Initial Contribution
diff --git a/froofle/protobuf/internal/input_stream.py b/froofle/protobuf/internal/input_stream.py
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+# Protocol Buffers - Google's data interchange format
+# Copyright 2008 Google Inc. All rights reserved.
+# http://code.google.com/p/protobuf/
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+# * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+# * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+# * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+"""InputStream is the primitive interface for reading bits from the wire.
+
+All protocol buffer deserialization can be expressed in terms of
+the InputStream primitives provided here.
+"""
+
+__author__ = 'robinson@google.com (Will Robinson)'
+
+import struct
+from array import array
+from froofle.protobuf import message
+from froofle.protobuf.internal import wire_format
+
+
+# Note that much of this code is ported from //net/proto/ProtocolBuffer, and
+# that the interface is strongly inspired by CodedInputStream from the C++
+# proto2 implementation.
+
+
+class InputStreamBuffer(object):
+
+ """Contains all logic for reading bits, and dealing with stream position.
+
+ If an InputStream method ever raises an exception, the stream is left
+ in an indeterminate state and is not safe for further use.
+ """
+
+ def __init__(self, s):
+ # What we really want is something like array('B', s), where elements we
+ # read from the array are already given to us as one-byte integers. BUT
+ # using array() instead of buffer() would force full string copies to result
+ # from each GetSubBuffer() call.
+ #
+ # So, if the N serialized bytes of a single protocol buffer object are
+ # split evenly between 2 child messages, and so on recursively, using
+ # array('B', s) instead of buffer() would incur an additional N*logN bytes
+ # copied during deserialization.
+ #
+ # The higher constant overhead of having to ord() for every byte we read
+ # from the buffer in _ReadVarintHelper() could definitely lead to worse
+ # performance in many real-world scenarios, even if the asymptotic
+ # complexity is better. However, our real answer is that the mythical
+ # Python/C extension module output mode for the protocol compiler will
+ # be blazing-fast and will eliminate most use of this class anyway.
+ self._buffer = buffer(s)
+ self._pos = 0
+
+ def EndOfStream(self):
+ """Returns true iff we're at the end of the stream.
+ If this returns true, then a call to any other InputStream method
+ will raise an exception.
+ """
+ return self._pos >= len(self._buffer)
+
+ def Position(self):
+ """Returns the current position in the stream, or equivalently, the
+ number of bytes read so far.
+ """
+ return self._pos
+
+ def GetSubBuffer(self, size=None):
+ """Returns a sequence-like object that represents a portion of our
+ underlying sequence.
+
+ Position 0 in the returned object corresponds to self.Position()
+ in this stream.
+
+ If size is specified, then the returned object ends after the
+ next "size" bytes in this stream. If size is not specified,
+ then the returned object ends at the end of this stream.
+
+ We guarantee that the returned object R supports the Python buffer
+ interface (and thus that the call buffer(R) will work).
+
+ Note that the returned buffer is read-only.
+
+ The intended use for this method is for nested-message and nested-group
+ deserialization, where we want to make a recursive MergeFromString()
+ call on the portion of the original sequence that contains the serialized
+ nested message. (And we'd like to do so without making unnecessary string
+ copies).
+
+ REQUIRES: size is nonnegative.
+ """
+ # Note that buffer() doesn't perform any actual string copy.
+ if size is None:
+ return buffer(self._buffer, self._pos)
+ else:
+ if size < 0:
+ raise message.DecodeError('Negative size %d' % size)
+ return buffer(self._buffer, self._pos, size)
+
+ def SkipBytes(self, num_bytes):
+ """Skip num_bytes bytes ahead, or go to the end of the stream, whichever
+ comes first.
+
+ REQUIRES: num_bytes is nonnegative.
+ """
+ if num_bytes < 0:
+ raise message.DecodeError('Negative num_bytes %d' % num_bytes)
+ self._pos += num_bytes
+ self._pos = min(self._pos, len(self._buffer))
+
+ def ReadBytes(self, size):
+ """Reads up to 'size' bytes from the stream, stopping early
+ only if we reach the end of the stream. Returns the bytes read
+ as a string.
+ """
+ if size < 0:
+ raise message.DecodeError('Negative size %d' % size)
+ s = (self._buffer[self._pos : self._pos + size])
+ self._pos += len(s) # Only advance by the number of bytes actually read.
+ return s
+
+ def ReadLittleEndian32(self):
+ """Interprets the next 4 bytes of the stream as a little-endian
+ encoded, unsiged 32-bit integer, and returns that integer.
+ """
+ try:
+ i = struct.unpack(wire_format.FORMAT_UINT32_LITTLE_ENDIAN,
+ self._buffer[self._pos : self._pos + 4])
+ self._pos += 4
+ return i[0] # unpack() result is a 1-element tuple.
+ except struct.error, e:
+ raise message.DecodeError(e)
+
+ def ReadLittleEndian64(self):
+ """Interprets the next 8 bytes of the stream as a little-endian
+ encoded, unsiged 64-bit integer, and returns that integer.
+ """
+ try:
+ i = struct.unpack(wire_format.FORMAT_UINT64_LITTLE_ENDIAN,
+ self._buffer[self._pos : self._pos + 8])
+ self._pos += 8
+ return i[0] # unpack() result is a 1-element tuple.
+ except struct.error, e:
+ raise message.DecodeError(e)
+
+ def ReadVarint32(self):
+ """Reads a varint from the stream, interprets this varint
+ as a signed, 32-bit integer, and returns the integer.
+ """
+ i = self.ReadVarint64()
+ if not wire_format.INT32_MIN <= i <= wire_format.INT32_MAX:
+ raise message.DecodeError('Value out of range for int32: %d' % i)
+ return int(i)
+
+ def ReadVarUInt32(self):
+ """Reads a varint from the stream, interprets this varint
+ as an unsigned, 32-bit integer, and returns the integer.
+ """
+ i = self.ReadVarUInt64()
+ if i > wire_format.UINT32_MAX:
+ raise message.DecodeError('Value out of range for uint32: %d' % i)
+ return i
+
+ def ReadVarint64(self):
+ """Reads a varint from the stream, interprets this varint
+ as a signed, 64-bit integer, and returns the integer.
+ """
+ i = self.ReadVarUInt64()
+ if i > wire_format.INT64_MAX:
+ i -= (1 << 64)
+ return i
+
+ def ReadVarUInt64(self):
+ """Reads a varint from the stream, interprets this varint
+ as an unsigned, 64-bit integer, and returns the integer.
+ """
+ i = self._ReadVarintHelper()
+ if not 0 <= i <= wire_format.UINT64_MAX:
+ raise message.DecodeError('Value out of range for uint64: %d' % i)
+ return i
+
+ def _ReadVarintHelper(self):
+ """Helper for the various varint-reading methods above.
+ Reads an unsigned, varint-encoded integer from the stream and
+ returns this integer.
+
+ Does no bounds checking except to ensure that we read at most as many bytes
+ as could possibly be present in a varint-encoded 64-bit number.
+ """
+ result = 0
+ shift = 0
+ while 1:
+ if shift >= 64:
+ raise message.DecodeError('Too many bytes when decoding varint.')
+ try:
+ b = ord(self._buffer[self._pos])
+ except IndexError:
+ raise message.DecodeError('Truncated varint.')
+ self._pos += 1
+ result |= ((b & 0x7f) << shift)
+ shift += 7
+ if not (b & 0x80):
+ return result
+
+class InputStreamArray(object):
+ def __init__(self, s):
+ self._buffer = array('B', s)
+ self._pos = 0
+
+ def EndOfStream(self):
+ return self._pos >= len(self._buffer)
+
+ def Position(self):
+ return self._pos
+
+ def GetSubBuffer(self, size=None):
+ if size is None:
+ return self._buffer[self._pos : ].tostring()
+ else:
+ if size < 0:
+ raise message.DecodeError('Negative size %d' % size)
+ return self._buffer[self._pos : self._pos + size].tostring()
+
+ def SkipBytes(self, num_bytes):
+ if num_bytes < 0:
+ raise message.DecodeError('Negative num_bytes %d' % num_bytes)
+ self._pos += num_bytes
+ self._pos = min(self._pos, len(self._buffer))
+
+ def ReadBytes(self, size):
+ if size < 0:
+ raise message.DecodeError('Negative size %d' % size)
+ s = self._buffer[self._pos : self._pos + size].tostring()
+ self._pos += len(s) # Only advance by the number of bytes actually read.
+ return s
+
+ def ReadLittleEndian32(self):
+ try:
+ i = struct.unpack(wire_format.FORMAT_UINT32_LITTLE_ENDIAN,
+ self._buffer[self._pos : self._pos + 4])
+ self._pos += 4
+ return i[0] # unpack() result is a 1-element tuple.
+ except struct.error, e:
+ raise message.DecodeError(e)
+
+ def ReadLittleEndian64(self):
+ try:
+ i = struct.unpack(wire_format.FORMAT_UINT64_LITTLE_ENDIAN,
+ self._buffer[self._pos : self._pos + 8])
+ self._pos += 8
+ return i[0] # unpack() result is a 1-element tuple.
+ except struct.error, e:
+ raise message.DecodeError(e)
+
+ def ReadVarint32(self):
+ i = self.ReadVarint64()
+ if not wire_format.INT32_MIN <= i <= wire_format.INT32_MAX:
+ raise message.DecodeError('Value out of range for int32: %d' % i)
+ return int(i)
+
+ def ReadVarUInt32(self):
+ i = self.ReadVarUInt64()
+ if i > wire_format.UINT32_MAX:
+ raise message.DecodeError('Value out of range for uint32: %d' % i)
+ return i
+
+ def ReadVarint64(self):
+ i = self.ReadVarUInt64()
+ if i > wire_format.INT64_MAX:
+ i -= (1 << 64)
+ return i
+
+ def ReadVarUInt64(self):
+ i = self._ReadVarintHelper()
+ if not 0 <= i <= wire_format.UINT64_MAX:
+ raise message.DecodeError('Value out of range for uint64: %d' % i)
+ return i
+
+ def _ReadVarintHelper(self):
+ result = 0
+ shift = 0
+ while 1:
+ if shift >= 64:
+ raise message.DecodeError('Too many bytes when decoding varint.')
+ try:
+ b = self._buffer[self._pos]
+ except IndexError:
+ raise message.DecodeError('Truncated varint.')
+ self._pos += 1
+ result |= ((b & 0x7f) << shift)
+ shift += 7
+ if not (b & 0x80):
+ return result
+
+try:
+ buffer("")
+ InputStream = InputStreamBuffer
+except NotImplementedError:
+ # Google App Engine: dev_appserver.py
+ InputStream = InputStreamArray
+except RuntimeError:
+ # Google App Engine: production
+ InputStream = InputStreamArray