CRC32

I need to find a way to duplicate java's CRC32 implementation for C# in Microsoft Visual Studio. Does anyone know of a way to do this? There are other CRC32 implementation out there but none that give the result that I need.

[232 byte] By [Moses84a] at [2007-11-27 8:34:04]

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# 1

All CRC 32 implementations do the same thing. What is different is (a) the CRC32 polynomial: there are several in common use; and (b) the initial value, usually zero or -1.

ejpa at 2007-7-12 20:30:15 >

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# 2

thanks, I know that all the implementation do the same thing. I am looking for the value of the polynomial. I've tried several other crc32 and they all come out to the same value that is different fromt the value that the java polynomial uses. Java ends up being in the 20........ and the other implementations produce a number in the 19.......... I don't have them on me right now to tell you the exact numbers being produced. Is there anyway I can find out the polynomial value? and possible the seed value?

Moses84a at 2007-7-12 20:30:15 >

# 3

For some reason the Java CRC 32 polynomial isn't specified, which is pretty incredible, but it is 0xedb88320UL, and the initial value is zero.

ejpa at 2007-7-12 20:30:15 >

# 4

thanks for the info. I've been looking for that for a while....where did you find it?

Moses84a at 2007-7-12 20:30:15 >

# 5

in the source code ...

ejpa at 2007-7-12 20:30:15 >

# 6

oh, I need to explain myself more when I post to this thing. When I looked at the source code, I just found a call to a native method, but couldn't find the native method. What I meant to ask was where in the source code did you find it? was there another level that I just didn't see?

Moses84a at 2007-7-12 20:30:15 >

# 7

In the native code. If you drill deep enough (and have the SCSL source, not just src.zip) you will find it in src/classes/native/java/util/zip/zlib-1.1.3/zcrc32.c.

ejpa at 2007-7-12 20:30:15 >

# 8

thanks for all the help, it works now.

Moses84a at 2007-7-12 20:30:15 >

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