CRC32Fingerprint()

Syntax

Result = CRC32Fingerprint(*Buffer, Size [, InitialValue])

Perform a CRC32 checksum on the given buffer.

Parameters

*Buffer	The buffer containing the data for the checksum calculation.
Size	The size of the given buffer.
InitialValue (optional)	The optional InitialValue parameter can be used to pass the checksum of a previous buffer. The result will then be the checksum of both buffers, as if it were calculated from one continuous buffer. This way calculating the checksum of large data can be broken down into a number of calculations on smaller buffers.

Return value

Returns the calculated checksum.

Remarks

CRC32 is a 32-bit fingerprint not intended for password storage as it's easily crackable, but for quick data integrity check. For example, zip files have a CRC32 checksum at the end of each file to be sure that the zip is not corrupted. The main advantage of CRC32 over MD5 or other hash algorithm is its very high speed.

Example

  *Buffer = AllocateMemory(200)                 ; Prepare a buffer with data
  If *Buffer
    PokeS(*Buffer, "The quick brown fox jumps over the lazy dog.")
    Length = MemoryStringLength(*Buffer)
    
    CRC32 = CRC32Fingerprint(*Buffer, Length)   ; Calculate the checksum in 1 step
    Debug "CRC32 checksum = " + Str(CRC32)
    
    Part1 = CRC32Fingerprint(*Buffer, Length/2) ; Calculate the checksum in 2 steps
    CRC32 = CRC32Fingerprint(*Buffer+Length/2, Length/2, Part1)
    Debug "CRC32 checksum = " + Str(CRC32)
  
    FreeMemory(*Buffer)
  EndIf

See Also

CRC32FileFingerprint(), MD5Fingerprint(), SHA1Fingerprint()

Supported OS

All