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README.md

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+GoZBar
+---
+ZBar bindings for golang. Only scanner supported.
+
+Read the ZBar documentations for explanations on constants and arguments.
+
+The ZBar library must be installed for this to compile.

const.go

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+// Package gozbar config bindings for golang.
+// Read the ZBar documents for details
+package gozbar
+
+// #cgo LDFLAGS: -lzbar
+// #include <zbar.h>
+import "C"
+
+// Symbol types (Scanner.SetConfig() argument symbology)
+const (
+	NONE    = C.ZBAR_NONE
+	PARTIAL = C.ZBAR_PARTIAL
+	EAN8    = C.ZBAR_EAN8
+	UPCE    = C.ZBAR_UPCE
+	ISBN10  = C.ZBAR_ISBN10
+	UPCA    = C.ZBAR_UPCA
+	EAN13   = C.ZBAR_EAN13
+	ISBN13  = C.ZBAR_ISBN13
+	I25     = C.ZBAR_I25
+	CODE39  = C.ZBAR_CODE39
+	PDF417  = C.ZBAR_PDF417
+	QRCODE  = C.ZBAR_QRCODE
+	CODE128 = C.ZBAR_CODE128
+	SYMBOL  = C.ZBAR_SYMBOL
+	ADDON   = C.ZBAR_ADDON
+	ADDON2  = C.ZBAR_ADDON2
+	ADDON5  = C.ZBAR_ADDON5
+)
+
+// Configuration keys
+const (
+	CFG_ENABLE     = C.ZBAR_CFG_ENABLE
+	CFG_ADD_CHECK  = C.ZBAR_CFG_ADD_CHECK
+	CFG_EMIT_CHECK = C.ZBAR_CFG_EMIT_CHECK
+	CFG_ASCII      = C.ZBAR_CFG_ASCII
+	CFG_NUM        = C.ZBAR_CFG_NUM
+	CFG_MIN_LEN    = C.ZBAR_CFG_MIN_LEN
+	CFG_MAX_LEN    = C.ZBAR_CFG_MAX_LEN
+	CFG_POSITION   = C.ZBAR_CFG_POSITION
+	CFG_X_DENSITY  = C.ZBAR_CFG_X_DENSITY
+	CFG_Y_DENSITY  = C.ZBAR_CFG_Y_DENSITY
+)

image.go

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+// Package gozbar image bindings for golang.
+// Read the ZBar documents for details
+package gozbar
+
+// #cgo LDFLAGS: -lzbar
+// #include <zbar.h>
+import "C"
+
+import (
+	"image"
+	"runtime"
+	"unsafe"
+)
+
+// Image contains a zbar image and the grayscale values.
+type Image struct {
+	image *C.zbar_image_t
+	gray  *image.Gray
+}
+
+// FromImage will create an ZBar image object from an image.Image.
+// To scan the image, call a Scanner.
+func FromImage(img image.Image) *Image {
+	// allocate the image wrapper
+	ret := &Image{
+		image: C.zbar_image_create(),
+	}
+
+	// get the height and width of the given image
+	bounds := img.Bounds()
+	w := bounds.Max.X - bounds.Min.X
+	h := bounds.Max.Y - bounds.Min.Y
+
+	// Create a grayscale image
+	ret.gray = image.NewGray(bounds)
+
+	// populate all the pixels in the gray image faster than draw.Draw()
+	for y := bounds.Min.Y; y < bounds.Max.Y; y++ {
+		for x := bounds.Min.X; x < bounds.Max.X; x++ {
+			ret.gray.Set(x, y, img.At(x, y))
+		}
+	}
+
+	C.zbar_image_set_format(ret.image, C.ulong(0x30303859)) // Y800 (grayscale)
+	C.zbar_image_set_size(ret.image, C.uint(w), C.uint(h))
+	C.zbar_image_set_data(ret.image, unsafe.Pointer(&ret.gray.Pix[0]), C.ulong(len(ret.gray.Pix)), nil)
+
+	// finalizer
+	runtime.SetFinalizer(ret, (*Image).Destroy)
+
+	return ret
+}
+
+// First will return the first scanned symbol of this image.
+// To iterate over the symbols, use Symbol.Each() function
+func (i *Image) First() *Symbol {
+	s := C.zbar_image_first_symbol(i.image)
+
+	if s == nil {
+		return nil
+	}
+
+	return &Symbol{
+		symbol: s,
+	}
+}
+
+// Destroy this object
+func (i *Image) Destroy() {
+	C.zbar_image_destroy(i.image)
+}

scanner.go

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+// Package gozbar scanner bindings for golang.
+// Read the ZBar documents for details
+package gozbar
+
+// #cgo LDFLAGS: -lzbar
+// #include <zbar.h>
+import "C"
+
+import (
+	"errors"
+	"fmt"
+)
+
+// Scanner contains a reference to zbar scanner.
+type Scanner struct {
+	scanner *C.zbar_image_scanner_t
+}
+
+// NewScanner returns a new instance of Scanner.
+func NewScanner() *Scanner {
+	return &Scanner{
+		scanner: C.zbar_image_scanner_create(),
+	}
+}
+
+// SetConfig gives the zbar scanner the configuration to run..
+// Read the ZBar docs for details.
+func (s *Scanner) SetConfig(symbology C.zbar_symbol_type_t, config C.zbar_config_t, value int) error {
+	// returns 0 for success, non-0 for failure
+	resp := int(C.zbar_image_scanner_set_config(s.scanner, symbology, config, C.int(value)))
+	if resp != 0 {
+		return fmt.Errorf("error encountered when setting config status: %d", resp)
+	}
+
+	return nil
+}
+
+// Scan parses the given image and loads the scanner.
+func (s *Scanner) Scan(img *Image) error {
+	status := int(C.zbar_scan_image(s.scanner, img.image))
+	switch status {
+	// no symbols were found
+	case 0:
+		return errors.New("no symbols found")
+	// an error occurred
+	case -1:
+		return errors.New("an error was encountered during scan")
+	default:
+		return nil
+	}
+}
+
+// Destroy destroys the scanner.
+func (s *Scanner) Destroy() {
+	C.zbar_image_scanner_destroy(s.scanner)
+}

scanner_test.go

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+package gozbar
+
+import (
+	"image/jpeg"
+	"image/png"
+	"os"
+	"testing"
+)
+
+func TestBarcode(t *testing.T) {
+	const expectedVal = "9876543210128"
+
+	f, err := os.Open("testdata/barcode.png")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	i, err := png.Decode(f)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	img := FromImage(i)
+
+	s := NewScanner()
+	err = s.SetConfig(0, CFG_ENABLE, 1)
+	if err != nil {
+		t.Fatal("error setting config", err)
+	}
+
+	err = s.Scan(img)
+	if err != nil {
+		t.Fatal("error scanning", err)
+	}
+	defer s.Destroy()
+
+	img.First().Each(func(str string) {
+		if str != expectedVal {
+			t.Fatalf("expected [%s] got [%s]", expectedVal, str)
+		}
+	})
+}
+
+func TestQRCode(t *testing.T) {
+	const expectedVal = "ZBar big law good! ZBar螟ｧ豕募･ｽ!"
+
+	f, err := os.Open("testdata/qr.jpg")
+	if err != nil {
+		t.Fail()
+		return
+	}
+
+	i, _ := jpeg.Decode(f)
+	img := FromImage(i)
+
+	s := NewScanner()
+	err = s.SetConfig(0, CFG_ENABLE, 1)
+	if err != nil {
+		t.Fatal("error setting config", err)
+	}
+
+	err = s.Scan(img)
+	if err != nil {
+		t.Fatal("error scanning", err)
+	}
+	defer s.Destroy()
+
+	img.First().Each(func(str string) {
+		if str != expectedVal {
+			t.Fatalf("expected [%s] got [%s]", expectedVal, str)
+		}
+	})
+}
+
+func TestPhoto(t *testing.T) {
+	const expectedStr = "http://www.searchenginestrategies.com/sanfrancisco/share.html"
+
+	f, err := os.Open("./testdata/photo.jpg")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	i, err := jpeg.Decode(f)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	img := FromImage(i)
+
+	s := NewScanner()
+	err = s.SetConfig(0, CFG_ENABLE, 1)
+	if err != nil {
+		t.Fatal("error setting config", err)
+	}
+
+	err = s.Scan(img)
+	if err != nil {
+		t.Fatal("error scanning", err)
+	}
+
+	defer s.Destroy()
+
+	img.First().Each(func(str string) {
+		if str != expectedStr {
+			t.Fatalf("expected [%s] got [%s]", expectedStr, str)
+		}
+	})
+}

symbol.go

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+// Package gozbar symbol bindings.
+// Read the ZBar documents for details
+package gozbar
+
+// #cgo LDFLAGS: -lzbar
+// #include <zbar.h>
+import "C"
+
+// Symbol is a wrapper around a zbar symbol.
+type Symbol struct {
+	symbol *C.zbar_symbol_t
+}
+
+// Next returns the next symbol or nil if there is none.
+func (s *Symbol) Next() *Symbol {
+	n := C.zbar_symbol_next(s.symbol)
+
+	if n == nil {
+		return nil
+	}
+
+	return &Symbol{
+		symbol: n,
+	}
+}
+
+// Data returns the scanned data for this symbol.
+func (s *Symbol) Data() string {
+	sym := C.zbar_symbol_get_data(s.symbol)
+
+	if sym == nil {
+		return ""
+	}
+
+	return C.GoString(sym)
+}
+
+// Type returns the symbol type.
+// Compare it with types in constants to get the accurate symbol type.
+func (s *Symbol) Type() C.zbar_symbol_type_t {
+	return C.zbar_symbol_get_type(s.symbol)
+}
+
+// Each will iterate over all symbols after this symbol.
+// passing them into the provided callback
+func (s *Symbol) Each(f func(string)) {
+	t := s
+
+	for {
+		f(t.Data())
+
+		t = t.Next()
+
+		if t == nil {
+			break
+		}
+	}
+}