aboutsummaryrefslogtreecommitdiffhomepage
path: root/include/core/Sk64.h
blob: b86e0be7d4661526e5e710adafa7f23ffeb077e9 (plain)
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
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231

/*
 * 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 Sk64_DEFINED
#define Sk64_DEFINED

#include "SkFixed.h"

/** \class Sk64

    Sk64 is a 64-bit math package that does not require long long support from the compiler.
*/
struct SK_API Sk64 {
    int32_t  fHi;   //!< the high 32 bits of the number (including sign)
    uint32_t fLo;   //!< the low 32 bits of the number

    /** Returns non-zero if the Sk64 can be represented as a signed 32 bit integer
    */
    SkBool is32() const { return fHi == ((int32_t)fLo >> 31); }

    /** Returns non-zero if the Sk64 cannot be represented as a signed 32 bit integer
    */
    SkBool is64() const { return fHi != ((int32_t)fLo >> 31); }

    /** Returns non-zero if the Sk64 can be represented as a signed 48 bit integer. Used to know
        if we can shift the value down by 16 to treat it as a SkFixed.
    */
    SkBool isFixed() const;

    /** Return the signed 32 bit integer equivalent. Asserts that is32() returns non-zero.
    */
    int32_t get32() const { SkASSERT(this->is32()); return (int32_t)fLo; }

    /** Return the number >> 16. Asserts that this does not loose any significant high bits.
    */
    SkFixed getFixed() const {
        SkASSERT(this->isFixed());

        uint32_t sum = fLo + (1 << 15);
        int32_t  hi = fHi;
        if (sum < fLo) {
            hi += 1;
        }
        return (hi << 16) | (sum >> 16);
    }

    /** Return the number >> 30. Asserts that this does not loose any
        significant high bits.
    */
    SkFract getFract() const;

    /** Returns the square-root of the number as a signed 32 bit value. */
    int32_t getSqrt() const;

    /** Returns the number of leading zeros of the absolute value of this.
        Will return in the range [0..64]
    */
    int getClzAbs() const;

    /** Returns non-zero if the number is zero */
    SkBool  isZero() const { return (fHi | fLo) == 0; }

    /** Returns non-zero if the number is non-zero */
    SkBool  nonZero() const { return fHi | fLo; }

    /** Returns non-zero if the number is negative (number < 0) */
    SkBool  isNeg() const { return (uint32_t)fHi >> 31; }

    /** Returns non-zero if the number is positive (number > 0) */
    SkBool  isPos() const { return ~(fHi >> 31) & (fHi | fLo); }

    /** Returns -1,0,+1 based on the sign of the number */
    int     getSign() const { return (fHi >> 31) | Sk32ToBool(fHi | fLo); }

    /** Negate the number */
    void    negate();

    /** If the number < 0, negate the number
    */
    void    abs();

    /** Returns the number of bits needed to shift the Sk64 to the right
        in order to make it fit in a signed 32 bit integer.
    */
    int     shiftToMake32() const;

    /** Set the number to zero */
    void    setZero() { fHi = fLo = 0; }

    /** Set the high and low 32 bit values of the number */
    void    set(int32_t hi, uint32_t lo) { fHi = hi; fLo = lo; }

    /** Set the number to the specified 32 bit integer */
    void    set(int32_t a) { fHi = a >> 31; fLo = a; }

    /** Set the number to the product of the two 32 bit integers */
    void    setMul(int32_t a, int32_t b);

    /** extract 32bits after shifting right by bitCount.
        Note: itCount must be [0..63].
        Asserts that no significant high bits were lost.
    */
    int32_t getShiftRight(unsigned bitCount) const;

    /** Shift the number left by the specified number of bits.
        @param bits How far to shift left, must be [0..63]
    */
    void    shiftLeft(unsigned bits);

    /** Shift the number right by the specified number of bits.
        @param bits How far to shift right, must be [0..63]. This
        performs an arithmetic right-shift (sign extending).
    */
    void    shiftRight(unsigned bits);

    /** Shift the number right by the specified number of bits, but
        round the result.
        @param bits How far to shift right, must be [0..63]. This
        performs an arithmetic right-shift (sign extending).
    */
    void    roundRight(unsigned bits);

    /** Add the specified 32 bit integer to the number */
    void add(int32_t lo) {
        int32_t  hi = lo >> 31; // 0 or -1
        uint32_t sum = fLo + (uint32_t)lo;

        fHi = fHi + hi + (sum < fLo);
        fLo = sum;
    }
    
    /** Add the specified Sk64 to the number */
    void add(int32_t hi, uint32_t lo) {
        uint32_t sum = fLo + lo;

        fHi = fHi + hi + (sum < fLo);
        fLo = sum;
    }
    
    /** Add the specified Sk64 to the number */
    void    add(const Sk64& other) { this->add(other.fHi, other.fLo); }
    
    /** Subtract the specified Sk64 from the number. (*this) = (*this) - num
    */
    void    sub(const Sk64& num);
    
    /** Subtract the number from the specified Sk64. (*this) = num - (*this)
    */
    void    rsub(const Sk64& num);
    
    /** Multiply the number by the specified 32 bit integer
    */
    void    mul(int32_t);

    enum DivOptions {
        kTrunc_DivOption,   //!< truncate the result when calling div()
        kRound_DivOption    //!< round the result when calling div()
    };
    
    /** Divide the number by the specified 32 bit integer, using the specified
        divide option (either truncate or round).
    */
    void    div(int32_t, DivOptions);

    /** return (this + other >> 16) as a 32bit result */
    SkFixed addGetFixed(const Sk64& other) const {
        return this->addGetFixed(other.fHi, other.fLo);
    }

    /** return (this + Sk64(hi, lo) >> 16) as a 32bit result */
    SkFixed addGetFixed(int32_t hi, uint32_t lo) const {
#ifdef SK_DEBUG
        Sk64    tmp(*this);
        tmp.add(hi, lo);
#endif

        uint32_t sum = fLo + lo;
        hi += fHi + (sum < fLo);
        lo = sum;

        sum = lo + (1 << 15);
        if (sum < lo)
            hi += 1;

        hi = (hi << 16) | (sum >> 16);
        SkASSERT(hi == tmp.getFixed());
        return hi;
    }

    /** Return the result of dividing the number by denom, treating the answer
        as a SkFixed. (*this) << 16 / denom. It is an error for denom to be 0.
    */
    SkFixed getFixedDiv(const Sk64& denom) const;

    friend bool operator==(const Sk64& a, const Sk64& b) {
        return a.fHi == b.fHi && a.fLo == b.fLo;
    }

    friend bool operator!=(const Sk64& a, const Sk64& b) {
        return a.fHi != b.fHi || a.fLo != b.fLo;
    }
    
    friend bool operator<(const Sk64& a, const Sk64& b) {
        return a.fHi < b.fHi || (a.fHi == b.fHi && a.fLo < b.fLo);
    }
    
    friend bool operator<=(const Sk64& a, const Sk64& b) {
        return a.fHi < b.fHi || (a.fHi == b.fHi && a.fLo <= b.fLo);
    }
    
    friend bool operator>(const Sk64& a, const Sk64& b) {
        return a.fHi > b.fHi || (a.fHi == b.fHi && a.fLo > b.fLo);
    }
    
    friend bool operator>=(const Sk64& a, const Sk64& b) {
        return a.fHi > b.fHi || (a.fHi == b.fHi && a.fLo >= b.fLo);
    }

#ifdef SkLONGLONG
    SkLONGLONG getLongLong() const;
#endif
};

#endif