c640d0dc96
This reverts commit fdcfb8b7c2.
> Original change's description:
> > SkTypes: extract SkTo
> >
> > Change-Id: I8de790d5013db2105ad885fa2683303d7c250b09
> > Reviewed-on: https://skia-review.googlesource.com/133620
> > Reviewed-by: Mike Klein <mtklein@google.com>
Change-Id: Ida74fbc5c21248a724a5edbf9fae18a33bcb23aa
Reviewed-on: https://skia-review.googlesource.com/134506
Reviewed-by: Mike Klein <mtklein@google.com>
Commit-Queue: Hal Canary <halcanary@google.com>
116 lines
3.3 KiB
C++
116 lines
3.3 KiB
C++
/*
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* Copyright 2006 The Android Open Source Project
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*
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* Use of this source code is governed by a BSD-style license that can be
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* found in the LICENSE file.
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*/
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#ifndef SkMath_DEFINED
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#define SkMath_DEFINED
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#include "../private/SkTo.h"
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#include "SkTypes.h"
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// 64bit -> 32bit utilities
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// Handy util that can be passed two ints, and will automatically promote to
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// 64bits before the multiply, so the caller doesn't have to remember to cast
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// e.g. (int64_t)a * b;
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static inline int64_t sk_64_mul(int64_t a, int64_t b) {
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return a * b;
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}
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///////////////////////////////////////////////////////////////////////////////
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/**
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* Return the integer square root of value, with a bias of bitBias
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*/
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int32_t SkSqrtBits(int32_t value, int bitBias);
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/** Return the integer square root of n, treated as a SkFixed (16.16)
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*/
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#define SkSqrt32(n) SkSqrtBits(n, 15)
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/**
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* Returns (value < 0 ? 0 : value) efficiently (i.e. no compares or branches)
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*/
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static inline int SkClampPos(int value) {
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return value & ~(value >> 31);
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}
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/** Given an integer and a positive (max) integer, return the value
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* pinned against 0 and max, inclusive.
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* @param value The value we want returned pinned between [0...max]
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* @param max The positive max value
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* @return 0 if value < 0, max if value > max, else value
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*/
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static inline int SkClampMax(int value, int max) {
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// ensure that max is positive
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SkASSERT(max >= 0);
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if (value < 0) {
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value = 0;
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}
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if (value > max) {
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value = max;
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}
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return value;
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}
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/**
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* Returns true if value is a power of 2. Does not explicitly check for
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* value <= 0.
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*/
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template <typename T> constexpr inline bool SkIsPow2(T value) {
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return (value & (value - 1)) == 0;
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}
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///////////////////////////////////////////////////////////////////////////////
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/**
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* Return a*b/((1 << shift) - 1), rounding any fractional bits.
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* Only valid if a and b are unsigned and <= 32767 and shift is > 0 and <= 8
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*/
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static inline unsigned SkMul16ShiftRound(U16CPU a, U16CPU b, int shift) {
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SkASSERT(a <= 32767);
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SkASSERT(b <= 32767);
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SkASSERT(shift > 0 && shift <= 8);
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unsigned prod = a*b + (1 << (shift - 1));
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return (prod + (prod >> shift)) >> shift;
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}
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/**
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* Return a*b/255, rounding any fractional bits.
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* Only valid if a and b are unsigned and <= 32767.
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*/
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static inline U8CPU SkMulDiv255Round(U16CPU a, U16CPU b) {
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SkASSERT(a <= 32767);
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SkASSERT(b <= 32767);
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unsigned prod = a*b + 128;
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return (prod + (prod >> 8)) >> 8;
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}
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/**
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* Stores numer/denom and numer%denom into div and mod respectively.
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*/
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template <typename In, typename Out>
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inline void SkTDivMod(In numer, In denom, Out* div, Out* mod) {
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#ifdef SK_CPU_ARM32
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// If we wrote this as in the else branch, GCC won't fuse the two into one
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// divmod call, but rather a div call followed by a divmod. Silly! This
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// version is just as fast as calling __aeabi_[u]idivmod manually, but with
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// prettier code.
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//
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// This benches as around 2x faster than the code in the else branch.
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const In d = numer/denom;
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*div = static_cast<Out>(d);
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*mod = static_cast<Out>(numer-d*denom);
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#else
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// On x86 this will just be a single idiv.
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*div = static_cast<Out>(numer/denom);
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*mod = static_cast<Out>(numer%denom);
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#endif
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}
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#endif
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