/*
 * File:	DataSource.h
 *
 * Copyright (c) Freescale Semiconductor, Inc. All rights reserved.
 * See included license file for license details.
 */
#if !defined(_DataSource_h_)
#define _DataSource_h_

#include <vector>
#include "Value.h"
#include "smart_ptr.h"
#include "StExecutableImage.h"

namespace elftosb
{
// Forward declaration
class DataTarget;

/*!
 * \brief Abstract base class for data sources.
 *
 * Data sources represent any sort of data that can be placed or loaded
 * into a target region. Sources may be a single blob of data read from
 * a file or may consist of many segments.
 *
 * The three most important features of data sources are:
 * - Sources may be multi-segmented.
 * - Sources and/or segments can have a "natural" or default target location.
 * - The target for a source may be taken into consideration when the source
 *		describes itself.
 */
class DataSource
{
public:
    /*!
     * \brief Discrete, contiguous part of the source's data.
     *
     * This class is purely abstract and subclasses of DataSource are expected
     * to subclass it to implement a segment particular to their needs.
     */
    class Segment
    {
    public:
        //! \brief Default constructor.
        Segment(DataSource &source)
            : m_source(source)
        {
        }

        //! \brief Destructor.
        virtual ~Segment() {}
        //! \brief Gets all or a portion of the segment's data.
        //!
        //! The data is copied into \a buffer. Up to \a maxBytes bytes may be
        //! copied, so \a buffer must be at least that large.
        //!
        //! \param offset Index of the first byte to start copying from.
        //! \param maxBytes The maximum number of bytes that can be returned. \a buffer
        //!		must be at least this large.
        //! \param buffer Pointer to buffer where the data is copied.
        //! \return The number of bytes copied into \a buffer.
        virtual unsigned getData(unsigned offset, unsigned maxBytes, uint8_t *buffer) = 0;

        //! \brief Gets the length of the segment's data.
        virtual unsigned getLength() = 0;

        //! \brief Returns whether the segment has an associated address.
        virtual bool hasNaturalLocation() = 0;

        //! \brief Returns the address associated with the segment.
        virtual uint32_t getBaseAddress() { return 0; }
    protected:
        DataSource &m_source; //!< The data source to which this segment belongs.
    };

    /*!
     * \brief This is a special type of segment containing a repeating pattern.
     *
     * By default the segment doesn't have a specific length or data. The length depends
     * on the target's address range. And the data is just the pattern, repeated
     * many times. In addition, pattern segments do not have a natural location.
     *
     * Calling code should look for instances of PatternSegment and handle them
     * as special cases that can be optimized.
     */
    class PatternSegment : public Segment
    {
    public:
        //! \brief Default constructor.
        PatternSegment(DataSource &source);

        //! \brief Constructor taking a fill pattern.
        PatternSegment(DataSource &source, const SizedIntegerValue &pattern);

        //! \brief Constructor taking a byte fill pattern.
        PatternSegment(DataSource &source, uint8_t pattern);

        //! \brief Constructor taking a half-word fill pattern.
        PatternSegment(DataSource &source, uint16_t pattern);

        //! \brief Constructor taking a word fill pattern.
        PatternSegment(DataSource &source, uint32_t pattern);

        //! \name Segment methods
        //@{
        //! \brief Pattern segments have no natural address.
        virtual bool hasNaturalLocation() { return false; }
        //! \brief Performs a pattern fill into the \a buffer.
        virtual unsigned getData(unsigned offset, unsigned maxBytes, uint8_t *buffer);

        //! \brief Returns a length based on the data target's address range.
        virtual unsigned getLength();
        //@}

        //! \name Pattern accessors
        //@{
        //! \brief Assigns a new fill pattern.
        inline void setPattern(const SizedIntegerValue &newPattern) { m_pattern = newPattern; }
        //! \brief Return the fill pattern for the segment.
        inline SizedIntegerValue &getPattern() { return m_pattern; }
        //! \brief Assignment operator, sets the pattern value and length.
        PatternSegment &operator=(const SizedIntegerValue &value)
        {
            m_pattern = value;
            return *this;
        }
        //@}

    protected:
        SizedIntegerValue m_pattern; //!< The fill pattern.
    };

public:
    //! \brief Default constructor.
    DataSource()
        : m_target(0)
    {
    }

    //! \brief Destructor.
    virtual ~DataSource() {}
    //! \name Data target
    //@{
    //! \brief Sets the associated data target.
    inline void setTarget(DataTarget *target) { m_target = target; }
    //! \brief Gets the associated data target.
    inline DataTarget *getTarget() const { return m_target; }
    //@}

    //! \name Segments
    //@{
    //! \brief Returns the number of segments in this data source.
    virtual unsigned getSegmentCount() = 0;

    //! \brief Returns segment number \a index of the data source.
    virtual Segment *getSegmentAt(unsigned index) = 0;
    //@}

protected:
    DataTarget *m_target; //!< Corresponding target for this source.
};

/*!
 * \brief Data source for a repeating pattern.
 *
 * The pattern is represented by a SizedIntegerValue object. Thus the pattern
 * can be either byte, half-word, or word sized.
 *
 * This data source has only one segment, and the PatternSource instance acts
 * as its own single segment.
 */
class PatternSource : public DataSource, public DataSource::PatternSegment
{
public:
    //! \brief Default constructor.
    PatternSource();

    //! \brief Constructor taking the pattern value.
    PatternSource(const SizedIntegerValue &value);

    //! \brief There is only one segment.
    virtual unsigned getSegmentCount() { return 1; }
    //! \brief Returns this object, as it is its own segment.
    virtual DataSource::Segment *getSegmentAt(unsigned index) { return this; }
    //! \brief Assignment operator, sets the pattern value and length.
    PatternSource &operator=(const SizedIntegerValue &value)
    {
        setPattern(value);
        return *this;
    }
};

/*!
 * \brief Data source for data that is not memory mapped (has no natural address).
 *
 * This data source can only manage a single block of data, which has no
 * associated address. It acts as its own Segment.
 */
class UnmappedDataSource : public DataSource, public DataSource::Segment
{
public:
    //! \brief Default constructor.
    UnmappedDataSource();

    //! \brief Constructor taking the data, which is copied.
    UnmappedDataSource(const uint8_t *data, unsigned length);

    //! \brief Sets the source's data.
    void setData(const uint8_t *data, unsigned length);

    //! \brief There is only one segment.
    virtual unsigned getSegmentCount() { return 1; }
    //! \brief Returns this object, as it is its own segment.
    virtual DataSource::Segment *getSegmentAt(unsigned index) { return this; }
    //! \name Segment methods
    //@{
    //! \brief Unmapped data sources have no natural address.
    virtual bool hasNaturalLocation() { return false; }
    //! \brief Copies a portion of the data into \a buffer.
    virtual unsigned getData(unsigned offset, unsigned maxBytes, uint8_t *buffer);

    //! \brief Returns the number of bytes of data managed by the source.
    virtual unsigned getLength() { return m_length; }
    //@}

protected:
    smart_array_ptr<uint8_t> m_data; //!< The data.
    unsigned m_length;               //!< Byte count of the data.
};

/*!
 * \brief Data source that takes its data from an executable image.
 *
 * \see StExecutableImage
 */
class MemoryImageDataSource : public DataSource
{
public:
    //! \brief Default constructor.
    MemoryImageDataSource(StExecutableImage *image);

    //! \brief Destructor.
    virtual ~MemoryImageDataSource();

    //! \brief Returns the number of memory regions in the image.
    virtual unsigned getSegmentCount();

    //! \brief Returns the data source segment at position \a index.
    virtual DataSource::Segment *getSegmentAt(unsigned index);

protected:
    /*!
     * \brief Segment corresponding to a text region of the executable image.
     */
    class TextSegment : public DataSource::Segment
    {
    public:
        //! \brief Default constructor
        TextSegment(MemoryImageDataSource &source, StExecutableImage *image, unsigned index);

        virtual unsigned getData(unsigned offset, unsigned maxBytes, uint8_t *buffer);
        virtual unsigned getLength();

        virtual bool hasNaturalLocation() { return true; }
        virtual uint32_t getBaseAddress();

    protected:
        StExecutableImage *m_image; //!< Coalesced image of the file.
        unsigned m_index;           //!< Record index.
    };

    /*!
     * \brief Segment corresponding to a fill region of the executable image.
     */
    class FillSegment : public DataSource::PatternSegment
    {
    public:
        FillSegment(MemoryImageDataSource &source, StExecutableImage *image, unsigned index);

        virtual unsigned getLength();

        virtual bool hasNaturalLocation() { return true; }
        virtual uint32_t getBaseAddress();

    protected:
        StExecutableImage *m_image; //!< Coalesced image of the file.
        unsigned m_index;           //!< Record index.
    };

protected:
    StExecutableImage *m_image; //!< The memory image that is the data source.

    typedef std::vector<DataSource::Segment *> segment_array_t; //!< An array of segments.
    segment_array_t m_segments;                                 //!< The array of Segment instances.
};

}; // namespace elftosb

#endif // _DataSource_h_
