windows-nt/Source/XPSP1/NT/enduser/netmeeting/as/dd/com.c
2020-09-26 16:20:57 +08:00

176 lines
3.9 KiB
C

#include "precomp.h"
//
// COM.C
// Common functions, simple
//
// Copyright(c) Microsoft 1997-
//
//
// COM_BasedListInsertBefore(...)
//
// See com.h for description.
//
void COM_BasedListInsertBefore(PBASEDLIST pExisting, PBASEDLIST pNew)
{
PBASEDLIST pTemp;
DebugEntry(COM_BasedListInsertBefore);
//
// Check for bad parameters.
//
ASSERT((pNew != NULL));
ASSERT((pExisting != NULL));
//
// Find the item before pExisting:
//
pTemp = COM_BasedPrevListField(pExisting);
ASSERT((pTemp != NULL));
TRACE_OUT(("Inserting item at %#lx into list between %#lx and %#lx",
pNew, pTemp, pExisting));
//
// Set its <next> field to point to the new item
//
pTemp->next = PTRBASE_TO_OFFSET(pNew, pTemp);
pNew->prev = PTRBASE_TO_OFFSET(pTemp, pNew);
//
// Set <prev> field of pExisting to point to new item:
//
pExisting->prev = PTRBASE_TO_OFFSET(pNew, pExisting);
pNew->next = PTRBASE_TO_OFFSET(pExisting, pNew);
DebugExitVOID(COM_BasedListInsertBefore);
} // COM_BasedListInsertBefore
//
// COM_BasedListInsertAfter(...)
//
// See com.h for description.
//
void COM_BasedListInsertAfter(PBASEDLIST pExisting, PBASEDLIST pNew)
{
PBASEDLIST pTemp;
DebugEntry(COM_BasedListInsertAfter);
//
// Check for bad parameters.
//
ASSERT((pNew != NULL));
ASSERT((pExisting != NULL));
//
// Find the item after pExisting:
//
pTemp = COM_BasedNextListField(pExisting);
ASSERT((pTemp != NULL));
TRACE_OUT(("Inserting item at %#lx into list between %#lx and %#lx",
pNew, pExisting, pTemp));
//
// Set its <prev> field to point to the new item
//
pTemp->prev = PTRBASE_TO_OFFSET(pNew, pTemp);
pNew->next = PTRBASE_TO_OFFSET(pTemp, pNew);
//
// Set <next> field of pExisting to point to new item:
//
pExisting->next = PTRBASE_TO_OFFSET(pNew, pExisting);
pNew->prev = PTRBASE_TO_OFFSET(pExisting, pNew);
DebugExitVOID(COM_BasedListInsertAfter);
} // COM_BasedListInsertAfter
//
// COM_BasedListRemove(...)
//
// See com.h for description.
//
void COM_BasedListRemove(PBASEDLIST pListItem)
{
PBASEDLIST pNext = NULL;
PBASEDLIST pPrev = NULL;
DebugEntry(COM_BasedListRemove);
//
// Check for bad parameters.
//
ASSERT((pListItem != NULL));
pPrev = COM_BasedPrevListField(pListItem);
pNext = COM_BasedNextListField(pListItem);
ASSERT((pPrev != NULL));
ASSERT((pNext != NULL));
TRACE_OUT(("Removing item at %#lx from list", pListItem));
pPrev->next = PTRBASE_TO_OFFSET(pNext, pPrev);
pNext->prev = PTRBASE_TO_OFFSET(pPrev, pNext);
DebugExitVOID(COM_BasedListRemove);
} // COM_BasedListRemove
//
//
// List manipulation routines
// COM_BasedListNext
// COM_BasedListPrev
// COM_BasedListFirst
// COM_BasedListLast
//
//
void FAR * COM_BasedListNext( PBASEDLIST pHead, void FAR * pEntry, UINT nOffset )
{
PBASEDLIST p;
ASSERT(pHead != NULL);
ASSERT(pEntry != NULL);
p = COM_BasedNextListField(COM_BasedStructToField(pEntry, nOffset));
return ((p == pHead) ? NULL : COM_BasedFieldToStruct(p, nOffset));
}
void FAR * COM_BasedListPrev ( PBASEDLIST pHead, void FAR * pEntry, UINT nOffset )
{
PBASEDLIST p;
ASSERT(pHead != NULL);
ASSERT(pEntry != NULL);
p = COM_BasedPrevListField(COM_BasedStructToField(pEntry, nOffset));
return ((p == pHead) ? NULL : COM_BasedFieldToStruct(p, nOffset));
}
void FAR * COM_BasedListFirst ( PBASEDLIST pHead, UINT nOffset )
{
return (COM_BasedListIsEmpty(pHead) ?
NULL :
COM_BasedFieldToStruct(COM_BasedNextListField(pHead), nOffset));
}
void FAR * COM_BasedListLast ( PBASEDLIST pHead, UINT nOffset )
{
return (COM_BasedListIsEmpty(pHead) ?
NULL :
COM_BasedFieldToStruct(COM_BasedPrevListField(pHead), nOffset));
}