2 * Copyright (C) 1994, Index Data I/S
4 * Sebastian Hammer, Adam Dickmeiss
7 * Revision 1.8 1995-12-06 14:48:27 quinn
8 * Fixed some strange bugs.
10 * Revision 1.7 1995/12/06 09:59:46 quinn
11 * Fixed memory-consumption bug in memory.c
12 * Added more blocksizes to the default ISAM configuration.
14 * Revision 1.6 1995/09/04 12:33:47 adam
15 * Various cleanup. YAZ util used instead.
17 * Revision 1.5 1994/09/28 16:58:33 quinn
20 * Revision 1.4 1994/09/27 20:03:52 quinn
21 * Seems relatively bug-free.
23 * Revision 1.3 1994/09/26 17:11:30 quinn
26 * Revision 1.2 1994/09/26 17:06:35 quinn
29 * Revision 1.1 1994/09/26 16:07:56 quinn
30 * Most of the functionality in place.
35 * This module accesses and rearranges the records of the tables.
44 int is_mbuf_size[3] = { 0, 1024, 4096 };
46 static is_mblock *mblock_tmplist = 0, *mblock_freelist = 0;
47 static is_mbuf *mbuf_freelist[3] = {0, 0, 0};
49 #define MALLOC_CHUNK 20
51 is_mblock *xmalloc_mblock()
58 mblock_freelist = xmalloc(sizeof(is_mblock) * MALLOC_CHUNK);
59 for (i = 0; i < MALLOC_CHUNK - 1; i++)
60 mblock_freelist[i].next = &mblock_freelist[i+1];
61 mblock_freelist[i].next = 0;
63 tmp = mblock_freelist;
64 mblock_freelist = mblock_freelist->next;
66 tmp->state = IS_MBSTATE_UNREAD;
71 is_mbuf *xmalloc_mbuf(int type)
75 if (mbuf_freelist[type])
77 tmp = mbuf_freelist[type];
78 mbuf_freelist[type] = tmp->next;
82 tmp = xmalloc(sizeof(is_mbuf) + is_mbuf_size[type]);
85 tmp->refcount = type ? 1 : 0;
86 tmp->offset = tmp->num = tmp->cur_record = 0;
87 tmp->data = (char*) tmp + sizeof(is_mbuf);
92 void xfree_mbuf(is_mbuf *p)
94 p->next = mbuf_freelist[p->type];
95 mbuf_freelist[p->type] = p;
98 void xfree_mbufs(is_mbuf *l)
110 void xfree_mblock(is_mblock *p)
112 xfree_mbufs(p->data);
113 p->next = mblock_freelist;
117 void xrelease_mblock(is_mblock *p)
119 p->next = mblock_tmplist;
123 void xfree_mblocks(is_mblock *l)
135 void is_m_establish_tab(ISAM is, is_mtable *tab, ISAM_P pos)
137 tab->data = xmalloc_mblock();
140 tab->pos_type = is_type(pos);
141 tab->num_records = -1;
142 tab->data->num_records = -1;
143 tab->data->diskpos = is_block(pos);
144 tab->data->state = IS_MBSTATE_UNREAD;
146 tab->cur_mblock = tab->data;
147 tab->cur_mblock->cur_mbuf = 0;
152 tab->num_records = 0;
153 tab->data->num_records = 0;
154 tab->data->diskpos = -1;
155 tab->data->state = IS_MBSTATE_CLEAN;
156 tab->data->data = xmalloc_mbuf(IS_MBUF_TYPE_LARGE);
157 tab->cur_mblock = tab->data;
158 tab->cur_mblock->cur_mbuf = tab->data->data;
159 tab->cur_mblock->cur_mbuf->cur_record = 0;
164 void is_m_release_tab(is_mtable *tab)
166 xfree_mblocks(tab->data);
167 xfree_mblocks(mblock_tmplist);
171 void is_m_rewind(is_mtable *tab)
173 tab->cur_mblock = tab->data;
176 tab->data->cur_mbuf = tab->data->data;
178 tab->data->data->cur_record = 0;
182 static int read_current_full(is_mtable *tab, is_mblock *mblock)
184 if (is_p_read_full(tab, mblock) < 0)
186 if (mblock->nextpos && !mblock->next)
188 mblock->next = xmalloc_mblock();
189 mblock->next->diskpos = mblock->nextpos;
190 mblock->next->state = IS_MBSTATE_UNREAD;
191 mblock->next->data = 0;
193 mblock->cur_mbuf = mblock->data;
194 mblock->data->cur_record = 0;
198 int is_m_read_full(is_mtable *tab, is_mblock *mblock)
200 return read_current_full(tab, mblock);
204 * replace the record right behind the pointer.
206 void is_m_replace_record(is_mtable *tab, const void *rec)
208 is_mbuf *mbuf = tab->cur_mblock->cur_mbuf;
210 /* we assume that block is already in memory and that we are in the
211 * right mbuf, and that it has space for us. */
212 memcpy(mbuf->data + mbuf->offset + (mbuf->cur_record - 1) *
213 is_keysize(tab->is), rec, is_keysize(tab->is));
214 tab->cur_mblock->state = IS_MBSTATE_DIRTY;
218 * Delete the record right behind the pointer.
220 void is_m_delete_record(is_mtable *tab)
224 mbuf = tab->cur_mblock->cur_mbuf;
225 if (mbuf->cur_record >= mbuf->num) /* top of mbuf */
230 else /* middle of a block */
232 new = xmalloc_mbuf(IS_MBUF_TYPE_SMALL);
233 new->next = mbuf->next;
235 new->data = mbuf->data;
237 new->offset = mbuf->offset + mbuf->cur_record * is_keysize(tab->is);
238 new->num = mbuf->num - mbuf->cur_record;
239 mbuf->num = mbuf->cur_record -1;
241 mbuf->cur_record = 0;
244 tab->cur_mblock->num_records--;
245 tab->cur_mblock->state = tab->data->state = IS_MBSTATE_DIRTY;
248 int is_m_write_record(is_mtable *tab, const void *rec)
250 is_mbuf *mbuf, *oldnext, *dmbuf;
252 /* make sure block is all in memory */
253 if (tab->cur_mblock->state <= IS_MBSTATE_PARTIAL)
254 if (read_current_full(tab, tab->cur_mblock) < 0)
256 mbuf = tab->cur_mblock->cur_mbuf;
257 if (mbuf->cur_record >= mbuf->num) /* top of mbuf */
259 /* mbuf is reference or full */
260 if (mbuf->refcount != 1 || mbuf->offset + (mbuf->num + 1) *
261 is_keysize(tab->is) > is_mbuf_size[mbuf->type])
263 oldnext = mbuf->next;
264 mbuf->next = xmalloc_mbuf(IS_MBUF_TYPE_LARGE);
265 mbuf->next->next = oldnext;
267 tab->cur_mblock->cur_mbuf = mbuf;
268 mbuf->cur_record = 0;
273 oldnext = mbuf->next;
274 mbuf->next = xmalloc_mbuf(IS_MBUF_TYPE_MEDIUM);
275 mbuf->next->next = dmbuf = xmalloc_mbuf(IS_MBUF_TYPE_SMALL);
276 dmbuf->data = mbuf->data;
277 dmbuf->next = oldnext;
278 dmbuf->offset = mbuf->offset + mbuf->cur_record * is_keysize(tab->is);
279 dmbuf->num = mbuf->num - mbuf->cur_record;
280 mbuf->num -= dmbuf->num;
282 mbuf = tab->cur_mblock->cur_mbuf = mbuf->next;
283 mbuf->cur_record = 0;
285 logf (LOG_DEBUG, "is_m_write_rec(rec == %d)", mbuf->cur_record);
286 memcpy(mbuf->data + mbuf->offset + mbuf->cur_record * is_keysize(tab->is),
287 rec, is_keysize(tab->is));
291 tab->cur_mblock->num_records++;
292 tab->cur_mblock->state = tab->data->state = IS_MBSTATE_DIRTY;
296 void is_m_unread_record(is_mtable *tab)
298 assert(tab->cur_mblock->cur_mbuf->cur_record);
299 tab->cur_mblock->cur_mbuf->cur_record--;
303 * non-destructive read.
305 int is_m_peek_record(is_mtable *tab, void *rec)
310 /* make sure block is all in memory */
311 if (tab->cur_mblock->state <= IS_MBSTATE_PARTIAL)
312 if (read_current_full(tab, tab->cur_mblock) < 0)
314 mblock = tab->cur_mblock;
315 mbuf = mblock->cur_mbuf;
316 if (mbuf->cur_record >= mbuf->num) /* are we at end of mbuf? */
318 if (!mbuf->next) /* end of mblock */
322 mblock = mblock->next;
323 if (mblock->state <= IS_MBSTATE_PARTIAL)
324 if (read_current_full(tab, mblock) < 0)
329 return 0; /* EOTable */
333 mbuf->cur_record = 0;
335 memcpy(rec, mbuf->data + mbuf->offset + mbuf->cur_record *
336 is_keysize(tab->is), is_keysize(tab->is));
340 int is_m_read_record(is_mtable *tab, void *buf)
344 /* make sure block is all in memory */
345 if (tab->cur_mblock->state <= IS_MBSTATE_PARTIAL)
346 if (read_current_full(tab, tab->cur_mblock) < 0)
348 mbuf = tab->cur_mblock->cur_mbuf;
349 if (mbuf->cur_record >= mbuf->num) /* are we at end of mbuf? */
351 if (!mbuf->next) /* end of mblock */
353 if (tab->cur_mblock->state == IS_MBSTATE_CLEAN &&
354 tab->cur_mblock->diskpos > 0)
356 xfree_mbufs(tab->cur_mblock->data);
357 tab->cur_mblock->data = 0;
358 tab->cur_mblock->state = IS_MBSTATE_UNREAD;
360 if (tab->cur_mblock->next)
362 tab->cur_mblock = tab->cur_mblock->next;
363 if (tab->cur_mblock->state <= IS_MBSTATE_PARTIAL)
364 if (read_current_full(tab, tab->cur_mblock) < 0)
366 tab->cur_mblock->cur_mbuf = mbuf = tab->cur_mblock->data;
369 return 0; /* EOTable */
372 tab->cur_mblock->cur_mbuf = mbuf = mbuf->next;
373 mbuf->cur_record = 0;
375 memcpy(buf, mbuf->data + mbuf->offset + mbuf->cur_record *
376 is_keysize(tab->is), is_keysize(tab->is));
382 * TODO: optimize this function by introducing a higher-level search.
384 int is_m_seek_record(is_mtable *tab, const void *rec)
386 char peek[IS_MAX_RECORD];
391 if (is_m_read_record(tab, &peek) <= 0)
393 if ((rs = (*tab->is->cmp)(peek, rec)) > 0)
395 is_m_unread_record(tab);
403 int is_m_num_records(is_mtable *tab)
405 if (tab->data->state < IS_MBSTATE_PARTIAL)
406 if (read_current_full(tab, tab->data) < 0)
408 logf (LOG_FATAL, "read full failed");
411 return tab->num_records;