unforgiven said:

You are one of the first developers to take advantage of our new layout and create a channel for your app. Were the instructions clear enough?

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scary alien said:

Nice job, Marcel!

I've often thought of writing such an app, but was worried it would be to slow (which it probably would be on many older devices and their relatively slow SD cards).

Are you calculating an MD5 or SHA1 in order to (easily) tell if the files are identical? (that would have been my methodology)

Also, you might (if you're not already) sort the list by file (byte) size first and only compare the files with the same file size (if they're different sizes, the content must be different, of course)--that could really speed-up your scan.

I also really like how you annotated the screenshots in the Play Store listing--that's a great idea and I'm sure very helpful to folks reviewing and using your app.

Cheers and best of luck!

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1. group files by size (this gain a lot of speed) .
2. exclude groups that have just one file
3. compare files' content from each group byte by byte (when a single byte is different return from procedure)
   • when two files are different two different groups are created.
   • for each group a file is used as key , when a new file has to be processed, I compare it only with the key file (this also gain a lot of speed)

1. I ignore extension or file name because very often we may find different file names that have identical content.
2. The most time consuming process is reading files from external SD card. Any CRCsum (I've try MD5) didn't help. To calculate the CRCsum the files have to be read once, so it helps when we have at least 3 very large identical files . And the cases where we have more than two files of the same size, identical and very large size (100MB+) are very very rare.
3. I've did a lot of fine tuning to see what is the proper buffer size to be used when reading files from storage, and I ended with 4KB . On most devices if I increase or decrease the size of the buffer the read time will increase.

• made few things faster to avoid ANRs
• few fixes - accessing files from SD Card files is different from vendor to vendor, and required some updates which depend by Android version

Sean Low said:

downloaded. still trying... thanks

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