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1.1 root 1: # include <ingres.h>
2: # include <aux.h>
3: # include <symbol.h>
4: # include <access.h>
5: # include <lock.h>
6: # include <btree.h>
7: # include <sccs.h>
8:
9: SCCSID(@(#)find.c 8.1 12/31/84)
10:
11:
12: /*
13: ** Find - determine limits for scan of a relation
14: **
15: ** Find determines the values of an initial TID
16: ** and an ending TID for scanning a relation.
17: ** The possible calls to find are:
18: **
19: ** find(desc, NOKEY, lotid, hightid)
20: ** sets tids to scan entire relation
21: **
22: ** find(desc, EXACTKEY, lotid, hightid, key)
23: ** sets tids according to structure
24: ** of the relation. Key should have
25: ** been build using setkey.
26: **
27: ** find(desc, LRANGEKEY, lotid, hightid, keylow)
28: ** Finds lotid less then or equal to keylow
29: ** for isam relations. Otherwise scans whole relation.
30: ** This call should be followed by a call with HRANGEKEY.
31: **
32: ** find(desc, HRANGEKEY, lotid, hightid, keyhigh)
33: ** Finds hightid greater than or equal to
34: ** keyhigh for isam relations. Otherwise sets
35: ** hightid to maximum scan.
36: **
37: ** find(desc, FULLKEY, lotid, hightid, key)
38: ** Same as find with EXACTKEY and all keys
39: ** provided. This mode is used only by findbest
40: ** and replace.
41: **
42: ** returns:
43: ** <0 fatal error
44: ** 0 success
45: **
46: ** Trace Flags:
47: ** 22.0-8
48: */
49:
50:
51: find(d, mode, lotid, hightid, key)
52: register DESC *d;
53: int mode;
54: TID *lotid;
55: TID *hightid;
56: char *key;
57: {
58: register int ret;
59: bool keyok;
60: long pageid, lid[MAXLID], page;
61: long rhash(), get_tid();
62: struct locator tid_id;
63: char *tp;
64: int i;
65: extern int Btree_fd;
66:
67: # ifdef xATR1
68: if (tTf(22, 0))
69: {
70: printf("find: m%d,s%d,%.14s\n", mode, d->reldum.relspec, d->reldum.relid);
71: if (mode != NOKEY)
72: printup(d, key);
73: }
74: # endif
75:
76: ret = 0; /* assume successful return */
77: keyok = FALSE;
78:
79: switch (mode)
80: {
81:
82: case EXACTKEY:
83: keyok = fullkey(d);
84: break;
85:
86: case FULLKEY:
87: keyok = TRUE;
88:
89: case NOKEY:
90: case LRANGEKEY:
91: case HRANGEKEY:
92: case BTREEKEY:
93: break;
94:
95: default:
96: syserr("FIND: bad mode %d", mode);
97: }
98:
99: /* set lotid for beginning of scan */
100: if (mode != HRANGEKEY)
101: {
102: pageid = 0;
103: stuff_page(lotid, &pageid);
104: lotid->line_id = -1;
105: }
106:
107: /* set hitid for end of scan */
108: if (mode != LRANGEKEY)
109: {
110: pageid = -1;
111: stuff_page(hightid, &pageid);
112: hightid->line_id = -1;
113: }
114:
115: if (mode == BTREEKEY)
116: /* set tid to value as found using B-Tree */
117: {
118: tp = key + d->reldum.relwid - LIDSIZE * d->reldum.reldim;
119: bmove(tp, lid, LIDSIZE * d->reldum.reldim);
120: Btree_fd = d->btree_fd;
121: page = RT;
122: for (i = 0; i < d->reldum.reldim; ++i)
123: {
124: pageid = get_tid(page, lid[i], &tid_id);
125: if (pageid < 0)
126: break;
127: page = pageid;
128: }
129: if (pageid >= 0)
130: bmove(&pageid, lotid, LIDSIZE);
131:
132: }
133: else if (mode != NOKEY)
134: {
135: switch (abs(d->reldum.relspec))
136: {
137:
138: case M_HEAP:
139: break;
140:
141: case M_ISAM:
142: if (mode != HRANGEKEY)
143: {
144: /* compute lo limit */
145: if (ret = ndxsearch(d, lotid, key, -1, keyok))
146: break; /* fatal error */
147: }
148:
149: /* if the full key was provided and mode is exact, then done */
150: if (keyok)
151: {
152: bmove((char *) lotid, (char *) hightid, sizeof *lotid);
153: break;
154: }
155:
156: if (mode != LRANGEKEY)
157: ret = ndxsearch(d, hightid, key, 1, keyok);
158: break;
159:
160: case M_HASH:
161: if (!keyok)
162: break; /* can't do anything */
163: pageid = rhash(d, key);
164: stuff_page(lotid, &pageid);
165: stuff_page(hightid, &pageid);
166: break;
167:
168: default:
169: ret = acc_err(AMFIND_ERR);
170: }
171: }
172:
173: # ifdef xATR2
174: if (tTf(22, 1))
175: {
176: printf("find: ret %d\tlow", ret);
177: dumptid(lotid);
178: printf("hi");
179: dumptid(hightid);
180: }
181: # endif
182: return (ret);
183: }
184: /*
185: ** This routine will check that enough of the tuple has been specified
186: ** to enable a key access.
187: */
188:
189: fullkey(des)
190: DESC *des;
191: {
192: register DESC *d;
193: register int i;
194:
195: d = des;
196: for (i = 1; i <= d->reldum.relatts; i++)
197: if (d->relxtra[i] && !d->relgiven[i])
198: return (FALSE);
199: return (TRUE);
200: }
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