From 29d3fcfa989cfa55a371faf6c929953e62b3075e Mon Sep 17 00:00:00 2001
From: boombuler <boombuler@googlemail.com>
Date: Wed, 11 Dec 2013 20:26:35 +0100
Subject: [PATCH] added unicode support for qr codes and some minor fixes

---
 qr/alphanumeric.go | 37 +++++++++++++++++++++++++------------
 qr/automatic.go    |  5 ++++-
 qr/encoder.go      |  6 ++++++
 qr/utf8.go         | 26 ++++++++++++++++++++++++++
 4 files changed, 61 insertions(+), 13 deletions(-)
 create mode 100644 qr/utf8.go

diff --git a/qr/alphanumeric.go b/qr/alphanumeric.go
index 749a0fa..7ce5b4d 100644
--- a/qr/alphanumeric.go
+++ b/qr/alphanumeric.go
@@ -4,14 +4,25 @@ import (
 	"errors"
 	"fmt"
 	"github.com/boombuler/barcode"
+	"strings"
 )
 
-var alphaNumericTable map[byte]int = map[byte]int{
-	'0': 0, '1': 1, '2': 2, '3': 3, '4': 4, '5': 5, '6': 6, '7': 7, '8': 8, '9': 9,
-	'A': 10, 'B': 11, 'C': 12, 'D': 13, 'E': 14, 'F': 15, 'G': 16, 'H': 17, 'I': 18, 'J': 19,
-	'K': 20, 'L': 21, 'M': 22, 'N': 23, 'O': 24, 'P': 25, 'Q': 26, 'R': 27, 'S': 28, 'T': 29,
-	'U': 30, 'V': 31, 'W': 32, 'X': 33, 'Y': 34, 'Z': 35, ' ': 36, '$': 37, '%': 38, '*': 39,
-	'+': 40, '-': 41, '.': 42, '/': 43, ':': 44,
+const charSet string = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ $%*+-./:"
+
+func stringToAlphaIdx(content string) <-chan int {
+	result := make(chan int)
+	go func() {
+		for _, r := range content {
+			idx := strings.IndexRune(charSet, r)
+			result <- idx
+			if idx < 0 {
+				break
+			}
+		}
+		close(result)
+	}()
+
+	return result
 }
 
 func encodeAlphaNumeric(content string, ecl ErrorCorrectionLevel) (*barcode.BitList, *versionInfo, error) {
@@ -30,20 +41,22 @@ func encodeAlphaNumeric(content string, ecl ErrorCorrectionLevel) (*barcode.BitL
 	res.AddBits(int(alphaNumericMode), 4)
 	res.AddBits(len(content), vi.charCountBits(alphaNumericMode))
 
+	encoder := stringToAlphaIdx(content)
+
 	for idx := 0; idx < len(content)/2; idx++ {
-		c1, ok1 := alphaNumericTable[content[idx*2]]
-		c2, ok2 := alphaNumericTable[content[(idx*2)+1]]
-		if !ok1 || !ok2 {
+		c1 := <-encoder
+		c2 := <-encoder
+		if c1 < 0 || c2 < 0 {
 			return nil, nil, fmt.Errorf("\"%s\" can not be encoded as %s", content, AlphaNumeric)
 		}
 		res.AddBits(c1*45+c2, 11)
 	}
 	if contentLenIsOdd {
-		c1, ok := alphaNumericTable[content[len(content)-1]]
-		if !ok {
+		c := <-encoder
+		if c < 0 {
 			return nil, nil, fmt.Errorf("\"%s\" can not be encoded as %s", content, AlphaNumeric)
 		}
-		res.AddBits(c1, 6)
+		res.AddBits(c, 6)
 	}
 
 	addPaddingAndTerminator(res, vi)
diff --git a/qr/automatic.go b/qr/automatic.go
index c82bd38..e1be37a 100644
--- a/qr/automatic.go
+++ b/qr/automatic.go
@@ -14,6 +14,9 @@ func encodeAuto(content string, ecl ErrorCorrectionLevel) (*barcode.BitList, *ve
 	if bits != nil && vi != nil {
 		return bits, vi, nil
 	}
-
+	bits, vi, _ = Unicode.getEncoder()(content, ecl)
+	if bits != nil && vi != nil {
+		return bits, vi, nil
+	}
 	return nil, nil, fmt.Errorf("No encoding found to encode \"%s\"", content)
 }
diff --git a/qr/encoder.go b/qr/encoder.go
index 4b7d4ab..da18951 100644
--- a/qr/encoder.go
+++ b/qr/encoder.go
@@ -18,6 +18,8 @@ const (
 	Numeric
 	// Encode only uppercase letters, numbers and  [Space], $, %, *, +, -, ., /, :
 	AlphaNumeric
+	// Encodes string as utf-8
+	Unicode
 )
 
 func (e Encoding) getEncoder() encodeFn {
@@ -28,6 +30,8 @@ func (e Encoding) getEncoder() encodeFn {
 		return encodeNumeric
 	case AlphaNumeric:
 		return encodeAlphaNumeric
+	case Unicode:
+		return encodeUnicode
 	}
 	return nil
 }
@@ -40,6 +44,8 @@ func (e Encoding) String() string {
 		return "Numeric"
 	case AlphaNumeric:
 		return "AlphaNumeric"
+	case Unicode:
+		return "Unicode"
 	}
 	return ""
 }
diff --git a/qr/utf8.go b/qr/utf8.go
new file mode 100644
index 0000000..eb4ad71
--- /dev/null
+++ b/qr/utf8.go
@@ -0,0 +1,26 @@
+package qr
+
+import (
+	"errors"
+	"github.com/boombuler/barcode"
+)
+
+func encodeUnicode(content string, ecl ErrorCorrectionLevel) (*barcode.BitList, *versionInfo, error) {
+	data := []byte(content)
+
+	vi := findSmallestVersionInfo(ecl, byteMode, len(data)*8)
+	if vi == nil {
+		return nil, nil, errors.New("To much data to encode")
+	}
+
+	// It's not correct to add the unicode bytes to the result directly but most readers can't handle the
+	// required ECI header...
+	res := new(barcode.BitList)
+	res.AddBits(int(byteMode), 4)
+	res.AddBits(len(content), vi.charCountBits(byteMode))
+	for _, b := range data {
+		res.AddByte(b)
+	}
+	addPaddingAndTerminator(res, vi)
+	return res, vi, nil
+}