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/table.py b/python/flatbuffers/table.py
new file mode 100644
index 0000000..adc76ca
--- /dev/null
+++ b/python/flatbuffers/table.py
@@ -0,0 +1,129 @@
+# Copyright 2014 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 as N
+
+
+class Table(object):
+ """Table wraps a byte slice and provides read access to its data.
+
+ The variable `Pos` indicates the root of the FlatBuffers object therein."""
+
+ __slots__ = ("Bytes", "Pos")
+
+ def __init__(self, buf, pos):
+ N.enforce_number(pos, N.UOffsetTFlags)
+
+ self.Bytes = buf
+ self.Pos = pos
+
+ def Offset(self, vtableOffset):
+ """Offset provides access into the Table's vtable.
+
+ Deprecated fields are ignored by checking the vtable's length."""
+
+ vtable = self.Pos - self.Get(N.SOffsetTFlags, self.Pos)
+ vtableEnd = self.Get(N.VOffsetTFlags, vtable)
+ if vtableOffset < vtableEnd:
+ return self.Get(N.VOffsetTFlags, vtable + vtableOffset)
+ return 0
+
+ def Indirect(self, off):
+ """Indirect retrieves the relative offset stored at `offset`."""
+ N.enforce_number(off, N.UOffsetTFlags)
+ return off + encode.Get(N.UOffsetTFlags.packer_type, self.Bytes, off)
+
+ def String(self, off):
+ """String gets a string from data stored inside the flatbuffer."""
+ N.enforce_number(off, N.UOffsetTFlags)
+ off += encode.Get(N.UOffsetTFlags.packer_type, self.Bytes, off)
+ start = off + N.UOffsetTFlags.bytewidth
+ length = encode.Get(N.UOffsetTFlags.packer_type, self.Bytes, off)
+ return bytes(self.Bytes[start:start+length])
+
+ def VectorLen(self, off):
+ """VectorLen retrieves the length of the vector whose offset is stored
+ at "off" in this object."""
+ N.enforce_number(off, N.UOffsetTFlags)
+
+ off += self.Pos
+ off += encode.Get(N.UOffsetTFlags.packer_type, self.Bytes, off)
+ ret = encode.Get(N.UOffsetTFlags.packer_type, self.Bytes, off)
+ return ret
+
+ def Vector(self, off):
+ """Vector retrieves the start of data of the vector whose offset is
+ stored at "off" in this object."""
+ N.enforce_number(off, N.UOffsetTFlags)
+
+ off += self.Pos
+ x = off + self.Get(N.UOffsetTFlags, off)
+ # data starts after metadata containing the vector length
+ x += N.UOffsetTFlags.bytewidth
+ return x
+
+ def Union(self, t2, off):
+ """Union initializes any Table-derived type to point to the union at
+ the given offset."""
+ assert type(t2) is Table
+ N.enforce_number(off, N.UOffsetTFlags)
+
+ off += self.Pos
+ t2.Pos = off + self.Get(N.UOffsetTFlags, off)
+ t2.Bytes = self.Bytes
+
+ def Get(self, flags, off):
+ """
+ Get retrieves a value of the type specified by `flags` at the
+ given offset.
+ """
+ N.enforce_number(off, N.UOffsetTFlags)
+ return flags.py_type(encode.Get(flags.packer_type, self.Bytes, off))
+
+ def GetSlot(self, slot, d, validator_flags):
+ N.enforce_number(slot, N.VOffsetTFlags)
+ if validator_flags is not None:
+ N.enforce_number(d, validator_flags)
+ off = self.Offset(slot)
+ if off == 0:
+ return d
+ return self.Get(validator_flags, self.Pos + off)
+
+ def GetVectorAsNumpy(self, flags, off):
+ """
+ GetVectorAsNumpy returns the vector that starts at `Vector(off)`
+ as a numpy array with the type specified by `flags`. The array is
+ a `view` into Bytes, so modifying the returned array will
+ modify Bytes in place.
+ """
+ offset = self.Vector(off)
+ length = self.VectorLen(off) # TODO: length accounts for bytewidth, right?
+ numpy_dtype = N.to_numpy_type(flags)
+ return encode.GetVectorAsNumpy(numpy_dtype, self.Bytes, length, offset)
+
+ def GetVOffsetTSlot(self, slot, d):
+ """
+ GetVOffsetTSlot retrieves the VOffsetT that the given vtable location
+ points to. If the vtable value is zero, the default value `d`
+ will be returned.
+ """
+
+ N.enforce_number(slot, N.VOffsetTFlags)
+ N.enforce_number(d, N.VOffsetTFlags)
+
+ off = self.Offset(slot)
+ if off == 0:
+ return d
+ return off