1// Package code128 can create Code128 barcodes
2package code128
3
4import (
5	"fmt"
6	"strings"
7	"unicode/utf8"
8
9	"github.com/boombuler/barcode"
10	"github.com/boombuler/barcode/utils"
11)
12
13func strToRunes(str string) []rune {
14	result := make([]rune, utf8.RuneCountInString(str))
15	i := 0
16	for _, r := range str {
17		result[i] = r
18		i++
19	}
20	return result
21}
22
23func shouldUseCTable(nextRunes []rune, curEncoding byte) bool {
24	requiredDigits := 4
25	if curEncoding == startCSymbol {
26		requiredDigits = 2
27	}
28	if len(nextRunes) < requiredDigits {
29		return false
30	}
31	for i := 0; i < requiredDigits; i++ {
32		if i%2 == 0 && nextRunes[i] == FNC1 {
33			requiredDigits++
34			if len(nextRunes) < requiredDigits {
35				return false
36			}
37			continue
38		}
39		if nextRunes[i] < '0' || nextRunes[i] > '9' {
40			return false
41		}
42	}
43	return true
44}
45
46func tableContainsRune(table string, r rune) bool {
47	return strings.ContainsRune(table, r) || r == FNC1 || r == FNC2 || r == FNC3 || r == FNC4
48}
49
50func shouldUseATable(nextRunes []rune, curEncoding byte) bool {
51	nextRune := nextRunes[0]
52	if !tableContainsRune(bTable, nextRune) || curEncoding == startASymbol {
53		return tableContainsRune(aTable, nextRune)
54	}
55	if curEncoding == 0 {
56		for _, r := range nextRunes {
57			if tableContainsRune(abTable, r) {
58				continue
59			}
60			if strings.ContainsRune(aOnlyTable, r) {
61				return true
62			}
63			break
64		}
65	}
66	return false
67}
68
69func getCodeIndexList(content []rune) *utils.BitList {
70	result := new(utils.BitList)
71	curEncoding := byte(0)
72	for i := 0; i < len(content); i++ {
73		if shouldUseCTable(content[i:], curEncoding) {
74			if curEncoding != startCSymbol {
75				if curEncoding == byte(0) {
76					result.AddByte(startCSymbol)
77				} else {
78					result.AddByte(codeCSymbol)
79				}
80				curEncoding = startCSymbol
81			}
82			if content[i] == FNC1 {
83				result.AddByte(102)
84			} else {
85				idx := (content[i] - '0') * 10
86				i++
87				idx = idx + (content[i] - '0')
88				result.AddByte(byte(idx))
89			}
90		} else if shouldUseATable(content[i:], curEncoding) {
91			if curEncoding != startASymbol {
92				if curEncoding == byte(0) {
93					result.AddByte(startASymbol)
94				} else {
95					result.AddByte(codeASymbol)
96				}
97				curEncoding = startASymbol
98			}
99			var idx int
100			switch content[i] {
101			case FNC1:
102				idx = 102
103				break
104			case FNC2:
105				idx = 97
106				break
107			case FNC3:
108				idx = 96
109				break
110			case FNC4:
111				idx = 101
112				break
113			default:
114				idx = strings.IndexRune(aTable, content[i])
115				break
116			}
117			if idx < 0 {
118				return nil
119			}
120			result.AddByte(byte(idx))
121		} else {
122			if curEncoding != startBSymbol {
123				if curEncoding == byte(0) {
124					result.AddByte(startBSymbol)
125				} else {
126					result.AddByte(codeBSymbol)
127				}
128				curEncoding = startBSymbol
129			}
130			var idx int
131			switch content[i] {
132			case FNC1:
133				idx = 102
134				break
135			case FNC2:
136				idx = 97
137				break
138			case FNC3:
139				idx = 96
140				break
141			case FNC4:
142				idx = 100
143				break
144			default:
145				idx = strings.IndexRune(bTable, content[i])
146				break
147			}
148
149			if idx < 0 {
150				return nil
151			}
152			result.AddByte(byte(idx))
153		}
154	}
155	return result
156}
157
158// Encode creates a Code 128 barcode for the given content
159func Encode(content string) (barcode.BarcodeIntCS, error) {
160	contentRunes := strToRunes(content)
161	if len(contentRunes) <= 0 || len(contentRunes) > 80 {
162		return nil, fmt.Errorf("content length should be between 1 and 80 runes but got %d", len(contentRunes))
163	}
164	idxList := getCodeIndexList(contentRunes)
165
166	if idxList == nil {
167		return nil, fmt.Errorf("\"%s\" could not be encoded", content)
168	}
169
170	result := new(utils.BitList)
171	sum := 0
172	for i, idx := range idxList.GetBytes() {
173		if i == 0 {
174			sum = int(idx)
175		} else {
176			sum += i * int(idx)
177		}
178		result.AddBit(encodingTable[idx]...)
179	}
180	sum = sum % 103
181	result.AddBit(encodingTable[sum]...)
182	result.AddBit(encodingTable[stopSymbol]...)
183	return utils.New1DCodeIntCheckSum(barcode.TypeCode128, content, result, sum), nil
184}
185
186func EncodeWithoutChecksum(content string) (barcode.Barcode, error) {
187	contentRunes := strToRunes(content)
188	if len(contentRunes) <= 0 || len(contentRunes) > 80 {
189		return nil, fmt.Errorf("content length should be between 1 and 80 runes but got %d", len(contentRunes))
190	}
191	idxList := getCodeIndexList(contentRunes)
192
193	if idxList == nil {
194		return nil, fmt.Errorf("\"%s\" could not be encoded", content)
195	}
196
197	result := new(utils.BitList)
198	for _, idx := range idxList.GetBytes() {
199		result.AddBit(encodingTable[idx]...)
200	}
201	result.AddBit(encodingTable[stopSymbol]...)
202	return utils.New1DCode(barcode.TypeCode128, content, result), nil
203}
204