1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/gfx/skia/trunk/include/device/xps/SkConstexprMath.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,54 @@
1.4 +/*
1.5 + * Copyright 2011 Google Inc.
1.6 + *
1.7 + * Use of this source code is governed by a BSD-style license that can be
1.8 + * found in the LICENSE file.
1.9 + */
1.10 +
1.11 +#ifndef SkConstexprMath_DEFINED
1.12 +#define SkConstexprMath_DEFINED
1.13 +
1.14 +#include "SkTypes.h"
1.15 +#include <limits.h>
1.16 +
1.17 +template <uintmax_t N, uintmax_t B>
1.18 +struct SK_LOG {
1.19 + //! Compile-time constant ceiling(logB(N)).
1.20 + static const uintmax_t value = 1 + SK_LOG<N/B, B>::value;
1.21 +};
1.22 +template <uintmax_t B>
1.23 +struct SK_LOG<1, B> {
1.24 + static const uintmax_t value = 0;
1.25 +};
1.26 +template <uintmax_t B>
1.27 +struct SK_LOG<0, B> {
1.28 + static const uintmax_t value = 0;
1.29 +};
1.30 +
1.31 +template<uintmax_t N>
1.32 +struct SK_2N1 {
1.33 + //! Compile-time constant (2^N)-1.
1.34 + static const uintmax_t value = (SK_2N1<N-1>::value << 1) + 1;
1.35 +};
1.36 +template<>
1.37 +struct SK_2N1<1> {
1.38 + static const uintmax_t value = 1;
1.39 +};
1.40 +
1.41 +/** Compile-time constant number of base n digits in type t
1.42 + if the bits of type t are considered as unsigned base two.
1.43 +*/
1.44 +#define SK_BASE_N_DIGITS_IN(n, t) (\
1.45 + SK_LOG<SK_2N1<(sizeof(t) * CHAR_BIT)>::value, n>::value\
1.46 +)
1.47 +/** Compile-time constant number of base 10 digits in type t
1.48 + if the bits of type t are considered as unsigned base two.
1.49 +*/
1.50 +#define SK_DIGITS_IN(t) SK_BASE_N_DIGITS_IN(10, (t))
1.51 +
1.52 +// Compile-time constant maximum value of two unsigned values.
1.53 +template <uintmax_t a, uintmax_t b> struct SkTUMax {
1.54 + static const uintmax_t value = (b < a) ? a : b;
1.55 +};
1.56 +
1.57 +#endif
