Bug in CIFAR after removing GetMutabble buffer

Fixes # I1KIPC

mindspore/ccsrc/dataset/engine/datasetops/source/cifar_op.cc

@@ -367,9 +367,14 @@ Status CifarOp::ParseCifarData() {
                                             TensorShape({kCifarImageHeight, kCifarImageWidth, kCifarImageChannel}),
                                             data_schema_->column(0).type()));
       auto itr = image_tensor->begin<uint8_t>();
-      for (; itr != image_tensor->end<uint8_t>(); itr++) {
-        *itr = block[cur_block_index++];
+      uint32_t total_pix = kCifarImageHeight * kCifarImageWidth;
+      for (int pix = 0; pix < total_pix; ++pix) {
+        for (int ch = 0; ch < kCifarImageChannel; ++ch) {
+          *itr = block[cur_block_index + ch * total_pix + pix];
+          itr++;
+        }
       }
+      cur_block_index += total_pix * kCifarImageChannel;
       cifar_image_label_pairs_.emplace_back(std::make_pair(image_tensor, labels));
     }
     RETURN_IF_NOT_OK(cifar_raw_data_block_->PopFront(&block));

tests/ut/python/dataset/test_cifarop.py

@@ -12,6 +12,10 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 # ==============================================================================
+import os
+
+import numpy as np
+
 import mindspore.dataset as ds
 from mindspore import log as logger
 
@@ -26,6 +30,20 @@ DATA_DIR_10 = "../data/dataset/testCifar10Data"
 DATA_DIR_100 = "../data/dataset/testCifar100Data"
 
 
+def load_cifar(path):
+    raw = np.empty(0, dtype=np.uint8)
+    for file_name in os.listdir(path):
+        if file_name.endswith(".bin"):
+            with open(os.path.join(path, file_name), mode='rb') as file:
+                raw = np.append(raw, np.fromfile(file, dtype=np.uint8), axis=0)
+    raw = raw.reshape(-1, 3073)
+    labels = raw[:, 0]
+    images = raw[:, 1:]
+    images = images.reshape(-1, 3, 32, 32)
+    images = images.transpose(0, 2, 3, 1)
+    return images, labels
+
+
 def test_case_dataset_cifar10():
     """
     dataset parameter
@@ -56,6 +74,18 @@ def test_case_dataset_cifar100():
     assert num_iter == 100
 
 
+def test_reading_cifar10():
+    """
+    Validate CIFAR10 image readings
+    """
+    data1 = ds.Cifar10Dataset(DATA_DIR_10, 100, shuffle=False)
+    images, labels = load_cifar(DATA_DIR_10)
+    for i, d in enumerate(data1.create_dict_iterator()):
+        np.testing.assert_array_equal(d["image"], images[i])
+        np.testing.assert_array_equal(d["label"], labels[i])
+
+
 if __name__ == '__main__':
     test_case_dataset_cifar10()
     test_case_dataset_cifar100()
+    test_reading_cifar10()