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authorGravatar bungeman <bungeman@google.com>2016-03-18 11:53:16 -0700
committerGravatar Commit bot <commit-bot@chromium.org>2016-03-18 11:53:17 -0700
commit89edf7a95ea694ba2c0a33adedf553c4183cdc19 (patch)
tree6dd865d3de54c759716c768ece94760a82b979a3 /include/private/SkTFitsIn.h
parent8bea8905e406fc1d15ef5a8294a735f3d33fb2d0 (diff)
Revert of Templatize SkToXXX. (patchset #2 id:20001 of https://codereview.chromium.org/1814153003/ )
Reason for revert: Chrome does not yet have std::underlying_type. Original issue's description: > Templatize SkToXXX. > > Makes the checked cast in debug more correct, avoiding new > warnings in vs2015. > > BUG=skia:4553 > > Committed: https://skia.googlesource.com/skia/+/0be9e806af72b3e029e691eef5c891c90d3fd320 TBR=reed@google.com,mtklein@google.com # Skipping CQ checks because original CL landed less than 1 days ago. NOPRESUBMIT=true NOTREECHECKS=true NOTRY=true BUG=skia:4553 Review URL: https://codereview.chromium.org/1820433002
Diffstat (limited to 'include/private/SkTFitsIn.h')
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1 files changed, 0 insertions, 227 deletions
diff --git a/include/private/SkTFitsIn.h b/include/private/SkTFitsIn.h
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-/*
- * Copyright 2013 Google Inc.
- *
- * Use of this source code is governed by a BSD-style license that can be
- * found in the LICENSE file.
- */
-
-#ifndef SkTFitsIn_DEFINED
-#define SkTFitsIn_DEFINED
-
-#include "../private/SkTLogic.h"
-#include <limits>
-#include <type_traits>
-
-namespace sktfitsin {
-namespace Private {
-
-/** SkTMux::type = (a && b) ? Both : (a) ? A : (b) ? B : Neither; */
-template <bool a, bool b, typename Both, typename A, typename B, typename Neither>
-struct SkTMux {
- using type = skstd::conditional_t<a, skstd::conditional_t<b, Both, A>,
- skstd::conditional_t<b, B, Neither>>;
-};
-
-/** SkTHasMoreDigits = (digits(A) >= digits(B)) ? true_type : false_type. */
-template <typename A, typename B> struct SkTHasMoreDigits
- : skstd::bool_constant<std::numeric_limits<A>::digits >= std::numeric_limits<B>::digits>
-{ };
-
-/** A high or low side predicate which is used when it is statically known
- * that source values are in the range of the Destination.
- */
-template <typename S> struct SkTOutOfRange_False {
- using can_be_true = std::false_type;
- using source_type = S;
- static bool apply(S) {
- return false;
- }
-};
-
-/** A low side predicate which tests if the source value < Min(D).
- * Assumes that Min(S) <= Min(D).
- */
-template <typename D, typename S> struct SkTOutOfRange_LT_MinD {
- using can_be_true = std::true_type;
- using source_type = S;
- static bool apply(S s) {
- using precondition = SkTHasMoreDigits<S, D>;
- static_assert(precondition::value, "minS > minD");
-
- return s < static_cast<S>((std::numeric_limits<D>::min)());
- }
-};
-
-/** A low side predicate which tests if the source value is less than 0. */
-template <typename D, typename S> struct SkTOutOfRange_LT_Zero {
- using can_be_true = std::true_type;
- using source_type = S;
- static bool apply(S s) {
- return s < static_cast<S>(0);
- }
-};
-
-/** A high side predicate which tests if the source value > Max(D).
- * Assumes that Max(S) >= Max(D).
- */
-template <typename D, typename S> struct SkTOutOfRange_GT_MaxD {
- using can_be_true = std::true_type;
- using source_type = S;
- static bool apply(S s) {
- using precondition = SkTHasMoreDigits<S, D>;
- static_assert(precondition::value, "maxS < maxD");
-
- return s > static_cast<S>((std::numeric_limits<D>::max)());
- }
-};
-
-/** Composes two SkTOutOfRange predicates.
- * First checks OutOfRange_Low then, if in range, OutOfRange_High.
- */
-template <typename OutOfRange_Low, typename OutOfRange_High> struct SkTOutOfRange_Either {
- using can_be_true = std::true_type;
- using source_type = typename OutOfRange_Low::source_type;
- static bool apply(source_type s) {
- bool outOfRange = OutOfRange_Low::apply(s);
- if (!outOfRange) {
- outOfRange = OutOfRange_High::apply(s);
- }
- return outOfRange;
- }
-};
-
-/** SkTCombineOutOfRange::type is an SkTOutOfRange_XXX type which is the
- * optimal combination of OutOfRange_Low and OutOfRange_High.
- */
-template <typename OutOfRange_Low, typename OutOfRange_High> struct SkTCombineOutOfRange {
- using Both = SkTOutOfRange_Either<OutOfRange_Low, OutOfRange_High>;
- using Neither = SkTOutOfRange_False<typename OutOfRange_Low::source_type>;
-
- using apply_low = typename OutOfRange_Low::can_be_true;
- using apply_high = typename OutOfRange_High::can_be_true;
-
- using type = typename SkTMux<apply_low::value, apply_high::value,
- Both, OutOfRange_Low, OutOfRange_High, Neither>::type;
-};
-
-template <typename D, typename S, typename OutOfRange_Low, typename OutOfRange_High>
-struct SkTRangeChecker {
- /** This is the method which is called at runtime to do the range check. */
- static bool OutOfRange(S s) {
- using Combined = typename SkTCombineOutOfRange<OutOfRange_Low, OutOfRange_High>::type;
- return Combined::apply(s);
- }
-};
-
-/** SkTFitsIn_Unsigned2Unsiged::type is an SkTRangeChecker with an OutOfRange(S s) method
- * the implementation of which is tailored for the source and destination types.
- * Assumes that S and D are unsigned integer types.
- */
-template <typename D, typename S> struct SkTFitsIn_Unsigned2Unsiged {
- using OutOfRange_Low = SkTOutOfRange_False<S>;
- using OutOfRange_High = SkTOutOfRange_GT_MaxD<D, S>;
-
- using HighSideOnlyCheck = SkTRangeChecker<D, S, OutOfRange_Low, OutOfRange_High>;
- using NoCheck = SkTRangeChecker<D, S, SkTOutOfRange_False<S>, SkTOutOfRange_False<S>>;
-
- // If std::numeric_limits<D>::digits >= std::numeric_limits<S>::digits, nothing to check.
- // This also protects the precondition of SkTOutOfRange_GT_MaxD.
- using sourceFitsInDesitination = SkTHasMoreDigits<D, S>;
- using type = skstd::conditional_t<sourceFitsInDesitination::value, NoCheck, HighSideOnlyCheck>;
-};
-
-/** SkTFitsIn_Signed2Signed::type is an SkTRangeChecker with an OutOfRange(S s) method
- * the implementation of which is tailored for the source and destination types.
- * Assumes that S and D are signed integer types.
- */
-template <typename D, typename S> struct SkTFitsIn_Signed2Signed {
- using OutOfRange_Low = SkTOutOfRange_LT_MinD<D, S>;
- using OutOfRange_High = SkTOutOfRange_GT_MaxD<D, S>;
-
- using FullCheck = SkTRangeChecker<D, S, OutOfRange_Low, OutOfRange_High>;
- using NoCheck = SkTRangeChecker<D, S, SkTOutOfRange_False<S>, SkTOutOfRange_False<S>>;
-
- // If std::numeric_limits<D>::digits >= std::numeric_limits<S>::digits, nothing to check.
- // This also protects the precondition of SkTOutOfRange_LT_MinD and SkTOutOfRange_GT_MaxD.
- using sourceFitsInDesitination = SkTHasMoreDigits<D, S>;
- using type = skstd::conditional_t<sourceFitsInDesitination::value, NoCheck, FullCheck>;
-};
-
-/** SkTFitsIn_Signed2Unsigned::type is an SkTRangeChecker with an OutOfRange(S s) method
- * the implementation of which is tailored for the source and destination types.
- * Assumes that S is a signed integer type and D is an unsigned integer type.
- */
-template <typename D, typename S> struct SkTFitsIn_Signed2Unsigned {
- using OutOfRange_Low = SkTOutOfRange_LT_Zero<D, S>;
- using OutOfRange_High = SkTOutOfRange_GT_MaxD<D, S>;
-
- using FullCheck = SkTRangeChecker<D, S, OutOfRange_Low, OutOfRange_High>;
- using LowSideOnlyCheck = SkTRangeChecker<D, S, OutOfRange_Low, SkTOutOfRange_False<S>>;
-
- // If std::numeric_limits<D>::max() >= std::numeric_limits<S>::max(),
- // no need to check the high side. (Until C++11, assume more digits means greater max.)
- // This also protects the precondition of SkTOutOfRange_GT_MaxD.
- using sourceCannotExceedDest = SkTHasMoreDigits<D, S>;
- using type = skstd::conditional_t<sourceCannotExceedDest::value, LowSideOnlyCheck, FullCheck>;
-};
-
-/** SkTFitsIn_Unsigned2Signed::type is an SkTRangeChecker with an OutOfRange(S s) method
- * the implementation of which is tailored for the source and destination types.
- * Assumes that S is an usigned integer type and D is a signed integer type.
- */
-template <typename D, typename S> struct SkTFitsIn_Unsigned2Signed {
- using OutOfRange_Low = SkTOutOfRange_False<S>;
- using OutOfRange_High = SkTOutOfRange_GT_MaxD<D, S>;
-
- using HighSideOnlyCheck = SkTRangeChecker<D, S, OutOfRange_Low, OutOfRange_High>;
- using NoCheck = SkTRangeChecker<D, S, SkTOutOfRange_False<S>, SkTOutOfRange_False<S>>;
-
- // If std::numeric_limits<D>::max() >= std::numeric_limits<S>::max(), nothing to check.
- // (Until C++11, assume more digits means greater max.)
- // This also protects the precondition of SkTOutOfRange_GT_MaxD.
- using sourceCannotExceedDest = SkTHasMoreDigits<D, S>;
- using type = skstd::conditional_t<sourceCannotExceedDest::value, NoCheck, HighSideOnlyCheck>;
-};
-
-/** SkTFitsIn::type is an SkTRangeChecker with an OutOfRange(S s) method
- * the implementation of which is tailored for the source and destination types.
- * Assumes that S and D are integer types.
- */
-template <typename D, typename S> struct SkTFitsIn {
- // One of the following will be the 'selector' type.
- using S2S = SkTFitsIn_Signed2Signed<D, S>;
- using S2U = SkTFitsIn_Signed2Unsigned<D, S>;
- using U2S = SkTFitsIn_Unsigned2Signed<D, S>;
- using U2U = SkTFitsIn_Unsigned2Unsiged<D, S>;
-
- using S_is_signed = skstd::bool_constant<std::numeric_limits<S>::is_signed>;
- using D_is_signed = skstd::bool_constant<std::numeric_limits<D>::is_signed>;
-
- using selector = typename SkTMux<S_is_signed::value, D_is_signed::value,
- S2S, S2U, U2S, U2U>::type;
- // This type is an SkTRangeChecker.
- using type = typename selector::type;
-};
-
-template <typename T, bool = std::is_enum<T>::value> struct underlying_type {
- using type = skstd::underlying_type_t<T>;
-};
-template <typename T> struct underlying_type<T, false> {
- using type = T;
-};
-
-} // namespace Private
-} // namespace sktfitsin
-
-/** Returns true if the integer source value 's' will fit in the integer destination type 'D'. */
-template <typename D, typename S> inline bool SkTFitsIn(S s) {
- static_assert(std::is_integral<S>::value || std::is_enum<S>::value, "S must be integral.");
- static_assert(std::is_integral<D>::value || std::is_enum<D>::value, "D must be integral.");
-
- using RealS = typename sktfitsin::Private::underlying_type<S>::type;
- using RealD = typename sktfitsin::Private::underlying_type<D>::type;
-
- return !sktfitsin::Private::SkTFitsIn<RealD, RealS>::type::OutOfRange(s);
-}
-
-#endif