def testXxdOutputToBytes(self):
# 1. SETUP
# Define the initial model
initial_model = test_utils.build_mock_model()
initial_bytes = flatbuffer_utils.convert_object_to_bytearray(
initial_model)
# Define temporary files
tmp_dir = self.get_temp_dir()
model_filename = os.path.join(tmp_dir, 'model.tflite')
# 2. Write model to temporary file (will be used as input for xxd)
flatbuffer_utils.write_model(initial_model, model_filename)
# 3. DUMP WITH xxd
input_cc_file = os.path.join(tmp_dir, 'model.cc')
command = 'xxd -i {} > {}'.format(model_filename, input_cc_file)
subprocess.call(command, shell=True)
# 4. VALIDATE
final_bytes = flatbuffer_utils.xxd_output_to_bytes(input_cc_file)
# Validate that the initial and final bytearray are the same
self.assertEqual(initial_bytes, final_bytes)
def deduplicate_readonly_buffers(tflite_model):
""""Generates a new model byte array after deduplicating readonly buffers.
This function should be invoked after the model optimization toolkit. The
model optimization toolkit assumes that each tensor object owns its each
buffer separately.
Args:
tflite_model: TFLite flatbuffer in a byte array to be deduplicated.
Returns:
TFLite flatbuffer in a bytes array, processed with the deduplication method.
"""
# Load TFLite Flatbuffer byte array into an object.
model = flatbuffer_utils.convert_bytearray_to_object(tflite_model)
# Get all the read-only buffers, which can be modified without causing any
# issue in the graph invocation stage.
read_only_buffer_indices = set()
for subgraph in model.subgraphs:
# To get all the read-only buffers:
# (1) Get all read-only input tensors.
# (2) Discard intermediate or output tensors.
# (3) Discard the subgraph's input/output tensors.
# (4) Gather the buffers of the read-only input tensors.
# (1) Get read-only input tensors.
read_only_input_tensor_indices = set()
for op in subgraph.operators:
if op.inputs is None:
continue
for i, input_tensor_idx in enumerate(op.inputs):
# Ignore mutable tensors.
if op.mutatingVariableInputs is not None:
# Ignore invalid tensors.
if (i < len(op.mutatingVariableInputs)
and op.mutatingVariableInputs[i]):
continue
# Ignore variable tensors.
if subgraph.tensors[input_tensor_idx].isVariable:
continue
read_only_input_tensor_indices.add(input_tensor_idx)
# (2) Discard intermediate or output tensors.
for op in subgraph.operators:
if op.outputs is not None:
for output_tensor_idx in op.outputs:
read_only_input_tensor_indices.discard(output_tensor_idx)
if op.intermediates is not None:
for intermediate_tensor_idx in op.intermediates:
read_only_input_tensor_indices.discard(
intermediate_tensor_idx)
# (3) Discard the subgraph's input and output tensors.
if subgraph.inputs is not None:
for input_tensor_idx in subgraph.inputs:
read_only_input_tensor_indices.discard(input_tensor_idx)
if subgraph.outputs is not None:
for output_tensor_idx in subgraph.outputs:
read_only_input_tensor_indices.discard(output_tensor_idx)
# (4) Gather the buffers of the read-only input tensors.
for tensor_idx in read_only_input_tensor_indices:
read_only_buffer_indices.add(subgraph.tensors[tensor_idx].buffer)
# Ignore invalid negative index or zero-sized buffers.
for buffer_idx in read_only_buffer_indices.copy():
if (buffer_idx < 0
or (model.buffers[buffer_idx].data is None
or isinstance(model.buffers[buffer_idx].data, list)
or model.buffers[buffer_idx].data.size == 0)):
read_only_buffer_indices.discard(buffer_idx)
# Sort by buffer size.
read_only_buffer_indices = list(read_only_buffer_indices)
sorted(read_only_buffer_indices,
key=lambda idx: model.buffers[idx].data.data.tobytes())
# Create a map of duplicate buffers (same size and same type).
# eg: In [1, 2, 3, 4, 5, 6] if (1, 4, 6) and (2, 5) are each, groups of buffer
# indices of the same size and type, then the map would be {4:1, 6:1, 5:2}
duplicate_buffer_map = {}
for i, buffer_i_idx in enumerate(read_only_buffer_indices):
# This buffer is a duplicate.
if buffer_i_idx in duplicate_buffer_map:
continue
# This buffer is unique. Scan rest of the list to find duplicates
# of this buffer and mark them accordingly.
buffer_i = model.buffers[buffer_i_idx]
for buffer_j_idx in read_only_buffer_indices[i + 1:]:
if buffer_j_idx in duplicate_buffer_map:
continue
buffer_j = model.buffers[buffer_j_idx]
if buffer_i.data.size != buffer_j.data.size:
break
if buffer_i.data.data != buffer_j.data.data:
continue
# Found duplicate. Nullify j-th buffer and use i-th buffer instead.
duplicate_buffer_map[buffer_j_idx] = buffer_i_idx
# Make the duplicated tensors use the single shared buffer index.
for subgraph in model.subgraphs:
for op in subgraph.operators:
if op.inputs is None:
continue
for input_tensor in op.inputs:
buffer_idx = subgraph.tensors[input_tensor].buffer
if buffer_idx in duplicate_buffer_map:
subgraph.tensors[input_tensor].buffer = (
duplicate_buffer_map[buffer_idx])
# Nullify the unused buffers.
for idx in duplicate_buffer_map:
model.buffers[idx].data = None
# Return a TFLite flatbuffer as a byte array.
return flatbuffer_utils.convert_object_to_bytearray(model)
