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49 lines
2.1 KiB
C++
49 lines
2.1 KiB
C++
// Copyright (c) 2009-2010 Satoshi Nakamoto
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// Copyright (c) 2009-2019 The Bitcoin Core developers
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// Distributed under the MIT software license, see the accompanying
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// file COPYING or http://www.opensource.org/licenses/mit-license.php.
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// Compile-time verification of assumptions we make.
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#ifndef BITCOIN_COMPAT_ASSUMPTIONS_H
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#define BITCOIN_COMPAT_ASSUMPTIONS_H
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#include <limits>
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// Assumption: We assume that the macro NDEBUG is not defined.
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// Example(s): We use assert(...) extensively with the assumption of it never
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// being a noop at runtime.
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#if defined(NDEBUG)
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# error "Bitcoin cannot be compiled without assertions."
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#endif
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// Assumption: We assume the floating-point types to fulfill the requirements of
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// IEC 559 (IEEE 754) standard.
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// Example(s): Floating-point division by zero in ConnectBlock, CreateTransaction
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// and EstimateMedianVal.
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static_assert(std::numeric_limits<float>::is_iec559, "IEEE 754 float assumed");
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static_assert(std::numeric_limits<double>::is_iec559, "IEEE 754 double assumed");
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// Assumption: We assume eight bits per byte (obviously, but remember: don't
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// trust -- verify!).
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// Example(s): Everywhere :-)
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static_assert(std::numeric_limits<unsigned char>::digits == 8, "8-bit byte assumed");
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// Assumption: We assume floating-point widths.
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// Example(s): Type punning in serialization code (ser_{float,double}_to_uint{32,64}).
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static_assert(sizeof(float) == 4, "32-bit float assumed");
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static_assert(sizeof(double) == 8, "64-bit double assumed");
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// Assumption: We assume integer widths.
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// Example(s): GetSizeOfCompactSize and WriteCompactSize in the serialization
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// code.
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static_assert(sizeof(short) == 2, "16-bit short assumed");
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static_assert(sizeof(int) == 4, "32-bit int assumed");
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// Some important things we are NOT assuming (non-exhaustive list):
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// * We are NOT assuming a specific value for sizeof(std::size_t).
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// * We are NOT assuming a specific value for std::endian::native.
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// * We are NOT assuming a specific value for std::locale("").name().
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// * We are NOT assuming a specific value for std::numeric_limits<char>::is_signed.
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#endif // BITCOIN_COMPAT_ASSUMPTIONS_H
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