added functions to read multiple images from file or URL

added test files and tests for reading multiple images from file

nn_wtf/input_data.py

@@ -33,6 +33,16 @@ def maybe_download(filename, base_url, work_directory):
     return file_path
 
 
+def read_images_from_file(filename, rows, cols, num_images, depth=1):
+    with open(filename, 'rb') as bytestream:
+        return images_from_bytestream(bytestream, rows, cols, num_images, depth)
+
+
+def read_images_from_url(url, rows, cols, num_images, depth=1):
+    with urllib.request.urlopen(url) as bytestream:
+        return images_from_bytestream(bytestream, rows, cols, num_images, depth)
+
+
 def images_from_bytestream(bytestream, rows, cols, num_images, depth=1):
     buf = bytestream.read(rows * cols * depth * num_images)
     data = numpy.frombuffer(buf, dtype=numpy.uint8)
@@ -41,14 +51,14 @@ def images_from_bytestream(bytestream, rows, cols, num_images, depth=1):
 
 def read_one_image_from_file(filename, rows, cols, depth=1):
     with open(filename, 'rb') as bytestream:
-        return read_one_image_from_bytestream(bytestream, rows, cols)
+        return one_image_from_bytestream(bytestream, rows, cols, depth)
 
 
 def read_one_image_from_url(url, rows, cols, depth=1):
     with urllib.request.urlopen(url) as bytestream:
-        return read_one_image_from_bytestream(bytestream, rows, cols)
+        return one_image_from_bytestream(bytestream, rows, cols, depth)
 
 
-def read_one_image_from_bytestream(bytestream, rows, cols, depth=1):
+def one_image_from_bytestream(bytestream, rows, cols, depth=1):
     return images_from_bytestream(bytestream, rows, cols, depth)
 

nn_wtf/mnist_data_sets.py

@@ -1,7 +1,7 @@
 from nn_wtf.data_sets import DataSets
 from nn_wtf.images_labels_data_set import ImagesLabelsDataSet
 from nn_wtf.input_data import maybe_download, images_from_bytestream, \
-    read_one_image_from_file, read_one_image_from_url
+    read_one_image_from_file, read_one_image_from_url, read_images_from_file, read_images_from_url
 
 import numpy
 
@@ -54,6 +54,14 @@ def read_one_image_from_file(cls, filename):
     def read_one_image_from_url(cls, url):
         return read_one_image_from_url(url, MNISTGraph.IMAGE_SIZE, MNISTGraph.IMAGE_SIZE)
 
+    @classmethod
+    def read_images_from_file(cls, filename, num_images):
+        return read_images_from_file(filename, MNISTGraph.IMAGE_SIZE, MNISTGraph.IMAGE_SIZE, num_images)
+
+    @classmethod
+    def read_images_from_url(cls, url, num_images):
+        return read_images_from_url(url, MNISTGraph.IMAGE_SIZE, MNISTGraph.IMAGE_SIZE, num_images)
+
     def get_extracted_data(self, file_name, extract_function):
         local_file = maybe_download(file_name, self.SOURCE_URL, self.train_dir)
         return extract_function(local_file, one_hot=self.one_hot)

nn_wtf/tests/input_data_test.py

@@ -1,5 +1,5 @@
 from nn_wtf.images_labels_data_set import ImagesLabelsDataSet
-from nn_wtf.input_data import read_one_image_from_file
+from nn_wtf.input_data import read_images_from_file
 from nn_wtf.mnist_data_sets import MNISTDataSets
 
 from nn_wtf.mnist_graph import MNISTGraph
@@ -21,13 +21,52 @@ def setUp(self):
 
     def test_read_one_image_from_file(self):
         self.assertIsInstance(self.data, numpy.ndarray)
-        self.assertEqual(4, len(self.data.shape))
-        self.assertEqual(1, self.data.shape[0])
-        self.assertEqual(MNISTGraph.IMAGE_SIZE, self.data.shape[1])
-        self.assertEqual(MNISTGraph.IMAGE_SIZE, self.data.shape[2])
-        self.assertEqual(1, self.data.shape[3])
+        self._check_is_one_mnist_image(self.data)
 
     def test_image_labels_data_set_from_image(self):
         labels = numpy.fromiter([0], dtype=numpy.uint8)
         data_set = ImagesLabelsDataSet(self.data, labels)
 
+    def test_read_images_from_file_one(self):
+        data = read_images_from_file(
+            get_project_root_folder()+'/nn_wtf/data/0.raw',
+            MNISTGraph.IMAGE_SIZE, MNISTGraph.IMAGE_SIZE, 1
+        )
+        self._check_is_one_mnist_image(data)
+
+    def test_read_images_from_file_two(self):
+        data = read_images_from_file(
+            get_project_root_folder()+'/nn_wtf/data/7_2.raw',
+            MNISTGraph.IMAGE_SIZE, MNISTGraph.IMAGE_SIZE, 2
+        )
+        self._check_is_n_mnist_images(2, data)
+
+    def test_read_images_from_file_fails_if_file_too_short(self):
+        with self.assertRaises(ValueError):
+            data = read_images_from_file(
+                get_project_root_folder()+'/nn_wtf/data/7_2.raw',
+                MNISTGraph.IMAGE_SIZE, MNISTGraph.IMAGE_SIZE, 3
+            )
+
+    def test_read_images_from_file_two_using_mnist_data_sets(self):
+        data = MNISTDataSets.read_images_from_file(
+            get_project_root_folder()+'/nn_wtf/data/7_2.raw', 2
+        )
+        self._check_is_n_mnist_images(2, data)
+
+    def test_read_images_from_file_using_mnist_data_sets_fails_if_file_too_short(self):
+        with self.assertRaises(ValueError):
+            data = MNISTDataSets.read_images_from_file(
+                get_project_root_folder()+'/nn_wtf/data/7_2.raw', 3
+            )
+
+    def _check_is_one_mnist_image(self, data):
+        self._check_is_n_mnist_images(1, data)
+
+    def _check_is_n_mnist_images(self, n, data):
+        self.assertEqual(4, len(data.shape))
+        self.assertEqual(n, data.shape[0])
+        self.assertEqual(MNISTGraph.IMAGE_SIZE, data.shape[1])
+        self.assertEqual(MNISTGraph.IMAGE_SIZE, data.shape[2])
+        self.assertEqual(1, data.shape[3])
+