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#ifndef CYGONCE_MEMALLOC_MVARIMPL_INL

#define CYGONCE_MEMALLOC_MVARIMPL_INL

//==========================================================================

//

//      mvarimpl.inl

//

//      Memory pool with variable block class declarations

//

//==========================================================================

//####ECOSGPLCOPYRIGHTBEGIN####

// -------------------------------------------

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//

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//

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// or inline functions from this file, or you compile this file and link it

// with other works to produce a work based on this file, this file does not

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// -------------------------------------------

//####ECOSGPLCOPYRIGHTEND####

//==========================================================================

//#####DESCRIPTIONBEGIN####

//

// Author(s):    hmt

// Contributors: jlarmour

// Date:         2000-06-12

// Purpose:      Define Mvarimpl class interface

// Description:  Inline class for constructing a variable block allocator

// Usage:        #include 

//

//

//####DESCRIPTIONEND####

//

//==========================================================================

#include 

#include 

#include            // assertion support

#include           // tracing support

// Simple allocator

// The free list is stored on a doubly linked list, each member of

// which is stored in the body of the free memory.  The head of the

// list has the same structure but its size field is zero.  This

// resides in the memory pool structure.  Always having at least one

// item on the list simplifies the alloc and free code.

//

inline cyg_int32

Cyg_Mempool_Variable_Implementation::roundup( cyg_int32 size )

{

    size += sizeof(struct memdq);

    size = (size + alignment - 1) & -alignment;

    return size;

}

inline struct Cyg_Mempool_Variable_Implementation::memdq *

Cyg_Mempool_Variable_Implementation::addr2memdq( cyg_uint8 *addr )

{

    struct memdq *dq;

    dq = (struct memdq *)(roundup((cyg_int32)addr) - sizeof(struct memdq));

    return dq;

}

inline struct Cyg_Mempool_Variable_Implementation::memdq *

Cyg_Mempool_Variable_Implementation::alloc2memdq( cyg_uint8 *addr )

{

    return (struct memdq *)(addr - sizeof(struct memdq));

}

inline cyg_uint8 *

Cyg_Mempool_Variable_Implementation::memdq2alloc( struct memdq *dq )

{

    return ((cyg_uint8 *)dq + sizeof(struct memdq));

}

// -------------------------------------------------------------------------

inline void

Cyg_Mempool_Variable_Implementation::insert_free_block( struct memdq *dq )

{

    struct memdq *hdq=&head;

    freemem += dq->size;

#ifdef CYGSEM_MEMALLOC_ALLOCATOR_VARIABLE_COALESCE

// For simple coalescing have the free list be sorted by memory base address

    struct memdq *idq;

    for (idq = hdq->next; idq != hdq; idq = idq->next) {

        if (idq > dq)

            break;

    }

    // we want to insert immediately before idq

    dq->next = idq;

    dq->prev = idq->prev;

    idq->prev = dq;

    dq->prev->next = dq;

    // Now do coalescing, but leave the head of the list alone.

    if (dq->next != hdq && (char *)dq + dq->size == (char *)dq->next) {

        dq->size += dq->next->size;

        dq->next = dq->next->next;

        dq->next->prev = dq;

    }

    if (dq->prev != hdq && (char *)dq->prev + dq->prev->size == (char *)dq) {

        dq->prev->size += dq->size;

        dq->prev->next = dq->next;

        dq->next->prev = dq->prev;

        dq = dq->prev;

    }

#else

    dq->prev = hdq;

    dq->next = hdq->next;

    hdq->next = dq;

    dq->next->prev=dq;

#endif

}

// -------------------------------------------------------------------------

inline

Cyg_Mempool_Variable_Implementation::Cyg_Mempool_Variable_Implementation(

        cyg_uint8 *base,

        cyg_int32 size,

        CYG_ADDRWORD align )

{

    CYG_REPORT_FUNCTION();

    CYG_ASSERT( align > 0, "Bad alignment" );

    CYG_ASSERT(0!=align ,"align is zero");

    CYG_ASSERT(0==(align & align-1),"align not a power of 2");

    if ((unsigned)size < sizeof(struct memdq)) {

        bottom = NULL;

        return;

    }

    obase=base;

    osize=size;

    alignment = align;

    while (alignment < (cyg_int32)sizeof(struct memdq))

        alignment += alignment;

    CYG_ASSERT(0==(alignment & alignment-1),"alignment not a power of 2");

    // the memdq for each allocation is always positioned immediately before

    // an aligned address, so that the allocation (i.e. what eventually gets

    // returned from alloc()) is at the correctly aligned address

    // Therefore bottom is set to the lowest available address given the size of

    // struct memdq and the alignment.

    bottom = (cyg_uint8 *)addr2memdq(base);

    // because we split free blocks by allocating memory from the end, not

    // the beginning, then to preserve alignment, the *top* must also be

    // aligned such that (top-bottom) is a multiple of the alignment

    top = (cyg_uint8 *)((cyg_int32)(base+size+sizeof(struct memdq)) & -alignment) -

        sizeof(struct memdq);

    CYG_ASSERT( top > bottom , "heap too small" );

    CYG_ASSERT( top <= (base+size), "top too large" );

    CYG_ASSERT( ((cyg_int32)(top+sizeof(struct memdq)) & alignment-1)==0,

                "top badly aligned" );

    struct memdq *hdq = &head, *dq = (struct memdq *)bottom;

    CYG_ASSERT( ((cyg_int32)memdq2alloc(dq) & alignment-1)==0,

                 "bottom badly aligned" );

    hdq->prev = hdq->next = dq;

    hdq->size = 0;

    dq->prev = dq->next = hdq;

    freemem = dq->size = top - bottom;

}

// -------------------------------------------------------------------------

inline

Cyg_Mempool_Variable_Implementation::~Cyg_Mempool_Variable_Implementation()

{

}

// -------------------------------------------------------------------------

// allocation is simple

// First we look down the free list for a large enough block

// If we find a block the right size, we unlink the block from

//    the free list and return a pointer to it.

// If we find a larger block, we chop a piece off the end

//    and return that

// Otherwise we will eventually get back to the head of the list

//    and return NULL

inline cyg_uint8 *

Cyg_Mempool_Variable_Implementation::try_alloc( cyg_int32 size )

{

    struct memdq *dq = &head;

    cyg_uint8 *alloced;

    CYG_REPORT_FUNCTION();

    //  Allow uninitialised (zero sized) heaps because they could exist as a

    //  quirk of the MLT setup where a dynamically sized heap is at the top of

    //  memory.

    if (NULL == bottom)

        return NULL;

    size = roundup(size);

    do {

        CYG_ASSERT( dq->next->prev==dq, "Bad link in dq");

        dq = dq->next;

        if(0 == dq->size) {

            CYG_ASSERT(dq == &head, "bad free block");

            return NULL;

        }

    } while(dq->size < size);

    if( size == dq->size ) {

        // exact fit -- unlink from free list

        dq->prev->next = dq->next;

        dq->next->prev = dq->prev;

        alloced = (cyg_uint8 *)dq;

    } else {

        CYG_ASSERT( dq->size > size, "block found is too small");

        // allocate portion of memory from end of block

        dq->size -=size;

        // The portion left over has to be large enough to store a

        // struct memdq.  This is guaranteed because the alignment is

        // larger than the size of this structure.

        CYG_ASSERT( (cyg_int32)sizeof(struct memdq)<=dq->size ,

                "not enough space for list item" );

        alloced = (cyg_uint8 *)dq + dq->size;

    }

    CYG_ASSERT( bottom<=alloced && alloced<=top, "alloced outside pool" );

    // Set size on allocated block

    dq = (struct memdq *)alloced;

    dq->size = size;

    dq->next = dq->prev = (struct memdq *)0xd530d53; // magic number

    freemem -=size;

    cyg_uint8 *ptr = memdq2alloc( dq );

    CYG_ASSERT( ((CYG_ADDRESS)ptr & (alignment-1)) == 0,

                "returned memory not aligned" );

    return ptr;

}

// -------------------------------------------------------------------------

// resize existing allocation, if oldsize is non-NULL, previous

// allocation size is placed into it. If previous size not available,

// it is set to 0. NB previous allocation size may have been rounded up.

// Occasionally the allocation can be adjusted *backwards* as well as,

// or instead of forwards, therefore the address of the resized

// allocation is returned, or NULL if no resizing was possible.

// Note that this differs from ::realloc() in that no attempt is

// made to call malloc() if resizing is not possible - that is left

// to higher layers. The data is copied from old to new though.

// The effects of alloc_ptr==NULL or newsize==0 are undefined

inline cyg_uint8 *

Cyg_Mempool_Variable_Implementation::resize_alloc( cyg_uint8 *alloc_ptr,

                                                   cyg_int32 newsize,

                                                   cyg_int32 *oldsize )

{

    cyg_uint8 *ret = NULL;

    CYG_REPORT_FUNCTION();

    CYG_CHECK_DATA_PTRC( alloc_ptr );

    if ( NULL != oldsize )

        CYG_CHECK_DATA_PTRC( oldsize );

    CYG_ASSERT( (bottom <= alloc_ptr) && (alloc_ptr <= top),

                "alloc_ptr outside pool" );

    struct memdq *dq=alloc2memdq( alloc_ptr );

    // check magic number in block for validity

    CYG_ASSERT( (dq->next == dq->prev) &&

                (dq->next == (struct memdq *)0xd530d53), "bad alloc_ptr" );

    newsize = roundup(newsize);

    if ( NULL != oldsize )

        *oldsize = dq->size;

    if ( newsize > dq->size ) {

        // see if we can increase the allocation size

        if ( (cyg_uint8 *)dq + newsize <= top ) { // obviously can't exceed pool

            struct memdq *nextdq = (struct memdq *)((cyg_uint8 *)dq + dq->size);

            if ( (nextdq->next != nextdq->prev) &&

                 (nextdq->size >= (newsize - dq->size)) ) {

                // it's free and it's big enough

                // we therefore temporarily join this block and *all* of

                // the next block, so that the code below can then split it

                nextdq->next->prev = nextdq->prev;

                nextdq->prev->next = nextdq->next;

                dq->size += nextdq->size;

                freemem -= nextdq->size;

            }

        } // if

    } // if

    // this is also used if the allocation size was increased and we need

    // to split it

    if ( newsize < dq->size ) {

        // We can shrink the allocation by splitting into smaller allocation and

        // new free block

        struct memdq *newdq = (struct memdq *)((cyg_uint8 *)dq + newsize);

        newdq->size = dq->size - newsize;

        dq->size = newsize;

        CYG_ASSERT( (cyg_int32)sizeof(struct memdq)<=newdq->size ,

                    "not enough space for list item" );

        // now return the new space back to the freelist

        insert_free_block( newdq );

        ret = alloc_ptr;

    } // if

    else if ( newsize == dq->size ) {

        ret = alloc_ptr;

    }

    return ret;

} // resize_alloc()

// -------------------------------------------------------------------------

// When no coalescing is done, free is simply a matter of using the

// freed memory as an element of the free list linking it in at the

// start. When coalescing, the free list is sorted

inline cyg_bool

Cyg_Mempool_Variable_Implementation::free( cyg_uint8 *p, cyg_int32 size )

{

    CYG_REPORT_FUNCTION();

    CYG_CHECK_DATA_PTRC( p );

    if (!((bottom <= p) && (p <= top)))

        return false;

    struct memdq *dq=alloc2memdq( p );

    // check magic number in block for validity

    if ( (dq->next != dq->prev) ||

         (dq->next != (struct memdq *)0xd530d53) )

        return false;

    if ( 0==size ) {

        size = dq->size;

    } else {

        size = roundup(size);

    }

    if( dq->size != size )

        return false;

    CYG_ASSERT( (cyg_int32)sizeof(struct memdq)<=size ,

                "not enough space for list item" );

    insert_free_block( dq );

    return true;

}

// -------------------------------------------------------------------------

inline void

Cyg_Mempool_Variable_Implementation::get_status(

    cyg_mempool_status_flag_t flags,

    Cyg_Mempool_Status &status )

{

    CYG_REPORT_FUNCTION();

// as quick or quicker to just set it, rather than test flag first

    status.arenabase = obase;

    if ( 0 != (flags & CYG_MEMPOOL_STAT_ARENASIZE) )

        status.arenasize = top - bottom;

    if ( 0 != (flags & CYG_MEMPOOL_STAT_TOTALALLOCATED) )

        status.totalallocated = (top-bottom) - freemem;

// as quick or quicker to just set it, rather than test flag first

    status.totalfree = freemem;

    if ( 0 != (flags & CYG_MEMPOOL_STAT_MAXFREE) ) {

        struct memdq *dq = &head;

        cyg_int32 mf = 0;

        do {

            CYG_ASSERT( dq->next->prev==dq, "Bad link in dq");

            dq = dq->next;

            if(0 == dq->size) {

                CYG_ASSERT(dq == &head, "bad free block");

                break;

            }

            if(dq->size > mf)

                mf = dq->size;

        } while(1);

        status.maxfree = mf - sizeof(struct memdq);

    }

// as quick or quicker to just set it, rather than test flag first

    status.origbase = obase;

// as quick or quicker to just set it, rather than test flag first

    status.origsize = osize;

    CYG_REPORT_RETURN();

} // get_status()

// -------------------------------------------------------------------------

#endif // ifndef CYGONCE_MEMALLOC_MVARIMPL_INL

// EOF mvarimpl.inl