numeric.go raw

   1  package qr
   2  
   3  import (
   4  	"errors"
   5  	"fmt"
   6  	"strconv"
   7  
   8  	"github.com/boombuler/barcode/utils"
   9  )
  10  
  11  func encodeNumeric(content string, ecl ErrorCorrectionLevel) (*utils.BitList, *versionInfo, error) {
  12  	contentBitCount := (len(content) / 3) * 10
  13  	switch len(content) % 3 {
  14  	case 1:
  15  		contentBitCount += 4
  16  	case 2:
  17  		contentBitCount += 7
  18  	}
  19  	vi := findSmallestVersionInfo(ecl, numericMode, contentBitCount)
  20  	if vi == nil {
  21  		return nil, nil, errors.New("To much data to encode")
  22  	}
  23  	res := new(utils.BitList)
  24  	res.AddBits(int(numericMode), 4)
  25  	res.AddBits(len(content), vi.charCountBits(numericMode))
  26  
  27  	for pos := 0; pos < len(content); pos += 3 {
  28  		var curStr string
  29  		if pos+3 <= len(content) {
  30  			curStr = content[pos : pos+3]
  31  		} else {
  32  			curStr = content[pos:]
  33  		}
  34  
  35  		i, err := strconv.Atoi(curStr)
  36  		if err != nil || i < 0 {
  37  			return nil, nil, fmt.Errorf("\"%s\" can not be encoded as %s", content, Numeric)
  38  		}
  39  		var bitCnt byte
  40  		switch len(curStr) % 3 {
  41  		case 0:
  42  			bitCnt = 10
  43  		case 1:
  44  			bitCnt = 4
  45  			break
  46  		case 2:
  47  			bitCnt = 7
  48  			break
  49  		}
  50  
  51  		res.AddBits(i, bitCnt)
  52  	}
  53  
  54  	addPaddingAndTerminator(res, vi)
  55  	return res, vi, nil
  56  }
  57