2 * Copyright (C) 1994, Index Data I/S
4 * Sebastian Hammer, Adam Dickmeiss
7 * Revision 1.8 1996-01-29 09:47:11 quinn
8 * Fixed mean little bug in the read-table code.
10 * Revision 1.7 1995/12/06 14:48:27 quinn
11 * Fixed some strange bugs.
13 * Revision 1.6 1995/09/04 12:33:47 adam
14 * Various cleanup. YAZ util used instead.
16 * Revision 1.5 1994/09/28 11:29:33 quinn
17 * Added cmp parameter.
19 * Revision 1.4 1994/09/27 20:03:53 quinn
20 * Seems relatively bug-free.
22 * Revision 1.3 1994/09/26 17:11:31 quinn
25 * Revision 1.2 1994/09/26 17:06:36 quinn
28 * Revision 1.1 1994/09/26 16:07:57 quinn
29 * Most of the functionality in place.
34 * This module handles the representation of tables in the bfiles.
42 static int is_freestore_alloc(ISAM is, int type)
46 if (is->types[type].freelist >= 0)
48 tmp = is->types[type].freelist;
49 if (bf_read(is->types[type].bf, tmp, 0, sizeof(tmp),
50 &is->types[type].freelist) <=0)
52 logf (LOG_FATAL, "Failed to allocate block");
57 tmp = is->types[type].top++;
59 logf (LOG_DEBUG, "Allocating block #%d", tmp);
63 static void is_freestore_free(ISAM is, int type, int block)
67 logf (LOG_DEBUG, "Releasing block #%d", block);
68 tmp = is->types[type].freelist;
69 is->types[type].freelist = block;
70 if (bf_write(is->types[type].bf, block, 0, sizeof(tmp), &tmp) < 0)
72 logf (LOG_FATAL, "Failed to deallocate block.");
77 /* this code must be modified to handle an index */
78 int is_p_read_partial(is_mtable *tab, is_mblock *block)
83 assert(block->state == IS_MBSTATE_UNREAD);
84 block->data = buf = xmalloc_mbuf(IS_MBUF_TYPE_LARGE);
85 toread = tab->is->types[tab->pos_type].blocksize;
86 if (toread > is_mbuf_size[buf->type])
88 toread = is_mbuf_size[buf->type];
89 block->state = IS_MBSTATE_PARTIAL;
92 block->state = IS_MBSTATE_CLEAN;
93 if (bf_read(tab->is->types[tab->pos_type].bf, block->diskpos, 0, toread,
96 logf (LOG_FATAL, "bfread failed.");
99 /* extract header info */
101 memcpy(&block->num_records, buf->data, sizeof(block->num_records));
102 buf->offset += sizeof(block->num_records);
103 memcpy(&block->nextpos, buf->data + buf->offset,
104 sizeof(block->nextpos));
105 buf->offset += sizeof(block->nextpos);
106 if (block == tab->data) /* first block */
108 memcpy(&tab->num_records, buf->data + buf->offset,
109 sizeof(tab->num_records));
110 buf->offset +=sizeof(tab->num_records);
112 buf->num = (toread - buf->offset) / is_keysize(tab->is);
113 if (buf->num >= block->num_records)
115 buf->num = block->num_records;
116 block->state = IS_MBSTATE_CLEAN;
119 block->bread = buf->offset + buf->num * is_keysize(tab->is);
123 int is_p_read_full(is_mtable *tab, is_mblock *block)
128 if (block->state == IS_MBSTATE_UNREAD && is_p_read_partial(tab, block) < 0)
130 logf (LOG_FATAL, "partial read failed.");
133 if (block->state == IS_MBSTATE_PARTIAL)
136 dread = block->data->num;
137 while (dread < block->num_records)
139 buf->next = xmalloc_mbuf(IS_MBUF_TYPE_LARGE);
142 toread = is_mbuf_size[buf->type] / is_keysize(tab->is);
143 if (toread > block->num_records - dread)
144 toread = block->num_records - dread;
146 if (bf_read(tab->is->types[tab->pos_type].bf, block->diskpos, block->bread, toread *
147 is_keysize(tab->is), buf->data) < 0)
149 logf (LOG_FATAL, "bfread failed.");
155 block->bread += toread * is_keysize(tab->is);
157 block->state = IS_MBSTATE_CLEAN;
159 logf (LOG_DEBUG, "R: Block #%d contains %d records.", block->diskpos, block->num_records);
164 * write dirty blocks to bfile.
165 * Allocate blocks as necessary.
167 void is_p_sync(is_mtable *tab)
172 isam_blocktype *type;
174 type = &tab->is->types[tab->pos_type];
175 for (p = tab->data; p; p = p->next)
177 if (p->state < IS_MBSTATE_DIRTY)
179 /* make sure that blocks are allocated. */
181 p->diskpos = is_freestore_alloc(tab->is, tab->pos_type);
184 if (p->next->diskpos < 0)
185 p->nextpos = p->next->diskpos = is_freestore_alloc(tab->is,
188 p->nextpos = p->next->diskpos;
193 memcpy(type->dbuf, &p->num_records, sizeof(p->num_records));
194 sum += sizeof(p->num_records);
195 memcpy(type->dbuf + sum, &p->nextpos, sizeof(p->nextpos));
196 sum += sizeof(p->nextpos);
197 if (p == tab->data) /* first block */
199 memcpy(type->dbuf + sum, &tab->num_records,
200 sizeof(tab->num_records));
201 sum += sizeof(tab->num_records);
203 for (b = p->data; b; b = b->next)
205 memcpy(type->dbuf + sum, b->data + b->offset, v = b->num *
206 is_keysize(tab->is));
209 assert(sum <= type->blocksize);
211 if (bf_write(type->bf, p->diskpos, 0, sum, type->dbuf) < 0)
213 logf (LOG_FATAL, "Failed to write block.");
216 logf (LOG_DEBUG, "W: Block #%d contains %d records.", p->diskpos, p->num_records);
221 * Free all disk blocks associated with table.
223 void is_p_unmap(is_mtable *tab)
227 for (p = tab->data; p; p = p->next)
230 is_freestore_free(tab->is, tab->pos_type, p->diskpos);
235 static is_mbuf *mbuf_takehead(is_mbuf **mb, int *num, int keysize)
237 is_mbuf *p = 0, **pp = &p, *new;
242 while (*mb && toget >= (*mb)->num)
250 if (toget > 0 && *mb)
252 new = xmalloc_mbuf(IS_MBUF_TYPE_SMALL);
253 new->next = (*mb)->next;
255 new->data = (*mb)->data;
257 new->offset = (*mb)->offset + toget * keysize;
258 new->num = (*mb)->num - toget;
270 * Split up individual blocks which have grown too large.
271 * is_p_align and is_p_remap are alternative functions which trade off
272 * speed in updating versus optimum usage of disk blocks.
274 void is_p_align(is_mtable *tab)
276 is_mblock *mblock, *new, *last = 0, *next;
277 is_mbuf *mbufs, *mbp;
278 int blocks, recsblock;
280 logf (LOG_DEBUG, "Realigning table.");
281 for (mblock = tab->data; mblock; mblock = next)
284 if (mblock->state == IS_MBSTATE_DIRTY && mblock->num_records == 0)
288 last->next = mblock->next;
289 last->state = IS_MBSTATE_DIRTY;
294 tab->data = tab->data->next;
295 tab->data->state = IS_MBSTATE_DIRTY;
298 if (mblock->diskpos >= 0)
299 is_freestore_free(tab->is, tab->pos_type, mblock->diskpos);
300 xrelease_mblock(mblock);
302 else if (mblock->state == IS_MBSTATE_DIRTY && mblock->num_records >
303 (mblock == tab->data ?
304 tab->is->types[tab->pos_type].max_keys_block0 :
305 tab->is->types[tab->pos_type].max_keys_block))
307 blocks = tab->num_records /
308 tab->is->types[tab->pos_type].nice_keys_block;
309 if (tab->num_records %
310 tab->is->types[tab->pos_type].nice_keys_block)
312 recsblock = tab->num_records / blocks;
315 mbufs = mblock->data;
316 while ((mbp = mbuf_takehead(&mbufs, &recsblock,
317 is_keysize(tab->is))) && recsblock)
321 new = xmalloc_mblock();
323 new->state = IS_MBSTATE_DIRTY;
324 new->next = mblock->next;
328 mblock->num_records = recsblock;
330 mblock = mblock->next;
340 * Reorganize data in blocks for minimum block usage and quick access.
341 * Free surplus blocks.
342 * is_p_align and is_p_remap are alternative functions which trade off
343 * speed in updating versus optimum usage of disk blocks.
345 void is_p_remap(is_mtable *tab)
347 is_mbuf *mbufs, **bufpp, *mbp;
348 is_mblock *blockp, **blockpp;
349 int recsblock, blocks;
351 logf (LOG_DEBUG, "Remapping table.");
352 /* collect all data */
354 for (blockp = tab->data; blockp; blockp = blockp->next)
356 if (blockp->state < IS_MBSTATE_CLEAN && is_m_read_full(tab, blockp) < 0)
358 logf (LOG_FATAL, "Read-full failed in remap.");
361 *bufpp = blockp->data;
363 bufpp = &(*bufpp)->next;
366 blocks = tab->num_records / tab->is->types[tab->pos_type].nice_keys_block;
367 if (tab->num_records % tab->is->types[tab->pos_type].nice_keys_block)
371 recsblock = tab->num_records / blocks + 1;
372 if (recsblock > tab->is->types[tab->pos_type].nice_keys_block)
374 blockpp = &tab->data;
375 while ((mbp = mbuf_takehead(&mbufs, &recsblock, is_keysize(tab->is))) &&
380 *blockpp = xmalloc_mblock();
381 (*blockpp)->diskpos = -1;
383 (*blockpp)->data = mbp;
384 (*blockpp)->num_records = recsblock;
385 (*blockpp)->state = IS_MBSTATE_DIRTY;
386 blockpp = &(*blockpp)->next;
392 for (blockp = *blockpp; blockp; blockp = blockp->next)
393 if (blockp->diskpos >= 0)
394 is_freestore_free(tab->is, tab->pos_type, blockp->diskpos);
395 xfree_mblocks(*blockpp);