228 lines
		
	
	
		
			6.6 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
			
		
		
	
	
			228 lines
		
	
	
		
			6.6 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
/**
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  ******************************************************************************
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  * This file is part of the TouchGFX 4.16.1 distribution.
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  *
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  * <h2><center>© Copyright (c) 2021 STMicroelectronics.
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  * All rights reserved.</center></h2>
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  *
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  * This software component is licensed by ST under Ultimate Liberty license
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  * SLA0044, the "License"; You may not use this file except in compliance with
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  * the License. You may obtain a copy of the License at:
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  *                             www.st.com/SLA0044
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  *
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  ******************************************************************************
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  */
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/**
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 * @file common/AbstractPartition.hpp
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 *
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 * Declares the touchgfx::AbstractPartition class.
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 */
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#ifndef ABSTRACTPARTITION_HPP
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#define ABSTRACTPARTITION_HPP
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#include <touchgfx/hal/Types.hpp>
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namespace touchgfx
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{
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/**
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 * This type defines an abstract interface to a storage partition for allocating memory slots of
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 * equal size. The "partition" is not aware of the actual types stored in the partition
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 * memory, hence it provides no mechanism for deleting C++ objects when clear()'ed.
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 */
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class AbstractPartition
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{
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public:
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    /** Finalizes an instance of the AbstractPartition class. */
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    virtual ~AbstractPartition();
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    /**
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     * Gets the address of the next available storage slot. The slot size is compared with
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     * the specified size.
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     *
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     * @param  size The size.
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     *
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     * @return The address of an empty storage slot which contains minimum 'size' bytes.
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     *
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     * @note Asserts if 'size' is too large, or the storage is depleted.
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     */
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    virtual void* allocate(uint16_t size);
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    /**
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     * Gets the address of the specified index.
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     *
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     * @param  index Zero-based index of the.
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     * @param  size  The size.
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     *
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     * @return The address of the appropriate storage slot which contains minimum 'size'
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     *         bytes.
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     *
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     * @note Asserts if 'size' is too large.
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     */
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    virtual void* allocateAt(uint16_t index, uint16_t size);
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    /**
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     * Gets allocation count.
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     *
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     * @return The currently allocated storage slots.
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     */
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    virtual uint16_t getAllocationCount() const;
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    /**
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     * Determines index of previously allocated location. Since the Partition concept is
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     * loosely typed this method shall be used with care. The method does not guarantee that
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     * the found object at the returned index is a valid object. It only tests whether or
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     * not the object is within the bounds of the current partition allocations.
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     *
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     * @param  address The location address to lookup.
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     *
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     * @return An uint16_t.
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     */
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    virtual uint16_t indexOf(const void* address);
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    /**
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     * Prepares the Partition for new allocations. Any objects present in the Partition
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     * shall not be used after invoking this method.
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     */
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    virtual void clear();
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    /**
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     * Gets the capacity, i.e. the maximum allocation count.
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     *
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     * @return The maximum allocation count.
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     */
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    virtual uint16_t capacity() const = 0;
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    /**
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     * Gets the address of the next available storage slot. The slot size is determined from
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     * the size of type T.
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     *
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     * @tparam T Generic type parameter.
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     *
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     * @return The address of an empty storage slot.
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     *
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     * @note Asserts if T is too large, or the storage is depleted.
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     */
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    template <typename T>
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    void* allocate()
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    {
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        return allocate(static_cast<uint16_t>(sizeof(T)));
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    }
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    /**
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     * Gets the address of the specified storage slot. The slot size is determined from the
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     * size of type T.
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     *
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     * @tparam T Generic type parameter.
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     * @param  index Zero-based index of the.
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     *
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     * @return The address of the appropriate storage slot.
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     *
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     * @note Asserts if T is too large.
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     */
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    template <typename T>
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    void* allocateAt(uint16_t index)
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    {
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        return allocateAt(index, static_cast<uint16_t>(sizeof(T)));
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    }
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    /**
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     * Gets the object at the specified index.
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     *
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     * @tparam T Generic type parameter.
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     * @param  index The index into the Partition storage where the returned object is located.
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     *
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     * @return A typed reference to the object at the specified index.
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     */
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    template <typename T>
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    T& at(const uint16_t index)
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    {
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        return *static_cast<T*>(element(index));
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    }
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    /**
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     * const version of at().
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     *
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     * @tparam T Generic type parameter.
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     * @param  index Zero-based index of the.
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     *
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     * @return A T&
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     */
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    template <typename T>
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    const T& at(const uint16_t index) const
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    {
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        return *static_cast<const T*>(element(index));
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    }
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    /**
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     * Determines if the specified object could have been previously allocated in the
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     * partition. Since the Partition concept is loosely typed this method shall be used
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     * with care. The method does not guarantee that the found object at the returned index
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     * is a valid object. It only tests whether or not the object is within the bounds of
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     * the current partition allocations.
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     *
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     * @tparam T Generic type parameter.
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     * @param  pT Pointer to the object to look up.
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     *
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     * @return If the object seems to be allocated in the Partition, a Pair object
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     *         containing a typed pointer to the object and an index into the Partition
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     *         storage is returned. Otherwise, a Pair<0, 0> is returned.
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     */
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    template <class T>
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    Pair<T*, uint16_t> find(const void* pT)
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    {
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        uint16_t index = indexOf(pT);
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        if (0 < getAllocationCount() && index < getAllocationCount())
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        {
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            return Pair<T*, uint16_t>(&at<T>(index), index);
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        }
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        return Pair<T*, uint16_t>(0, (uint16_t) -1);
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    }
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    /** Decreases number of allocations. */
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    void dec()
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    {
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        if (allocations)
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        {
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            allocations--;
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        }
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    }
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    /**
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     * Access to concrete element-size. Used internally.
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     *
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     * @return An uint32_t.
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     */
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    virtual uint32_t element_size() = 0;
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protected:
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    /**
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     * Access to stored element. Used internally.
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     *
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     * @param  index Zero-based index of the.
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     *
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     * @return null if it fails, else a void*.
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     */
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    virtual void* element(uint16_t index) = 0;
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    /**
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     * Access to stored element, const version.
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     *
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     * @param  index Zero-based index of the.
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     *
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     * @return null if it fails, else a void*.
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     */
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    virtual const void* element(uint16_t index) const = 0;
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    /** Initializes a new instance of the AbstractPartition class. */
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    AbstractPartition();
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private:
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    uint16_t allocations;
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};
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} // namespace touchgfx
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#endif // ABSTRACTPARTITION_HPP
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