gfx/skia/trunk/src/core/SkMathPriv.h@129ffea94266
gfx/skia/trunk/src/core/SkMathPriv.h
Sat, 03 Jan 2015 20:18:00 +0100
- author
- Michael Schloh von Bennewitz <michael@schloh.com>
- date
- Sat, 03 Jan 2015 20:18:00 +0100
- branch
- TOR_BUG_3246
- changeset 7
- 129ffea94266
- permissions
- -rw-r--r--
Conditionally enable double key logic according to:
private browsing mode or privacy.thirdparty.isolate preference and
implement in GetCookieStringCommon and FindCookie where it counts...
With some reservations of how to convince FindCookie users to test
condition and pass a nullptr when disabling double key logic.
1 /*
2 * Copyright 2012 Google Inc.
3 *
4 * Use of this source code is governed by a BSD-style license that can be
5 * found in the LICENSE file.
6 */
8 #ifndef SkMathPriv_DEFINED
9 #define SkMathPriv_DEFINED
11 #include "SkMath.h"
13 /** Returns -1 if n < 0, else returns 0
14 */
15 #define SkExtractSign(n) ((int32_t)(n) >> 31)
17 /** If sign == -1, returns -n, else sign must be 0, and returns n.
18 Typically used in conjunction with SkExtractSign().
19 */
20 static inline int32_t SkApplySign(int32_t n, int32_t sign) {
21 SkASSERT(sign == 0 || sign == -1);
22 return (n ^ sign) - sign;
23 }
25 /** Return x with the sign of y */
26 static inline int32_t SkCopySign32(int32_t x, int32_t y) {
27 return SkApplySign(x, SkExtractSign(x ^ y));
28 }
30 /** Given a positive value and a positive max, return the value
31 pinned against max.
32 Note: only works as long as max - value doesn't wrap around
33 @return max if value >= max, else value
34 */
35 static inline unsigned SkClampUMax(unsigned value, unsigned max) {
36 if (value > max) {
37 value = max;
38 }
39 return value;
40 }
42 ///////////////////////////////////////////////////////////////////////////////
44 /** Return a*b/255, truncating away any fractional bits. Only valid if both
45 a and b are 0..255
46 */
47 static inline U8CPU SkMulDiv255Trunc(U8CPU a, U8CPU b) {
48 SkASSERT((uint8_t)a == a);
49 SkASSERT((uint8_t)b == b);
50 unsigned prod = SkMulS16(a, b) + 1;
51 return (prod + (prod >> 8)) >> 8;
52 }
54 /** Return (a*b)/255, taking the ceiling of any fractional bits. Only valid if
55 both a and b are 0..255. The expected result equals (a * b + 254) / 255.
56 */
57 static inline U8CPU SkMulDiv255Ceiling(U8CPU a, U8CPU b) {
58 SkASSERT((uint8_t)a == a);
59 SkASSERT((uint8_t)b == b);
60 unsigned prod = SkMulS16(a, b) + 255;
61 return (prod + (prod >> 8)) >> 8;
62 }
64 /** Just the rounding step in SkDiv255Round: round(value / 255)
65 */
66 static inline unsigned SkDiv255Round(unsigned prod) {
67 prod += 128;
68 return (prod + (prod >> 8)) >> 8;
69 }
71 #endif
