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Terenz

CRC32 or Byte by Byte?

7 posts in this topic

Hello guys

If i need to compare two files and see if they are equal, what is best method?

For CRC32 there are some example, Byte by Byte is pratically FileRead. 

Thanks


Nothing is so strong as gentleness. Nothing is so gentle as real strength

 

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md5

 

This is a pretty good method. Be aware that getting a md5 checksum can take quite long if you're using big files (> 100 MB).

If you just want to check if a file has been modified, you can use FileGetTime.

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Radiance,

Given that AutoIt has a FileSetTime function I would not recommend the file modification date as a sensible check on whether file modification has occurred. ;)

M23


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ArrayMultiColSort ---- Sort arrays on multiple columns
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Date_Time_Convert -- Easily convert date/time formats, including the language used
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M23,

this is a pretty paranoid way of thinking (not in a bad way) and also of course correct.

I just assumed he was the only one using AutoIt on his file(s), so if he had used FileSetTime, he would probably know.

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#6 ·  Posted (edited)

FileGetTime is not accurate, date can be changed. MD5 is too slow for this reason i have think CRC32 or Byte by Byte, maybe partially.

Edited by Terenz

Nothing is so strong as gentleness. Nothing is so gentle as real strength

 

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#7 ·  Posted (edited)

Hashes are great to determine if the files are unique distinct or identical, byte by byte is best for actual comparision. Depends on what you are really trying to accomplish.  Dealing with large files there's going to be an increase in processing no matter what method you use.

Edited by spudw2k

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