2 * Copyright (C) 1994, Index Data I/S
4 * Sebastian Hammer, Adam Dickmeiss
7 * Revision 1.9 1996-02-06 10:19:57 quinn
8 * Attempt at fixing bug. Not all blocks were read before they were unlinked
9 * prior to a remap operation.
11 * Revision 1.8 1996/01/29 09:47:11 quinn
12 * Fixed mean little bug in the read-table code.
14 * Revision 1.7 1995/12/06 14:48:27 quinn
15 * Fixed some strange bugs.
17 * Revision 1.6 1995/09/04 12:33:47 adam
18 * Various cleanup. YAZ util used instead.
20 * Revision 1.5 1994/09/28 11:29:33 quinn
21 * Added cmp parameter.
23 * Revision 1.4 1994/09/27 20:03:53 quinn
24 * Seems relatively bug-free.
26 * Revision 1.3 1994/09/26 17:11:31 quinn
29 * Revision 1.2 1994/09/26 17:06:36 quinn
32 * Revision 1.1 1994/09/26 16:07:57 quinn
33 * Most of the functionality in place.
38 * This module handles the representation of tables in the bfiles.
46 static int is_freestore_alloc(ISAM is, int type)
50 if (is->types[type].freelist >= 0)
52 tmp = is->types[type].freelist;
53 if (bf_read(is->types[type].bf, tmp, 0, sizeof(tmp),
54 &is->types[type].freelist) <=0)
56 logf (LOG_FATAL, "Failed to allocate block");
61 tmp = is->types[type].top++;
63 logf (LOG_DEBUG, "Allocating block #%d", tmp);
67 static void is_freestore_free(ISAM is, int type, int block)
71 logf (LOG_DEBUG, "Releasing block #%d", block);
72 tmp = is->types[type].freelist;
73 is->types[type].freelist = block;
74 if (bf_write(is->types[type].bf, block, 0, sizeof(tmp), &tmp) < 0)
76 logf (LOG_FATAL, "Failed to deallocate block.");
81 /* this code must be modified to handle an index */
82 int is_p_read_partial(is_mtable *tab, is_mblock *block)
87 assert(block->state == IS_MBSTATE_UNREAD);
88 block->data = buf = xmalloc_mbuf(IS_MBUF_TYPE_LARGE);
89 toread = tab->is->types[tab->pos_type].blocksize;
90 if (toread > is_mbuf_size[buf->type])
92 toread = is_mbuf_size[buf->type];
93 block->state = IS_MBSTATE_PARTIAL;
96 block->state = IS_MBSTATE_CLEAN;
97 if (bf_read(tab->is->types[tab->pos_type].bf, block->diskpos, 0, toread,
100 logf (LOG_FATAL, "bfread failed.");
103 /* extract header info */
105 memcpy(&block->num_records, buf->data, sizeof(block->num_records));
106 buf->offset += sizeof(block->num_records);
107 memcpy(&block->nextpos, buf->data + buf->offset,
108 sizeof(block->nextpos));
109 buf->offset += sizeof(block->nextpos);
110 if (block == tab->data) /* first block */
112 memcpy(&tab->num_records, buf->data + buf->offset,
113 sizeof(tab->num_records));
114 buf->offset +=sizeof(tab->num_records);
116 buf->num = (toread - buf->offset) / is_keysize(tab->is);
117 if (buf->num >= block->num_records)
119 buf->num = block->num_records;
120 block->state = IS_MBSTATE_CLEAN;
123 block->bread = buf->offset + buf->num * is_keysize(tab->is);
127 int is_p_read_full(is_mtable *tab, is_mblock *block)
132 if (block->state == IS_MBSTATE_UNREAD && is_p_read_partial(tab, block) < 0)
134 logf (LOG_FATAL, "partial read failed.");
137 if (block->state == IS_MBSTATE_PARTIAL)
140 dread = block->data->num;
141 while (dread < block->num_records)
143 buf->next = xmalloc_mbuf(IS_MBUF_TYPE_LARGE);
146 toread = is_mbuf_size[buf->type] / is_keysize(tab->is);
147 if (toread > block->num_records - dread)
148 toread = block->num_records - dread;
150 if (bf_read(tab->is->types[tab->pos_type].bf, block->diskpos, block->bread, toread *
151 is_keysize(tab->is), buf->data) < 0)
153 logf (LOG_FATAL, "bfread failed.");
159 block->bread += toread * is_keysize(tab->is);
161 block->state = IS_MBSTATE_CLEAN;
163 logf (LOG_DEBUG, "R: Block #%d contains %d records.", block->diskpos, block->num_records);
168 * write dirty blocks to bfile.
169 * Allocate blocks as necessary.
171 void is_p_sync(is_mtable *tab)
176 isam_blocktype *type;
178 type = &tab->is->types[tab->pos_type];
179 for (p = tab->data; p; p = p->next)
181 if (p->state < IS_MBSTATE_DIRTY)
183 /* make sure that blocks are allocated. */
185 p->diskpos = is_freestore_alloc(tab->is, tab->pos_type);
188 if (p->next->diskpos < 0)
189 p->nextpos = p->next->diskpos = is_freestore_alloc(tab->is,
192 p->nextpos = p->next->diskpos;
197 memcpy(type->dbuf, &p->num_records, sizeof(p->num_records));
198 sum += sizeof(p->num_records);
199 memcpy(type->dbuf + sum, &p->nextpos, sizeof(p->nextpos));
200 sum += sizeof(p->nextpos);
201 if (p == tab->data) /* first block */
203 memcpy(type->dbuf + sum, &tab->num_records,
204 sizeof(tab->num_records));
205 sum += sizeof(tab->num_records);
207 for (b = p->data; b; b = b->next)
209 memcpy(type->dbuf + sum, b->data + b->offset, v = b->num *
210 is_keysize(tab->is));
213 assert(sum <= type->blocksize);
215 if (bf_write(type->bf, p->diskpos, 0, sum, type->dbuf) < 0)
217 logf (LOG_FATAL, "Failed to write block.");
220 logf (LOG_DEBUG, "W: Block #%d contains %d records.", p->diskpos, p->num_records);
225 * Free all disk blocks associated with table.
227 void is_p_unmap(is_mtable *tab)
231 for (p = tab->data; p; p = p->next)
235 is_freestore_free(tab->is, tab->pos_type, p->diskpos);
241 static is_mbuf *mbuf_takehead(is_mbuf **mb, int *num, int keysize)
243 is_mbuf *p = 0, **pp = &p, *new;
248 while (*mb && toget >= (*mb)->num)
256 if (toget > 0 && *mb)
258 new = xmalloc_mbuf(IS_MBUF_TYPE_SMALL);
259 new->next = (*mb)->next;
261 new->data = (*mb)->data;
263 new->offset = (*mb)->offset + toget * keysize;
264 new->num = (*mb)->num - toget;
276 * Split up individual blocks which have grown too large.
277 * is_p_align and is_p_remap are alternative functions which trade off
278 * speed in updating versus optimum usage of disk blocks.
280 void is_p_align(is_mtable *tab)
282 is_mblock *mblock, *new, *last = 0, *next;
283 is_mbuf *mbufs, *mbp;
284 int blocks, recsblock;
286 logf (LOG_DEBUG, "Realigning table.");
287 for (mblock = tab->data; mblock; mblock = next)
290 if (mblock->state == IS_MBSTATE_DIRTY && mblock->num_records == 0)
294 last->next = mblock->next;
295 last->state = IS_MBSTATE_DIRTY;
300 tab->data = tab->data->next;
301 tab->data->state = IS_MBSTATE_DIRTY;
304 if (mblock->diskpos >= 0)
305 is_freestore_free(tab->is, tab->pos_type, mblock->diskpos);
306 xrelease_mblock(mblock);
308 else if (mblock->state == IS_MBSTATE_DIRTY && mblock->num_records >
309 (mblock == tab->data ?
310 tab->is->types[tab->pos_type].max_keys_block0 :
311 tab->is->types[tab->pos_type].max_keys_block))
313 blocks = tab->num_records /
314 tab->is->types[tab->pos_type].nice_keys_block;
315 if (tab->num_records %
316 tab->is->types[tab->pos_type].nice_keys_block)
318 recsblock = tab->num_records / blocks;
321 mbufs = mblock->data;
322 while ((mbp = mbuf_takehead(&mbufs, &recsblock,
323 is_keysize(tab->is))) && recsblock)
327 new = xmalloc_mblock();
329 new->state = IS_MBSTATE_DIRTY;
330 new->next = mblock->next;
334 mblock->num_records = recsblock;
336 mblock = mblock->next;
346 * Reorganize data in blocks for minimum block usage and quick access.
347 * Free surplus blocks.
348 * is_p_align and is_p_remap are alternative functions which trade off
349 * speed in updating versus optimum usage of disk blocks.
351 void is_p_remap(is_mtable *tab)
353 is_mbuf *mbufs, **bufpp, *mbp;
354 is_mblock *blockp, **blockpp;
355 int recsblock, blocks;
357 logf (LOG_DEBUG, "Remapping table.");
358 /* collect all data */
360 for (blockp = tab->data; blockp; blockp = blockp->next)
362 if (blockp->state < IS_MBSTATE_CLEAN && is_m_read_full(tab, blockp) < 0)
364 logf (LOG_FATAL, "Read-full failed in remap.");
367 *bufpp = blockp->data;
369 bufpp = &(*bufpp)->next;
372 blocks = tab->num_records / tab->is->types[tab->pos_type].nice_keys_block;
373 if (tab->num_records % tab->is->types[tab->pos_type].nice_keys_block)
377 recsblock = tab->num_records / blocks + 1;
378 if (recsblock > tab->is->types[tab->pos_type].nice_keys_block)
380 blockpp = &tab->data;
381 while ((mbp = mbuf_takehead(&mbufs, &recsblock, is_keysize(tab->is))) &&
386 *blockpp = xmalloc_mblock();
387 (*blockpp)->diskpos = -1;
389 (*blockpp)->data = mbp;
390 (*blockpp)->num_records = recsblock;
391 (*blockpp)->state = IS_MBSTATE_DIRTY;
392 blockpp = &(*blockpp)->next;
398 for (blockp = *blockpp; blockp; blockp = blockp->next)
399 if (blockp->diskpos >= 0)
400 is_freestore_free(tab->is, tab->pos_type, blockp->diskpos);
401 xfree_mblocks(*blockpp);