memory_segment.h

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// Copyright (C) 2012-2015 Internet Systems Consortium, Inc. ("ISC")
//
// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this
// file, You can obtain one at http://mozilla.org/MPL/2.0/.

#ifndef MEMORY_SEGMENT_H
#define MEMORY_SEGMENT_H

#include <exceptions/exceptions.h>

#include <utility>

#include <stdlib.h>

namespace isc {
namespace util {

class MemorySegmentOpenError : public Exception {
public:
    MemorySegmentOpenError(const char* file, size_t line, const char* what) :
        isc::Exception(file, line, what) {}
};

class MemorySegmentGrown : public Exception {
public:
    MemorySegmentGrown(const char* file, size_t line, const char* what) :
        isc::Exception(file, line, what) {}
};

class MemorySegmentError : public Exception {
public:
    MemorySegmentError(const char* file, size_t line, const char* what) :
        isc::Exception(file, line, what) {}
};

class MemorySegment {
public:
    virtual ~MemorySegment() {}

    virtual void* allocate(size_t size) = 0;

    virtual void deallocate(void* ptr, size_t size) = 0;

    virtual bool allMemoryDeallocated() const = 0;

    bool setNamedAddress(const char* name, void* addr) {
        // This public method implements common validation.  The actual
        // work specific to the derived segment is delegated to the
        // corresponding protected method.
        validateName(name);
        return (setNamedAddressImpl(name, addr));
    }

    typedef std::pair<bool, void*> NamedAddressResult;

    NamedAddressResult getNamedAddress(const char* name) const {
        // This public method implements common validation.  The actual
        // work specific to the derived segment is delegated to the
        // corresponding protected method.
        validateName(name);
        return (getNamedAddressImpl(name));
    }

    bool clearNamedAddress(const char* name) {
        // This public method implements common validation.  The actual
        // work specific to the derived segment is delegated to the
        // corresponding protected method.
        validateName(name);
        return (clearNamedAddressImpl(name));
    }

private:
    static void validateName(const char* name) {
        if (!name) {
            isc_throw(InvalidParameter, "NULL is invalid for a name.");
        } else if (*name == '\0') {
            isc_throw(InvalidParameter, "Empty names are invalid.");
        } else if (*name == '_') {
            isc_throw(InvalidParameter,
                      "Names beginning with '_' are reserved for "
                      "internal use only.");
        }
    }

protected:
    virtual bool setNamedAddressImpl(const char* name, void* addr) = 0;

    virtual NamedAddressResult getNamedAddressImpl(const char* name) const = 0;

    virtual bool clearNamedAddressImpl(const char* name) = 0;
};

} // namespace util
} // namespace isc

#endif // MEMORY_SEGMENT_H

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