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zagibu

Working with binary data

3 posts in this topic

I have this large binary blob. It's the pixel information of a 32bit bitmap. I'd like to convert it into 24bit by cutting out every fourth byte of the binary blob.

I've had the idea to use BinaryMid($blob, $index, 3) in a loop to get the first three bytes of the blob. But how do I chain all those three-byte pieces together? And how do I cut them out of the blob, so that loop iterations don't get all the same three bytes?

Another idea I had was to use BitShift() and BitOR(), but it seems the blob is too large for BitShift()...

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Des this work?

$oldBlob = "0xABCD124EF..."
$newBlob= "0x"
For $i = 1 To BinaryLen($oldBlob) Step 4
    $newBlob &= StringTrimLeft(BinaryMid($oldblob, $i, 3),2)
Next
$newBlob = Binary($newBlob)

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#3 ·  Posted (edited)

If you want to keep it pure AutoIt, you are better off working with that binary data as a hex string, and doing StringRegExpReplace. Any kind of looping (including the one suggested by ProgAndy above) will be pathetically slow on any decent sized data.

Edited by Siao

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