SkXPS: clean up SkConstexprMath

GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2000853003

Review-Url: https://codereview.chromium.org/2000853003

3 files changed, 11 insertions, 62 deletions

diff --git a/gyp/xps.gyp b/gyp/xps.gyp
index 2c96e36137..f326770ec4 100644
--- a/gyp/xps.gyp
+++ b/gyp/xps.gyp
@@ -22,7 +22,6 @@
             '../src/utils', # needed to get SkBitSet.h
           ],
           'sources': [
-            '../src/xps/SkConstexprMath.h',
             '../src/xps/SkDocument_XPS.cpp',
             '../src/xps/SkXPSDevice.cpp',
             '../src/xps/SkXPSDevice.h',
diff --git a/src/xps/SkConstexprMath.h b/src/xps/SkConstexprMath.h
deleted file mode 100644
index 9625d5112b..0000000000
--- a/src/xps/SkConstexprMath.h
+++ /dev/null
@@ -1,54 +0,0 @@
-/*
- * 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
diff --git a/src/xps/SkXPSDevice.cpp b/src/xps/SkXPSDevice.cpp
index aef9dc8baf..eb983fc0d7 100644
--- a/src/xps/SkXPSDevice.cpp
+++ b/src/xps/SkXPSDevice.cpp
@@ -18,9 +18,9 @@
 #include <XpsObjectModel.h>
 #include <T2EmbApi.h>
 #include <FontSub.h>
+#include <limits>
 
 #include "SkColor.h"
-#include "SkConstexprMath.h"
 #include "SkData.h"
 #include "SkDraw.h"
 #include "SkEndian.h"
@@ -190,6 +190,10 @@ bool SkXPSDevice::beginSheet(
     return true;
 }
 
+template <typename T> static constexpr size_t sk_digits_in() {
+    return static_cast<size_t>(std::numeric_limits<T>::digits10 + 1);
+}
+
 HRESULT SkXPSDevice::createXpsThumbnail(IXpsOMPage* page,
                                         const unsigned int pageNum,
                                         IXpsOMImageResource** image) {
@@ -202,10 +206,9 @@ HRESULT SkXPSDevice::createXpsThumbnail(IXpsOMPage* page,
         "Could not create thumbnail generator.");
 
     SkTScopedComPtr<IOpcPartUri> partUri;
-    static const size_t size = SkTUMax<
-        SK_ARRAY_COUNT(L"/Documents/1/Metadata/.png") + SK_DIGITS_IN(pageNum),
-        SK_ARRAY_COUNT(L"/Metadata/" L_GUID_ID L".png")
-    >::value;
+    constexpr size_t size = SkTMax(
+            SK_ARRAY_COUNT(L"/Documents/1/Metadata/.png") + sk_digits_in<decltype(pageNum)>(),
+            SK_ARRAY_COUNT(L"/Metadata/" L_GUID_ID L".png"));
     wchar_t buffer[size];
     if (pageNum > 0) {
         swprintf_s(buffer, size, L"/Documents/1/Metadata/%u.png", pageNum);
@@ -229,8 +232,9 @@ HRESULT SkXPSDevice::createXpsThumbnail(IXpsOMPage* page,
 
 HRESULT SkXPSDevice::createXpsPage(const XPS_SIZE& pageSize,
                                    IXpsOMPage** page) {
-    static const size_t size = SK_ARRAY_COUNT(L"/Documents/1/Pages/.fpage")
-                             + SK_DIGITS_IN(fCurrentPage);
+    constexpr size_t size =
+        SK_ARRAY_COUNT(L"/Documents/1/Pages/.fpage")
+        + sk_digits_in<decltype(fCurrentPage)>();
     wchar_t buffer[size];
     swprintf_s(buffer, size, L"/Documents/1/Pages/%u.fpage",
                              this->fCurrentPage);