1/*
2 * Copyright 2008 The Android Open Source Project
3 *
4 * Use of this source code is governed by a BSD-style license that can be
5 * found in the LICENSE file.
6 */
7
8#include "SkMathPriv.h"
9#include "SkFixed.h"
10#include "SkFloatBits.h"
11#include "SkFloatingPoint.h"
12#include "SkSafeMath.h"
13#include "SkScalar.h"
14
15#define sub_shift(zeros, x, n)  \
16    zeros -= n;                 \
17    x >>= n
18
19int SkCLZ_portable(uint32_t x) {
20    if (x == 0) {
21        return 32;
22    }
23
24    int zeros = 31;
25    if (x & 0xFFFF0000) {
26        sub_shift(zeros, x, 16);
27    }
28    if (x & 0xFF00) {
29        sub_shift(zeros, x, 8);
30    }
31    if (x & 0xF0) {
32        sub_shift(zeros, x, 4);
33    }
34    if (x & 0xC) {
35        sub_shift(zeros, x, 2);
36    }
37    if (x & 0x2) {
38        sub_shift(zeros, x, 1);
39    }
40
41    return zeros;
42}
43
44///////////////////////////////////////////////////////////////////////////////
45
46/* www.worldserver.com/turk/computergraphics/FixedSqrt.pdf
47*/
48int32_t SkSqrtBits(int32_t x, int count) {
49    SkASSERT(x >= 0 && count > 0 && (unsigned)count <= 30);
50
51    uint32_t    root = 0;
52    uint32_t    remHi = 0;
53    uint32_t    remLo = x;
54
55    do {
56        root <<= 1;
57
58        remHi = (remHi<<2) | (remLo>>30);
59        remLo <<= 2;
60
61        uint32_t testDiv = (root << 1) + 1;
62        if (remHi >= testDiv) {
63            remHi -= testDiv;
64            root++;
65        }
66    } while (--count >= 0);
67
68    return root;
69}
70
71float SkScalarSinCos(float radians, float* cosValue) {
72    float sinValue = sk_float_sin(radians);
73
74    if (cosValue) {
75        *cosValue = sk_float_cos(radians);
76        if (SkScalarNearlyZero(*cosValue)) {
77            *cosValue = 0;
78        }
79    }
80
81    if (SkScalarNearlyZero(sinValue)) {
82        sinValue = 0;
83    }
84    return sinValue;
85}
86
87///////////////////////////////////////////////////////////////////////////////////////////////////
88
89size_t SkSafeMath::Add(size_t x, size_t y) {
90    SkSafeMath tmp;
91    size_t sum = tmp.add(x, y);
92    return tmp.ok() ? sum : SK_MaxSizeT;
93}
94
95size_t SkSafeMath::Mul(size_t x, size_t y) {
96    SkSafeMath tmp;
97    size_t prod = tmp.mul(x, y);
98    return tmp.ok() ? prod : SK_MaxSizeT;
99}
100