Squashed 'third_party/flatbuffers/' content from commit acc9990ab
Change-Id: I48550d40d78fea996ebe74e9723a5d1f910de491
git-subtree-dir: third_party/flatbuffers
git-subtree-split: acc9990abd2206491480291b0f85f925110102ea
diff --git a/python/flatbuffers/util.py b/python/flatbuffers/util.py
new file mode 100644
index 0000000..a5a7838
--- /dev/null
+++ b/python/flatbuffers/util.py
@@ -0,0 +1,43 @@
+# Copyright 2017 Google Inc. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from . import encode
+from . import number_types
+from . import packer
+
+def GetSizePrefix(buf, offset):
+ """Extract the size prefix from a buffer."""
+ return encode.Get(packer.int32, buf, offset)
+
+def GetBufferIdentifier(buf, offset, size_prefixed=False):
+ """Extract the file_identifier from a buffer"""
+ if size_prefixed:
+ # increase offset by size of UOffsetTFlags
+ offset += number_types.UOffsetTFlags.bytewidth
+ # increase offset by size of root table pointer
+ offset += number_types.UOffsetTFlags.bytewidth
+ # end of FILE_IDENTIFIER
+ end = offset + encode.FILE_IDENTIFIER_LENGTH
+ return buf[offset:end]
+
+def BufferHasIdentifier(buf, offset, file_identifier, size_prefixed=False):
+ got = GetBufferIdentifier(buf, offset, size_prefixed=size_prefixed)
+ return got == file_identifier
+
+def RemoveSizePrefix(buf, offset):
+ """
+ Create a slice of a size-prefixed buffer that has
+ its position advanced just past the size prefix.
+ """
+ return buf, offset + number_types.Int32Flags.bytewidth