Finding the file size in the swf header help ... please

[booma_tooma]

Hello all,

I was wondering if anyone could tell me how to find the file size in the swf header. I am looking at the swf file format spec v10 pdf and it says that “The FileLength field is the total length of the SWF file, including the header. If this is an

uncompressed SWF file (FWS signature), the FileLength field should exactly match the file

size. If this is a compressed SWF file (CWS signature), the FileLength field indicates the total

length of the file after decompression, and thus generally does not match the file size. Having

the uncompressed size available can make the decompression process more efficient.”

Only problem is I can’t find this.

If I were to look at the hex value of a swf what would I look for to find the file size?

Here is the file:

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

[Guest · Accepted solution]

The file size field value is 5f030000, but the byte order is little endian and needs to be inverted. The inverted bytes are 00 00 03 5f (0x35f) (863).

Here's a utility function to invert an unsigned int:

function invertUint(value:uint):uint
{
    var result:uint=0;

    try{
         var ba:ByteArray=new ByteArray();
         ba.writeUnsignedInt(value);
         ba.position=0;
         ba.endian = Endian.LITTLE_ENDIAN;
         result = ba.readUnsignedInt();

    }

    catch(err){}
    return result;

}

[booma_tooma]

Thank you very much!

[Guest]

You're welcome.