How to Make Ruby Barcode Reader with C++ Barcode SDK on Mac OS X

Dynamsoft Barcode SDK, which written in C/C++, supports both Windows and Mac OS X. Last week, I spent some time taking the Ruby online course on codecademy, thereby I decided to create a Ruby Barcode Reader by wrapping Dynamsoft C/C++ Barcode APIs.

Download and Installation

How to Create and Build Ruby Barcode Reader Project

Create extconf.rb:

require 'mkmf'

extension_name = 'dynamsoftbarcode'



Automatically generate Makefile with:

ruby extconf.rb

Open Makefile and change configurations.

  • Dynamsoft Barcode include directory:
    dbrdir = /Applications/Dynamsoft/Barcode\ Reader\ 3.0\ Trial/Include
    INCFLAGS = -I. -I$(arch_hdrdir) -I$(hdrdir)/ruby/backward -I$(hdrdir) -I$(srcdir) -I$(dbrdir)
  • Dynamsoft Barcode dylib:
    LIBS = $(LIBRUBYARG_SHARED)  -lpthread -ldl -lobjc -lDynamsoftBarcodeReader

Open dynamsoftbarcode.c. Add entry point and methods:

VALUE BarcodeReader = Qnil;

void Init_dynamsoftbarcode();

VALUE method_decodeFile(VALUE self, VALUE path);

void Init_dynamsoftbarcode() {
	BarcodeReader = rb_define_module("BarcodeReader");
	rb_define_method(BarcodeReader, "decodeFile", method_decodeFile, 1);

VALUE method_decodeFile(VALUE self, VALUE path) {
	char *pszPath = StringValueCStr(path);
	VALUE ary = decode(pszPath);
	return ary;

Import the sample code and license that provided by Dynamsoft Barcode SDK:

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/time.h>
#include <If_DBR.h>

#define strcmpi(dst, src) strcasecmp(dst, src)

__int64 GetFormat(const char * pstr)
	__int64 llFormat = 0;
	const char * pszFormat = pstr;

	if (strcasestr(pszFormat, "code_39") != NULL)
		llFormat |= CODE_39;
	if (strcasestr(pszFormat, "code_128") != NULL)
		llFormat |= CODE_128;
	if (strcasestr(pszFormat, "code_93") != NULL)
		llFormat |= CODE_93;
	if (strcasestr(pszFormat, "codabar") != NULL)
		llFormat |= CODABAR;
	if (strcasestr(pszFormat, "itf") != NULL)
		llFormat |= ITF;
	if (strcasestr(pszFormat, "upc_a") != NULL)
		llFormat |= UPC_A;
	if (strcasestr(pszFormat, "upc_e") != NULL)
		llFormat |= UPC_E;
	if (strcasestr(pszFormat, "ean_13") != NULL)
		llFormat |= EAN_13;
	if (strcasestr(pszFormat, "ean_8") != NULL)
		llFormat |= EAN_8;
	if (strcasestr(pszFormat, "industrial_25") != NULL)
		llFormat |= INDUSTRIAL_25;
	if (strcasestr(pszFormat, "oned") != NULL)
		llFormat = OneD;
	if (strcasestr(pszFormat, "qr_code") != NULL)
		llFormat |= QR_CODE;

	return llFormat;

const char * GetFormatStr(__int64 format)
	if (format == CODE_39)
		return "CODE_39";
	if (format == CODE_128)
		return "CODE_128";
	if (format == CODE_93)
		return "CODE_93";
	if (format == CODABAR)
		return "CODABAR";
	if (format == ITF)
		return "ITF";
	if (format == UPC_A)
		return "UPC_A";
	if (format == UPC_E)
		return "UPC_E";
	if (format == EAN_13)
		return "EAN_13";
	if (format == EAN_8)
		return "EAN_8";
	if (format == INDUSTRIAL_25)
		return "INDUSTRIAL_25";
	if (format == QR_CODE)
		return "QR_CODE";

	return "UNKNOWN";

int decode(const char *pszImageFile)
	__int64 llFormat = (OneD |QR_CODE);
	int iMaxCount = 0x7FFFFFFF;
	int iIndex = 0;
	ReaderOptions ro = {0};
	pBarcodeResultArray paryResult = NULL;
	int iRet = -1;
	char * pszTemp = NULL;
	char * pszTemp1 = NULL;
	struct timeval begin, end;

	if (NULL == pszImageFile)
		printf("The syntax of the command is incorrect.\n");
		return 1;

	// Set license

	// Read barcode
	gettimeofday(&begin, NULL);
	ro.llBarcodeFormat = llFormat;
	ro.iMaxBarcodesNumPerPage = iMaxCount;
	iRet = DBR_DecodeFile(pszImageFile, &ro, &paryResult);
	gettimeofday(&end, NULL);

	// Output barcode result
	pszTemp = (char*)malloc(4096);
	if (iRet != DBR_OK)
		sprintf(pszTemp, "Failed to read barcode: %s\r\n", DBR_GetErrorString(iRet));
		printf("%s", pszTemp);
		return 1;

	if (paryResult->iBarcodeCount == 0)
		sprintf(pszTemp, "No barcode found. Total time spent: %.3f seconds.\r\n",
					((float)((end.tv_sec * 1000 * 1000 +  end.tv_usec) - (begin.tv_sec * 1000 * 1000 + begin.tv_usec))/(1000 * 1000)));
		printf("%s", pszTemp);
		return 0;

	sprintf(pszTemp, "Total barcode(s) found: %d. Total time spent: %.3f seconds\r\n\r\n", paryResult->iBarcodeCount,
					((float)((end.tv_sec * 1000 * 1000 +  end.tv_usec) - (begin.tv_sec * 1000 * 1000 + begin.tv_usec))/(1000 * 1000)));
	printf("%s", pszTemp);
	for (iIndex = 0; iIndex < paryResult->iBarcodeCount; iIndex++)
		sprintf(pszTemp, "Barcode %d:\r\n", iIndex + 1);
		// printf("%s", pszTemp);
		sprintf(pszTemp, "%s    Page: %d\r\n", pszTemp, paryResult->ppBarcodes[iIndex]->iPageNum);
		// printf("%s", pszTemp);
		sprintf(pszTemp, "%s    Type: %s\r\n", pszTemp, GetFormatStr(paryResult->ppBarcodes[iIndex]->llFormat));
		// printf("%s", pszTemp);
		pszTemp1 = (char*)malloc(paryResult->ppBarcodes[iIndex]->iBarcodeDataLength + 1);
		memset(pszTemp1, 0, paryResult->ppBarcodes[iIndex]->iBarcodeDataLength + 1);
		memcpy(pszTemp1, paryResult->ppBarcodes[iIndex]->pBarcodeData, paryResult->ppBarcodes[iIndex]->iBarcodeDataLength);
		sprintf(pszTemp, "%s    Value: %s\r\n", pszTemp, pszTemp1);
		// printf("%s", pszTemp);


	return iRet;

Convert returned C String to VALUE (VALUE is the C data type for all Ruby objects).

VALUE ary = rb_ary_new();
rb_ary_push(ary, rb_str_new_cstr(pszTemp));

Create a Ruby script barcode_reader.rb to invoke native API:

require 'dynamsoftbarcode'
include BarcodeReader

if ARGV.length == 0
  puts "Please add a barcode file path!"
  $filePath = ARGV[0]
  $results = decodeFile($filePath)
  $results.each do |i|
     puts "#{i}"

  puts "Game Over!"

Run make. If you get the warnings:

ld: warning: directory not found for option '-L/usr/local/lib'
ld: warning: directory not found for option '-L/usr/local/lib'

Open Makefile and change

ldflags = -L. -L/usr/local/lib


ldflags = -L. -L/usr/lib.

If there’s no warning, you will see:

linking shared-object dynamsoftbarcode.bundle

Run sudo make install (The command will copy dynamsoftbarcode.bundle to/Library/Ruby/Site/2.0.0/universal-darwin14).

Run Ruby script:

ruby barcode_reader.rb barcode_file

Here is the screenshot:
Ruby Barcode Reader


Source Code