Down-integrate from internal code base.

[ci skip]

Change-Id: I9391c09640e0b0b2b21c45a97a1fc91814d95c5d

1 files changed, 277 insertions, 0 deletions

diff --git a/src/google/protobuf/stubs/mathlimits.h b/src/google/protobuf/stubs/mathlimits.h
new file mode 100644
index 00000000..39957d69
--- /dev/null
+++ b/src/google/protobuf/stubs/mathlimits.h
@@ -0,0 +1,277 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// All Rights Reserved.
+//
+// Author: Maxim Lifantsev
+//
+// Useful integer and floating point limits and type traits.
+//
+// This partially replaces/duplictes numeric_limits<> from <limits>.
+// We get a Google-style class that we have a greater control over
+// and thus can add new features to it or fix whatever happens to be broken in
+// numeric_limits for the compilers we use.
+//
+
+#ifndef UTIL_MATH_MATHLIMITS_H__
+#define UTIL_MATH_MATHLIMITS_H__
+
+// <math.h> lacks a lot of prototypes. However, this file needs <math.h> to
+// access old-fashioned isinf et al. Even worse more: this file must not
+// include <cmath> because that breaks the definition of isinf with gcc 4.9.
+//
+// TODO(mec): after C++11 everywhere, use <cmath> and std::isinf in this file.
+#include <math.h>
+#include <string.h>
+
+#include <cfloat>
+
+// ========================================================================= //
+
+// Useful integer and floating point limits and type traits.
+// This is just for the documentation;
+// real members are defined in our specializations below.
+namespace google {
+namespace protobuf {
+template<typename T> struct MathLimits {
+  // Type name.
+  typedef T Type;
+  // Unsigned version of the Type with the same byte size.
+  // Same as Type for floating point and unsigned types.
+  typedef T UnsignedType;
+  // If the type supports negative values.
+  static const bool kIsSigned;
+  // If the type supports only integer values.
+  static const bool kIsInteger;
+  // Magnitude-wise smallest representable positive value.
+  static const Type kPosMin;
+  // Magnitude-wise largest representable positive value.
+  static const Type kPosMax;
+  // Smallest representable value.
+  static const Type kMin;
+  // Largest representable value.
+  static const Type kMax;
+  // Magnitude-wise smallest representable negative value.
+  // Present only if kIsSigned.
+  static const Type kNegMin;
+  // Magnitude-wise largest representable negative value.
+  // Present only if kIsSigned.
+  static const Type kNegMax;
+  // Smallest integer x such that 10^x is representable.
+  static const int kMin10Exp;
+  // Largest integer x such that 10^x is representable.
+  static const int kMax10Exp;
+  // Smallest positive value such that Type(1) + kEpsilon != Type(1)
+  static const Type kEpsilon;
+  // Typical rounding error that is enough to cover
+  // a few simple floating-point operations.
+  // Slightly larger than kEpsilon to account for a few rounding errors.
+  // Is zero if kIsInteger.
+  static const Type kStdError;
+  // Number of decimal digits of mantissa precision.
+  // Present only if !kIsInteger.
+  static const int kPrecisionDigits;
+  // Not a number, i.e. result of 0/0.
+  // Present only if !kIsInteger.
+  static const Type kNaN;
+  // Positive infinity, i.e. result of 1/0.
+  // Present only if !kIsInteger.
+  static const Type kPosInf;
+  // Negative infinity, i.e. result of -1/0.
+  // Present only if !kIsInteger.
+  static const Type kNegInf;
+
+  // NOTE: Special floating point values behave
+  // in a special (but mathematically-logical) way
+  // in terms of (in)equalty comparison and mathematical operations
+  // -- see out unittest for examples.
+
+  // Special floating point value testers.
+  // Present in integer types for convenience.
+  static bool IsFinite(const Type x);
+  static bool IsNaN(const Type x);
+  static bool IsInf(const Type x);
+  static bool IsPosInf(const Type x);
+  static bool IsNegInf(const Type x);
+};
+
+// ========================================================================= //
+
+// All #define-s below are simply to refactor the declarations of
+// MathLimits template specializations.
+// They are all #undef-ined below.
+
+// The hoop-jumping in *_INT_(MAX|MIN) below is so that the compiler does not
+// get an overflow while computing the constants.
+
+#define SIGNED_INT_MAX(Type) \
+  (((Type(1) << (sizeof(Type)*8 - 2)) - 1) + (Type(1) << (sizeof(Type)*8 - 2)))
+
+#define SIGNED_INT_MIN(Type) \
+  (-(Type(1) << (sizeof(Type)*8 - 2)) - (Type(1) << (sizeof(Type)*8 - 2)))
+
+#define UNSIGNED_INT_MAX(Type) \
+  (((Type(1) << (sizeof(Type)*8 - 1)) - 1) + (Type(1) << (sizeof(Type)*8 - 1)))
+
+// Compile-time selected log10-related constants for integer types.
+#define SIGNED_MAX_10_EXP(Type) \
+  (sizeof(Type) == 1 ? 2 : ( \
+    sizeof(Type) == 2 ? 4 : ( \
+      sizeof(Type) == 4 ? 9 : ( \
+        sizeof(Type) == 8 ? 18 : -1))))
+
+#define UNSIGNED_MAX_10_EXP(Type) \
+  (sizeof(Type) == 1 ? 2 : ( \
+    sizeof(Type) == 2 ? 4 : ( \
+      sizeof(Type) == 4 ? 9 : ( \
+        sizeof(Type) == 8 ? 19 : -1))))
+
+#define DECL_INT_LIMIT_FUNCS \
+  static bool IsFinite(const Type /*x*/) { return true; } \
+  static bool IsNaN(const Type /*x*/) { return false; } \
+  static bool IsInf(const Type /*x*/) { return false; } \
+  static bool IsPosInf(const Type /*x*/) { return false; } \
+  static bool IsNegInf(const Type /*x*/) { return false; }
+
+#define DECL_SIGNED_INT_LIMITS(IntType, UnsignedIntType) \
+template<> \
+struct MathLimits<IntType> { \
+  typedef IntType Type; \
+  typedef UnsignedIntType UnsignedType; \
+  static const bool kIsSigned = true; \
+  static const bool kIsInteger = true; \
+  static const Type kPosMin = 1; \
+  static const Type kPosMax = SIGNED_INT_MAX(Type); \
+  static const Type kMin = SIGNED_INT_MIN(Type); \
+  static const Type kMax = kPosMax; \
+  static const Type kNegMin = -1; \
+  static const Type kNegMax = kMin; \
+  static const int kMin10Exp = 0; \
+  static const int kMax10Exp = SIGNED_MAX_10_EXP(Type); \
+  static const Type kEpsilon = 1; \
+  static const Type kStdError = 0; \
+  DECL_INT_LIMIT_FUNCS \
+};
+
+#define DECL_UNSIGNED_INT_LIMITS(IntType) \
+template<> \
+struct MathLimits<IntType> { \
+  typedef IntType Type; \
+  typedef IntType UnsignedType; \
+  static const bool kIsSigned = false; \
+  static const bool kIsInteger = true; \
+  static const Type kPosMin = 1; \
+  static const Type kPosMax = UNSIGNED_INT_MAX(Type); \
+  static const Type kMin = 0; \
+  static const Type kMax = kPosMax; \
+  static const int kMin10Exp = 0; \
+  static const int kMax10Exp = UNSIGNED_MAX_10_EXP(Type); \
+  static const Type kEpsilon = 1; \
+  static const Type kStdError = 0; \
+  DECL_INT_LIMIT_FUNCS \
+};
+
+DECL_SIGNED_INT_LIMITS(signed char, unsigned char)
+DECL_SIGNED_INT_LIMITS(signed short int, unsigned short int)
+DECL_SIGNED_INT_LIMITS(signed int, unsigned int)
+DECL_SIGNED_INT_LIMITS(signed long int, unsigned long int)
+DECL_SIGNED_INT_LIMITS(signed long long int, unsigned long long int)
+DECL_UNSIGNED_INT_LIMITS(unsigned char)
+DECL_UNSIGNED_INT_LIMITS(unsigned short int)
+DECL_UNSIGNED_INT_LIMITS(unsigned int)
+DECL_UNSIGNED_INT_LIMITS(unsigned long int)
+DECL_UNSIGNED_INT_LIMITS(unsigned long long int)
+
+#undef DECL_SIGNED_INT_LIMITS
+#undef DECL_UNSIGNED_INT_LIMITS
+#undef SIGNED_INT_MAX
+#undef SIGNED_INT_MIN
+#undef UNSIGNED_INT_MAX
+#undef SIGNED_MAX_10_EXP
+#undef UNSIGNED_MAX_10_EXP
+#undef DECL_INT_LIMIT_FUNCS
+
+// ========================================================================= //
+#ifdef WIN32  // Lacks built-in isnan() and isinf()
+#define DECL_FP_LIMIT_FUNCS \
+  static bool IsFinite(const Type x) { return _finite(x); } \
+  static bool IsNaN(const Type x) { return _isnan(x); } \
+  static bool IsInf(const Type x) { return (_fpclass(x) & (_FPCLASS_NINF | _FPCLASS_PINF)) != 0; } \
+  static bool IsPosInf(const Type x) { return _fpclass(x) == _FPCLASS_PINF; } \
+  static bool IsNegInf(const Type x) { return _fpclass(x) == _FPCLASS_NINF; }
+#else
+#define DECL_FP_LIMIT_FUNCS \
+  static bool IsFinite(const Type x) { return !isinf(x)  &&  !isnan(x); } \
+  static bool IsNaN(const Type x) { return isnan(x); } \
+  static bool IsInf(const Type x) { return isinf(x); } \
+  static bool IsPosInf(const Type x) { return isinf(x)  &&  x > 0; } \
+  static bool IsNegInf(const Type x) { return isinf(x)  &&  x < 0; }
+#endif
+
+// We can't put floating-point constant values in the header here because
+// such constants are not considered to be primitive-type constants by gcc.
+// CAVEAT: Hence, they are going to be initialized only during
+// the global objects construction time.
+#define DECL_FP_LIMITS(FP_Type, PREFIX) \
+template<> \
+struct MathLimits<FP_Type> { \
+  typedef FP_Type Type; \
+  typedef FP_Type UnsignedType; \
+  static const bool kIsSigned = true; \
+  static const bool kIsInteger = false; \
+  static const Type kPosMin; \
+  static const Type kPosMax; \
+  static const Type kMin; \
+  static const Type kMax; \
+  static const Type kNegMin; \
+  static const Type kNegMax; \
+  static const int kMin10Exp = PREFIX##_MIN_10_EXP; \
+  static const int kMax10Exp = PREFIX##_MAX_10_EXP; \
+  static const Type kEpsilon; \
+  static const Type kStdError; \
+  static const int kPrecisionDigits = PREFIX##_DIG; \
+  static const Type kNaN; \
+  static const Type kPosInf; \
+  static const Type kNegInf; \
+  DECL_FP_LIMIT_FUNCS \
+};
+
+DECL_FP_LIMITS(float, FLT)
+DECL_FP_LIMITS(double, DBL)
+DECL_FP_LIMITS(long double, LDBL)
+
+#undef DECL_FP_LIMITS
+#undef DECL_FP_LIMIT_FUNCS
+
+// ========================================================================= //
+}  // namespace protobuf
+}  // namespace google
+
+#endif  // UTIL_MATH_MATHLIMITS_H__