38 lines
1.3 KiB
C++
38 lines
1.3 KiB
C++
/*
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Copyright (c) 2013 Microsoft Corporation. All rights reserved.
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Released under Apache 2.0 license as described in the file LICENSE.
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Author: Leonardo de Moura
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*/
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#include <limits>
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#include "util/exception.h"
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namespace lean {
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void check_int_overflow(long long n) {
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static_assert(sizeof(n) > sizeof(int), // NOLINT
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"sizeof(long long) is not bigger than sizeof(int).");
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if (n < std::numeric_limits<int>::min())
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throw exception("integer underflow");
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if (n > std::numeric_limits<int>::max())
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throw exception("integer overflow");
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}
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template<typename Num>
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int safe_sub_core(int v, Num k) {
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long long r = static_cast<long long>(v) - static_cast<long long>(k);
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check_int_overflow(r);
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return static_cast<int>(r);
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}
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int safe_sub(int v, int k) { return safe_sub_core(v, k); }
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int safe_sub(int v, unsigned k) { return safe_sub_core(v, k); }
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template<typename Num1, typename Num2>
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Num1 safe_add_core(Num1 v, Num2 k) {
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long long r = static_cast<long long>(v) + static_cast<long long>(k);
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check_int_overflow(r);
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return static_cast<Num1>(r);
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}
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int safe_add(int v, int k) { return safe_add_core(v, k); }
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int safe_add(int v, unsigned k) { return safe_add_core(v, k); }
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unsigned safe_add(unsigned v, unsigned k) { return safe_add_core(v, k); }
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}
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