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/*
* Copyright 2006 The Android Open Source Project
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#ifndef SkUtils_DEFINED
#define SkUtils_DEFINED
#include "include/private/base/SkAttributes.h"
#include <cstring>
#include <type_traits> // is_trivially_copyable
namespace SkHexadecimalDigits {
extern const char gUpper[16]; // 0-9A-F
extern const char gLower[16]; // 0-9a-f
} // namespace SkHexadecimalDigits
///////////////////////////////////////////////////////////////////////////////
// If T is an 8-byte GCC or Clang vector extension type, it would naturally
// pass or return in the MMX mm0 register on 32-bit x86 builds. This has the
// fun side effect of clobbering any state in the x87 st0 register. (There is
// no ABI governing who should preserve mm?/st? registers, so no one does!)
//
// We force-inline sk_unaligned_load() and sk_unaligned_store() to avoid that,
// making them safe to use for all types on all platforms, thus solving the
// problem once and for all!
template <typename T, typename P>
static SK_ALWAYS_INLINE T sk_unaligned_load(const P* ptr) {
static_assert(std::is_trivially_copyable<T>::value);
static_assert(std::is_trivially_copyable<P>::value);
T val;
memcpy(&val, ptr, sizeof(val));
return val;
}
template <typename T, typename P>
static SK_ALWAYS_INLINE void sk_unaligned_store(P* ptr, T val) {
static_assert(std::is_trivially_copyable<T>::value);
static_assert(std::is_trivially_copyable<P>::value);
memcpy(ptr, &val, sizeof(val));
}
// Copy the bytes from src into an instance of type Dst and return it.
template <typename Dst, typename Src>
static SK_ALWAYS_INLINE Dst sk_bit_cast(const Src& src) {
static_assert(sizeof(Dst) == sizeof(Src));
return sk_unaligned_load<Dst>(&src);
}
#endif
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