2 * Copyright (C) 1994, Index Data I/S
4 * Sebastian Hammer, Adam Dickmeiss
7 * Revision 1.7 1995-12-06 14:48:27 quinn
8 * Fixed some strange bugs.
10 * Revision 1.6 1995/09/04 12:33:47 adam
11 * Various cleanup. YAZ util used instead.
13 * Revision 1.5 1994/09/28 11:29:33 quinn
14 * Added cmp parameter.
16 * Revision 1.4 1994/09/27 20:03:53 quinn
17 * Seems relatively bug-free.
19 * Revision 1.3 1994/09/26 17:11:31 quinn
22 * Revision 1.2 1994/09/26 17:06:36 quinn
25 * Revision 1.1 1994/09/26 16:07:57 quinn
26 * Most of the functionality in place.
31 * This module handles the representation of tables in the bfiles.
39 static int is_freestore_alloc(ISAM is, int type)
43 if (is->types[type].freelist >= 0)
45 tmp = is->types[type].freelist;
46 if (bf_read(is->types[type].bf, tmp, 0, sizeof(tmp),
47 &is->types[type].freelist) <=0)
49 logf (LOG_FATAL, "Failed to allocate block");
54 tmp = is->types[type].top++;
56 logf (LOG_DEBUG, "Allocating block #%d", tmp);
60 static void is_freestore_free(ISAM is, int type, int block)
64 logf (LOG_DEBUG, "Releasing block #%d", block);
65 tmp = is->types[type].freelist;
66 is->types[type].freelist = block;
67 if (bf_write(is->types[type].bf, block, 0, sizeof(tmp), &tmp) < 0)
69 logf (LOG_FATAL, "Failed to deallocate block.");
74 /* this code must be modified to handle an index */
75 int is_p_read_partial(is_mtable *tab, is_mblock *block)
80 assert(block->state == IS_MBSTATE_UNREAD);
81 block->data = buf = xmalloc_mbuf(IS_MBUF_TYPE_LARGE);
82 toread = tab->is->types[tab->pos_type].blocksize;
83 if (toread > is_mbuf_size[buf->type])
85 toread = is_mbuf_size[buf->type];
86 block->state = IS_MBSTATE_PARTIAL;
89 block->state = IS_MBSTATE_CLEAN;
90 if (bf_read(tab->is->types[tab->pos_type].bf, block->diskpos, 0, toread,
93 logf (LOG_FATAL, "bfread failed.");
96 /* extract header info */
98 memcpy(&block->num_records, buf->data, sizeof(block->num_records));
99 buf->offset += sizeof(block->num_records);
100 memcpy(&block->nextpos, buf->data + buf->offset,
101 sizeof(block->nextpos));
102 buf->offset += sizeof(block->nextpos);
103 if (block == tab->data) /* first block */
105 memcpy(&tab->num_records, buf->data + buf->offset,
106 sizeof(tab->num_records));
107 buf->offset +=sizeof(tab->num_records);
109 buf->num = (toread - buf->offset) / is_keysize(tab->is);
110 if (buf->num >= block->num_records)
112 buf->num = block->num_records;
113 block->state = IS_MBSTATE_CLEAN;
116 block->bread = buf->num * is_keysize(tab->is);
120 int is_p_read_full(is_mtable *tab, is_mblock *block)
125 if (block->state == IS_MBSTATE_UNREAD && is_p_read_partial(tab, block) < 0)
127 logf (LOG_FATAL, "partial read failed.");
130 if (block->state == IS_MBSTATE_PARTIAL)
133 dread = block->data->num;
134 while (dread < block->num_records)
136 buf->next = xmalloc_mbuf(IS_MBUF_TYPE_LARGE);
139 toread = is_mbuf_size[buf->type] / is_keysize(tab->is);
140 if (toread > block->num_records - dread)
141 toread = block->num_records - dread;
143 if (bf_read(tab->is->types[tab->pos_type].bf, block->diskpos, block->bread, toread *
144 is_keysize(tab->is), buf->data) < 0)
146 logf (LOG_FATAL, "bfread failed.");
152 block->bread += toread * is_keysize(tab->is);
154 block->state = IS_MBSTATE_CLEAN;
156 logf (LOG_DEBUG, "R: Block #%d contains %d records.", block->diskpos, block->num_records);
161 * write dirty blocks to bfile.
162 * Allocate blocks as necessary.
164 void is_p_sync(is_mtable *tab)
169 isam_blocktype *type;
171 type = &tab->is->types[tab->pos_type];
172 for (p = tab->data; p; p = p->next)
174 if (p->state < IS_MBSTATE_DIRTY)
176 /* make sure that blocks are allocated. */
178 p->diskpos = is_freestore_alloc(tab->is, tab->pos_type);
181 if (p->next->diskpos < 0)
182 p->nextpos = p->next->diskpos = is_freestore_alloc(tab->is,
185 p->nextpos = p->next->diskpos;
190 memcpy(type->dbuf, &p->num_records, sizeof(p->num_records));
191 sum += sizeof(p->num_records);
192 memcpy(type->dbuf + sum, &p->nextpos, sizeof(p->nextpos));
193 sum += sizeof(p->nextpos);
194 if (p == tab->data) /* first block */
196 memcpy(type->dbuf + sum, &tab->num_records,
197 sizeof(tab->num_records));
198 sum += sizeof(tab->num_records);
200 for (b = p->data; b; b = b->next)
202 memcpy(type->dbuf + sum, b->data + b->offset, v = b->num *
203 is_keysize(tab->is));
205 assert(sum <= type->blocksize);
207 if (bf_write(type->bf, p->diskpos, 0, sum, type->dbuf) < 0)
209 logf (LOG_FATAL, "Failed to write block.");
212 logf (LOG_DEBUG, "W: Block #%d contains %d records.", p->diskpos, p->num_records);
217 * Free all disk blocks associated with table.
219 void is_p_unmap(is_mtable *tab)
223 for (p = tab->data; p; p = p->next)
226 is_freestore_free(tab->is, tab->pos_type, p->diskpos);
231 static is_mbuf *mbuf_takehead(is_mbuf **mb, int *num, int keysize)
233 is_mbuf *p = 0, **pp = &p, *new;
238 while (*mb && toget >= (*mb)->num)
246 if (toget > 0 && *mb)
248 new = xmalloc_mbuf(IS_MBUF_TYPE_SMALL);
249 new->next = (*mb)->next;
251 new->data = (*mb)->data;
253 new->offset = (*mb)->offset + toget * keysize;
254 new->num = (*mb)->num - toget;
266 * Split up individual blocks which have grown too large.
267 * is_p_align and is_p_remap are alternative functions which trade off
268 * speed in updating versus optimum usage of disk blocks.
270 void is_p_align(is_mtable *tab)
272 is_mblock *mblock, *new, *last = 0, *next;
273 is_mbuf *mbufs, *mbp;
274 int blocks, recsblock;
276 logf (LOG_DEBUG, "Realigning table.");
277 for (mblock = tab->data; mblock; mblock = next)
280 if (mblock->state == IS_MBSTATE_DIRTY && mblock->num_records == 0)
284 last->next = mblock->next;
285 last->state = IS_MBSTATE_DIRTY;
290 tab->data = tab->data->next;
291 tab->data->state = IS_MBSTATE_DIRTY;
294 if (mblock->diskpos >= 0)
295 is_freestore_free(tab->is, tab->pos_type, mblock->diskpos);
296 xrelease_mblock(mblock);
298 else if (mblock->state == IS_MBSTATE_DIRTY && mblock->num_records >
299 (mblock == tab->data ?
300 tab->is->types[tab->pos_type].max_keys_block0 :
301 tab->is->types[tab->pos_type].max_keys_block))
303 blocks = tab->num_records /
304 tab->is->types[tab->pos_type].nice_keys_block;
305 if (tab->num_records %
306 tab->is->types[tab->pos_type].nice_keys_block)
308 recsblock = tab->num_records / blocks;
311 mbufs = mblock->data;
312 while ((mbp = mbuf_takehead(&mbufs, &recsblock,
313 is_keysize(tab->is))) && recsblock)
317 new = xmalloc_mblock();
319 new->state = IS_MBSTATE_DIRTY;
320 new->next = mblock->next;
324 mblock->num_records = recsblock;
326 mblock = mblock->next;
336 * Reorganize data in blocks for minimum block usage and quick access.
337 * Free surplus blocks.
338 * is_p_align and is_p_remap are alternative functions which trade off
339 * speed in updating versus optimum usage of disk blocks.
341 void is_p_remap(is_mtable *tab)
343 is_mbuf *mbufs, **bufpp, *mbp;
344 is_mblock *blockp, **blockpp;
345 int recsblock, blocks;
347 logf (LOG_DEBUG, "Remapping table.");
348 /* collect all data */
350 for (blockp = tab->data; blockp; blockp = blockp->next)
352 if (blockp->state < IS_MBSTATE_CLEAN && is_m_read_full(tab, blockp) < 0)
354 logf (LOG_FATAL, "Read-full failed in remap.");
357 *bufpp = blockp->data;
359 bufpp = &(*bufpp)->next;
362 blocks = tab->num_records / tab->is->types[tab->pos_type].nice_keys_block;
363 if (tab->num_records % tab->is->types[tab->pos_type].nice_keys_block)
367 recsblock = tab->num_records / blocks + 1;
368 if (recsblock > tab->is->types[tab->pos_type].nice_keys_block)
370 blockpp = &tab->data;
371 while ((mbp = mbuf_takehead(&mbufs, &recsblock, is_keysize(tab->is))) &&
376 *blockpp = xmalloc_mblock();
377 (*blockpp)->diskpos = -1;
379 (*blockpp)->data = mbp;
380 (*blockpp)->num_records = recsblock;
381 (*blockpp)->state = IS_MBSTATE_DIRTY;
382 blockpp = &(*blockpp)->next;
388 for (blockp = *blockpp; blockp; blockp = blockp->next)
389 if (blockp->diskpos >= 0)
390 is_freestore_free(tab->is, tab->pos_type, blockp->diskpos);
391 xfree_mblocks(*blockpp);