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Diffstat (limited to 'third_party/protobuf/3.6.0/python/google/protobuf/pyext/safe_numerics.h')
-rw-r--r-- | third_party/protobuf/3.6.0/python/google/protobuf/pyext/safe_numerics.h | 164 |
1 files changed, 164 insertions, 0 deletions
diff --git a/third_party/protobuf/3.6.0/python/google/protobuf/pyext/safe_numerics.h b/third_party/protobuf/3.6.0/python/google/protobuf/pyext/safe_numerics.h new file mode 100644 index 0000000000..639ba2c8e3 --- /dev/null +++ b/third_party/protobuf/3.6.0/python/google/protobuf/pyext/safe_numerics.h @@ -0,0 +1,164 @@ +// 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. + +#ifndef GOOGLE_PROTOBUF_PYTHON_CPP_SAFE_NUMERICS_H__ +#define GOOGLE_PROTOBUF_PYTHON_CPP_SAFE_NUMERICS_H__ +// Copied from chromium with only changes to the namespace. + +#include <limits> + +#include <google/protobuf/stubs/logging.h> +#include <google/protobuf/stubs/common.h> + +namespace google { +namespace protobuf { +namespace python { + +template <bool SameSize, bool DestLarger, + bool DestIsSigned, bool SourceIsSigned> +struct IsValidNumericCastImpl; + +#define BASE_NUMERIC_CAST_CASE_SPECIALIZATION(A, B, C, D, Code) \ +template <> struct IsValidNumericCastImpl<A, B, C, D> { \ + template <class Source, class DestBounds> static inline bool Test( \ + Source source, DestBounds min, DestBounds max) { \ + return Code; \ + } \ +} + +#define BASE_NUMERIC_CAST_CASE_SAME_SIZE(DestSigned, SourceSigned, Code) \ + BASE_NUMERIC_CAST_CASE_SPECIALIZATION( \ + true, true, DestSigned, SourceSigned, Code); \ + BASE_NUMERIC_CAST_CASE_SPECIALIZATION( \ + true, false, DestSigned, SourceSigned, Code) + +#define BASE_NUMERIC_CAST_CASE_SOURCE_LARGER(DestSigned, SourceSigned, Code) \ + BASE_NUMERIC_CAST_CASE_SPECIALIZATION( \ + false, false, DestSigned, SourceSigned, Code); \ + +#define BASE_NUMERIC_CAST_CASE_DEST_LARGER(DestSigned, SourceSigned, Code) \ + BASE_NUMERIC_CAST_CASE_SPECIALIZATION( \ + false, true, DestSigned, SourceSigned, Code); \ + +// The three top level cases are: +// - Same size +// - Source larger +// - Dest larger +// And for each of those three cases, we handle the 4 different possibilities +// of signed and unsigned. This gives 12 cases to handle, which we enumerate +// below. +// +// The last argument in each of the macros is the actual comparison code. It +// has three arguments available, source (the value), and min/max which are +// the ranges of the destination. + + +// These are the cases where both types have the same size. + +// Both signed. +BASE_NUMERIC_CAST_CASE_SAME_SIZE(true, true, true); +// Both unsigned. +BASE_NUMERIC_CAST_CASE_SAME_SIZE(false, false, true); +// Dest unsigned, Source signed. +BASE_NUMERIC_CAST_CASE_SAME_SIZE(false, true, source >= 0); +// Dest signed, Source unsigned. +// This cast is OK because Dest's max must be less than Source's. +BASE_NUMERIC_CAST_CASE_SAME_SIZE(true, false, + source <= static_cast<Source>(max)); + + +// These are the cases where Source is larger. + +// Both unsigned. +BASE_NUMERIC_CAST_CASE_SOURCE_LARGER(false, false, source <= max); +// Both signed. +BASE_NUMERIC_CAST_CASE_SOURCE_LARGER(true, true, + source >= min && source <= max); +// Dest is unsigned, Source is signed. +BASE_NUMERIC_CAST_CASE_SOURCE_LARGER(false, true, + source >= 0 && source <= max); +// Dest is signed, Source is unsigned. +// This cast is OK because Dest's max must be less than Source's. +BASE_NUMERIC_CAST_CASE_SOURCE_LARGER(true, false, + source <= static_cast<Source>(max)); + + +// These are the cases where Dest is larger. + +// Both unsigned. +BASE_NUMERIC_CAST_CASE_DEST_LARGER(false, false, true); +// Both signed. +BASE_NUMERIC_CAST_CASE_DEST_LARGER(true, true, true); +// Dest is unsigned, Source is signed. +BASE_NUMERIC_CAST_CASE_DEST_LARGER(false, true, source >= 0); +// Dest is signed, Source is unsigned. +BASE_NUMERIC_CAST_CASE_DEST_LARGER(true, false, true); + +#undef BASE_NUMERIC_CAST_CASE_SPECIALIZATION +#undef BASE_NUMERIC_CAST_CASE_SAME_SIZE +#undef BASE_NUMERIC_CAST_CASE_SOURCE_LARGER +#undef BASE_NUMERIC_CAST_CASE_DEST_LARGER + + +// The main test for whether the conversion will under or overflow. +template <class Dest, class Source> +inline bool IsValidNumericCast(Source source) { + typedef std::numeric_limits<Source> SourceLimits; + typedef std::numeric_limits<Dest> DestLimits; + GOOGLE_COMPILE_ASSERT(SourceLimits::is_specialized, argument_must_be_numeric); + GOOGLE_COMPILE_ASSERT(SourceLimits::is_integer, argument_must_be_integral); + GOOGLE_COMPILE_ASSERT(DestLimits::is_specialized, result_must_be_numeric); + GOOGLE_COMPILE_ASSERT(DestLimits::is_integer, result_must_be_integral); + + return IsValidNumericCastImpl< + sizeof(Dest) == sizeof(Source), + (sizeof(Dest) > sizeof(Source)), + DestLimits::is_signed, + SourceLimits::is_signed>::Test( + source, + DestLimits::min(), + DestLimits::max()); +} + +// checked_numeric_cast<> is analogous to static_cast<> for numeric types, +// except that it CHECKs that the specified numeric conversion will not +// overflow or underflow. Floating point arguments are not currently allowed +// (this is COMPILE_ASSERTd), though this could be supported if necessary. +template <class Dest, class Source> +inline Dest checked_numeric_cast(Source source) { + GOOGLE_CHECK(IsValidNumericCast<Dest>(source)); + return static_cast<Dest>(source); +} + +} // namespace python +} // namespace protobuf + +} // namespace google +#endif // GOOGLE_PROTOBUF_PYTHON_CPP_SAFE_NUMERICS_H__ |