/*************/
/* queue.cpp */
/*************/

#include "fctsys.h"

#include "common.h"
#include "pcbnew.h"
#include "autorout.h"

#include "cell.h"

struct PcbQueue /* search queue structure */
{
    struct PcbQueue* Next;
    int              Row;       /* current row					*/
    int              Col;       /* current column				*/
    int              Side;      /* 0=top, 1=bottom				*/
    int              Dist;      /* path distance to this cell so far		*/
    int              ApxDist;   /* approximate distance to target from here	*/
};

static long             qlen = 0;   /* current queue length */
static struct PcbQueue* Head = NULL;
static struct PcbQueue* Tail = NULL;
static struct PcbQueue* Save = NULL;    /* hold empty queue structs */


void InitQueue();
void GetQueue( int*, int*, int*, int*, int* );
int  SetQueue( int, int, int, int, int, int, int );
void ReSetQueue( int, int, int, int, int, int, int );


/* Free the memory used for storing all the queue */
void FreeQueue()
{
    struct PcbQueue* p;

    InitQueue();
    while( (p = Save) != NULL )
    {
        Save = p->Next; MyFree( p );
    }
}


/* initialize the search queue */
void InitQueue()
{
    struct PcbQueue* p;

    while( (p = Head) != NULL )
    {
        Head    = p->Next;
        p->Next = Save; Save = p;
    }

    Tail = NULL;
    OpenNodes = ClosNodes = MoveNodes = MaxNodes = qlen = 0;
}


/* get search queue item from list */
void GetQueue( int* r, int* c, int* s, int* d, int* a )
{
    struct PcbQueue* p;

    if( (p = Head) != NULL )  /* return first item in list */
    {
        *r = p->Row; *c = p->Col;
        *s = p->Side;
        *d = p->Dist; *a = p->ApxDist;
        if( (Head = p->Next) == NULL )
            Tail = NULL;

        /* put node on free list */
        p->Next = Save; Save = p;
        ClosNodes++; qlen--;
    }
    else /* empty list */
    {
        *r = *c = *s = *d = *a = ILLEGAL;
    }
}


/* add a search node to the list
 *	Return:
 *		1 - OK
 *		0 - Failed to allocate memory.
 */
int SetQueue( int r, int c, int side, int d, int a, int r2, int c2 )
{
    struct PcbQueue* p, * q, * t;
    int i, j;

    j = 0;                      // gcc warning fix

    if( (p = Save) != NULL )    /* try free list first */
    {
        Save = p->Next;
    }
    else if( ( p = (struct PcbQueue*) MyMalloc( sizeof(PcbQueue) ) ) == NULL )
        return 0;

    p->Row  = r;
    p->Col  = c;
    p->Side = side;
    i = (p->Dist = d) + (p->ApxDist = a);
    p->Next = NULL;
    if( (q = Head) != NULL ) /* insert in proper position in list */
    {
        if( q->Dist + q->ApxDist > i ) /* insert at head */
        {
            p->Next = q; Head = p;
        }
        else   /* search for proper position */
        {
            for( t = q, q = q->Next; q && i > ( j = q->Dist + q->ApxDist );
                 t = q, q = q->Next )
                ;

            if( q && i == j && q->Row == r2 && q->Col == c2 )
            {
                /* insert after q, which is a goal node */
                if( ( p->Next = q->Next ) == NULL )
                    Tail = p;
                q->Next = p;
            }
            else  /* insert in front of q */
            {
                if( ( p->Next = q ) == NULL )
                    Tail = p;
                t->Next = p;
            }
        }
    }
    else /* empty search list */
        Head = Tail = p;
    OpenNodes++;
    if( ++qlen > MaxNodes )
        MaxNodes = qlen;
    return 1;
}


/* reposition node in list */
void ReSetQueue( int r, int c, int s, int d, int a, int r2, int c2 )
{
    struct PcbQueue* p, * q;

    /* first, see if it is already in the list */
    for( q = NULL, p = Head; p; q = p, p = p->Next )
    {
        if( p->Row == r && p->Col == c && p->Side == s )
        {
            /* old one to remove */
            if( q )
            {
                if( ( q->Next = p->Next ) == NULL )
                    Tail = q;
            }
            else if( ( Head = p->Next ) == NULL )
                Tail = NULL;
            p->Next = Save;
            Save = p;
            OpenNodes--;
            MoveNodes++;
            qlen--;
            break;
        }
    }

    if( !p )            /* not found, it has already been closed once */
        ClosNodes--;    /* we will close it again, but just count once */
    /* if it was there, it's gone now; insert it at the proper position */
    SetQueue( r, c, s, d, a, r2, c2 );
}