Line data Source code
1 : /*-------------------------------------------------------------------------
2 : *
3 : * arrayutils.c
4 : * This file contains some support routines required for array functions.
5 : *
6 : * Portions Copyright (c) 1996-2023, PostgreSQL Global Development Group
7 : * Portions Copyright (c) 1994, Regents of the University of California
8 : *
9 : *
10 : * IDENTIFICATION
11 : * src/backend/utils/adt/arrayutils.c
12 : *
13 : *-------------------------------------------------------------------------
14 : */
15 :
16 : #include "postgres.h"
17 :
18 : #include "catalog/pg_type.h"
19 : #include "common/int.h"
20 : #include "utils/array.h"
21 : #include "utils/builtins.h"
22 : #include "utils/memutils.h"
23 :
24 :
25 : /*
26 : * Convert subscript list into linear element number (from 0)
27 : *
28 : * We assume caller has already range-checked the dimensions and subscripts,
29 : * so no overflow is possible.
30 : */
31 : int
32 653242 : ArrayGetOffset(int n, const int *dim, const int *lb, const int *indx)
33 : {
34 : int i,
35 653242 : scale = 1,
36 653242 : offset = 0;
37 :
38 1306802 : for (i = n - 1; i >= 0; i--)
39 : {
40 653560 : offset += (indx[i] - lb[i]) * scale;
41 653560 : scale *= dim[i];
42 : }
43 653242 : return offset;
44 : }
45 :
46 : /*
47 : * Same, but subscripts are assumed 0-based, and use a scale array
48 : * instead of raw dimension data (see mda_get_prod to create scale array)
49 : */
50 : int
51 1770664 : ArrayGetOffset0(int n, const int *tup, const int *scale)
52 : {
53 : int i,
54 1770664 : lin = 0;
55 :
56 3544018 : for (i = 0; i < n; i++)
57 1773354 : lin += tup[i] * scale[i];
58 1770664 : return lin;
59 : }
60 :
61 : /*
62 : * Convert array dimensions into number of elements
63 : *
64 : * This must do overflow checking, since it is used to validate that a user
65 : * dimensionality request doesn't overflow what we can handle.
66 : *
67 : * We limit array sizes to at most about a quarter billion elements,
68 : * so that it's not necessary to check for overflow in quite so many
69 : * places --- for instance when palloc'ing Datum arrays.
70 : *
71 : * The multiplication overflow check only works on machines that have int64
72 : * arithmetic, but that is nearly all platforms these days, and doing check
73 : * divides for those that don't seems way too expensive.
74 : */
75 : int
76 83004294 : ArrayGetNItems(int ndim, const int *dims)
77 : {
78 83004294 : return ArrayGetNItemsSafe(ndim, dims, NULL);
79 : }
80 :
81 : /*
82 : * This entry point can return the error into an ErrorSaveContext
83 : * instead of throwing an exception. -1 is returned after an error.
84 : */
85 : int
86 83368538 : ArrayGetNItemsSafe(int ndim, const int *dims, struct Node *escontext)
87 : {
88 : int32 ret;
89 : int i;
90 :
91 : #define MaxArraySize ((Size) (MaxAllocSize / sizeof(Datum)))
92 :
93 83368538 : if (ndim <= 0)
94 2427656 : return 0;
95 80940882 : ret = 1;
96 161886038 : for (i = 0; i < ndim; i++)
97 : {
98 : int64 prod;
99 :
100 : /* A negative dimension implies that UB-LB overflowed ... */
101 80945156 : if (dims[i] < 0)
102 0 : ereturn(escontext, -1,
103 : (errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
104 : errmsg("array size exceeds the maximum allowed (%d)",
105 : (int) MaxArraySize)));
106 :
107 80945156 : prod = (int64) ret * (int64) dims[i];
108 :
109 80945156 : ret = (int32) prod;
110 80945156 : if ((int64) ret != prod)
111 0 : ereturn(escontext, -1,
112 : (errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
113 : errmsg("array size exceeds the maximum allowed (%d)",
114 : (int) MaxArraySize)));
115 : }
116 : Assert(ret >= 0);
117 80940882 : if ((Size) ret > MaxArraySize)
118 0 : ereturn(escontext, -1,
119 : (errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
120 : errmsg("array size exceeds the maximum allowed (%d)",
121 : (int) MaxArraySize)));
122 80940882 : return (int) ret;
123 : }
124 :
125 : /*
126 : * Verify sanity of proposed lower-bound values for an array
127 : *
128 : * The lower-bound values must not be so large as to cause overflow when
129 : * calculating subscripts, e.g. lower bound 2147483640 with length 10
130 : * must be disallowed. We actually insist that dims[i] + lb[i] be
131 : * computable without overflow, meaning that an array with last subscript
132 : * equal to INT_MAX will be disallowed.
133 : *
134 : * It is assumed that the caller already called ArrayGetNItems, so that
135 : * overflowed (negative) dims[] values have been eliminated.
136 : */
137 : void
138 1970844 : ArrayCheckBounds(int ndim, const int *dims, const int *lb)
139 : {
140 1970844 : (void) ArrayCheckBoundsSafe(ndim, dims, lb, NULL);
141 1970844 : }
142 :
143 : /*
144 : * This entry point can return the error into an ErrorSaveContext
145 : * instead of throwing an exception.
146 : */
147 : bool
148 2335088 : ArrayCheckBoundsSafe(int ndim, const int *dims, const int *lb,
149 : struct Node *escontext)
150 : {
151 : int i;
152 :
153 4628340 : for (i = 0; i < ndim; i++)
154 : {
155 : /* PG_USED_FOR_ASSERTS_ONLY prevents variable-isn't-read warnings */
156 : int32 sum PG_USED_FOR_ASSERTS_ONLY;
157 :
158 2293252 : if (pg_add_s32_overflow(dims[i], lb[i], &sum))
159 0 : ereturn(escontext, false,
160 : (errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
161 : errmsg("array lower bound is too large: %d",
162 : lb[i])));
163 : }
164 :
165 2335088 : return true;
166 : }
167 :
168 : /*
169 : * Compute ranges (sub-array dimensions) for an array slice
170 : *
171 : * We assume caller has validated slice endpoints, so overflow is impossible
172 : */
173 : void
174 1016 : mda_get_range(int n, int *span, const int *st, const int *endp)
175 : {
176 : int i;
177 :
178 2554 : for (i = 0; i < n; i++)
179 1538 : span[i] = endp[i] - st[i] + 1;
180 1016 : }
181 :
182 : /*
183 : * Compute products of array dimensions, ie, scale factors for subscripts
184 : *
185 : * We assume caller has validated dimensions, so overflow is impossible
186 : */
187 : void
188 357628 : mda_get_prod(int n, const int *range, int *prod)
189 : {
190 : int i;
191 :
192 357628 : prod[n - 1] = 1;
193 358260 : for (i = n - 2; i >= 0; i--)
194 632 : prod[i] = prod[i + 1] * range[i + 1];
195 357628 : }
196 :
197 : /*
198 : * From products of whole-array dimensions and spans of a sub-array,
199 : * compute offset distances needed to step through subarray within array
200 : *
201 : * We assume caller has validated dimensions, so overflow is impossible
202 : */
203 : void
204 360 : mda_get_offset_values(int n, int *dist, const int *prod, const int *span)
205 : {
206 : int i,
207 : j;
208 :
209 360 : dist[n - 1] = 0;
210 576 : for (j = n - 2; j >= 0; j--)
211 : {
212 216 : dist[j] = prod[j] - 1;
213 462 : for (i = j + 1; i < n; i++)
214 246 : dist[j] -= (span[i] - 1) * prod[i];
215 : }
216 360 : }
217 :
218 : /*
219 : * Generates the tuple that is lexicographically one greater than the current
220 : * n-tuple in "curr", with the restriction that the i-th element of "curr" is
221 : * less than the i-th element of "span".
222 : *
223 : * Returns -1 if no next tuple exists, else the subscript position (0..n-1)
224 : * corresponding to the dimension to advance along.
225 : *
226 : * We assume caller has validated dimensions, so overflow is impossible
227 : */
228 : int
229 1290 : mda_next_tuple(int n, int *curr, const int *span)
230 : {
231 : int i;
232 :
233 1290 : if (n <= 0)
234 0 : return -1;
235 :
236 1290 : curr[n - 1] = (curr[n - 1] + 1) % span[n - 1];
237 1608 : for (i = n - 1; i && curr[i] == 0; i--)
238 318 : curr[i - 1] = (curr[i - 1] + 1) % span[i - 1];
239 :
240 1290 : if (i)
241 330 : return i;
242 960 : if (curr[0])
243 600 : return 0;
244 :
245 360 : return -1;
246 : }
247 :
248 : /*
249 : * ArrayGetIntegerTypmods: verify that argument is a 1-D cstring array,
250 : * and get the contents converted to integers. Returns a palloc'd array
251 : * and places the length at *n.
252 : */
253 : int32 *
254 8842 : ArrayGetIntegerTypmods(ArrayType *arr, int *n)
255 : {
256 : int32 *result;
257 : Datum *elem_values;
258 : int i;
259 :
260 8842 : if (ARR_ELEMTYPE(arr) != CSTRINGOID)
261 0 : ereport(ERROR,
262 : (errcode(ERRCODE_ARRAY_ELEMENT_ERROR),
263 : errmsg("typmod array must be type cstring[]")));
264 :
265 8842 : if (ARR_NDIM(arr) != 1)
266 0 : ereport(ERROR,
267 : (errcode(ERRCODE_ARRAY_SUBSCRIPT_ERROR),
268 : errmsg("typmod array must be one-dimensional")));
269 :
270 8842 : if (array_contains_nulls(arr))
271 0 : ereport(ERROR,
272 : (errcode(ERRCODE_NULL_VALUE_NOT_ALLOWED),
273 : errmsg("typmod array must not contain nulls")));
274 :
275 8842 : deconstruct_array_builtin(arr, CSTRINGOID, &elem_values, NULL, n);
276 :
277 8842 : result = (int32 *) palloc(*n * sizeof(int32));
278 :
279 19614 : for (i = 0; i < *n; i++)
280 10772 : result[i] = pg_strtoint32(DatumGetCString(elem_values[i]));
281 :
282 8842 : pfree(elem_values);
283 :
284 8842 : return result;
285 : }
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