boombuler__barcode/datamatrix/errorcorrection.go

package datamatrix

// a more generic way would be great!
// like qr.galoisField with 301

var gf_log []int = []int{
	0, 255, 1, 240, 2, 225, 241, 53, 3, 38, 226, 133, 242, 43, 54, 210,
	4, 195, 39, 114, 227, 106, 134, 28, 243, 140, 44, 23, 55, 118, 211, 234,
	5, 219, 196, 96, 40, 222, 115, 103, 228, 78, 107, 125, 135, 8, 29, 162,
	244, 186, 141, 180, 45, 99, 24, 49, 56, 13, 119, 153, 212, 199, 235, 91,
	6, 76, 220, 217, 197, 11, 97, 184, 41, 36, 223, 253, 116, 138, 104, 193,
	229, 86, 79, 171, 108, 165, 126, 145, 136, 34, 9, 74, 30, 32, 163, 84,
	245, 173, 187, 204, 142, 81, 181, 190, 46, 88, 100, 159, 25, 231, 50, 207,
	57, 147, 14, 67, 120, 128, 154, 248, 213, 167, 200, 63, 236, 110, 92, 176,
	7, 161, 77, 124, 221, 102, 218, 95, 198, 90, 12, 152, 98, 48, 185, 179,
	42, 209, 37, 132, 224, 52, 254, 239, 117, 233, 139, 22, 105, 27, 194, 113,
	230, 206, 87, 158, 80, 189, 172, 203, 109, 175, 166, 62, 127, 247, 146, 66,
	137, 192, 35, 252, 10, 183, 75, 216, 31, 83, 33, 73, 164, 144, 85, 170,
	246, 65, 174, 61, 188, 202, 205, 157, 143, 169, 82, 72, 182, 215, 191, 251,
	47, 178, 89, 151, 101, 94, 160, 123, 26, 112, 232, 21, 51, 238, 208, 131,
	58, 69, 148, 18, 15, 16, 68, 17, 121, 149, 129, 19, 155, 59, 249, 70,
	214, 250, 168, 71, 201, 156, 64, 60, 237, 130, 111, 20, 93, 122, 177, 150,
}

var gf_alog []int = []int{
	1, 2, 4, 8, 16, 32, 64, 128, 45, 90, 180, 69, 138, 57, 114, 228,
	229, 231, 227, 235, 251, 219, 155, 27, 54, 108, 216, 157, 23, 46, 92, 184,
	93, 186, 89, 178, 73, 146, 9, 18, 36, 72, 144, 13, 26, 52, 104, 208,
	141, 55, 110, 220, 149, 7, 14, 28, 56, 112, 224, 237, 247, 195, 171, 123,
	246, 193, 175, 115, 230, 225, 239, 243, 203, 187, 91, 182, 65, 130, 41, 82,
	164, 101, 202, 185, 95, 190, 81, 162, 105, 210, 137, 63, 126, 252, 213, 135,
	35, 70, 140, 53, 106, 212, 133, 39, 78, 156, 21, 42, 84, 168, 125, 250,
	217, 159, 19, 38, 76, 152, 29, 58, 116, 232, 253, 215, 131, 43, 86, 172,
	117, 234, 249, 223, 147, 11, 22, 44, 88, 176, 77, 154, 25, 50, 100, 200,
	189, 87, 174, 113, 226, 233, 255, 211, 139, 59, 118, 236, 245, 199, 163, 107,
	214, 129, 47, 94, 188, 85, 170, 121, 242, 201, 191, 83, 166, 97, 194, 169,
	127, 254, 209, 143, 51, 102, 204, 181, 71, 142, 49, 98, 196, 165, 103, 206,
	177, 79, 158, 17, 34, 68, 136, 61, 122, 244, 197, 167, 99, 198, 161, 111,
	222, 145, 15, 30, 60, 120, 240, 205, 183, 67, 134, 33, 66, 132, 37, 74,
	148, 5, 10, 20, 40, 80, 160, 109, 218, 153, 31, 62, 124, 248, 221, 151,
	3, 6, 12, 24, 48, 96, 192, 173, 119, 238, 241, 207, 179, 75, 150, 1,
}

var gf_polys map[int][]int = map[int][]int{
	5:  []int{228, 48, 15, 111, 62},
	7:  []int{23, 68, 144, 134, 240, 92, 254},
	10: []int{28, 24, 185, 166, 223, 248, 116, 255, 110, 61},
	11: []int{175, 138, 205, 12, 194, 168, 39, 245, 60, 97, 120},
	12: []int{41, 153, 158, 91, 61, 42, 142, 213, 97, 178, 100, 242},
	14: []int{156, 97, 192, 252, 95, 9, 157, 119, 138, 45, 18, 186, 83, 185},
	18: []int{83, 195, 100, 39, 188, 75, 66, 61, 241, 213, 109, 129, 94, 254, 225, 48, 90, 188},
	20: []int{15, 195, 244, 9, 233, 71, 168, 2, 188, 160, 153, 145, 253, 79, 108, 82, 27, 174, 186, 172},
	24: []int{52, 190, 88, 205, 109, 39, 176, 21, 155, 197, 251, 223, 155, 21, 5, 172, 254, 124, 12, 181, 184, 96, 50, 193},
	28: []int{211, 231, 43, 97, 71, 96, 103, 174, 37, 151, 170, 53, 75, 34, 249, 121, 17, 138, 110, 213, 141, 136, 120, 151, 233, 168, 93, 255},
	36: []int{245, 127, 242, 218, 130, 250, 162, 181, 102, 120, 84, 179, 220, 251, 80, 182, 229, 18, 2, 4, 68, 33, 101, 137, 95, 119, 115, 44, 175, 184, 59, 25, 225, 98, 81, 112},
	42: []int{77, 193, 137, 31, 19, 38, 22, 153, 247, 105, 122, 2, 245, 133, 242, 8, 175, 95, 100, 9, 167, 105, 214, 111, 57, 121, 21, 1, 253, 57, 54, 101, 248, 202, 69, 50, 150, 177, 226, 5, 9, 5},
	48: []int{245, 132, 172, 223, 96, 32, 117, 22, 238, 133, 238, 231, 205, 188, 237, 87, 191, 106, 16, 147, 118, 23, 37, 90, 170, 205, 131, 88, 120, 100, 66, 138, 186, 240, 82, 44, 176, 87, 187, 147, 160, 175, 69, 213, 92, 253, 225, 19},
	56: []int{175, 9, 223, 238, 12, 17, 220, 208, 100, 29, 175, 170, 230, 192, 215, 235, 150, 159, 36, 223, 38, 200, 132, 54, 228, 146, 218, 234, 117, 203, 29, 232, 144, 238, 22, 150, 201, 117, 62, 207, 164, 13, 137, 245, 127, 67, 247, 28, 155, 43, 203, 107, 233, 53, 143, 46},
	62: []int{242, 93, 169, 50, 144, 210, 39, 118, 202, 188, 201, 189, 143, 108, 196, 37, 185, 112, 134, 230, 245, 63, 197, 190, 250, 106, 185, 221, 175, 64, 114, 71, 161, 44, 147, 6, 27, 218, 51, 63, 87, 10, 40, 130, 188, 17, 163, 31, 176, 170, 4, 107, 232, 7, 94, 166, 224, 124, 86, 47, 11, 204},
	68: []int{220, 228, 173, 89, 251, 149, 159, 56, 89, 33, 147, 244, 154, 36, 73, 127, 213, 136, 248, 180, 234, 197, 158, 177, 68, 122, 93, 213, 15, 160, 227, 236, 66, 139, 153, 185, 202, 167, 179, 25, 220, 232, 96, 210, 231, 136, 223, 239, 181, 241, 59, 52, 172, 25, 49, 232, 211, 189, 64, 54, 108, 153, 132, 63, 96, 103, 82, 186},
}

func rsBlock(data []byte, ncout []byte, poly []int) {
	for i := 0; i < len(ncout); i++ {
		ncout[i] = 0
	}

	for i := 0; i < len(data); i++ {
		k := (ncout[0] ^ data[i]) & 0xff
		for j := 0; j < len(ncout)-1; j++ {
			k1 := 0
			if k != 0 {
				k1 = gf_alog[(gf_log[k]+gf_log[poly[len(ncout)-j-2]])%255]
			}
			ncout[j] = ncout[j+1] ^ byte(k1)
		}
	}
}

func generateECC(data []byte, size *dmCodeSize) []byte {
	buff := make([]byte, size.DataCodewordsPerBlock())
	ecc := make([]byte, size.ErrorCorrectionCodewordsPerBlock()+1)
	poly := gf_polys[size.ErrorCorrectionCodewordsPerBlock()]

	dataSize := len(data)
	// make some space...
	space := make([]byte, size.ECCCount)
	data = append(data, space...)

	for b := 0; b < size.BlockCount; b++ {
		p := 0
		for n := b; n < dataSize; n += size.BlockCount {
			buff[p] = data[n]
			p++
		}
		rsBlock(buff, ecc, poly)
		p = 0
		for n := b; n < size.ErrorCorrectionCodewordsPerBlock()*size.BlockCount; n += size.BlockCount {
			data[dataSize+n] = ecc[p]
			p++
		}
	}

	return data
}