[C API] NP_GetDims implementation (#422)

### Summary:
Continue with basic implementation of a C API for Neuropod. Issue #407

### Test Plan:
Added test that test returned values of number of dims and data in dims array.

source/neuropod/bindings/c/np_tensor.cc

@@ -18,6 +18,15 @@ limitations under the License.
 #include "neuropod/bindings/c/np_tensor_internal.h"
 #include "neuropod/internal/neuropod_tensor_raw_data_access.hh"
 
+void NP_GetDims(const NP_NeuropodTensor *tensor, size_t *num_dims, const int64_t **dims)
+{
+    // get_dims returnis reference to internal tensor's dims collection.
+    // Use pointer to its data that is valid as long as tensor is valid.
+    const auto &dims_collection = tensor->tensor->as_tensor()->get_dims();
+    *num_dims                   = dims_collection.size();
+    *dims                       = dims_collection.data();
+}
+
 NP_TensorType NP_GetType(const NP_NeuropodTensor *tensor)
 {
     return static_cast<NP_TensorType>(tensor->tensor->as_tensor()->get_tensor_type());

source/neuropod/tests/test_c_api.c

@@ -50,6 +50,7 @@ static void CheckFailed(const char *expression, const char *filename, int line_n
 #define ASSERT_EQ(expected, actual) CHECK((expected) == (actual))
 #define ASSERT_NE(expected, actual) CHECK((expected) != (actual))
 #define ASSERT_STREQ(expected, actual) ASSERT_EQ(0, strcmp((expected), (actual)))
+#define ASSERT_ARRAYEQ(expected, actual, size) ASSERT_EQ(0, memcmp((expected), (actual), size))
 
 static void TestLoadAndInference(void)
 {
@@ -248,9 +249,16 @@ static void TestTensorGetters(void)
     NP_NeuropodTensor *y      = NP_AllocateTensor(allocator, sizeof(dims) / sizeof(int64_t), dims, DOUBLE_TENSOR);
     NP_NeuropodTensor *z      = NP_AllocateTensor(allocator, sizeof(dims) / sizeof(int64_t), dims, STRING_TENSOR);
 
-    ASSERT_EQ(NP_GetType(x), FLOAT_TENSOR);
-    ASSERT_EQ(NP_GetType(y), DOUBLE_TENSOR);
-    ASSERT_EQ(NP_GetType(z), STRING_TENSOR);
+    ASSERT_EQ(FLOAT_TENSOR, NP_GetType(x));
+    ASSERT_EQ(DOUBLE_TENSOR, NP_GetType(y));
+    ASSERT_EQ(STRING_TENSOR, NP_GetType(z));
+
+    size_t         test_num_dims;
+    const int64_t *test_dims;
+    NP_GetDims(x, &test_num_dims, &test_dims);
+
+    ASSERT_EQ(sizeof(dims) / sizeof(dims[0]), test_num_dims);
+    ASSERT_ARRAYEQ(&dims[0], test_dims, test_num_dims);
 
     NP_FreeTensor(x);
     NP_FreeTensor(y);

tools/autofix.sh

@@ -14,7 +14,7 @@ fi
 pushd source
 
 # Reformat with clang-format
-find . -name "*.hh" -o -name "*.h" -o -name "*.cc" | xargs -L1 clang-format -style=file -i
+find . -name "*.hh" -o -name "*.h" -o -name "*.cc" -o -name "*.c" | xargs -L1 clang-format -style=file -i
 
 pushd python