// Protocol Buffers - Google's data interchange format
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// Copyright 2008 Google Inc. All rights reserved.
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// https://developers.google.com/protocol-buffers/
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//
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// Redistribution and use in source and binary forms, with or without
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// modification, are permitted provided that the following conditions are
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// met:
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//
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// * Redistributions of source code must retain the above copyright
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// notice, this list of conditions and the following disclaimer.
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// * Redistributions in binary form must reproduce the above
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// copyright notice, this list of conditions and the following disclaimer
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// in the documentation and/or other materials provided with the
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// distribution.
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// * Neither the name of Google Inc. nor the names of its
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// contributors may be used to endorse or promote products derived from
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// this software without specific prior written permission.
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//
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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// Defines classes for field comparison.
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#ifndef GOOGLE_PROTOBUF_UTIL_FIELD_COMPARATOR_H__
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#define GOOGLE_PROTOBUF_UTIL_FIELD_COMPARATOR_H__
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#include <map>
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#include <string>
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#include <google/protobuf/stubs/common.h>
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namespace google {
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namespace protobuf {
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class Message;
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class EnumValueDescriptor;
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class FieldDescriptor;
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namespace util {
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class FieldContext;
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// Base class specifying the interface for comparing protocol buffer fields.
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// Regular users should consider using or subclassing DefaultFieldComparator
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// rather than this interface.
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// Currently, this does not support comparing unknown fields.
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class LIBPROTOBUF_EXPORT FieldComparator {
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public:
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FieldComparator();
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virtual ~FieldComparator();
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enum ComparisonResult {
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SAME, // Compared fields are equal. In case of comparing submessages,
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// user should not recursively compare their contents.
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DIFFERENT, // Compared fields are different. In case of comparing
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// submessages, user should not recursively compare their
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// contents.
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RECURSE, // Compared submessages need to be compared recursively.
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// FieldComparator does not specify the semantics of recursive
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// comparison. This value should not be returned for simple
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// values.
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};
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// Compares the values of a field in two protocol buffer messages.
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// Returns SAME or DIFFERENT for simple values, and SAME, DIFFERENT or RECURSE
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// for submessages. Returning RECURSE for fields not being submessages is
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// illegal.
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// In case the given FieldDescriptor points to a repeated field, the indices
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// need to be valid. Otherwise they should be ignored.
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//
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// FieldContext contains information about the specific instances of the
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// fields being compared, versus FieldDescriptor which only contains general
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// type information about the fields.
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virtual ComparisonResult Compare(
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const google::protobuf::Message& message_1,
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const google::protobuf::Message& message_2,
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const google::protobuf::FieldDescriptor* field,
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int index_1, int index_2,
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const google::protobuf::util::FieldContext* field_context) = 0;
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private:
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GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(FieldComparator);
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};
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// Basic implementation of FieldComparator. Supports three modes of floating
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// point value comparison: exact, approximate using MathUtil::AlmostEqual
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// method, and arbitrarily precise using MathUtil::WithinFractionOrMargin.
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class LIBPROTOBUF_EXPORT DefaultFieldComparator : public FieldComparator {
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public:
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enum FloatComparison {
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EXACT, // Floats and doubles are compared exactly.
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APPROXIMATE, // Floats and doubles are compared using the
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// MathUtil::AlmostEqual method or
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// MathUtil::WithinFractionOrMargin method.
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// TODO(ksroka): Introduce third value to differenciate uses of AlmostEqual
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// and WithinFractionOrMargin.
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};
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// Creates new comparator with float comparison set to EXACT.
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DefaultFieldComparator();
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virtual ~DefaultFieldComparator();
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virtual ComparisonResult Compare(
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const google::protobuf::Message& message_1,
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const google::protobuf::Message& message_2,
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const google::protobuf::FieldDescriptor* field,
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int index_1, int index_2,
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const google::protobuf::util::FieldContext* field_context);
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void set_float_comparison(FloatComparison float_comparison) {
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float_comparison_ = float_comparison;
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}
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FloatComparison float_comparison() const {
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return float_comparison_;
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}
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// Set whether the FieldComparator shall treat floats or doubles that are both
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// NaN as equal (treat_nan_as_equal = true) or as different
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// (treat_nan_as_equal = false). Default is treating NaNs always as different.
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void set_treat_nan_as_equal(bool treat_nan_as_equal) {
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treat_nan_as_equal_ = treat_nan_as_equal;
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}
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bool treat_nan_as_equal() const {
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return treat_nan_as_equal_;
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}
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// Sets the fraction and margin for the float comparison of a given field.
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// Uses MathUtil::WithinFractionOrMargin to compare the values.
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//
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// REQUIRES: field->cpp_type == FieldDescriptor::CPPTYPE_DOUBLE or
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// field->cpp_type == FieldDescriptor::CPPTYPE_FLOAT
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// REQUIRES: float_comparison_ == APPROXIMATE
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void SetFractionAndMargin(const FieldDescriptor* field, double fraction,
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double margin);
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// Sets the fraction and margin for the float comparison of all float and
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// double fields, unless a field has been given a specific setting via
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// SetFractionAndMargin() above.
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// Uses MathUtil::WithinFractionOrMargin to compare the values.
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//
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// REQUIRES: float_comparison_ == APPROXIMATE
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void SetDefaultFractionAndMargin(double fraction, double margin);
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private:
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// Defines the tolerance for floating point comparison (fraction and margin).
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struct Tolerance {
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double fraction;
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double margin;
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Tolerance()
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: fraction(0.0),
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margin(0.0) {}
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Tolerance(double f, double m)
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: fraction(f),
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margin(m) {}
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};
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// Defines the map to store the tolerances for floating point comparison.
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typedef std::map<const FieldDescriptor*, Tolerance> ToleranceMap;
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// The following methods get executed when CompareFields is called for the
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// basic types (instead of submessages). They return true on success. One
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// can use ResultFromBoolean() to convert that boolean to a ComparisonResult
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// value.
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bool CompareBool(const google::protobuf::FieldDescriptor& field,
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bool value_1, bool value_2) {
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return value_1 == value_2;
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}
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// Uses CompareDoubleOrFloat, a helper function used by both CompareDouble and
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// CompareFloat.
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bool CompareDouble(const google::protobuf::FieldDescriptor& field,
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double value_1, double value_2);
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bool CompareEnum(const google::protobuf::FieldDescriptor& field,
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const EnumValueDescriptor* value_1,
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const EnumValueDescriptor* value_2);
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// Uses CompareDoubleOrFloat, a helper function used by both CompareDouble and
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// CompareFloat.
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bool CompareFloat(const google::protobuf::FieldDescriptor& field,
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float value_1, float value_2);
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bool CompareInt32(const google::protobuf::FieldDescriptor& field,
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int32 value_1, int32 value_2) {
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return value_1 == value_2;
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}
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bool CompareInt64(const google::protobuf::FieldDescriptor& field,
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int64 value_1, int64 value_2) {
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return value_1 == value_2;
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}
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bool CompareString(const google::protobuf::FieldDescriptor& field,
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const string& value_1, const string& value_2) {
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return value_1 == value_2;
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}
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bool CompareUInt32(const google::protobuf::FieldDescriptor& field,
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uint32 value_1, uint32 value_2) {
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return value_1 == value_2;
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}
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bool CompareUInt64(const google::protobuf::FieldDescriptor& field,
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uint64 value_1, uint64 value_2) {
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return value_1 == value_2;
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}
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// This function is used by CompareDouble and CompareFloat to avoid code
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// duplication. There are no checks done against types of the values passed,
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// but it's likely to fail if passed non-numeric arguments.
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template<typename T>
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bool CompareDoubleOrFloat(const google::protobuf::FieldDescriptor& field,
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T value_1, T value_2);
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// Returns FieldComparator::SAME if boolean_result is true and
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// FieldComparator::DIFFERENT otherwise.
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ComparisonResult ResultFromBoolean(bool boolean_result) const;
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FloatComparison float_comparison_;
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// If true, floats and doubles that are both NaN are considered to be
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// equal. Otherwise, two floats or doubles that are NaN are considered to be
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// different.
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bool treat_nan_as_equal_;
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// True iff default_tolerance_ has been explicitly set.
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//
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// If false, then the default tolerance for flaots and doubles is that which
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// is used by MathUtil::AlmostEquals().
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bool has_default_tolerance_;
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// Default float/double tolerance. Only meaningful if
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// has_default_tolerance_ == true.
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Tolerance default_tolerance_;
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// Field-specific float/double tolerances, which override any default for
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// those particular fields.
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ToleranceMap map_tolerance_;
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GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(DefaultFieldComparator);
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};
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} // namespace util
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} // namespace protobuf
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} // namespace google
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#endif // GOOGLE_PROTOBUF_UTIL_FIELD_COMPARATOR_H__
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