46 lines
1.1 KiB
Go
46 lines
1.1 KiB
Go
package datamatrix
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import (
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"github.com/boombuler/barcode/utils"
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)
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type errorCorrection struct {
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rs *utils.ReedSolomonEncoder
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}
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var ec *errorCorrection = newErrorCorrection()
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func newErrorCorrection() *errorCorrection {
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gf := utils.NewGaloisField(301, 256, 1)
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return &errorCorrection{utils.NewReedSolomonEncoder(gf)}
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}
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func (ec *errorCorrection) calcECC(data []byte, size *dmCodeSize) []byte {
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dataSize := len(data)
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// make some space for error correction codes
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data = append(data, make([]byte, size.ECCCount)...)
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for block := 0; block < size.BlockCount; block++ {
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dataCnt := size.DataCodewordsForBlock(block)
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buff := make([]int, dataCnt)
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// copy the data for the current block to buff
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j := 0
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for i := block; i < dataSize; i += size.BlockCount {
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buff[j] = int(data[i])
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j++
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}
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// calc the error correction codes
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ecc := ec.rs.Encode(buff, size.ErrorCorrectionCodewordsPerBlock())
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// and append them to the result
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j = 0
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for i := block; i < size.ErrorCorrectionCodewordsPerBlock()*size.BlockCount; i += size.BlockCount {
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data[dataSize+i] = byte(ecc[j])
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j++
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}
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}
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return data
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}
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