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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.
*/
#pragma once
#include "include/core/SkTypes.h"
namespace pk {
// 64bit -> 32bit utilities
// Handy util that can be passed two ints, and will automatically promote to
// 64bits before the multiply, so the caller doesn't have to remember to cast
// e.g. (int64_t)a * b;
static inline int64_t sk_64_mul(int64_t a, int64_t b) {
return a * b;
}
///////////////////////////////////////////////////////////////////////////////
/**
* Returns true if value is a power of 2. Does not explicitly check for
* value <= 0.
*/
template <typename T> constexpr inline bool SkIsPow2(T value) {
return (value & (value - 1)) == 0;
}
///////////////////////////////////////////////////////////////////////////////
/**
* Return a*b/((1 << shift) - 1), rounding any fractional bits.
* Only valid if a and b are unsigned and <= 32767 and shift is > 0 and <= 8
*/
static inline unsigned SkMul16ShiftRound(U16CPU a, U16CPU b, int shift) {
unsigned prod = a*b + (1 << (shift - 1));
return (prod + (prod >> shift)) >> shift;
}
/**
* Return a*b/255, rounding any fractional bits.
* Only valid if a and b are unsigned and <= 32767.
*/
static inline U8CPU SkMulDiv255Round(U16CPU a, U16CPU b) {
return SkMul16ShiftRound(a,b,8);
}
} // namespace pk