SkXPS: clean up SkConstexprMath

src/xps/SkConstexprMath.h

-/*
- * Copyright 2011 Google Inc.
- *
- * Use of this source code is governed by a BSD-style license that can be
- * found in the LICENSE file.
- */
-
-#ifndef SkConstexprMath_DEFINED
-#define SkConstexprMath_DEFINED
-
-#include "SkTypes.h"
-#include <limits.h>
-
-template <uintmax_t N, uintmax_t B>
-struct SK_LOG {
-    //! Compile-time constant ceiling(logB(N)).
-    static const uintmax_t value = 1 + SK_LOG<N/B, B>::value;
-};
-template <uintmax_t B>
-struct SK_LOG<1, B> {
-    static const uintmax_t value = 0;
-};
-template <uintmax_t B>
-struct SK_LOG<0, B> {
-    static const uintmax_t value = 0;
-};
-
-template<uintmax_t N>
-struct SK_2N1 {
-    //! Compile-time constant (2^N)-1.
-    static const uintmax_t value = (SK_2N1<N-1>::value << 1) + 1;
-};
-template<>
-struct SK_2N1<1> {
-    static const uintmax_t value = 1;
-};
-
-/** Compile-time constant number of base n digits in type t
-    if the bits of type t are considered as unsigned base two.
-*/
-#define SK_BASE_N_DIGITS_IN(n, t) (\
-    SK_LOG<SK_2N1<(sizeof(t) * CHAR_BIT)>::value, n>::value\
-)
-/** Compile-time constant number of base 10 digits in type t
-    if the bits of type t are considered as unsigned base two.
-*/
-#define SK_DIGITS_IN(t) SK_BASE_N_DIGITS_IN(10, (t))
-
-// Compile-time constant maximum value of two unsigned values.
-template <uintmax_t a, uintmax_t b> struct SkTUMax {
-    static const uintmax_t value = (b < a) ? a : b;
-};
-
-#endif