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Same code for CRC32 in JScript and VB.Net produce different result
Bicurico:
Hello,
Please don't ask why: I need to calculate CRC32 in JScript (embedded in another application, so no access to Crypto stuff) and in VB.Net.
I have this source code for JScript, which at least doesn't produce an error:
--- Code: ---function CRC32(str){
var CRCTable=[0x00000000,0x77073096,0xEE0E612C,0x990951BA,0x076DC419,0x706AF48F,0xE963A535,0x9E6495A3,0x0EDB8832,0x79DCB8A4,0xE0D5E91E,0x97D2D988,0x09B64C2B,0x7EB17CBD,0xE7B82D07,0x90BF1D91,0x1DB71064,0x6AB020F2,0xF3B97148,0x84BE41DE,0x1ADAD47D,0x6DDDE4EB,0xF4D4B551,0x83D385C7,0x136C9856,0x646BA8C0,0xFD62F97A,0x8A65C9EC,0x14015C4F,0x63066CD9,0xFA0F3D63,0x8D080DF5,0x3B6E20C8,0x4C69105E,0xD56041E4,0xA2677172,0x3C03E4D1,0x4B04D447,0xD20D85FD,0xA50AB56B,0x35B5A8FA,0x42B2986C,0xDBBBC9D6,0xACBCF940,0x32D86CE3,0x45DF5C75,0xDCD60DCF,0xABD13D59,0x26D930AC,0x51DE003A,0xC8D75180,0xBFD06116,0x21B4F4B5,0x56B3C423,0xCFBA9599,0xB8BDA50F,0x2802B89E,0x5F058808,0xC60CD9B2,0xB10BE924,0x2F6F7C87,0x58684C11,0xC1611DAB,0xB6662D3D,0x76DC4190,0x01DB7106,0x98D220BC,0xEFD5102A,0x71B18589,0x06B6B51F,0x9FBFE4A5,0xE8B8D433,0x7807C9A2,0x0F00F934,0x9609A88E,0xE10E9818,0x7F6A0DBB,0x086D3D2D,0x91646C97,0xE6635C01,0x6B6B51F4,0x1C6C6162,0x856530D8,0xF262004E,0x6C0695ED,0x1B01A57B,0x8208F4C1,0xF50FC457,0x65B0D9C6,0x12B7E950,0x8BBEB8EA,0xFCB9887C,0x62DD1DDF,0x15DA2D49,0x8CD37CF3,0xFBD44C65,0x4DB26158,0x3AB551CE,0xA3BC0074,0xD4BB30E2,0x4ADFA541,0x3DD895D7,0xA4D1C46D,0xD3D6F4FB,0x4369E96A,0x346ED9FC,0xAD678846,0xDA60B8D0,0x44042D73,0x33031DE5,0xAA0A4C5F,0xDD0D7CC9,0x5005713C,0x270241AA,0xBE0B1010,0xC90C2086,0x5768B525,0x206F85B3,0xB966D409,0xCE61E49F,0x5EDEF90E,0x29D9C998,0xB0D09822,0xC7D7A8B4,0x59B33D17,0x2EB40D81,0xB7BD5C3B,0xC0BA6CAD,0xEDB88320,0x9ABFB3B6,0x03B6E20C,0x74B1D29A,0xEAD54739,0x9DD277AF,0x04DB2615,0x73DC1683,0xE3630B12,0x94643B84,0x0D6D6A3E,0x7A6A5AA8,0xE40ECF0B,0x9309FF9D,0x0A00AE27,0x7D079EB1,0xF00F9344,0x8708A3D2,0x1E01F268,0x6906C2FE,0xF762575D,0x806567CB,0x196C3671,0x6E6B06E7,0xFED41B76,0x89D32BE0,0x10DA7A5A,0x67DD4ACC,0xF9B9DF6F,0x8EBEEFF9,0x17B7BE43,0x60B08ED5,0xD6D6A3E8,0xA1D1937E,0x38D8C2C4,0x4FDFF252,0xD1BB67F1,0xA6BC5767,0x3FB506DD,0x48B2364B,0xD80D2BDA,0xAF0A1B4C,0x36034AF6,0x41047A60,0xDF60EFC3,0xA867DF55,0x316E8EEF,0x4669BE79,0xCB61B38C,0xBC66831A,0x256FD2A0,0x5268E236,0xCC0C7795,0xBB0B4703,0x220216B9,0x5505262F,0xC5BA3BBE,0xB2BD0B28,0x2BB45A92,0x5CB36A04,0xC2D7FFA7,0xB5D0CF31,0x2CD99E8B,0x5BDEAE1D,0x9B64C2B0,0xEC63F226,0x756AA39C,0x026D930A,0x9C0906A9,0xEB0E363F,0x72076785,0x05005713,0x95BF4A82,0xE2B87A14,0x7BB12BAE,0x0CB61B38,0x92D28E9B,0xE5D5BE0D,0x7CDCEFB7,0x0BDBDF21,0x86D3D2D4,0xF1D4E242,0x68DDB3F8,0x1FDA836E,0x81BE16CD,0xF6B9265B,0x6FB077E1,0x18B74777,0x88085AE6,0xFF0F6A70,0x66063BCA,0x11010B5C,0x8F659EFF,0xF862AE69,0x616BFFD3,0x166CCF45,0xA00AE278,0xD70DD2EE,0x4E048354,0x3903B3C2,0xA7672661,0xD06016F7,0x4969474D,0x3E6E77DB,0xAED16A4A,0xD9D65ADC,0x40DF0B66,0x37D83BF0,0xA9BCAE53,0xDEBB9EC5,0x47B2CF7F,0x30B5FFE9,0xBDBDF21C,0xCABAC28A,0x53B39330,0x24B4A3A6,0xBAD03605,0xCDD70693,0x54DE5729,0x23D967BF,0xB3667A2E,0xC4614AB8,0x5D681B02,0x2A6F2B94,0xB40BBE37,0xC30C8EA1,0x5A05DF1B,0x2D02EF8D];
var len=str.length;
var r=0xffffffff;
for(var i=0;i<len;i++){
r=(r>>8)^CRCTable[str[i]^(r&0x000000FF)];
}
return~r;
}
--- End code ---
I used ChatGPT to help me convert this code into VB.Net and ended up with this:
--- Code: --- Function CRC32(text As String) As UInt64
Dim CRCTable As UInt32() = {&H0UI, &H77073096UI, &HEE0E612CUI, &H990951BAUI, &H76DC419UI, &H706AF48FUI, &HE963A535UI, &H9E6495A3UI, &HEDB8832UI, &H79DCB8A4UI, &HE0D5E91EUI, &H97D2D988UI, &H9B64C2BUI, &H7EB17CBDUI, &HE7B82D07UI, &H90BF1D91UI, &H1DB71064UI, &H6AB020F2UI, &HF3B97148UI, &H84BE41DEUI, &H1ADAD47DUI, &H6DDDE4EBUI, &HF4D4B551UI, &H83D385C7UI, &H136C9856UI, &H646BA8C0UI, &HFD62F97AUI, &H8A65C9ECUI, &H14015C4FUI, &H63066CD9UI, &HFA0F3D63UI, &H8D080DF5UI, &H3B6E20C8UI, &H4C69105EUI, &HD56041E4UI, &HA2677172UI, &H3C03E4D1UI, &H4B04D447UI, &HD20D85FDUI, &HA50AB56BUI, &H35B5A8FAUI, &H42B2986CUI, &HDBBBC9D6UI, &HACBCF940UI, &H32D86CE3UI, &H45DF5C75UI, &HDCD60DCFUI, &HABD13D59UI, &H26D930ACUI, &H51DE003AUI, &HC8D75180UI, &HBFD06116UI, &H21B4F4B5UI, &H56B3C423UI, &HCFBA9599UI, &HB8BDA50FUI, &H2802B89EUI, &H5F058808UI, &HC60CD9B2UI, &HB10BE924UI, &H2F6F7C87UI, &H58684C11UI, &HC1611DABUI, &HB6662D3DUI, &H76DC4190UI, &H1DB7106UI, &H98D220BCUI, &HEFD5102AUI, &H71B18589UI, &H6B6B51FUI, &H9FBFE4A5UI, &HE8B8D433UI, &H7807C9A2UI, &HF00F934UI, &H9609A88EUI, &HE10E9818UI, &H7F6A0DBBUI, &H86D3D2DUI, &H91646C97UI, &HE6635C01UI, &H6B6B51F4UI, &H1C6C6162UI, &H856530D8UI, &HF262004EUI, &H6C0695EDUI, &H1B01A57BUI, &H8208F4C1UI, &HF50FC457UI, &H65B0D9C6UI, &H12B7E950UI, &H8BBEB8EAUI, &HFCB9887CUI, &H62DD1DDFUI, &H15DA2D49UI, &H8CD37CF3UI, &HFBD44C65UI, &H4DB26158UI, &H3AB551CEUI, &HA3BC0074UI, &HD4BB30E2UI, &H4ADFA541UI, &H3DD895D7UI, &HA4D1C46DUI, &HD3D6F4FBUI, &H4369E96AUI, &H346ED9FCUI, &HAD678846UI, &HDA60B8D0UI, &H44042D73UI, &H33031DE5UI, &HAA0A4C5FUI, &HDD0D7CC9UI, &H5005713CUI, &H270241AAUI, &HBE0B1010UI, &HC90C2086UI, &H5768B525UI, &H206F85B3UI, &HB966D409UI, &HCE61E49FUI, &H5EDEF90EUI, &H29D9C998UI, &HB0D09822UI, &HC7D7A8B4UI, &H59B33D17UI, &H2EB40D81UI, &HB7BD5C3BUI, &HC0BA6CADUI, &HEDB88320UI, &H9ABFB3B6UI, &H3B6E20CUI, &H74B1D29AUI, &HEAD54739UI, &H9DD277AFUI, &H4DB2615UI, &H73DC1683UI, &HE3630B12UI, &H94643B84UI, &HD6D6A3EUI, &H7A6A5AA8UI, &HE40ECF0BUI, &H9309FF9DUI, &HA00AE27UI, &H7D079EB1UI, &HF00F9344UI, &H8708A3D2UI, &H1E01F268UI, &H6906C2FEUI, &HF762575DUI, &H806567CBUI, &H196C3671UI, &H6E6B06E7UI, &HFED41B76UI, &H89D32BE0UI, &H10DA7A5AUI, &H67DD4ACCUI, &HF9B9DF6FUI, &H8EBEEFF9UI, &H17B7BE43UI, &H60B08ED5UI, &HD6D6A3E8UI, &HA1D1937EUI, &H38D8C2C4UI, &H4FDFF252UI, &HD1BB67F1UI, &HA6BC5767UI, &H3FB506DDUI, &H48B2364BUI, &HD80D2BDAUI, &HAF0A1B4CUI, &H36034AF6UI, &H41047A60UI, &HDF60EFC3UI, &HA867DF55UI, &H316E8EEFUI, &H4669BE79UI, &HCB61B38CUI, &HBC66831AUI, &H256FD2A0UI, &H5268E236UI, &HCC0C7795UI, &HBB0B4703UI, &H220216B9UI, &H5505262FUI, &HC5BA3BBEUI, &HB2BD0B28UI, &H2BB45A92UI, &H5CB36A04UI, &HC2D7FFA7UI, &HB5D0CF31UI, &H2CD99E8BUI, &H5BDEAE1DUI, &H9B64C2B0UI, &HEC63F226UI, &H756AA39CUI, &H26D930AUI, &H9C0906A9UI, &HEB0E363FUI, &H72076785UI, &H5005713UI, &H95BF4A82UI, &HE2B87A14UI, &H7BB12BAEUI, &HCB61B38UI, &H92D28E9BUI, &HE5D5BE0DUI, &H7CDCEFB7UI, &HBDBDF21CUI, &HCABAC28AUI, &H53B39330UI, &H24B4A3A6UI, &HBAD03605UI, &HCDD70693UI, &H54DE5729UI, &H23D967BFUI, &HB3667A2EUI, &HC4614AB8UI, &H5D681B02UI, &H2A6F2B94UI, &HB40BBE37UI, &HC30C8EA1UI, &H5A05DF1BUI, &H2D02EF8D}
Dim len As Integer = text.Length
Dim r As UInt32 = &HFFFFFFFFUI
For i As Integer = 0 To len - 1
r = (r >> 8) Xor CRCTable(Convert.ToByte(text(i)) Xor (r And &HFF))
Next
Return Not r
End Function
--- End code ---
If I call the JScript function with argument "AAAAA" I get 337647727 as the result for the CRC32.
But calling the VB.Net function with argument "AAAAA" produces 435704073 as the result for the CRC32.
Has anyone an idea why this is happening?
I don't need this source code to be compatible with any other CRC32 algorithm - I just need the JScript and VB.Net versions to output the same result for any given equal string.
The string can be simple ASCII (just numbers and letters).
Thanks,
Vitor
Bicurico:
Also, the JScript function produces negative CRC32 numbers for some strings, while the VB.Net version will complain with out of range error.
magic:
Dunno, I would probably make it print the current values of internal variables on every iteration to see where things go unexpected.
The long expression could be split into parts and each part printed separately.
ataradov:
The tables are completely different. That's ChatGPT programming for you, the way of the future.
jm_araujo:
I get the same results with:
--- Code: ---function CRC32(str){
var CRCTable=[0x00000000,0x77073096,0xEE0E612C,0x990951BA,0x076DC419,0x706AF48F,0xE963A535,0x9E6495A3,0x0EDB8832,0x79DCB8A4,0xE0D5E91E,0x97D2D988,0x09B64C2B,0x7EB17CBD,0xE7B82D07,0x90BF1D91,0x1DB71064,0x6AB020F2,0xF3B97148,0x84BE41DE,0x1ADAD47D,0x6DDDE4EB,0xF4D4B551,0x83D385C7,0x136C9856,0x646BA8C0,0xFD62F97A,0x8A65C9EC,0x14015C4F,0x63066CD9,0xFA0F3D63,0x8D080DF5,0x3B6E20C8,0x4C69105E,0xD56041E4,0xA2677172,0x3C03E4D1,0x4B04D447,0xD20D85FD,0xA50AB56B,0x35B5A8FA,0x42B2986C,0xDBBBC9D6,0xACBCF940,0x32D86CE3,0x45DF5C75,0xDCD60DCF,0xABD13D59,0x26D930AC,0x51DE003A,0xC8D75180,0xBFD06116,0x21B4F4B5,0x56B3C423,0xCFBA9599,0xB8BDA50F,0x2802B89E,0x5F058808,0xC60CD9B2,0xB10BE924,0x2F6F7C87,0x58684C11,0xC1611DAB,0xB6662D3D,0x76DC4190,0x01DB7106,0x98D220BC,0xEFD5102A,0x71B18589,0x06B6B51F,0x9FBFE4A5,0xE8B8D433,0x7807C9A2,0x0F00F934,0x9609A88E,0xE10E9818,0x7F6A0DBB,0x086D3D2D,0x91646C97,0xE6635C01,0x6B6B51F4,0x1C6C6162,0x856530D8,0xF262004E,0x6C0695ED,0x1B01A57B,0x8208F4C1,0xF50FC457,0x65B0D9C6,0x12B7E950,0x8BBEB8EA,0xFCB9887C,0x62DD1DDF,0x15DA2D49,0x8CD37CF3,0xFBD44C65,0x4DB26158,0x3AB551CE,0xA3BC0074,0xD4BB30E2,0x4ADFA541,0x3DD895D7,0xA4D1C46D,0xD3D6F4FB,0x4369E96A,0x346ED9FC,0xAD678846,0xDA60B8D0,0x44042D73,0x33031DE5,0xAA0A4C5F,0xDD0D7CC9,0x5005713C,0x270241AA,0xBE0B1010,0xC90C2086,0x5768B525,0x206F85B3,0xB966D409,0xCE61E49F,0x5EDEF90E,0x29D9C998,0xB0D09822,0xC7D7A8B4,0x59B33D17,0x2EB40D81,0xB7BD5C3B,0xC0BA6CAD,0xEDB88320,0x9ABFB3B6,0x03B6E20C,0x74B1D29A,0xEAD54739,0x9DD277AF,0x04DB2615,0x73DC1683,0xE3630B12,0x94643B84,0x0D6D6A3E,0x7A6A5AA8,0xE40ECF0B,0x9309FF9D,0x0A00AE27,0x7D079EB1,0xF00F9344,0x8708A3D2,0x1E01F268,0x6906C2FE,0xF762575D,0x806567CB,0x196C3671,0x6E6B06E7,0xFED41B76,0x89D32BE0,0x10DA7A5A,0x67DD4ACC,0xF9B9DF6F,0x8EBEEFF9,0x17B7BE43,0x60B08ED5,0xD6D6A3E8,0xA1D1937E,0x38D8C2C4,0x4FDFF252,0xD1BB67F1,0xA6BC5767,0x3FB506DD,0x48B2364B,0xD80D2BDA,0xAF0A1B4C,0x36034AF6,0x41047A60,0xDF60EFC3,0xA867DF55,0x316E8EEF,0x4669BE79,0xCB61B38C,0xBC66831A,0x256FD2A0,0x5268E236,0xCC0C7795,0xBB0B4703,0x220216B9,0x5505262F,0xC5BA3BBE,0xB2BD0B28,0x2BB45A92,0x5CB36A04,0xC2D7FFA7,0xB5D0CF31,0x2CD99E8B,0x5BDEAE1D,0x9B64C2B0,0xEC63F226,0x756AA39C,0x026D930A,0x9C0906A9,0xEB0E363F,0x72076785,0x05005713,0x95BF4A82,0xE2B87A14,0x7BB12BAE,0x0CB61B38,0x92D28E9B,0xE5D5BE0D,0x7CDCEFB7,0x0BDBDF21,0x86D3D2D4,0xF1D4E242,0x68DDB3F8,0x1FDA836E,0x81BE16CD,0xF6B9265B,0x6FB077E1,0x18B74777,0x88085AE6,0xFF0F6A70,0x66063BCA,0x11010B5C,0x8F659EFF,0xF862AE69,0x616BFFD3,0x166CCF45,0xA00AE278,0xD70DD2EE,0x4E048354,0x3903B3C2,0xA7672661,0xD06016F7,0x4969474D,0x3E6E77DB,0xAED16A4A,0xD9D65ADC,0x40DF0B66,0x37D83BF0,0xA9BCAE53,0xDEBB9EC5,0x47B2CF7F,0x30B5FFE9,0xBDBDF21C,0xCABAC28A,0x53B39330,0x24B4A3A6,0xBAD03605,0xCDD70693,0x54DE5729,0x23D967BF,0xB3667A2E,0xC4614AB8,0x5D681B02,0x2A6F2B94,0xB40BBE37,0xC30C8EA1,0x5A05DF1B,0x2D02EF8D];
var len=str.length;
var r=0xffffffff;
for(var i=0;i<len;i++){
r=((r>>8)^CRCTable[str[i].charCodeAt()^(r&0x000000FF)]);
}
return(~r>>>0);;
}
--- End code ---
In my debugging found out you need the "charCodeAt()" to convert from string to int.
The return with ">>>0" was a trick found online to return unsigned numbers in js
Edit: the VB.Net table is incomplete.
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