Crc16 – Evaluate the 16-bit CRC of an array of bytes

Option Explicit' Evalutate the 16-bit CRC (Cyclic Redundancy Checksum) of an array of bytes'' If you omit the second argument, the entire array is consideredFunction Crc16(cp() As Byte, Optional ByVal Size As Long = -1) As Long  Dim i As Long  Dim fcs As Long  Static fcstab(255) As Long    Const pppinitfcs16 = &HFFFF& 'Initial FCS value    If Size < 0 Then Size = UBound(cp) - LBound(cp) + 1  If fcstab(1) = 0 Then    ' Initialize array once and for all    fcstab(0) = &H0&    fcstab(1) = &H1189&    fcstab(2) = &H2312&    fcstab(3) = &H329B&    fcstab(4) = &H4624&    fcstab(5) = &H57AD&    fcstab(6) = &H6536&    fcstab(7) = &H74BF&    fcstab(8) = &H8C48&    fcstab(9) = &H9DC1&    fcstab(10) = &HAF5A&    fcstab(11) = &HBED3&    fcstab(12) = &HCA6C&    fcstab(13) = &HDBE5&    fcstab(14) = &HE97E&    fcstab(15) = &HF8F7&    fcstab(16) = &H1081&    fcstab(17) = &H108&    fcstab(18) = &H3393&    fcstab(19) = &H221A&    fcstab(20) = &H56A5&    fcstab(21) = &H472C&    fcstab(22) = &H75B7&    fcstab(23) = &H643E&    fcstab(24) = &H9CC9&    fcstab(25) = &H8D40&    fcstab(26) = &HBFDB&    fcstab(27) = &HAE52&    fcstab(28) = &HDAED&    fcstab(29) = &HCB64&    fcstab(30) = &HF9FF&    fcstab(31) = &HE876&    fcstab(32) = &H2102&    fcstab(33) = &H308B&    fcstab(34) = &H210&    fcstab(35) = &H1399&    fcstab(36) = &H6726&    fcstab(37) = &H76AF&    fcstab(38) = &H4434&    fcstab(39) = &H55BD&    fcstab(40) = &HAD4A&    fcstab(41) = &HBCC3&    fcstab(42) = &H8E58&    fcstab(43) = &H9FD1&    fcstab(44) = &HEB6E&    fcstab(45) = &HFAE7&    fcstab(46) = &HC87C&    fcstab(47) = &HD9F5&    fcstab(48) = &H3183&    fcstab(49) = &H200A&    fcstab(50) = &H1291&    fcstab(51) = &H318&    fcstab(52) = &H77A7&    fcstab(53) = &H662E&    fcstab(54) = &H54B5&    fcstab(55) = &H453C&    fcstab(56) = &HBDCB&    fcstab(57) = &HAC42&    fcstab(58) = &H9ED9&    fcstab(59) = &H8F50&    fcstab(60) = &HFBEF&    fcstab(61) = &HEA66&    fcstab(62) = &HD8FD&    fcstab(63) = &HC974&    fcstab(64) = &H4204&    fcstab(65) = &H538D&    fcstab(66) = &H6116&    fcstab(67) = &H709F&    fcstab(68) = &H420&    fcstab(69) = &H15A9&    fcstab(70) = &H2732&    fcstab(71) = &H36BB&    fcstab(72) = &HCE4C&    fcstab(73) = &HDFC5&    fcstab(74) = &HED5E&    fcstab(75) = &HFCD7&    fcstab(76) = &H8868&    fcstab(77) = &H99E1&    fcstab(78) = &HAB7A&    fcstab(79) = &HBAF3&    fcstab(80) = &H5285&    fcstab(81) = &H430C&    fcstab(82) = &H7197&    fcstab(83) = &H601E&    fcstab(84) = &H14A1&    fcstab(85) = &H528&    fcstab(86) = &H37B3&    fcstab(87) = &H263A&    fcstab(88) = &HDECD&    fcstab(89) = &HCF44&    fcstab(90) = &HFDDF&    fcstab(91) = &HEC56&    fcstab(92) = &H98E9&    fcstab(93) = &H8960&    fcstab(94) = &HBBFB&    fcstab(95) = &HAA72&    fcstab(96) = &H6306&    fcstab(97) = &H728F&    fcstab(98) = &H4014&    fcstab(99) = &H519D&    fcstab(100) = &H2522&    fcstab(101) = &H34AB&    fcstab(102) = &H630&    fcstab(103) = &H17B9&    fcstab(104) = &HEF4E&    fcstab(105) = &HFEC7&    fcstab(106) = &HCC5C&    fcstab(107) = &HDDD5&    fcstab(108) = &HA96A&    fcstab(109) = &HB8E3&    fcstab(110) = &H8A78&    fcstab(111) = &H9BF1&    fcstab(112) = &H7387&    fcstab(113) = &H620E&    fcstab(114) = &H5095&    fcstab(115) = &H411C&    fcstab(116) = &H35A3&    fcstab(117) = &H242A&    fcstab(118) = &H16B1&    fcstab(119) = &H738&    fcstab(120) = &HFFCF&    fcstab(121) = &HEE46&    fcstab(122) = &HDCDD&    fcstab(123) = &HCD54&    fcstab(124) = &HB9EB&    fcstab(125) = &HA862&    fcstab(126) = &H9AF9&    fcstab(127) = &H8B70&    fcstab(128) = &H8408&    fcstab(129) = &H9581&    fcstab(130) = &HA71A&    fcstab(131) = &HB693&    fcstab(132) = &HC22C&    fcstab(133) = &HD3A5&    fcstab(134) = &HE13E&    fcstab(135) = &HF0B7&    fcstab(136) = &H840&    fcstab(137) = &H19C9&    fcstab(138) = &H2B52&    fcstab(139) = &H3ADB&    fcstab(140) = &H4E64&    fcstab(141) = &H5FED&    fcstab(142) = &H6D76&    fcstab(143) = &H7CFF&    fcstab(144) = &H9489&    fcstab(145) = &H8500&    fcstab(146) = &HB79B&    fcstab(147) = &HA612&    fcstab(148) = &HD2AD&    fcstab(149) = &HC324&    fcstab(150) = &HF1BF&    fcstab(151) = &HE036&    fcstab(152) = &H18C1&    fcstab(153) = &H948&    fcstab(154) = &H3BD3&    fcstab(155) = &H2A5A&    fcstab(156) = &H5EE5&    fcstab(157) = &H4F6C&    fcstab(158) = &H7DF7&    fcstab(159) = &H6C7E&    fcstab(160) = &HA50A&    fcstab(161) = &HB483&    fcstab(162) = &H8618&    fcstab(163) = &H9791&    fcstab(164) = &HE32E&    fcstab(165) = &HF2A7&    fcstab(166) = &HC03C&    fcstab(167) = &HD1B5&    fcstab(168) = &H2942&    fcstab(169) = &H38CB&    fcstab(170) = &HA50&    fcstab(171) = &H1BD9&    fcstab(172) = &H6F66&    fcstab(173) = &H7EEF&    fcstab(174) = &H4C74&    fcstab(175) = &H5DFD&    fcstab(176) = &HB58B&    fcstab(177) = &HA402&    fcstab(178) = &H9699&    fcstab(179) = &H8710&    fcstab(180) = &HF3AF&    fcstab(181) = &HE226&    fcstab(182) = &HD0BD&    fcstab(183) = &HC134&    fcstab(184) = &H39C3&    fcstab(185) = &H284A&    fcstab(186) = &H1AD1&    fcstab(187) = &HB58&    fcstab(188) = &H7FE7&    fcstab(189) = &H6E6E&    fcstab(190) = &H5CF5&    fcstab(191) = &H4D7C&    fcstab(192) = &HC60C&    fcstab(193) = &HD785&    fcstab(194) = &HE51E&    fcstab(195) = &HF497&    fcstab(196) = &H8028&    fcstab(197) = &H91A1&    fcstab(198) = &HA33A&    fcstab(199) = &HB2B3&    fcstab(200) = &H4A44&    fcstab(201) = &H5BCD&    fcstab(202) = &H6956&    fcstab(203) = &H78DF&    fcstab(204) = &HC60&    fcstab(205) = &H1DE9&    fcstab(206) = &H2F72&    fcstab(207) = &H3EFB&    fcstab(208) = &HD68D&    fcstab(209) = &HC704&    fcstab(210) = &HF59F&    fcstab(211) = &HE416&    fcstab(212) = &H90A9&    fcstab(213) = &H8120&    fcstab(214) = &HB3BB&    fcstab(215) = &HA232&    fcstab(216) = &H5AC5&    fcstab(217) = &H4B4C&    fcstab(218) = &H79D7&    fcstab(219) = &H685E&    fcstab(220) = &H1CE1&    fcstab(221) = &HD68&    fcstab(222) = &H3FF3&    fcstab(223) = &H2E7A&    fcstab(224) = &HE70E&    fcstab(225) = &HF687&    fcstab(226) = &HC41C&    fcstab(227) = &HD595&    fcstab(228) = &HA12A&    fcstab(229) = &HB0A3&    fcstab(230) = &H8238&    fcstab(231) = &H93B1&    fcstab(232) = &H6B46&    fcstab(233) = &H7ACF&    fcstab(234) = &H4854&    fcstab(235) = &H59DD&    fcstab(236) = &H2D62&    fcstab(237) = &H3CEB&    fcstab(238) = &HE70&    fcstab(239) = &H1FF9&    fcstab(240) = &HF78F&    fcstab(241) = &HE606&    fcstab(242) = &HD49D&    fcstab(243) = &HC514&    fcstab(244) = &HB1AB&    fcstab(245) = &HA022&    fcstab(246) = &H92B9&    fcstab(247) = &H8330&    fcstab(248) = &H7BC7&    fcstab(249) = &H6A4E&    fcstab(250) = &H58D5&    fcstab(251) = &H495C&    fcstab(252) = &H3DE3&    fcstab(253) = &H2C6A&    fcstab(254) = &H1EF1&    fcstab(255) = &HF78&  End If    ' The initial FCS value  fcs = pppinitfcs16    ' evaluate the FCS  For i = LBound(cp) To LBound(cp) + Size - 1    fcs = (fcs  &H100&) Xor fcstab((fcs Xor cp(i)) And &HFF&)  Next i    ' return the result  Crc16 = fcsEnd Function