encoder.go

Documentation: github.com/boombuler/barcode/code93

     1  // Package code93 can create Code93 barcodes
     2  package code93
     3  
     4  import (
     5  	"errors"
     6  	"strings"
     7  
     8  	"github.com/boombuler/barcode"
     9  	"github.com/boombuler/barcode/utils"
    10  )
    11  
    12  type encodeInfo struct {
    13  	value int
    14  	data  int
    15  }
    16  
    17  const (
    18  	// Special Function 1 ($)
    19  	FNC1 = '\u00f1'
    20  	// Special Function 2 (%)
    21  	FNC2 = '\u00f2'
    22  	// Special Function 3 (/)
    23  	FNC3 = '\u00f3'
    24  	// Special Function 4 (+)
    25  	FNC4 = '\u00f4'
    26  )
    27  
    28  var encodeTable = map[rune]encodeInfo{
    29  	'0': encodeInfo{0, 0x114}, '1': encodeInfo{1, 0x148}, '2': encodeInfo{2, 0x144},
    30  	'3': encodeInfo{3, 0x142}, '4': encodeInfo{4, 0x128}, '5': encodeInfo{5, 0x124},
    31  	'6': encodeInfo{6, 0x122}, '7': encodeInfo{7, 0x150}, '8': encodeInfo{8, 0x112},
    32  	'9': encodeInfo{9, 0x10A}, 'A': encodeInfo{10, 0x1A8}, 'B': encodeInfo{11, 0x1A4},
    33  	'C': encodeInfo{12, 0x1A2}, 'D': encodeInfo{13, 0x194}, 'E': encodeInfo{14, 0x192},
    34  	'F': encodeInfo{15, 0x18A}, 'G': encodeInfo{16, 0x168}, 'H': encodeInfo{17, 0x164},
    35  	'I': encodeInfo{18, 0x162}, 'J': encodeInfo{19, 0x134}, 'K': encodeInfo{20, 0x11A},
    36  	'L': encodeInfo{21, 0x158}, 'M': encodeInfo{22, 0x14C}, 'N': encodeInfo{23, 0x146},
    37  	'O': encodeInfo{24, 0x12C}, 'P': encodeInfo{25, 0x116}, 'Q': encodeInfo{26, 0x1B4},
    38  	'R': encodeInfo{27, 0x1B2}, 'S': encodeInfo{28, 0x1AC}, 'T': encodeInfo{29, 0x1A6},
    39  	'U': encodeInfo{30, 0x196}, 'V': encodeInfo{31, 0x19A}, 'W': encodeInfo{32, 0x16C},
    40  	'X': encodeInfo{33, 0x166}, 'Y': encodeInfo{34, 0x136}, 'Z': encodeInfo{35, 0x13A},
    41  	'-': encodeInfo{36, 0x12E}, '.': encodeInfo{37, 0x1D4}, ' ': encodeInfo{38, 0x1D2},
    42  	'$': encodeInfo{39, 0x1CA}, '/': encodeInfo{40, 0x16E}, '+': encodeInfo{41, 0x176},
    43  	'%': encodeInfo{42, 0x1AE}, FNC1: encodeInfo{43, 0x126}, FNC2: encodeInfo{44, 0x1DA},
    44  	FNC3: encodeInfo{45, 0x1D6}, FNC4: encodeInfo{46, 0x132}, '*': encodeInfo{47, 0x15E},
    45  }
    46  
    47  var extendedTable = []string{
    48  	"\u00f2U", "\u00f1A", "\u00f1B", "\u00f1C", "\u00f1D", "\u00f1E", "\u00f1F", "\u00f1G",
    49  	"\u00f1H", "\u00f1I", "\u00f1J", "\u00f1K", "\u00f1L", "\u00f1M", "\u00f1N", "\u00f1O",
    50  	"\u00f1P", "\u00f1Q", "\u00f1R", "\u00f1S", "\u00f1T", "\u00f1U", "\u00f1V", "\u00f1W",
    51  	"\u00f1X", "\u00f1Y", "\u00f1Z", "\u00f2A", "\u00f2B", "\u00f2C", "\u00f2D", "\u00f2E",
    52  	" ", "\u00f3A", "\u00f3B", "\u00f3C", "\u00f3D", "\u00f3E", "\u00f3F", "\u00f3G",
    53  	"\u00f3H", "\u00f3I", "\u00f3J", "\u00f3K", "\u00f3L", "-", ".", "\u00f3O",
    54  	"0", "1", "2", "3", "4", "5", "6", "7",
    55  	"8", "9", "\u00f3Z", "\u00f2F", "\u00f2G", "\u00f2H", "\u00f2I", "\u00f2J",
    56  	"\u00f2V", "A", "B", "C", "D", "E", "F", "G",
    57  	"H", "I", "J", "K", "L", "M", "N", "O",
    58  	"P", "Q", "R", "S", "T", "U", "V", "W",
    59  	"X", "Y", "Z", "\u00f2K", "\u00f2L", "\u00f2M", "\u00f2N", "\u00f2O",
    60  	"\u00f2W", "\u00f4A", "\u00f4B", "\u00f4C", "\u00f4D", "\u00f4E", "\u00f4F", "\u00f4G",
    61  	"\u00f4H", "\u00f4I", "\u00f4J", "\u00f4K", "\u00f4L", "\u00f4M", "\u00f4N", "\u00f4O",
    62  	"\u00f4P", "\u00f4Q", "\u00f4R", "\u00f4S", "\u00f4T", "\u00f4U", "\u00f4V", "\u00f4W",
    63  	"\u00f4X", "\u00f4Y", "\u00f4Z", "\u00f2P", "\u00f2Q", "\u00f2R", "\u00f2S", "\u00f2T",
    64  }
    65  
    66  func prepare(content string) (string, error) {
    67  	result := ""
    68  	for _, r := range content {
    69  		if r > 127 {
    70  			return "", errors.New("Only ASCII strings can be encoded")
    71  		}
    72  		result += extendedTable[int(r)]
    73  	}
    74  	return result, nil
    75  }
    76  
    77  // Encode returns a code93 barcode for the given content
    78  // if includeChecksum is set to true, two checksum characters are calculated and added to the content
    79  func Encode(content string, includeChecksum bool, fullASCIIMode bool) (barcode.Barcode, error) {
    80  	if fullASCIIMode {
    81  		var err error
    82  		content, err = prepare(content)
    83  		if err != nil {
    84  			return nil, err
    85  		}
    86  	} else if strings.ContainsRune(content, '*') {
    87  		return nil, errors.New("invalid data! content may not contain '*'")
    88  	}
    89  
    90  	data := content + string(getChecksum(content, 20))
    91  	data += string(getChecksum(data, 15))
    92  
    93  	data = "*" + data + "*"
    94  	result := new(utils.BitList)
    95  
    96  	for _, r := range data {
    97  		info, ok := encodeTable[r]
    98  		if !ok {
    99  			return nil, errors.New("invalid data!")
   100  		}
   101  		result.AddBits(info.data, 9)
   102  	}
   103  	result.AddBit(true)
   104  
   105  	return utils.New1DCode(barcode.TypeCode93, content, result), nil
   106  }
   107  
   108  func getChecksum(content string, maxWeight int) rune {
   109  	weight := 1
   110  	total := 0
   111  
   112  	data := []rune(content)
   113  	for i := len(data) - 1; i >= 0; i-- {
   114  		r := data[i]
   115  		info, ok := encodeTable[r]
   116  		if !ok {
   117  			return ' '
   118  		}
   119  		total += info.value * weight
   120  		if weight++; weight > maxWeight {
   121  			weight = 1
   122  		}
   123  	}
   124  	total = total % 47
   125  	for r, info := range encodeTable {
   126  		if info.value == total {
   127  			return r
   128  		}
   129  	}
   130  	return ' '
   131  }
   132
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