windows-nt/Source/XPSP1/NT/multimedia/media/dplayx/dplay/serial/bilink.c
2020-09-26 16:20:57 +08:00

115 lines
2.1 KiB
C

/*++
Copyright (c) 1993 Microsoft Corporation
Module Name:
BILINK.C
Abstract:
Management for doubly linked lists
Author:
George Joy
Environment:
32-bit 'C'
Revision History:
--*/
#include <windows.h>
#include <dpf.h>
#include "bilink.h"
// Note: serialization of access to BILINK structures must
// take place in the calling code. Operations are
// not intrinsically atomic.
#ifdef DEBUG
int FindObject(
BILINK *link,
BILINK *list
)
{
BILINK *p = list->next;
while(p != link && p != list)
p= p->next;
return (p==link);
}
#endif
void InsertAfter(
BILINK *in,
BILINK *after
)
/*=========================================================================
* Description:
* Insert an object after a specified object in the doubly linked list.
* The after object could be the Head BILINK for adding to the head of a
* queue.
* Returns:
*
*/
{
#ifdef DEBUG
if(FindObject(in,after)) {
DPF(0,"Attempt to re-insert object in BILINK queue\n");
DEBUG_BREAK();
}
#endif
in->next = after->next;
in->prev = after;
after->next->prev = in;
after->next = in;
}
void InsertBefore(
BILINK *in,
BILINK *before
)
/*=========================================================================
* Description:
* Inserts an object before a specified object in the doubly linked list.
* The before object could be the Head BILINK for adding to the end
* of the queue
* CALLED WITH INTERRUPTS_OFF
*
* Returns:
*
*/
{
#ifdef DEBUG
if(FindObject(in,before)) {
DPF(0,"Attempt to re-insert object in BILINK queue\n");
DEBUG_BREAK();
}
#endif
in->next = before;
in->prev = before->prev;
before->prev->next = in;
before->prev = in;
}
void Delete(
BILINK *p
)
/*=========================================================================
* Description:
*
* Delete a object from a doubly linked list. Make sure it IS on a list!
* CALLED WITH INTERRUPTS OFF (must be atomic).
*
* Returns:
*
*/
{
p->next->prev = p->prev;
p->prev->next = p->next;
// p->next = p->prev = 0;
}