mirror of
https://github.com/netsurf-browser/netsurf
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138 lines
4.1 KiB
C
138 lines
4.1 KiB
C
/*
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* Copyright 2006, 2007 Daniel Silverstone <dsilvers@digital-scurf.org>
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*
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* This file is part of NetSurf, http://www.netsurf-browser.org/
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*
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* NetSurf is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; version 2 of the License.
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*
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* NetSurf is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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/** \file
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* Ring list structure.
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*
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* Rings are structures which have an r_next pointer and an r_prev
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* pointer which are always initialised and always point at the next
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* or previous element respectively.
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*
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* The degenerate case of a single element in the ring simply points
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* at itself in both directions. A zero element ring is NULL.
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*
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* Some of the ring functions are specific to the fetcher but may be
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* of use to others and are thus included here.
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*/
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#ifndef _NETSURF_UTILS_RING_H_
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#define _NETSURF_UTILS_RING_H_
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/** Insert the given item into the specified ring.
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* Assumes that the element is zeroed as appropriate.
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*/
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#define RING_INSERT(ring,element) \
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/*LOG(("RING_INSERT(%s, %p(%s))", #ring, element, element->host));*/ \
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if (ring) { \
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element->r_next = ring; \
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element->r_prev = ring->r_prev; \
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ring->r_prev = element; \
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element->r_prev->r_next = element; \
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} else \
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ring = element->r_prev = element->r_next = element
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/** Remove the given element from the specified ring.
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* Will zero the element as needed
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*/
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#define RING_REMOVE(ring, element) \
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/*LOG(("RING_REMOVE(%s, %p(%s)", #ring, element, element->host));*/ \
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if (element->r_next != element ) { \
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/* Not the only thing in the ring */ \
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element->r_next->r_prev = element->r_prev; \
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element->r_prev->r_next = element->r_next; \
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if (ring == element) ring = element->r_next; \
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} else { \
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/* Only thing in the ring */ \
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ring = 0; \
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} \
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element->r_next = element->r_prev = 0
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/** Find the element (by hostname) in the given ring, leave it in the
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* provided element variable
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*/
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#define RING_FINDBYHOST(ring, element, hostname) \
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/*LOG(("RING_FINDBYHOST(%s, %s)", #ring, hostname));*/ \
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if (ring) { \
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bool found = false; \
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element = ring; \
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do { \
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if (strcasecmp(element->host, hostname) == 0) { \
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found = true; \
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break; \
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} \
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element = element->r_next; \
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} while (element != ring); \
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if (!found) element = 0; \
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} else element = 0
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/** Measure the size of a ring and put it in the supplied variable */
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#define RING_GETSIZE(ringtype, ring, sizevar) \
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/*LOG(("RING_GETSIZE(%s)", #ring));*/ \
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if (ring) { \
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ringtype *p = ring; \
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sizevar = 0; \
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do { \
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sizevar++; \
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p = p->r_next; \
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} while (p != ring); \
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} else sizevar = 0
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/** Count the number of elements in the ring which match the provided hostname */
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#define RING_COUNTBYHOST(ringtype, ring, sizevar, hostname) \
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/*LOG(("RING_COUNTBYHOST(%s, %s)", #ring, hostname));*/ \
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if (ring) { \
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ringtype *p = ring; \
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sizevar = 0; \
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do { \
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if (strcasecmp(p->host, hostname) == 0) \
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sizevar++; \
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p = p->r_next; \
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} while (p != ring); \
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} else sizevar = 0
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/*
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* Ring iteration works as follows:
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*
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* RING_ITERATE_START(ringtype, ring, iteratorptr) {
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* code_using(iteratorptr);
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* } RING_ITERATE_END(ring, iteratorptr);
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*
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* If you want to stop iterating (e.g. you found your answer)
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* RING_ITERATE_STOP(ring, iteratorptr);
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* You *MUST* abort the iteration if you do something to modify
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* the ring such as deleting or adding an element.
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*/
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#define RING_ITERATE_START(ringtype, ring, iteratorptr) \
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if (ring != NULL) { \
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ringtype *iteratorptr = ring; \
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do { \
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do { \
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#define RING_ITERATE_STOP(ring, iteratorptr) \
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goto iteration_end_##ring##_##iteratorptr
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#define RING_ITERATE_END(ring, iteratorptr) \
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} while (false); \
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} while (iteratorptr != ring); \
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} \
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iteration_end_##ring##_##iteratorptr:
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#endif
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