Expose "multi" as an API option.

ZXing has multiple detectors available.
The two main ones, judging from their own CLI,
are GenericMultipleBarcodeReader and MultiFormatReader.

On my system, GenericMultipleBarcodeReader
is crashing (#5),
so I would like the option to use the other one.

tests/test_read_codes.py

@@ -36,7 +36,18 @@ def test_two_qr_code(self):
             'first zxinglight test qr code', 'second zxinglight test qr code'
         ])
 
+    def test_finding_one_of_two_qr_code(self):
+        self.assertEqual(
+            read_codes(get_image('two_qr_codes'), multi=False), ['first zxinglight test qr code'],
+        )
+
     def test_small_rotated_qr_code(self):
-        self.assertEqual(read_codes(get_image('small_rotated_qr_code'), try_harder=True), [
-            '217EXP0112'
-        ])
+        self.assertEqual(
+            read_codes(get_image('small_rotated_qr_code'), try_harder=True), ['217EXP0112'],
+        )
+
+    def test_small_rotated_qr_code_single(self):
+        self.assertEqual(
+            read_codes(get_image('small_rotated_qr_code'), try_harder=True, multi=False),
+            ['217EXP0112'],
+        )

zxinglight/__init__.py

@@ -67,7 +67,7 @@ class BarcodeType(IntEnum):
     UPC_EAN_EXTENSION = 17
 
 
-def read_codes(image, barcode_type=BarcodeType.NONE, try_harder=False, hybrid=False):
+def read_codes(image, barcode_type=BarcodeType.NONE, try_harder=False, hybrid=False, multi=True):
     """
     Reads codes from a PIL Image.
 
@@ -77,6 +77,7 @@ def read_codes(image, barcode_type=BarcodeType.NONE, try_harder=False, hybrid=Fa
         try_harder (bool): Spend more time trying to find a barcode.
         hybrid (bool): Use Hybrid Binarizer instead of Global Binarizer. For more information,
             see `ZXing's documentation`_.
+        multi (bool): Search for multiple barcodes in a single image.
 
     Returns:
         A list of barcode values.
@@ -96,4 +97,4 @@ def read_codes(image, barcode_type=BarcodeType.NONE, try_harder=False, hybrid=Fa
     raw_image = grayscale_image.tobytes()
     width, height = grayscale_image.size
 
-    return zxing_read_codes(raw_image, width, height, barcode_type, try_harder, hybrid)
+    return zxing_read_codes(raw_image, width, height, barcode_type, try_harder, hybrid, multi)

zxinglight/_zxinglight.cpp

@@ -35,8 +35,10 @@ static void log_error(const string &msg) {
     PyObject_CallMethod(logger, "error", "O", PyUnicode_FromString(msg.c_str()));
 }
 
-static vector<string> *_zxing_read_codes(char *image, int image_size, int width, int height,
-                                         int barcode_type, bool try_harder, bool hybrid) {
+static vector<string> *_zxing_read_codes(
+    char *image, int image_size, int width, int height,int barcode_type, bool try_harder,
+    bool hybrid, bool multi
+    ) {
     try {
         ArrayRef<char> data = ArrayRef<char>(image, image_size);
 
@@ -65,9 +67,16 @@ static vector<string> *_zxing_read_codes(char *image, int image_size, int width,
 
         Ref<BinaryBitmap> bitmap(new BinaryBitmap(binarizer));
 
-        MultiFormatReader delegate;
-        GenericMultipleBarcodeReader reader(delegate);
-        vector<Ref<Result> > results = reader.decodeMultiple(bitmap, hints);
+        vector<Ref<Result> > results;
+        if (multi) {
+            MultiFormatReader delegate;
+            GenericMultipleBarcodeReader reader(delegate);
+            results = reader.decodeMultiple(bitmap, hints);
+        } else {
+            // Ref<T> is an autodestructor; the `new` *does not leak*.
+            Ref<Reader> reader(new MultiFormatReader);
+            results = vector<Ref<Result> >(1, reader->decode(bitmap, hints));
+        }
 
         vector<string> *codes = new vector<string>();
 
@@ -92,10 +101,10 @@ static vector<string> *_zxing_read_codes(char *image, int image_size, int width,
 static PyObject* zxing_read_codes(PyObject *self, PyObject *args) {
     PyObject *python_image;
     int width, height, barcode_type;
-    int try_harder, hybrid;
+    int try_harder, hybrid, multi;
 
-    if (!PyArg_ParseTuple(args, "Siiipp", &python_image, &width, &height, &barcode_type,
-                          &try_harder, &hybrid)) {
+    if (!PyArg_ParseTuple(args, "Siiippp", &python_image, &width, &height, &barcode_type,
+                          &try_harder, &hybrid, &multi)) {
         return NULL;
     }
 
@@ -105,7 +114,7 @@ static PyObject* zxing_read_codes(PyObject *self, PyObject *args) {
     PyBytes_AsStringAndSize(python_image, &image, &image_size);
 
     vector<string> *results = _zxing_read_codes(
-        image, image_size, width, height, barcode_type, try_harder, hybrid
+        image, image_size, width, height, barcode_type, try_harder, hybrid, multi
         );
 
     PyObject *codes = PyList_New(0);