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author | Feng Xiao <xfxyjwf@gmail.com> | 2015-06-17 13:12:11 -0700 |
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committer | Feng Xiao <xfxyjwf@gmail.com> | 2015-06-17 13:12:11 -0700 |
commit | e9a122eb19ec54dbca15da80355ed0c17cada9b1 (patch) | |
tree | fac37489873ccf47777b2e652db580f9315d7bc7 /src/google/protobuf/stubs/mathlimits.cc | |
parent | b36395b2bac88f70070544c325bc09234cb1f1a6 (diff) | |
parent | 818c5eee08840355d70d2f3bdf1a2f17986a5e70 (diff) | |
download | protobuf-e9a122eb19ec54dbca15da80355ed0c17cada9b1.tar.gz protobuf-e9a122eb19ec54dbca15da80355ed0c17cada9b1.tar.bz2 protobuf-e9a122eb19ec54dbca15da80355ed0c17cada9b1.zip |
Merge pull request #501 from xfxyjwf/down
Down-integrate from internal code base.
Diffstat (limited to 'src/google/protobuf/stubs/mathlimits.cc')
-rw-r--r-- | src/google/protobuf/stubs/mathlimits.cc | 144 |
1 files changed, 144 insertions, 0 deletions
diff --git a/src/google/protobuf/stubs/mathlimits.cc b/src/google/protobuf/stubs/mathlimits.cc new file mode 100644 index 00000000..0373b2bb --- /dev/null +++ b/src/google/protobuf/stubs/mathlimits.cc @@ -0,0 +1,144 @@ +// 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 +// + +#include <google/protobuf/stubs/mathlimits.h> + +#include <google/protobuf/stubs/common.h> + +namespace google { +namespace protobuf { + +// MSVC++ 2005 and older compilers think the header declaration was a +// definition, and erroneously flag these as a duplicate definition. +#if defined(COMPILER_MSVC) || __cpluscplus < 201103L + +#define DEF_COMMON_LIMITS(Type) +#define DEF_UNSIGNED_INT_LIMITS(Type) +#define DEF_SIGNED_INT_LIMITS(Type) +#define DEF_PRECISION_LIMITS(Type) + +#else + +#define DEF_COMMON_LIMITS(Type) \ +const bool MathLimits<Type>::kIsSigned; \ +const bool MathLimits<Type>::kIsInteger; \ +const int MathLimits<Type>::kMin10Exp; \ +const int MathLimits<Type>::kMax10Exp; + +#define DEF_UNSIGNED_INT_LIMITS(Type) \ +DEF_COMMON_LIMITS(Type) \ +const Type MathLimits<Type>::kPosMin; \ +const Type MathLimits<Type>::kPosMax; \ +const Type MathLimits<Type>::kMin; \ +const Type MathLimits<Type>::kMax; \ +const Type MathLimits<Type>::kEpsilon; \ +const Type MathLimits<Type>::kStdError; + +#define DEF_SIGNED_INT_LIMITS(Type) \ +DEF_UNSIGNED_INT_LIMITS(Type) \ +const Type MathLimits<Type>::kNegMin; \ +const Type MathLimits<Type>::kNegMax; + +#define DEF_PRECISION_LIMITS(Type) \ +const int MathLimits<Type>::kPrecisionDigits; + +#endif // not COMPILER_MSVC + +// http://en.wikipedia.org/wiki/Quadruple_precision_floating-point_format#Double-double_arithmetic +// With some compilers (gcc 4.6.x) on some platforms (powerpc64), +// "long double" is implemented as a pair of double: "double double" format. +// This causes a problem with epsilon (eps). +// eps is the smallest positive number such that 1.0 + eps > 1.0 +// +// Normal format: 1.0 + e = 1.0...01 // N-1 zeros for N fraction bits +// D-D format: 1.0 + e = 1.000...0001 // epsilon can be very small +// +// In the normal format, 1.0 + e has to fit in one stretch of bits. +// The maximum rounding error is half of eps. +// +// In the double-double format, 1.0 + e splits across two doubles: +// 1.0 in the high double, e in the low double, and they do not have to +// be contiguous. The maximum rounding error on a value close to 1.0 is +// much larger than eps. +// +// Some code checks for errors by comparing a computed value to a golden +// value +/- some multiple of the maximum rounding error. The maximum +// rounding error is not available so we use eps as an approximation +// instead. That fails when long double is in the double-double format. +// Therefore, we define kStdError as a multiple of +// max(DBL_EPSILON * DBL_EPSILON, kEpsilon) rather than a multiple of kEpsilon. + +#define DEF_FP_LIMITS(Type, PREFIX) \ +DEF_COMMON_LIMITS(Type) \ +const Type MathLimits<Type>::kPosMin = PREFIX##_MIN; \ +const Type MathLimits<Type>::kPosMax = PREFIX##_MAX; \ +const Type MathLimits<Type>::kMin = -MathLimits<Type>::kPosMax; \ +const Type MathLimits<Type>::kMax = MathLimits<Type>::kPosMax; \ +const Type MathLimits<Type>::kNegMin = -MathLimits<Type>::kPosMin; \ +const Type MathLimits<Type>::kNegMax = -MathLimits<Type>::kPosMax; \ +const Type MathLimits<Type>::kEpsilon = PREFIX##_EPSILON; \ +/* 32 is 5 bits of mantissa error; should be adequate for common errors */ \ +const Type MathLimits<Type>::kStdError = \ + 32 * (DBL_EPSILON * DBL_EPSILON > MathLimits<Type>::kEpsilon \ + ? DBL_EPSILON * DBL_EPSILON : MathLimits<Type>::kEpsilon); \ +DEF_PRECISION_LIMITS(Type) \ +const Type MathLimits<Type>::kNaN = HUGE_VAL - HUGE_VAL; \ +const Type MathLimits<Type>::kPosInf = HUGE_VAL; \ +const Type MathLimits<Type>::kNegInf = -HUGE_VAL; + +// The following are *not* casts! +DEF_SIGNED_INT_LIMITS(int8) +DEF_SIGNED_INT_LIMITS(int16) // NOLINT(readability/casting) +DEF_SIGNED_INT_LIMITS(int32) // NOLINT(readability/casting) +DEF_SIGNED_INT_LIMITS(int64) // NOLINT(readability/casting) +DEF_UNSIGNED_INT_LIMITS(uint8) +DEF_UNSIGNED_INT_LIMITS(uint16) // NOLINT(readability/casting) +DEF_UNSIGNED_INT_LIMITS(uint32) // NOLINT(readability/casting) +DEF_UNSIGNED_INT_LIMITS(uint64) // NOLINT(readability/casting) + +DEF_SIGNED_INT_LIMITS(long int) +DEF_UNSIGNED_INT_LIMITS(unsigned long int) + +DEF_FP_LIMITS(float, FLT) +DEF_FP_LIMITS(double, DBL) +DEF_FP_LIMITS(long double, LDBL); + +#undef DEF_COMMON_LIMITS +#undef DEF_SIGNED_INT_LIMITS +#undef DEF_UNSIGNED_INT_LIMITS +#undef DEF_FP_LIMITS +#undef DEF_PRECISION_LIMITS +} // namespace protobuf +} // namespace google |