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"""
*******************************************************************************
* BTChip Bitcoin Hardware Wallet Python API
* (c) 2014 BTChip - 1BTChip7VfTnrPra5jqci7ejnMguuHogTn
*
* 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 .btchipException import BTChipException
def readVarint(buffer, offset):
varintSize = 0
value = 0
if (buffer[offset] < 0xfd):
value = buffer[offset]
varintSize = 1
elif (buffer[offset] == 0xfd):
value = (buffer[offset + 2] << 8) | (buffer[offset + 1])
varintSize = 3
elif (buffer[offset] == 0xfe):
value = (buffer[offset + 4] << 24) | (buffer[offset + 3] << 16) | (buffer[offset + 2] << 8) | (buffer[offset + 1])
varintSize = 5
else:
raise BTChipException("unsupported varint")
return { "value": value, "size": varintSize }
def writeVarint(value, buffer):
if (value < 0xfd):
buffer.append(value)
elif (value <= 0xffff):
buffer.append(0xfd)
buffer.append(value & 0xff)
buffer.append((value >> 8) & 0xff)
elif (value <= 0xffffffff):
buffer.append(0xfe)
buffer.append(value & 0xff)
buffer.append((value >> 8) & 0xff)
buffer.append((value >> 16) & 0xff)
buffer.append((value >> 24) & 0xff)
else:
raise BTChipException("unsupported encoding")
return buffer
def getVarintSize(value):
if (value < 0xfd):
return 1
elif (value <= 0xffff):
return 3
elif (value <= 0xffffffff):
return 5
else:
raise BTChipException("unsupported encoding")
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