2 * Copyright (c) 1995-1999, Index Data.
3 * See the file LICENSE for details.
4 * Sebastian Hammer, Adam Dickmeiss
7 * Revision 1.1 1999-05-12 13:08:06 adam
8 * First version of ISAMS.
24 typedef unsigned ISAMS_BLOCK_SIZE;
41 void *decodeClientData;
46 ISAMS_M isams_getmethod (void)
48 ISAMS_M m = xmalloc (sizeof(*m));
54 m->compare_item = NULL;
62 ISAMS isams_open (BFiles bfs, const char *name, int writeflag,
65 ISAMS is = xmalloc (sizeof(*is));
67 is->method = xmalloc (sizeof(*is->method));
68 memcpy (is->method, method, sizeof(*method));
69 is->block_size = is->method->block_size;
71 is->bf = bf_open (bfs, name, is->block_size, writeflag);
73 if (!bf_read (is->bf, 0, 0, sizeof(ISAMS_head), &is->head))
75 is->head.last_block = 1;
76 is->head.last_offset = 0;
78 memcpy (&is->head_old, &is->head, sizeof(is->head));
79 is->merge_buf = xmalloc(2*is->block_size);
80 memset(is->merge_buf, 0, 2*is->block_size);
84 int isams_close (ISAMS is)
86 if (memcmp(&is->head, &is->head_old, sizeof(is->head)))
88 if (is->head.last_offset)
89 bf_write(is->bf, is->head.last_block, 0, is->head.last_offset,
91 bf_write (is->bf, 0, 0, sizeof(is->head), &is->head);
94 xfree (is->merge_buf);
100 ISAMS_P isams_merge (ISAMS is, ISAMS_I data)
102 char i_item[128], *i_item_ptr;
105 int first_block = is->head.last_block;
106 int first_offset = is->head.last_offset;
109 r_clientData = (*is->method->code_start)(ISAMC_ENCODE);
111 is->head.last_offset += sizeof(int);
112 if (is->head.last_offset > is->block_size)
114 logf (LOG_LOG, "first_block=%d", first_block);
115 bf_write(is->bf, is->head.last_block, 0, 0, is->merge_buf);
116 (is->head.last_block)++;
117 is->head.last_offset -= is->block_size;
118 memcpy (is->merge_buf, is->merge_buf + is->block_size,
119 is->head.last_offset);
124 i_more = (*data->read_item)(data->clientData, &i_item_ptr, &i_mode);
131 char *r_out_ptr = is->merge_buf + is->head.last_offset;
134 (*is->method->code_item)(ISAMC_ENCODE, r_clientData,
135 &r_out_ptr, &i_item_ptr);
136 is->head.last_offset = r_out_ptr - is->merge_buf;
137 if (is->head.last_offset > is->block_size)
139 bf_write(is->bf, is->head.last_block, 0, 0, is->merge_buf);
140 (is->head.last_block)++;
141 is->head.last_offset -= is->block_size;
142 memcpy (is->merge_buf, is->merge_buf + is->block_size,
143 is->head.last_offset);
148 (*is->method->code_stop)(ISAMC_ENCODE, r_clientData);
149 if (first_block == is->head.last_block)
150 memcpy(is->merge_buf + first_offset, &count, sizeof(int));
151 else if (first_block == is->head.last_block-1)
153 int gap = first_offset + sizeof(int) - is->block_size;
154 assert (gap <= (int) sizeof(int));
157 if (gap < sizeof(int))
158 bf_write(is->bf, first_block, first_offset, sizeof(int)-gap,
160 memcpy (is->merge_buf, ((char*)&count)+(sizeof(int)-gap), gap);
163 bf_write(is->bf, first_block, first_offset, sizeof(int), &count);
167 bf_write(is->bf, first_block, first_offset, sizeof(int), &count);
169 return first_block * is->block_size + first_offset;
172 ISAMS_PP isams_pp_open (ISAMS is, ISAMS_P pos)
174 ISAMS_PP pp = xmalloc (sizeof(*pp));
176 logf (LOG_LOG, "isams: isams_pp_open pos=%ld", (long) pos);
178 pp->decodeClientData = (*is->method->code_start)(ISAMC_DECODE);
181 pp->buf = xmalloc(is->block_size*2);
182 pp->block_no = pos/is->block_size;
183 pp->block_offset = pos - pp->block_no * is->block_size;
184 logf (LOG_LOG, "isams: isams_pp_open off=%d no=%d",
185 pp->block_offset, pp->block_no);
188 bf_read (is->bf, pp->block_no, 0, 0, pp->buf);
189 bf_read (is->bf, pp->block_no+1, 0, 0, pp->buf + is->block_size);
190 memcpy(&pp->numKeys, pp->buf + pp->block_offset, sizeof(int));
191 logf (LOG_LOG, "isams: isams_pp_open numKeys=%d", pp->numKeys);
192 pp->block_offset += sizeof(int);
197 void isams_pp_close (ISAMS_PP pp)
199 (*pp->is->method->code_stop)(ISAMC_DECODE, pp->decodeClientData);
204 int isams_pp_num (ISAMS_PP pp)
209 int isams_pp_read (ISAMS_PP pp, void *buf)
211 return isams_read_item (pp, (char **) &buf);
214 int isams_read_item (ISAMS_PP pp, char **dst)
217 if (pp->numRead >= pp->numKeys)
220 if (pp->block_offset > pp->is->block_size)
222 pp->block_offset -= pp->is->block_size;
224 memcpy (pp->buf, pp->buf + pp->is->block_size, pp->is->block_size);
225 bf_read (pp->is->bf, pp->block_no+1, 0, 0,
226 pp->buf + pp->is->block_size);
228 src = pp->buf + pp->block_offset;
229 (*pp->is->method->code_item)(ISAMC_DECODE, pp->decodeClientData,
231 pp->block_offset = src - pp->buf;