Rico Wind
f34fae854a
Readd samples, samples-dev, tools/testing/bin, third_party removed by cleanup (no history, sorry) Add DEPS file which will replace the old all.deps and standalone.deps Add tools/deps/dartium.deps replacing the old dartium.deps (but now editable from a normal checkout) Fixup tools/utils.py to use the new archiving schema (git count for be, version number for dev/stable Fix codereview.settings
61 lines
1.8 KiB
Python
61 lines
1.8 KiB
Python
# Copyright (c) 2011, the Dart project authors. Please see the AUTHORS file
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# for details. All rights reserved. Use of this source code is governed by a
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# BSD-style license that can be found in the LICENSE file.
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'''
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This Encoder shares a lot in common with protobufs. It uses variable length
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ints and size-encoded strings and binary values. Other than being hugely
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stripped down, the major conceptual difference is that this encoding
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is UTF8 "safe". This means that it generates a form that should be passed
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on the wire as UTF8 and then can be very efficiently decoded by JS in the
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browser which natively handles these kinds of strings. To stay efficient in
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this range, all numeric data is encoded in only 7 bits.
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'''
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import base64
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class Encoder:
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def __init__(self):
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self.data = []
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def writeInt(self, value):
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'''Uses a 7-bit per byte encoding to stay UTF-8 "safe".'''
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bits = value & 0x3f
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value >>= 6
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while value:
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self.data.append(chr(0x40|bits))
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bits = value & 0x3f
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value >>= 6
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self.data.append(chr(bits))
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def writeBool(self, b):
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self.data.append(('F', 'T')[b])
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def writeString(self, s):
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if not s: s = ''
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self.writeInt(len(s))
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self.data.append(s)
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def writeBinary(self, s):
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'''Encode binary data using base64. This is less efficient than a 7-bit
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encoding would be; however, it can be decoded much faster on most
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browsers due to native support for the format.'''
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v = base64.b64encode(s)
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self.writeInt(len(v))
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self.data.append(v)
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def writeList(self, l):
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self.writeInt(len(l))
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for i in l:
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i.encode(self)
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def writeRaw(self, s):
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self.data.append(s)
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def finish(self):
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d = ''.join(self.data)
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return _encVarInt(len(d)) + d
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def getRaw(self):
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return ''.join(self.data)
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