netsurf/utils/ring.h

99 lines
2.9 KiB
C

/*
* This file is part of NetSurf, http://netsurf-browser.org/
* Licensed under the GNU General Public License,
* http://www.opensource.org/licenses/gpl-license
* Copyright 2006, 2007 Daniel Silverstone <dsilvers@digital-scurf.org>
*/
/** \file
* Ring list structure.
*
* Rings are structures which have an r_next pointer and an r_prev
* pointer which are always initialised and always point at the next
* or previous element respectively.
*
* The degenerate case of a single element in the ring simply points
* at itself in both directions. A zero element ring is NULL.
*
* Some of the ring functions are specific to the fetcher but may be
* of use to others and are thus included here.
*/
#ifndef _NETSURF_UTILS_RING_H_
#define _NETSURF_UTILS_RING_H_
/** Insert the given item into the specified ring.
* Assumes that the element is zeroed as appropriate.
*/
#define RING_INSERT(ring,element) \
/*LOG(("RING_INSERT(%s, %p(%s))", #ring, element, element->host));*/ \
if (ring) { \
element->r_next = ring; \
element->r_prev = ring->r_prev; \
ring->r_prev = element; \
element->r_prev->r_next = element; \
} else \
ring = element->r_prev = element->r_next = element
/** Remove the given element from the specified ring.
* Will zero the element as needed
*/
#define RING_REMOVE(ring, element) \
/*LOG(("RING_REMOVE(%s, %p(%s)", #ring, element, element->host));*/ \
if (element->r_next != element ) { \
/* Not the only thing in the ring */ \
element->r_next->r_prev = element->r_prev; \
element->r_prev->r_next = element->r_next; \
if (ring == element) ring = element->r_next; \
} else { \
/* Only thing in the ring */ \
ring = 0; \
} \
element->r_next = element->r_prev = 0
/** Find the element (by hostname) in the given ring, leave it in the
* provided element variable
*/
#define RING_FINDBYHOST(ring, element, hostname) \
/*LOG(("RING_FINDBYHOST(%s, %s)", #ring, hostname));*/ \
if (ring) { \
bool found = false; \
element = ring; \
do { \
if (strcasecmp(element->host, hostname) == 0) { \
found = true; \
break; \
} \
element = element->r_next; \
} while (element != ring); \
if (!found) element = 0; \
} else element = 0
/** Measure the size of a ring and put it in the supplied variable */
#define RING_GETSIZE(ringtype, ring, sizevar) \
/*LOG(("RING_GETSIZE(%s)", #ring));*/ \
if (ring) { \
ringtype *p = ring; \
sizevar = 0; \
do { \
sizevar++; \
p = p->r_next; \
} while (p != ring); \
} else sizevar = 0
/** Count the number of elements in the ring which match the provided hostname */
#define RING_COUNTBYHOST(ringtype, ring, sizevar, hostname) \
/*LOG(("RING_COUNTBYHOST(%s, %s)", #ring, hostname));*/ \
if (ring) { \
ringtype *p = ring; \
sizevar = 0; \
do { \
if (strcasecmp(p->host, hostname) == 0) \
sizevar++; \
p = p->r_next; \
} while (p != ring); \
} else sizevar = 0
#endif