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77 lines
2.5 KiB
Python
77 lines
2.5 KiB
Python
##===--- SwiftIntTypes.py -----------------------------*- coding: utf-8 -*-===##
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##
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## This source file is part of the Swift.org open source project
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##
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## Copyright (c) 2014 - 2015 Apple Inc. and the Swift project authors
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## Licensed under Apache License v2.0 with Runtime Library Exception
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##
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## See http://swift.org/LICENSE.txt for license information
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## See http://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
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##
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##===----------------------------------------------------------------------===##
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# Bit counts for all int types
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_all_integer_type_bitwidths = [8, 16, 32, 64]
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# Number of bits in the biggest int type
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int_max_bits = max(_all_integer_type_bitwidths)
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class SwiftIntegerType(object):
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def __init__(self, is_word, bits, is_signed):
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self.is_word = is_word
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self.bits = bits
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self.is_signed = is_signed
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if is_word:
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self.possible_bitwidths = [ 32, 64 ]
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else:
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self.possible_bitwidths = [ bits ]
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# Derived properties
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self.stdlib_name = \
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('' if is_signed else 'U') + \
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'Int' + \
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('' if is_word else str(bits))
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self.builtin_name = ('Word' if is_word else 'Int' + str(bits))
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def get_opposite_signedness(self):
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return SwiftIntegerType(self.is_word, self.bits, not self.is_signed)
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def __eq__(self, other):
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return self.is_word == other.is_word and \
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self.bits == other.bits and \
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self.is_signed == other.is_signed
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def __ne__(self, other):
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return not self.__eq__(other)
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def all_integer_types(word_bits):
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for bitwidth in _all_integer_type_bitwidths:
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for is_signed in [ False, True ]:
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yield SwiftIntegerType(is_word=False, bits=bitwidth,
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is_signed=is_signed)
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for is_signed in [ False, True ]:
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yield SwiftIntegerType(is_word=True, bits=word_bits,
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is_signed=is_signed)
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# 'truncatingBitPattern' initializer is defined if the conversion is truncating
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# on any platform that Swift supports.
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def should_define_truncating_bit_pattern_init(src_ty, dst_ty):
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# Don't define a truncating conversion between a type and itself.
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if src_ty == dst_ty:
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return False
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# Conversion to opposite signedness is never truncating.
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if src_ty == dst_ty.get_opposite_signedness():
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return False
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for src_ty_bits in src_ty.possible_bitwidths:
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for dst_ty_bits in dst_ty.possible_bitwidths:
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if src_ty_bits > dst_ty_bits:
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return True
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return False
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