Add xps device to skia.

http://codereview.appspot.com/5076041/


git-svn-id: http://skia.googlecode.com/svn/trunk@2437 2bbb7eff-a529-9590-31e7-b0007b416f81

1 files changed, 52 insertions, 0 deletions

diff --git a/include/device/xps/SkConstexprMath.h b/include/device/xps/SkConstexprMath.h
new file mode 100644
index 0000000000..65b70b6eea
--- /dev/null
+++ b/include/device/xps/SkConstexprMath.h
@@ -0,0 +1,52 @@
+/*
+ * 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))
+
+//! a > b ? a : b
+#define SK_MAX(a,b) (((a) > (b)) ? (a) : (b))
+
+#endif