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
37 /* Pointer Double Ended Queue */
38 #define PDEQ_MAGIC1 FOURCC('P','D','E','1')
39 #define PDEQ_MAGIC2 FOURCC('P','D','E','2')
41 /** Size of pdeq block cache. */
42 #define TUNE_NSAVED_PDEQS 16
44 /** A size handled efficiently by malloc(), at least 1K. */
45 #define PREF_MALLOC_SIZE 2048
48 * Maximal number of data items in a pdeq chunk.
50 #define NDATA ((PREF_MALLOC_SIZE - offsetof(pdeq, data)) / sizeof(void *))
53 # define VRFY(dq) ((void)0)
55 # define VRFY(dq) assert((dq) && ((dq)->magic == PDEQ_MAGIC1))
59 * A pointer double ended queue.
60 * This structure is used as a list chunk either.
64 unsigned magic; /**< debug magic */
66 pdeq *l_end, *r_end; /**< left and right ends of the queue */
67 pdeq *l, *r; /**< left and right neighbor */
68 size_t n; /**< number of elements in the current chunk */
69 size_t p; /**< the read/write pointer */
70 const void *data[1]; /**< storage for elements */
75 * cache of unused, pdeq blocks to speed up new_pdeq and del_pdeq.
76 * +1 for compilers that can't grok empty arrays
78 static pdeq *pdeq_block_cache[TUNE_NSAVED_PDEQS+1];
81 * Number of pdeqs in pdeq_store.
83 static unsigned pdeqs_cached;
86 * Free a pdeq chunk, put in into the cache if possible.
88 * @param p The pdeq chunk.
90 static inline void free_pdeq_block (pdeq *p)
93 p->magic = 0xbadf00d1;
95 if (pdeqs_cached < TUNE_NSAVED_PDEQS) {
96 pdeq_block_cache[pdeqs_cached++] = p;
103 * Allocate a new pdeq chunk, get it from the cache if possible.
105 * @return A new pdeq chunk.
107 static inline pdeq *alloc_pdeq_block (void)
110 if (TUNE_NSAVED_PDEQS && pdeqs_cached) {
111 p = pdeq_block_cache[--pdeqs_cached];
113 p = (pdeq*) xmalloc(PREF_MALLOC_SIZE);
121 * Verify a double ended list, assert if failure.
123 * @param dq The list to verify.
125 void _pdeq_vrfy(pdeq *dq)
130 && (dq->magic == PDEQ_MAGIC1)
131 && (dq->l_end && dq->r_end));
134 assert ( ((q == dq) || (q->magic == PDEQ_MAGIC2))
135 && ((q == dq->l_end) ^ (q->l != NULL))
136 && ((q == dq->r_end) ^ (q->r != NULL))
137 && (!q->l || (q == q->l->r))
139 && ((q == dq->l_end) || (q == dq->r_end) || (q->n == NDATA))
146 /* Creates a new double ended pointer list. */
151 dq = alloc_pdeq_block();
154 dq->magic = PDEQ_MAGIC1;
156 dq->l_end = dq->r_end = dq;
157 dq->l = dq->r = NULL;
164 /* Creates a new double ended pointer list and puts an initial pointer element in. */
165 pdeq *new_pdeq1(const void *x)
167 return pdeq_putr(new_pdeq(), x);
170 /* Delete a double ended pointer list. */
171 void del_pdeq(pdeq *dq)
177 q = dq->l_end; /* left end of chain */
178 /* pdeq trunk empty, but !pdeq_empty() ==> trunk not in chain */
179 if (dq->n == 0 && dq->l_end != dq ) {
183 /* Free all blocks in the pdeq chain */
191 /* Checks if a list is empty. */
192 int pdeq_empty(pdeq *dq)
195 return dq->l_end->n == 0;
198 /* Returns the length of a double ended pointer list. */
199 size_t pdeq_len(pdeq *dq)
216 /* Add a pointer to the right site of a double ended pointer list. */
217 pdeq *pdeq_putr(pdeq *dq, const void *x)
225 if (rdq->n >= NDATA) { /* tailblock full */
228 ndq = dq; /* try to reuse trunk, but ... */
229 if (dq->n) { /* ... if trunk used */
230 /* allocate and init new block */
231 ndq = alloc_pdeq_block();
233 ndq->magic = PDEQ_MAGIC2;
235 ndq->l_end = ndq->r_end = NULL;
239 ndq->l = rdq; rdq->r = ndq;
240 ndq->n = 0; ndq->p = 0;
245 n = rdq->n++ + rdq->p;
246 if (n >= NDATA) n -= NDATA;
254 /* Add a pointer to the left site of a double ended pointer list. */
255 pdeq *pdeq_putl(pdeq *dq, const void *x)
263 if (ldq->n >= NDATA) { /* headblock full */
266 ndq = dq; /* try to reuse trunk, but ... */
267 if (dq->n) { /* ... if trunk used */
268 /* allocate and init new block */
269 ndq = alloc_pdeq_block();
271 ndq->magic = PDEQ_MAGIC2;
273 ndq->l_end = ndq->r_end = NULL;
277 ndq->r = ldq; ldq->l = ndq;
278 ndq->n = 0; ndq->p = 0;
296 /* Retrieve a pointer from the right site of a double ended pointer list. */
297 void *pdeq_getr(pdeq *dq)
304 assert(dq->l_end->n);
307 n = rdq->p + --rdq->n;
308 if (n >= NDATA) n -= NDATA;
317 dq->r_end = dq->l_end = dq;
320 free_pdeq_block(rdq);
328 /* Retrieve a pointer from the left site of a double ended pointer list. */
329 void *pdeq_getl(pdeq *dq)
336 assert(dq->l_end->n);
341 if (++p >= NDATA) p = 0;
350 dq->l_end = dq->r_end = dq;
353 free_pdeq_block(ldq);
362 * Returns non-zero if a double ended pointer list
363 * contains a pointer x.
365 int pdeq_contains(pdeq *dq, const void *x)
375 p = q->p; ep = p + q->n;
379 if (q->data[p] == x) return 1;
380 } while (++p < NDATA);
386 if (q->data[p++] == x) return 1;
396 * Search a key in a double ended pointer list, the search
397 * is controlled by a compare function.
398 * An element is found, if the compare function returns 0.
399 * The search is started from the left site of the list.
401 void *pdeq_search(pdeq *dq, cmp_fun cmp, const void *key)
412 p = q->p; ep = p + q->n;
416 if (!cmp(q->data[p], key)) return (void *)q->data[p-1];
417 } while (++p < NDATA);
423 if (!cmp(q->data[p++], key)) return (void *)q->data[p-1];
433 * Convert the double ended pointer list into a linear array beginning from
434 * left, the first element in the linear array will be the left one.
436 void **pdeq_copyl(pdeq *dq, const void **dst)
439 const void **d = dst;
450 /* p is always < NDATA */
451 size_t nn = NDATA - p;
452 memcpy((void *) d, &q->data[p], nn * sizeof(void *)); d += nn;
456 memcpy((void *) d, &q->data[p], n * sizeof(void *)); d += n;
465 * Convert the double ended pointer list into a linear array beginning from
466 * right, the first element in the linear array will be the right one.
468 void **pdeq_copyr(pdeq *dq, const void **dst)
471 const void **d = dst;
479 p = q->p; i = q->n + p - 1;