/*
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* Copyright 2015 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*
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*/
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#ifndef GOOGLE_GATEKEEPER_UTILS_H_
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#define GOOGLE_GATEKEEPER_UTILS_H_
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#include <string.h>
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namespace gatekeeper {
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/**
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* Variant of memset() that uses GCC-specific pragmas to disable optimizations, so effect is not
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* optimized away. This is important because we often need to wipe blocks of sensitive data from
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* memory. As an additional convenience, this implementation avoids writing to NULL pointers.
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*/
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#ifdef __clang__
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#define OPTNONE __attribute__((optnone))
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#else // not __clang__
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#define OPTNONE __attribute__((optimize("O0")))
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#endif // not __clang__
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inline OPTNONE void* memset_s(void* s, int c, size_t n) {
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if (!s)
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return s;
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return memset(s, c, n);
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}
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#undef OPTNONE
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/**
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* Return the number of elements in array \p a.
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*/
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template <typename T, size_t N> inline size_t array_length(const T (&)[N]) {
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return N;
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}
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static inline int memcmp_s(const void* p1, const void* p2, size_t length) {
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const uint8_t* s1 = static_cast<const uint8_t*>(p1);
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const uint8_t* s2 = static_cast<const uint8_t*>(p2);
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uint8_t result = 0;
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while (length-- > 0)
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result |= *s1++ ^ *s2++;
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return result == 0 ? 0 : 1;
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}
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};
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#endif //GOOGLE_GATEKEEPER_UTILS_H_
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