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@mayoff mayoff/Decimal.py
Created Oct 10, 2018

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Decimal / NSDecimal support for lldb
# Decimal / NSDecimal support for lldb
#
# Put this file somewhere, e.g. ~/.../lldb/Decimal.py
# Then add this line to ~/.lldbinit:
# command script import ~/.../lldb/Decimal.py
import lldb
def stringForDecimal(sbValue, internal_dict):
from decimal import Decimal, getcontext
sbData = sbValue.GetData()
if not sbData.IsValid():
raise Exception('unable to get data: ' + sbError.GetCString())
if sbData.GetByteSize() != 20:
raise Exception('expected data to be 20 bytes but found ' + repr(sbData.GetByteSize()))
sbError = lldb.SBError()
exponent = sbData.GetSignedInt8(sbError, 0)
if sbError.Fail():
raise Exception('unable to read exponent byte: ' + sbError.GetCString())
flags = sbData.GetUnsignedInt8(sbError, 1)
if sbError.Fail():
raise Exception('unable to read flags byte: ' + sbError.GetCString())
length = flags & 0xf
isNegative = (flags & 0x10) != 0
if length == 0 and isNegative:
return 'NaN'
if length == 0:
return '0'
getcontext().prec = 200
value = Decimal(0)
scale = Decimal(1)
for i in range(length):
digit = sbData.GetUnsignedInt16(sbError, 4 + 2 * i)
if sbError.Fail():
raise Exception('unable to read memory: ' + sbError.GetCString())
value += scale * Decimal(digit)
scale *= 65536
value = value.scaleb(exponent)
if isNegative:
value = -value
return str(value)
def __lldb_init_module(debugger, internal_dict):
print('registering Decimal type summaries')
debugger.HandleCommand('type summary add Foundation.Decimal -F "' + __name__ + '.stringForDecimal"')
debugger.HandleCommand('type summary add NSDecimal -F "' + __name__ + '.stringForDecimal"')
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