skia2/include/core/SkMath.h
Mike Klein c0bd9f9fe5 rewrite includes to not need so much -Ifoo
Current strategy: everything from the top

Things to look at first are the manual changes:

   - added tools/rewrite_includes.py
   - removed -Idirectives from BUILD.gn
   - various compile.sh simplifications
   - tweak tools/embed_resources.py
   - update gn/find_headers.py to write paths from the top
   - update gn/gn_to_bp.py SkUserConfig.h layout
     so that #include "include/config/SkUserConfig.h" always
     gets the header we want.

No-Presubmit: true
Change-Id: I73a4b181654e0e38d229bc456c0d0854bae3363e
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/209706
Commit-Queue: Mike Klein <mtklein@google.com>
Reviewed-by: Hal Canary <halcanary@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
Reviewed-by: Florin Malita <fmalita@chromium.org>
2019-04-24 16:27:11 +00:00

76 lines
2.1 KiB
C++

/*
* 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 SkMath_DEFINED
#define SkMath_DEFINED
#include "include/core/SkTypes.h"
// 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;
}
///////////////////////////////////////////////////////////////////////////////
/** Given an integer and a positive (max) integer, return the value
* pinned against 0 and max, inclusive.
* @param value The value we want returned pinned between [0...max]
* @param max The positive max value
* @return 0 if value < 0, max if value > max, else value
*/
static inline int SkClampMax(int value, int max) {
// ensure that max is positive
SkASSERT(max >= 0);
if (value < 0) {
value = 0;
}
if (value > max) {
value = max;
}
return value;
}
/**
* 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) {
SkASSERT(a <= 32767);
SkASSERT(b <= 32767);
SkASSERT(shift > 0 && shift <= 8);
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) {
SkASSERT(a <= 32767);
SkASSERT(b <= 32767);
unsigned prod = a*b + 128;
return (prod + (prod >> 8)) >> 8;
}
#endif