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chain.h
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chain.h
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/* CHAIN.H (c) Mark L. Gaubatz, 1985-2012 */
/* Chain and queue macros and inline routines */
/* Adapted for use by Hercules */
/* */
/* Released under "The Q Public License Version 1" */
/* (http://www.hercules-390.org/herclic.html) as modifications to */
/* Hercules. */
/* */
/*********************************************************************/
#ifndef _CHAIN_H_
#define _CHAIN_H_
/*-------------------------------------------------------------------*/
/* Define local macros for inline routines */
/*-------------------------------------------------------------------*/
#define anchor_id "Anchor->"
#define aeyesize 8
#define eyesize 8
#define raise_chain_validation_error \
CRASH();
#define chain_validate_pointer(_arg) \
if (_arg == 0 || _arg == NULL) \
raise_chain_validation_error;
/*-------------------------------------------------------------------*/
/* Chain Block */
/*-------------------------------------------------------------------*/
typedef struct _CHAINBLK { /* Chain definition block */
char anchoreye[aeyesize]; /* Anchor identifier */
char eyecatcher[eyesize]; /* Eyecatcher to check */
u_int containersize; /* Size of container */
LOCK lock; /* Lock for chain */
uintptr_t *first; /* First entry pointer */
uintptr_t *last; /* Last entry pointer */
uintptr_t offset; /* Offset to container start */
} CHAINBLK;
/*-------------------------------------------------------------------*/
/* Chain */
/*-------------------------------------------------------------------*/
typedef struct _CHAIN { /* Chain member definition */
char eyecatcher[eyesize]; /* Eyecatcher to check */
u_int containersize; /* Size of container */
uintptr_t *prev; /* -> previous chain entry */
uintptr_t *next; /* -> next chain entry */
uintptr_t offset; /* Offset to container start */
CHAINBLK *anchor; /* -> owning CHAINBLK */
} CHAIN;
/*-------------------------------------------------------------------*/
/* Chain management inline routines */
/*-------------------------------------------------------------------*/
static INLINE uintptr_t *chain_container(CHAIN *entry)
{
return ((uintptr_t *)entry + entry->offset);
}
static INLINE CHAINBLK *chain_validate_entry_header(CHAIN *entry)
{
/* Ensure valid entry pointers */
chain_validate_pointer(entry);
chain_validate_pointer(entry->anchor);
/* Make sure this is the anchor for a chain */
if (memcmp(entry->anchor->anchoreye, anchor_id, aeyesize))
raise_chain_validation_error;
/* Validate eyecatcher */
if (memcmp(entry->anchor->eyecatcher, entry->eyecatcher, eyesize))
raise_chain_validation_error;
return entry->anchor;
}
static INLINE void chain_init_anchor(void *container, CHAINBLK *anchor, char *eyecatcher, const u_int containersize)
{
chain_validate_pointer(container);
chain_validate_pointer(anchor);
chain_validate_pointer(eyecatcher);
memcpy(anchor->anchoreye, anchor_id, aeyesize);
{
register char *a = anchor->eyecatcher;
register char *e = eyecatcher;
register char *limit = a + eyesize;
for (; a < limit && *e; a++, e++)
*a = *e;
if (a == anchor->eyecatcher)
raise_chain_validation_error;
for (; a < limit; a++)
*a = ' ';
}
anchor->containersize = containersize;
initialize_lock(&anchor->lock);
anchor->first = anchor->last = 0;
anchor->offset = (uintptr_t) container - (uintptr_t) anchor;
}
static INLINE void chain_init_entry(CHAINBLK *anchor, void *container, CHAIN *entry)
{
chain_validate_pointer(container);
chain_validate_pointer(anchor);
chain_validate_pointer(entry);
memcpy(&entry->eyecatcher, &anchor->eyecatcher, eyesize);
entry->containersize = anchor->containersize;
entry->prev = entry->next = 0;
entry->offset = (uintptr_t *) container - (uintptr_t *) entry;
entry->anchor = anchor;
}
static INLINE void chain_first(CHAIN *entry)
{
register CHAINBLK *anchor = chain_validate_entry_header(entry);
if (!anchor->first)
anchor->first = anchor->last = (uintptr_t *)entry;
else
{
CHAIN *next = (CHAIN *)anchor->first + entry->offset;
entry->next = anchor->first;
next->prev = anchor->first = (uintptr_t *)entry;
}
}
static INLINE void chain_first_locked(CHAIN *entry)
{
register CHAINBLK *anchor = chain_validate_entry_header(entry);
obtain_lock(&anchor->lock);
chain_first(entry);
release_lock(&anchor->lock);
}
static INLINE void chain_before(CHAIN *entry, CHAIN *before)
{
register CHAINBLK *anchor = chain_validate_entry_header(entry);
if ((!before->prev && anchor->first != (uintptr_t *)before) ||
(before->prev && anchor->first == (uintptr_t *)before))
raise_chain_validation_error;
entry->next = (uintptr_t *)before;
entry->prev = before->prev;
before->prev = (uintptr_t *)entry;
if (!entry->prev)
anchor->first = (uintptr_t *)entry;
}
static INLINE void chain_after(CHAIN *entry, CHAIN *after)
{
register CHAINBLK *anchor = chain_validate_entry_header(entry);
if ((!after->next && anchor->last != (uintptr_t *)after) ||
(after->next && anchor->last == (uintptr_t *)after))
raise_chain_validation_error;
entry->next = after->next;
entry->prev = (uintptr_t *)after;
after->next = (uintptr_t *)entry;
if (!entry->next)
anchor->last = (uintptr_t *)entry;
}
static INLINE void chain_last(CHAIN *entry)
{
register CHAINBLK *anchor = chain_validate_entry_header(entry);
if (!anchor->last)
anchor->first = anchor->last = (uintptr_t *)entry;
else
{
CHAIN *prev = (CHAIN *)anchor->last + entry->offset;
entry->prev = anchor->last;
prev->next = anchor->last = (uintptr_t *)entry;
}
}
static INLINE void chain_last_locked(CHAIN *entry)
{
register CHAINBLK *anchor = chain_validate_entry_header(entry);
obtain_lock(&anchor->lock);
chain_last(entry);
release_lock(&anchor->lock);
}
static INLINE void unchain(CHAIN *entry)
{
register CHAINBLK *anchor = chain_validate_entry_header(entry);
if (entry->prev)
{
CHAIN *t = (CHAIN *)entry->prev;
t->next = entry->next;
}
else
anchor->first = entry->next;
if (entry->next)
{
CHAIN *t = (CHAIN *)entry->next;
t->prev = entry->prev;
}
else
anchor->last = entry->prev;
entry->prev = entry->next = 0;
}
static INLINE uintptr_t *unchain_first(CHAINBLK *anchor)
{
register CHAIN *entry = (CHAIN *)anchor->first;
if (!entry)
return 0;
unchain(entry);
return chain_container(entry);
}
static INLINE uintptr_t *unchain_first_locked(CHAINBLK *anchor)
{
register CHAIN *entry = (CHAIN *)anchor->first;
if (!entry)
return 0;
obtain_lock(&anchor->lock);
entry = (CHAIN *)anchor->first;
if (entry)
unchain(entry);
release_lock(&anchor->lock);
return chain_container(entry);
}
static INLINE uintptr_t *unchain_last(CHAINBLK *anchor)
{
register CHAIN *entry = (CHAIN *)anchor->last;
if (!entry)
return 0;
unchain(entry);
return chain_container(entry);
}
static INLINE uintptr_t *unchain_last_locked(CHAINBLK *anchor)
{
register CHAIN *entry = (CHAIN *)anchor->last;
if (!entry)
return 0;
obtain_lock(&anchor->lock);
entry = (CHAIN *)anchor->last;
if (entry)
unchain(entry);
release_lock(&anchor->lock);
return chain_container(entry);
}
static INLINE void unchain_locked(CHAIN *entry)
{
register CHAINBLK *anchor = chain_validate_entry_header(entry);
obtain_lock(&anchor->lock);
unchain(entry);
release_lock(&anchor->lock);
}
/*-------------------------------------------------------------------*/
/* Chain aliases */
/*-------------------------------------------------------------------*/
static INLINE void chain(CHAIN *entry)
{chain_last(entry);}
/*-------------------------------------------------------------------*/
/* Queue aliases */
/*-------------------------------------------------------------------*/
#define QUEUEBLK CHAINBLK
#define QUEUE CHAIN
static INLINE void queue_init_anchor(void *container, QUEUEBLK *anchor, char *eyecatcher, const u_int containersize)
{chain_init_anchor(container, anchor, eyecatcher, containersize);}
static INLINE void queue_init_entry(QUEUEBLK *anchor, void *container, QUEUE *entry)
{chain_init_entry(anchor, container, entry);}
static INLINE void queue(QUEUE *entry)
{chain_last(entry);}
static INLINE void queue_fifo(QUEUE *entry)
{chain_last(entry);}
static INLINE void queue_lifo(QUEUE *entry)
{chain_first(entry);}
static INLINE uintptr_t *dequeue_locked(QUEUEBLK *anchor)
{return unchain_first_locked(anchor);}
static INLINE uintptr_t *dequeue(QUEUEBLK *anchor)
{return unchain_first(anchor);}
/*-------------------------------------------------------------------*/
/* Undefine local macros */
/*-------------------------------------------------------------------*/
#undef chain_validate_pointer
#undef raise_chain_validation_error
#undef eyesize
#undef aeyesize
#undef anchor_id
#endif /* _CHAIN_H_ */