!2858 JPEG decoder hangs if the image is sliced to 3 bytes

Merge pull request !2858 from h.farahat/slice_jpeg

mindspore/ccsrc/dataset/kernels/image/image_utils.cc

@@ -121,14 +121,14 @@ Status Resize(const std::shared_ptr<Tensor> &input, std::shared_ptr<Tensor> *out
   }
 }
 
-bool HasJpegMagic(const std::shared_ptr<Tensor> &input) {
+bool IsNonEmptyJPEG(const std::shared_ptr<Tensor> &input) {
   const unsigned char *kJpegMagic = (unsigned char *)"\xFF\xD8\xFF";
   constexpr size_t kJpegMagicLen = 3;
-  return input->SizeInBytes() >= kJpegMagicLen && memcmp(input->GetBuffer(), kJpegMagic, kJpegMagicLen) == 0;
+  return input->SizeInBytes() > kJpegMagicLen && memcmp(input->GetBuffer(), kJpegMagic, kJpegMagicLen) == 0;
 }
 
 Status Decode(const std::shared_ptr<Tensor> &input, std::shared_ptr<Tensor> *output) {
-  if (HasJpegMagic(input)) {
+  if (IsNonEmptyJPEG(input)) {
     return JpegCropAndDecode(input, output);
   } else {
     return DecodeCv(input, output);

mindspore/ccsrc/dataset/kernels/image/image_utils.h

@@ -96,7 +96,7 @@ Status Decode(const std::shared_ptr<Tensor> &input, std::shared_ptr<Tensor> *out
 
 Status DecodeCv(const std::shared_ptr<Tensor> &input, std::shared_ptr<Tensor> *output);
 
-bool HasJpegMagic(const std::shared_ptr<Tensor> &input);
+bool IsNonEmptyJPEG(const std::shared_ptr<Tensor> &input);
 
 void JpegSetSource(j_decompress_ptr c_info, const void *data, int64_t data_size);
 

mindspore/ccsrc/dataset/kernels/image/random_crop_decode_resize_op.cc

@@ -31,7 +31,7 @@ Status RandomCropDecodeResizeOp::Compute(const std::shared_ptr<Tensor> &input, s
   if (input == nullptr) {
     RETURN_STATUS_UNEXPECTED("input tensor is null");
   }
-  if (!HasJpegMagic(input)) {
+  if (!IsNonEmptyJPEG(input)) {
     DecodeOp op(true);
     std::shared_ptr<Tensor> decoded;
     RETURN_IF_NOT_OK(op.Compute(input, &decoded));