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comparison: gfx/skia/trunk/include/device/xps/SkConstexprMath.h
gfx/skia/trunk/include/device/xps/SkConstexprMath.h
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- TOR_BUG_3246
- changeset 7
- 129ffea94266
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| -1:000000000000 | 0:43d5812beb98 |
|---|---|
| 1 /* | |
| 2 * Copyright 2011 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 */ | |
| 7 | |
| 8 #ifndef SkConstexprMath_DEFINED | |
| 9 #define SkConstexprMath_DEFINED | |
| 10 | |
| 11 #include "SkTypes.h" | |
| 12 #include <limits.h> | |
| 13 | |
| 14 template <uintmax_t N, uintmax_t B> | |
| 15 struct SK_LOG { | |
| 16 //! Compile-time constant ceiling(logB(N)). | |
| 17 static const uintmax_t value = 1 + SK_LOG<N/B, B>::value; | |
| 18 }; | |
| 19 template <uintmax_t B> | |
| 20 struct SK_LOG<1, B> { | |
| 21 static const uintmax_t value = 0; | |
| 22 }; | |
| 23 template <uintmax_t B> | |
| 24 struct SK_LOG<0, B> { | |
| 25 static const uintmax_t value = 0; | |
| 26 }; | |
| 27 | |
| 28 template<uintmax_t N> | |
| 29 struct SK_2N1 { | |
| 30 //! Compile-time constant (2^N)-1. | |
| 31 static const uintmax_t value = (SK_2N1<N-1>::value << 1) + 1; | |
| 32 }; | |
| 33 template<> | |
| 34 struct SK_2N1<1> { | |
| 35 static const uintmax_t value = 1; | |
| 36 }; | |
| 37 | |
| 38 /** Compile-time constant number of base n digits in type t | |
| 39 if the bits of type t are considered as unsigned base two. | |
| 40 */ | |
| 41 #define SK_BASE_N_DIGITS_IN(n, t) (\ | |
| 42 SK_LOG<SK_2N1<(sizeof(t) * CHAR_BIT)>::value, n>::value\ | |
| 43 ) | |
| 44 /** Compile-time constant number of base 10 digits in type t | |
| 45 if the bits of type t are considered as unsigned base two. | |
| 46 */ | |
| 47 #define SK_DIGITS_IN(t) SK_BASE_N_DIGITS_IN(10, (t)) | |
| 48 | |
| 49 // Compile-time constant maximum value of two unsigned values. | |
| 50 template <uintmax_t a, uintmax_t b> struct SkTUMax { | |
| 51 static const uintmax_t value = (b < a) ? a : b; | |
| 52 }; | |
| 53 | |
| 54 #endif |
