winamp/Src/Wasabi/bfc/ptrlist.cpp

#include "ptrlist.h"
#include <bfc/bfc_assert.h>

// if this symbol is enabled, do sanity checking in a bunch of methods
//#define DO_VERIFY_PTRLIST

#if defined(ASSERTS_ENABLED) && defined(DO_VERIFY_PTRLIST)
#define VERIFY_PTRLIST verify()
#else
#define VERIFY_PTRLIST
#endif

#ifdef _DEBUG
int ptrlist_totalnitems = 0;
#endif

PtrListRoot::PtrListRoot( int initial_size )
{
    nitems = nslots = 0;
    items = NULL;
    //FG>why? we might as well save initial_size*4 bytes if nobody inserts anything in the list, no?
    //BU No. initial_size defaults to 0 and therefore no memory is actually
    //allocated in a typical construction. But, sometimes you want to start with
    //a specific size, generally when you know the exact size you want,
    //so that you can avoid REALLOCs when you initially populate the list.
    //FG>Ah, makes sense.
    setMinimumSize( initial_size );
}

PtrListRoot::PtrListRoot( const PtrListRoot *from )
{
    nitems = nslots = 0;
    items = NULL;
    copyFrom( from );
}

PtrListRoot::~PtrListRoot()
{
    removeAll();
}

void PtrListRoot::copyFrom( const PtrListRoot *from )
{
    ASSERT( from != NULL );

    removeAll();
    appendFrom( from );
    VERIFY_PTRLIST;
}

void PtrListRoot::appendFrom( const PtrListRoot *from )
{
    ASSERT( from != NULL );

    int n = from->getNumItems();

    if ( n <= 0 )
        return;

    void **mem = from->getItemList();

    ASSERT( mem != NULL );	// can't be NULL if getNumItems() >= 1

    setMinimumSize( getNumItems() + n );
    MEMCPY( items + getNumItems(), from->getItemList(), sizeof( void * ) * n );
    nitems += n;
#ifdef _DEBUG
    ptrlist_totalnitems += n;
#endif
    VERIFY_PTRLIST;
}

void PtrListRoot::setMinimumSize( int _nslots )
{
    ASSERT( _nslots >= 0 );
#ifdef DECREASE_PTRLISTS_SIZE
    if ( _nslots + 2 * DEF_PTRLIST_INCREMENT < nslots )
    {
        nslots = ( ( _nslots / DEF_PTRLIST_INCREMENT ) + 2 ) * DEF_PTRLIST_INCREMENT;
        items = (void **) REALLOC( items, sizeof( void * ) * nslots );
    }
#endif
    if ( _nslots == 0 || _nslots <= nslots )
        return;

    nslots = _nslots;

    if ( items )
        items = (void **) REALLOC( items, sizeof( void * ) * nslots );
    else
        items = (void **) MALLOC( sizeof( void * ) * nslots );

    VERIFY_PTRLIST;
}

int PtrListRoot::getNumItems() const
{
    return nitems;
}

void *PtrListRoot::enumItem( int n ) const
{
    if ( items == NULL || n < 0 || n >= nitems )
        return NULL;

    return items[ n ];
}

void *PtrListRoot::addItem( void *item, int pos, int increment )
{
    ASSERT( increment > 0 );
    ASSERTPR( item != NULL, "can't put NULLs into ptrlists" );
    ASSERT( nitems <= nslots );

#ifdef DECREASE_PTRLISTS_SIZE
    // expand or shrink as necessary
    if ( items == NULL || nslots == nitems )
        setMinimumSize( nslots + increment );
    else
        setMinimumSize( nitems );
#else
    // expand if necessary
    if ( items == NULL || nslots == nitems )
        setMinimumSize( nslots + increment );
#endif

    items[ nitems++ ] = item;

    if ( pos != PTRLIST_POS_LAST )
        moveItem( nitems - 1, pos );

    VERIFY_PTRLIST;

#ifdef _DEBUG
    ptrlist_totalnitems++;
#endif

    return item;
}

// replace what's in the slot with the new value
void *PtrListRoot::setItem( void *item, int pos )
{
    ASSERT( nitems >= pos );
    items[ pos ] = item;
    VERIFY_PTRLIST;
    return item;
}

void PtrListRoot::reverse()
{
    if ( nitems <= 1 )
        return;

    MemBlock<void *> block( nitems, items );
    void **blockmem = block.getMemory();

    for ( int i = 0, j = nitems - 1; j >= 0; i++, j-- )
    {
        items[ i ] = blockmem[ j ];
    }
}

void PtrListRoot::moveItem( int from, int to )
{
    if ( from == to )
        return;

    void *ptr = items[ from ];

    if ( nitems > from + 1 ) // if moving from the end, there is nothing to shift behind our src position
    {
        //IMPORTANT note for future ports: This assumes MEMCPY accepts overlapping segments.
        MEMCPY( &items[ from ], &items[ from + 1 ], ( nitems - from ) * sizeof( void * ) );
    }

    if ( to > from )
        to--;

    if ( nitems > to ) // if moving to the end, there is nothing to shift behind our target position
        MEMCPY( &items[ to + 1 ], &items[ to ], ( nitems - to - 1 ) * sizeof( void * ) );

    items[ to ] = ptr;
    VERIFY_PTRLIST;
}

int PtrListRoot::removeItem( void *item )
{
    int c = 0;

    if ( item == NULL || items == NULL || nitems <= 0 )
        return 0;

    // count occurences of item in items, remember the first one
    void **p = items;
    int first = -1;

    for ( int i = 0; i < nitems; i++, p++ )
    {
        if ( *p == item )
        {
            if ( c++ == 0 )
                first = i;
        }
    }

    // if we found one, remove it
    if ( c > 0 )
    {
        removeByPos( first ); // delByPos is faaast
        c--; // decrease count
    }

    VERIFY_PTRLIST;

    return c; // returns how many occurences of this item left
}

void PtrListRoot::removeEveryItem( void *item )
{
    while ( removeItem( item ) );
    VERIFY_PTRLIST;
}

void PtrListRoot::removeByPos( int pos )
{
    if ( pos < 0 || pos >= nitems )
        return;  //JC

    --nitems;
#ifdef _DEBUG
    ptrlist_totalnitems--;
#endif

    if ( pos == nitems )
        return;	// last one? nothing to copy over

    MEMCPY( items + pos, items + ( pos + 1 ), sizeof( void * ) * ( nitems - pos ) );  // CT:not (nitems-(pos+1)) as nitems has been decremented earlier
#ifdef DECREASE_PTRLISTS_SIZE
  // shrink if necessary
    setMinimumSize( nitems );
#endif
    VERIFY_PTRLIST;
}

void PtrListRoot::removeLastItem()
{
    if ( nitems == 0 || items == NULL ) return;
    nitems--;	// hee hee
#ifdef _DEBUG
    ptrlist_totalnitems--;
#endif
#ifdef DECREASE_PTRLISTS_SIZE
    // shrink if necessary
    setMinimumSize( nitems );
#endif
    VERIFY_PTRLIST;
}

void PtrListRoot::removeAll()
{
    FREE( items ); items = NULL;
#ifdef _DEBUG
    ptrlist_totalnitems -= nitems;
#endif
#ifdef DECREASE_PTRLISTS_SIZE
    // shrink if necessary
    setMinimumSize( nitems );
#endif
    nitems = 0;
    nslots = 0;
    VERIFY_PTRLIST;
}

void PtrListRoot::freeAll()
{
    for ( int i = 0; i < nitems; i++ )  //JC
        if ( items ) FREE( items[ i ] );

    removeAll();
    VERIFY_PTRLIST;
}

int PtrListRoot::searchItem( void *item ) const
{
    for ( int i = 0; i < nitems; i++ )
        if ( items[ i ] == item )
            return i;
    return -1;
}

void PtrListRoot::verify()
{
#ifdef DO_VERIFY_PTRLIST
    ASSERT( nitems >= 0 );
    ASSERT( nslots >= 0 );
    ASSERT( nitems <= nslots );
#endif
}

#if 0
int PtrListRoot::bsearchItem( void *item ) const
{
    // do binary search
    if ( nitems == 0 || items == NULL ) return -1;

    int bot = 0, top = nitems - 1, mid;

    for ( int c = 0; c < nitems + 16; c++ )
    {
        if ( bot > top ) return -1;
        mid = ( bot + top ) / 2;
        if ( item == items[ mid ] ) return mid;
        if ( item < items[ mid ] ) top = mid - 1;
        else bot = mid + 1;
    }
    ASSERTPR( 0, "binary search fucked up" );
    return -1;
}
#endif

void PtrListRoot::purge()
{
    ASSERT( nitems == 0 );
    if ( items != NULL )
    {
        FREE( items );
        items = NULL;
    }
}