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ortools-clone/util/const_int_array.h
2011-05-09 08:33:06 +00:00

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4.7 KiB
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// Copyright 2010-2011 Google
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#ifndef UTIL_CONST_INT_ARRAY_H_
#define UTIL_CONST_INT_ARRAY_H_
#include <string>
#include <vector>
#include "base/basictypes.h"
#include "base/logging.h"
#include "base/scoped_ptr.h"
namespace operations_research {
// This class is used to store constant copies of int64 arrays inside
// constraints or expression. When constructed with a C array or a
// vector, The const int array will make a internal copy and own that
// copy. It will not take ownership of the vector/array which can be
// deleted afterwards. This follows the semantics of constraints and
// expressions which store a read-only copy of the data.
//
// Its goals are:
// - to unify the construction code across the optimization libraries.
// - to provide one code to scan these arrays and compute given properties like
// monotonicity.
//
// As const int arrays provide scanning capabilities, the code inside
// a constraint and its factory looks like:
//
// IntExpr* MakeMyExpr(const vector<int64>& values) {
// ConstIntArray copy(values);
// if (copy.Status(ConstIntArray::IS_INCREASING)) {
// return new MyOptimizedExpr(copy.Release());
// } else {
// return new MyGenericExpr(copy.Release());
// }
// }
//
// With:
// class MyOptimizedExpr : IntExpr {
// public:
// MyOptimizedExpr(vector<int64>* data) : values_(data) {}
// private:
// ConstIntArray values_;
// };
class ConstIntArray {
public:
// These describe static properties of the int64 array.
enum Property {
IS_CONSTANT = 0,
IS_STRICTLY_INCREASING = 1,
IS_INCREASING = 2,
IS_STRICTLY_DECREASING = 3,
IS_DECREASING = 4,
IS_BOOLEAN = 5, // in {0, 1}
IS_POSITIVE = 6, // > 0
IS_NEGATIVE = 7, // < 0
IS_POSITIVE_OR_NULL = 8, // >= 0
IS_NEGATIVE_OR_NULL = 9, // <= 0
NUM_PROPERTY = 10 // Sentinel.
};
// These constructors remove the needs to explicitely create an
// intermediate data storage.
explicit ConstIntArray(int64 v0);
ConstIntArray(int64 v0, int64 v1);
ConstIntArray(int64 v0, int64 v1, int64 v2);
ConstIntArray(int64 v0, int64 v1, int64 v2, int64 v3);
ConstIntArray(int64 v0, int64 v1, int64 v2, int64 v3, int64 v4);
ConstIntArray(int64 v0, int64 v1, int64 v2, int64 v3, int64 v4, int64 v5);
// Build from a vector. Copy the data internally.
explicit ConstIntArray(const vector<int64>& data);
// Build from a vector. Copy the data internally.
explicit ConstIntArray(const vector<int>& data);
// Build from a C array. Copy the data internally.
ConstIntArray(const int64* const data, int size);
// Build from a C array. Copy the data internally.
ConstIntArray(const int* const data, int size);
// Build from a pointer to a vector (usually created by the
// Release(), or SortedCopy() method). This call will take ownership of
// the data and not make a copy.
explicit ConstIntArray(vector<int64>* data);
~ConstIntArray();
// Pretty print.
string DebugString() const;
// This code release the ownership of the data into the returned vector.
// After this method is called, data_ points to a null vector.
vector<int64>* Release();
// This will create a new data holder with the sorted array.
vector<int64>* SortedCopy(bool increasing) const;
// This will create a new data holder with the sorted array where
// the duplicate values have been removed.
vector<int64>* SortedCopyWithoutDuplicates(bool increasing) const;
// Equality test.
bool Equals(const ConstIntArray& other);
// Size of the array. This is not valid after Release() has been called.
int size() const;
// Operator to access the data at the given index. This is not valid
// after a release.
int64 operator[](int64 index) const {
CHECK_NOTNULL(data_.get());
return (*data_)[index];
}
// Check the status of a given info bit. It will scan the array on demand.
// This is not valid after Release() has been called.
bool HasProperty(Property info);
private:
void AndProperty(Property info, bool value);
void Scan();
scoped_ptr<vector<int64> > data_;
bool scanned_;
uint64 status_;
DISALLOW_COPY_AND_ASSIGN(ConstIntArray);
};
} // namespace operations_research
#endif // UTIL_CONST_INT_ARRAY_H_