2 * Copyright (C) 1995-2008 University of Karlsruhe. All right reserved.
4 * This file is part of libFirm.
6 * This file may be distributed and/or modified under the terms of the
7 * GNU General Public License version 2 as published by the Free Software
8 * Foundation and appearing in the file LICENSE.GPL included in the
9 * packaging of this file.
11 * Licensees holding valid libFirm Professional Edition licenses may use
12 * this file in accordance with the libFirm Commercial License.
13 * Agreement provided with the Software.
15 * This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
16 * WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * @brief double ended queue of generic pointers.
23 * @author Christian von Roques
24 * @date 1999 by getting from fiasco
46 /* Pointer Double Ended Queue */
47 #define PDEQ_MAGIC1 FOURCC('P','D','E','1')
48 #define PDEQ_MAGIC2 FOURCC('P','D','E','2')
50 /** Size of pdeq block cache. */
51 #define TUNE_NSAVED_PDEQS 16
54 * Maximal number of data items in a pdeq chunk.
56 #define NDATA ((int)((PREF_MALLOC_SIZE - offsetof (pdeq, data)) / sizeof (void *)))
59 # define VRFY(dq) ((void)0)
61 # define VRFY(dq) assert((dq) && ((dq)->magic == PDEQ_MAGIC1))
65 * A pointer double ended queue.
66 * This structure is used as a list chunk either.
70 unsigned magic; /**< debug magic */
72 pdeq *l_end, *r_end; /**< left and right ends of the queue */
73 pdeq *l, *r; /**< left and right neighbor */
74 int n; /**< number of elements in the current chunk */
75 int p; /**< the read/write pointer */
76 const void *data[1]; /**< storage for elements */
81 * cache of unused, pdeq blocks to speed up new_pdeq and del_pdeq.
82 * +1 for compilers that can't grok empty arrays
84 static pdeq *pdeq_block_cache[TUNE_NSAVED_PDEQS+1];
87 * Number of pdeqs in pdeq_store.
89 static unsigned pdeqs_cached;
92 * Free a pdeq chunk, put in into the cache if possible.
94 * @param p The pdeq chunk.
96 static inline void free_pdeq_block (pdeq *p)
99 p->magic = 0xbadf00d1;
101 if (pdeqs_cached < TUNE_NSAVED_PDEQS) {
102 pdeq_block_cache[pdeqs_cached++] = p;
109 * Allocate a new pdeq chunk, get it from the cache if possible.
111 * @return A new pdeq chunk.
113 static inline pdeq *alloc_pdeq_block (void)
116 if (TUNE_NSAVED_PDEQS && pdeqs_cached) {
117 p = pdeq_block_cache[--pdeqs_cached];
119 p = xmalloc(PREF_MALLOC_SIZE);
127 * Verify a double ended list, assert if failure.
129 * @param dq The list to verify.
131 void _pdeq_vrfy(pdeq *dq)
136 && (dq->magic == PDEQ_MAGIC1)
137 && (dq->l_end && dq->r_end));
140 assert ( ((q == dq) || (q->magic == PDEQ_MAGIC2))
141 && ((q == dq->l_end) ^ (q->l != NULL))
142 && ((q == dq->r_end) ^ (q->r != NULL))
143 && (!q->l || (q == q->l->r))
144 && ((q->n >= 0) && (q->n <= NDATA))
145 && ((q == dq->l_end) || (q == dq->r_end) || (q->n == NDATA))
146 && ((q->p >= 0) && (q->p < NDATA)));
152 /* Creates a new double ended pointer list. */
157 dq = alloc_pdeq_block();
160 dq->magic = PDEQ_MAGIC1;
162 dq->l_end = dq->r_end = dq;
163 dq->l = dq->r = NULL;
170 /* Creates a new double ended pointer list and puts an initial pointer element in. */
171 pdeq *new_pdeq1(const void *x)
173 return pdeq_putr(new_pdeq(), x);
176 /* Delete a double ended pointer list. */
177 void del_pdeq(pdeq *dq)
183 q = dq->l_end; /* left end of chain */
184 /* pdeq trunk empty, but !pdeq_empty() ==> trunk not in chain */
185 if (dq->n == 0 && dq->l_end != dq ) {
189 /* Free all blocks in the pdeq chain */
197 /* Checks if a list is empty. */
198 int pdeq_empty(pdeq *dq)
201 return dq->l_end->n == 0;
204 /* Returns the length of a double ended pointer list. */
205 int pdeq_len(pdeq *dq)
222 /* Add a pointer to the right site of a double ended pointer list. */
223 pdeq *pdeq_putr(pdeq *dq, const void *x)
231 if (rdq->n >= NDATA) { /* tailblock full */
234 ndq = dq; /* try to reuse trunk, but ... */
235 if (dq->n) { /* ... if trunk used */
236 /* allocate and init new block */
237 ndq = alloc_pdeq_block();
239 ndq->magic = PDEQ_MAGIC2;
241 ndq->l_end = ndq->r_end = NULL;
245 ndq->l = rdq; rdq->r = ndq;
246 ndq->n = 0; ndq->p = 0;
251 n = rdq->n++ + rdq->p;
252 if (n >= NDATA) n -= NDATA;
260 /* Add a pointer to the left site of a double ended pointer list. */
261 pdeq *pdeq_putl(pdeq *dq, const void *x)
269 if (ldq->n >= NDATA) { /* headblock full */
272 ndq = dq; /* try to reuse trunk, but ... */
273 if (dq->n) { /* ... if trunk used */
274 /* allocate and init new block */
275 ndq = alloc_pdeq_block();
277 ndq->magic = PDEQ_MAGIC2;
279 ndq->l_end = ndq->r_end = NULL;
283 ndq->r = ldq; ldq->l = ndq;
284 ndq->n = 0; ndq->p = 0;
291 if (p < 0) p += NDATA;
300 /* Retrieve a pointer from the right site of a double ended pointer list. */
301 void *pdeq_getr(pdeq *dq)
308 assert(dq->l_end->n);
311 n = rdq->p + --rdq->n;
312 if (n >= NDATA) n -= NDATA;
321 dq->r_end = dq->l_end = dq;
324 free_pdeq_block(rdq);
332 /* Retrieve a pointer from the left site of a double ended pointer list. */
333 void *pdeq_getl(pdeq *dq)
340 assert(dq->l_end->n);
345 if (++p >= NDATA) p = 0;
354 dq->l_end = dq->r_end = dq;
357 free_pdeq_block(ldq);
366 * Returns non-zero if a double ended pointer list
367 * contains a pointer x.
369 int pdeq_contains(pdeq *dq, const void *x)
379 p = q->p; ep = p + q->n;
383 if (q->data[p] == x) return 1;
384 } while (++p < NDATA);
390 if (q->data[p++] == x) return 1;
400 * Search a key in a double ended pointer list, the search
401 * is controlled by a compare function.
402 * An element is found, if the compare function returns 0.
403 * The search is started from the left site of the list.
405 void *pdeq_search(pdeq *dq, cmp_fun cmp, const void *key)
416 p = q->p; ep = p + q->n;
420 if (!cmp (q->data[p], key)) return (void *)q->data[p-1];
421 } while (++p < NDATA);
427 if (!cmp (q->data[p++], key)) return (void *)q->data[p-1];
437 * Convert the double ended pointer list into a linear array beginning from
438 * left, the first element in the linear array will be the left one.
440 void **pdeq_copyl(pdeq *dq, const void **dst)
443 const void **d = dst;
455 memcpy((void *) d, &q->data[p], nn * sizeof(void *)); d += nn;
459 memcpy((void *) d, &q->data[p], n * sizeof(void *)); d += n;
468 * Convert the double ended pointer list into a linear array beginning from
469 * right, the first element in the linear array will be the right one.
471 void **pdeq_copyr(pdeq *dq, const void **dst)
474 const void **d = dst;
482 p = q->p; i = q->n + p - 1;
485 do *d++ = q->data[i]; while (--i >= 0);
489 do *d++ = q->data[i]; while (--i >= p);