Il 24/07/2016 01:18, wkitt...@windstream.net ha scritto:
this is driving me battier than i already am :(
i have a binary file that contains a record of data... the first field
of the data is a crc32 value of a string of characters... the string
of characters is lower cased before being fed to the crc32 function...
i need to calculate the same crc32 value as what is stored in the file...
i've already checked the polynomial ($edb88320) is the same in both,
the original implementation (converted to TP4 in 1988) and this
implementation...
the original routine uses longint and speaks of initializing the
variable to $ffffffff before feeding it to the crc32 routine... the
existing routine in FPC says "Pre- and post-conditioning (one's
complement) is performed within this function so it shouldn't be done
by the application." but that doesn't give me the proper answer in
this case... i've tried using cardinal types and longint types to no
avail...
the following is so so so very close but now i'm bald headed,
completely lost in the deep dark woods and can't find my breadcrumbs
any more :(
What I'd do in your place would be to forget about strings, and use just
an array of bytes. This way you're sure that you don't have in the way
the string length value and some automatic encoding conversion, which
messes up things.
Giuliano
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