/usr/include/thunderbird/skia/SkMath.h is in thunderbird-dev 1:24.4.0+build1-0ubuntu1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 | /*
* 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"
/**
* Computes numer1 * numer2 / denom in full 64 intermediate precision.
* It is an error for denom to be 0. There is no special handling if
* the result overflows 32bits.
*/
int32_t SkMulDiv(int32_t numer1, int32_t numer2, int32_t denom);
/**
* Computes (numer1 << shift) / denom in full 64 intermediate precision.
* It is an error for denom to be 0. There is no special handling if
* the result overflows 32bits.
*/
int32_t SkDivBits(int32_t numer, int32_t denom, int shift);
/**
* Return the integer square root of value, with a bias of bitBias
*/
int32_t SkSqrtBits(int32_t value, int bitBias);
/** Return the integer square root of n, treated as a SkFixed (16.16)
*/
#define SkSqrt32(n) SkSqrtBits(n, 15)
///////////////////////////////////////////////////////////////////////////////
//! Returns the number of leading zero bits (0...32)
int SkCLZ_portable(uint32_t);
#if defined(__arm__)
#define SkCLZ(x) __builtin_clz(x)
#endif
#ifndef SkCLZ
#define SkCLZ(x) SkCLZ_portable(x)
#endif
/**
* Returns (value < 0 ? 0 : value) efficiently (i.e. no compares or branches)
*/
static inline int SkClampPos(int value) {
return value & ~(value >> 31);
}
/** 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 the smallest power-of-2 that is >= the specified value. If value
* is already a power of 2, then it is returned unchanged. It is undefined
* if value is <= 0.
*/
static inline int SkNextPow2(int value) {
SkASSERT(value > 0);
return 1 << (32 - SkCLZ(value - 1));
}
/**
* Returns the log2 of the specified value, were that value to be rounded up
* to the next power of 2. It is undefined to pass 0. Examples:
* SkNextLog2(1) -> 0
* SkNextLog2(2) -> 1
* SkNextLog2(3) -> 2
* SkNextLog2(4) -> 2
* SkNextLog2(5) -> 3
*/
static inline int SkNextLog2(uint32_t value) {
SkASSERT(value != 0);
return 32 - SkCLZ(value - 1);
}
/**
* Returns true if value is a power of 2. Does not explicitly check for
* value <= 0.
*/
static inline bool SkIsPow2(int value) {
return (value & (value - 1)) == 0;
}
///////////////////////////////////////////////////////////////////////////////
/**
* SkMulS16(a, b) multiplies a * b, but requires that a and b are both int16_t.
* With this requirement, we can generate faster instructions on some
* architectures.
*/
#ifdef SK_ARM_HAS_EDSP
static inline int32_t SkMulS16(S16CPU x, S16CPU y) {
SkASSERT((int16_t)x == x);
SkASSERT((int16_t)y == y);
int32_t product;
asm("smulbb %0, %1, %2 \n"
: "=r"(product)
: "r"(x), "r"(y)
);
return product;
}
#else
#ifdef SK_DEBUG
static inline int32_t SkMulS16(S16CPU x, S16CPU y) {
SkASSERT((int16_t)x == x);
SkASSERT((int16_t)y == y);
return x * y;
}
#else
#define SkMulS16(x, y) ((x) * (y))
#endif
#endif
/**
* 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(unsigned a, unsigned b, int shift) {
SkASSERT(a <= 32767);
SkASSERT(b <= 32767);
SkASSERT(shift > 0 && shift <= 8);
unsigned prod = SkMulS16(a, b) + (1 << (shift - 1));
return (prod + (prod >> shift)) >> shift;
}
/**
* Return a*b/255, rounding any fractional bits. Only valid if both
* a and b are 0..255
*/
static inline U8CPU SkMulDiv255Round(U8CPU a, U8CPU b) {
SkASSERT((uint8_t)a == a);
SkASSERT((uint8_t)b == b);
unsigned prod = SkMulS16(a, b) + 128;
return (prod + (prod >> 8)) >> 8;
}
#endif
|