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1 // Copyright (c) 1999-2009 Nokia Corporation and/or its subsidiary(-ies). |
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2 // All rights reserved. |
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3 // This component and the accompanying materials are made available |
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4 // under the terms of "Eclipse Public License v1.0" |
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5 // which accompanies this distribution, and is available |
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6 // at the URL "http://www.eclipse.org/legal/epl-v10.html". |
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7 // |
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8 // Initial Contributors: |
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9 // Nokia Corporation - initial contribution. |
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10 // |
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11 // Contributors: |
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12 // |
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13 // Description: |
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14 // Calculation for the RFCOMM (TS07.10) FCS |
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15 // |
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16 // |
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17 |
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18 #include <e32std.h> |
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19 #include "rfcommfcs.h" |
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20 #include "debug.h" |
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21 |
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22 #pragma warning( disable : 4244) // Conv from int to char |
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23 |
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24 /* |
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25 This table is lifted from the TS07.10 spec in the appendices. |
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26 */ |
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27 |
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28 static const TUint8 crctable[256] = { //reversed, 8-bit, poly=0x07 |
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29 0x00, 0x91, 0xE3, 0x72, 0x07, 0x96, 0xE4, 0x75, 0x0E, 0x9F, 0xED, 0x7C, 0x09, 0x98, 0xEA, 0x7B, |
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30 0x1C, 0x8D, 0xFF, 0x6E, 0x1B, 0x8A, 0xF8, 0x69, 0x12, 0x83, 0xF1, 0x60, 0x15, 0x84, 0xF6, 0x67, |
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31 0x38, 0xA9, 0xDB, 0x4A, 0x3F, 0xAE, 0xDC, 0x4D, 0x36, 0xA7, 0xD5, 0x44, 0x31, 0xA0, 0xD2, 0x43, |
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32 0x24, 0xB5, 0xC7, 0x56, 0x23, 0xB2, 0xC0, 0x51, 0x2A, 0xBB, 0xC9, 0x58, 0x2D, 0xBC, 0xCE, 0x5F, |
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33 0x70, 0xE1, 0x93, 0x02, 0x77, 0xE6, 0x94, 0x05, 0x7E, 0xEF, 0x9D, 0x0C, 0x79, 0xE8, 0x9A, 0x0B, |
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34 0x6C, 0xFD, 0x8F, 0x1E, 0x6B, 0xFA, 0x88, 0x19, 0x62, 0xF3, 0x81, 0x10, 0x65, 0xF4, 0x86, 0x17, |
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35 0x48, 0xD9, 0xAB, 0x3A, 0x4F, 0xDE, 0xAC, 0x3D, 0x46, 0xD7, 0xA5, 0x34, 0x41, 0xD0, 0xA2, 0x33, |
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36 0x54, 0xC5, 0xB7, 0x26, 0x53, 0xC2, 0xB0, 0x21, 0x5A, 0xCB, 0xB9, 0x28, 0x5D, 0xCC, 0xBE, 0x2F, |
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37 0xE0, 0x71, 0x03, 0x92, 0xE7, 0x76, 0x04, 0x95, 0xEE, 0x7F, 0x0D, 0x9C, 0xE9, 0x78, 0x0A, 0x9B, |
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38 0xFC, 0x6D, 0x1F, 0x8E, 0xFB, 0x6A, 0x18, 0x89, 0xF2, 0x63, 0x11, 0x80, 0xF5, 0x64, 0x16, 0x87, |
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39 0xD8, 0x49, 0x3B, 0xAA, 0xDF, 0x4E, 0x3C, 0xAD, 0xD6, 0x47, 0x35, 0xA4, 0xD1, 0x40, 0x32, 0xA3, |
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40 0xC4, 0x55, 0x27, 0xB6, 0xC3, 0x52, 0x20, 0xB1, 0xCA, 0x5B, 0x29, 0xB8, 0xCD, 0x5C, 0x2E, 0xBF, |
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41 0x90, 0x01, 0x73, 0xE2, 0x97, 0x06, 0x74, 0xE5, 0x9E, 0x0F, 0x7D, 0xEC, 0x99, 0x08, 0x7A, 0xEB, |
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42 0x8C, 0x1D, 0x6F, 0xFE, 0x8B, 0x1A, 0x68, 0xF9, 0x82, 0x13, 0x61, 0xF0, 0x85, 0x14, 0x66, 0xF7, |
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43 0xA8, 0x39, 0x4B, 0xDA, 0xAF, 0x3E, 0x4C, 0xDD, 0xA6, 0x37, 0x45, 0xD4, 0xA1, 0x30, 0x42, 0xD3, |
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44 0xB4, 0x25, 0x57, 0xC6, 0xB3, 0x22, 0x50, 0xC1, 0xBA, 0x2B, 0x59, 0xC8, 0xBD, 0x2C, 0x5E, 0xCF |
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45 }; |
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46 |
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47 |
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48 TUint8 CalcFCS(const TUint8* aData, TInt aLen) |
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49 /** |
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50 Calculates the FCS over data starting at aData and of length |
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51 aLen. Uses the algorithm from the TS07.10 spec. |
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52 **/ |
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53 { |
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54 TUint8 fcs=0xff; |
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55 |
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56 while(aLen--) |
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57 { |
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58 fcs=crctable[fcs^*aData++]; |
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59 } |
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60 |
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61 fcs=~fcs; |
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62 return fcs; |
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63 } |
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64 |
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65 TBool CheckFCS(const TUint8* aData, TInt aLen, TUint8 aFCS) |
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66 /** |
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67 Check a received FCS. |
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68 **/ |
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69 { |
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70 TUint8 fcs=0xFF; |
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71 while (aLen--) |
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72 { |
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73 fcs=crctable[fcs^*aData++]; |
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74 } |
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75 /*Ones complement*/ |
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76 fcs=crctable[fcs^aFCS]; |
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77 // log "PDU FCS:" aFCS - Shehla |
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78 RFQBLOG(KBlogTypeFCS, Log(KBlogActualFCS, aFCS)); |
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79 // log this as "Calculated FCS (should be 0xCF): " fcs - Shehla |
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80 RFQBLOG(KBlogTypeFCS, Log(KBlogComputedFCS, fcs)); |
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81 /*0xCF is the reversed order of 11110011.*/ |
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82 TBool result=EFalse; //- Shehla |
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83 if (fcs==0xCF) |
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84 //return ETrue; |
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85 result=ETrue; |
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86 else |
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87 //return EFalse; |
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88 result=EFalse; |
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89 //log "FCS Computation" result - Shehla |
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90 RFQBLOG(KBlogTypeFCS, Log(KBlogComparedFCS, result)); |
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91 |
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92 return result; |
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93 } |