You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
76 lines
2.1 KiB
76 lines
2.1 KiB
/*
|
|
* 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 "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
|