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) 1996-2024, 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 708246 : ArrayGetOffset(int n, const int *dim, const int *lb, const int *indx)
33 : {
34 : int i,
35 708246 : scale = 1,
36 708246 : offset = 0;
37 :
38 1416810 : for (i = n - 1; i >= 0; i--)
39 : {
40 708564 : offset += (indx[i] - lb[i]) * scale;
41 708564 : scale *= dim[i];
42 : }
43 708246 : return offset;
44 : }
45 :
46 : /*
47 : * Convert array dimensions into number of elements
48 : *
49 : * This must do overflow checking, since it is used to validate that a user
50 : * dimensionality request doesn't overflow what we can handle.
51 : *
52 : * The multiplication overflow check only works on machines that have int64
53 : * arithmetic, but that is nearly all platforms these days, and doing check
54 : * divides for those that don't seems way too expensive.
55 : */
56 : int
57 92437454 : ArrayGetNItems(int ndim, const int *dims)
58 : {
59 92437454 : return ArrayGetNItemsSafe(ndim, dims, NULL);
60 : }
61 :
62 : /*
63 : * This entry point can return the error into an ErrorSaveContext
64 : * instead of throwing an exception. -1 is returned after an error.
65 : */
66 : int
67 92437454 : ArrayGetNItemsSafe(int ndim, const int *dims, struct Node *escontext)
68 : {
69 : int32 ret;
70 : int i;
71 :
72 92437454 : if (ndim <= 0)
73 3004984 : return 0;
74 89432470 : ret = 1;
75 178868816 : for (i = 0; i < ndim; i++)
76 : {
77 : int64 prod;
78 :
79 : /* A negative dimension implies that UB-LB overflowed ... */
80 89436346 : if (dims[i] < 0)
81 0 : ereturn(escontext, -1,
82 : (errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
83 : errmsg("array size exceeds the maximum allowed (%d)",
84 : (int) MaxArraySize)));
85 :
86 89436346 : prod = (int64) ret * (int64) dims[i];
87 :
88 89436346 : ret = (int32) prod;
89 89436346 : if ((int64) ret != prod)
90 0 : ereturn(escontext, -1,
91 : (errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
92 : errmsg("array size exceeds the maximum allowed (%d)",
93 : (int) MaxArraySize)));
94 : }
95 : Assert(ret >= 0);
96 89432470 : if ((Size) ret > MaxArraySize)
97 0 : ereturn(escontext, -1,
98 : (errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
99 : errmsg("array size exceeds the maximum allowed (%d)",
100 : (int) MaxArraySize)));
101 89432470 : return (int) ret;
102 : }
103 :
104 : /*
105 : * Verify sanity of proposed lower-bound values for an array
106 : *
107 : * The lower-bound values must not be so large as to cause overflow when
108 : * calculating subscripts, e.g. lower bound 2147483640 with length 10
109 : * must be disallowed. We actually insist that dims[i] + lb[i] be
110 : * computable without overflow, meaning that an array with last subscript
111 : * equal to INT_MAX will be disallowed.
112 : *
113 : * It is assumed that the caller already called ArrayGetNItems, so that
114 : * overflowed (negative) dims[] values have been eliminated.
115 : */
116 : void
117 1361992 : ArrayCheckBounds(int ndim, const int *dims, const int *lb)
118 : {
119 1361992 : (void) ArrayCheckBoundsSafe(ndim, dims, lb, NULL);
120 1361992 : }
121 :
122 : /*
123 : * This entry point can return the error into an ErrorSaveContext
124 : * instead of throwing an exception.
125 : */
126 : bool
127 1361992 : ArrayCheckBoundsSafe(int ndim, const int *dims, const int *lb,
128 : struct Node *escontext)
129 : {
130 : int i;
131 :
132 2683448 : for (i = 0; i < ndim; i++)
133 : {
134 : /* PG_USED_FOR_ASSERTS_ONLY prevents variable-isn't-read warnings */
135 : int32 sum PG_USED_FOR_ASSERTS_ONLY;
136 :
137 1321456 : if (pg_add_s32_overflow(dims[i], lb[i], &sum))
138 0 : ereturn(escontext, false,
139 : (errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
140 : errmsg("array lower bound is too large: %d",
141 : lb[i])));
142 : }
143 :
144 1361992 : return true;
145 : }
146 :
147 : /*
148 : * Compute ranges (sub-array dimensions) for an array slice
149 : *
150 : * We assume caller has validated slice endpoints, so overflow is impossible
151 : */
152 : void
153 1016 : mda_get_range(int n, int *span, const int *st, const int *endp)
154 : {
155 : int i;
156 :
157 2554 : for (i = 0; i < n; i++)
158 1538 : span[i] = endp[i] - st[i] + 1;
159 1016 : }
160 :
161 : /*
162 : * Compute products of array dimensions, ie, scale factors for subscripts
163 : *
164 : * We assume caller has validated dimensions, so overflow is impossible
165 : */
166 : void
167 360 : mda_get_prod(int n, const int *range, int *prod)
168 : {
169 : int i;
170 :
171 360 : prod[n - 1] = 1;
172 576 : for (i = n - 2; i >= 0; i--)
173 216 : prod[i] = prod[i + 1] * range[i + 1];
174 360 : }
175 :
176 : /*
177 : * From products of whole-array dimensions and spans of a sub-array,
178 : * compute offset distances needed to step through subarray within array
179 : *
180 : * We assume caller has validated dimensions, so overflow is impossible
181 : */
182 : void
183 360 : mda_get_offset_values(int n, int *dist, const int *prod, const int *span)
184 : {
185 : int i,
186 : j;
187 :
188 360 : dist[n - 1] = 0;
189 576 : for (j = n - 2; j >= 0; j--)
190 : {
191 216 : dist[j] = prod[j] - 1;
192 462 : for (i = j + 1; i < n; i++)
193 246 : dist[j] -= (span[i] - 1) * prod[i];
194 : }
195 360 : }
196 :
197 : /*
198 : * Generates the tuple that is lexicographically one greater than the current
199 : * n-tuple in "curr", with the restriction that the i-th element of "curr" is
200 : * less than the i-th element of "span".
201 : *
202 : * Returns -1 if no next tuple exists, else the subscript position (0..n-1)
203 : * corresponding to the dimension to advance along.
204 : *
205 : * We assume caller has validated dimensions, so overflow is impossible
206 : */
207 : int
208 1290 : mda_next_tuple(int n, int *curr, const int *span)
209 : {
210 : int i;
211 :
212 1290 : if (n <= 0)
213 0 : return -1;
214 :
215 1290 : curr[n - 1] = (curr[n - 1] + 1) % span[n - 1];
216 1608 : for (i = n - 1; i && curr[i] == 0; i--)
217 318 : curr[i - 1] = (curr[i - 1] + 1) % span[i - 1];
218 :
219 1290 : if (i)
220 330 : return i;
221 960 : if (curr[0])
222 600 : return 0;
223 :
224 360 : return -1;
225 : }
226 :
227 : /*
228 : * ArrayGetIntegerTypmods: verify that argument is a 1-D cstring array,
229 : * and get the contents converted to integers. Returns a palloc'd array
230 : * and places the length at *n.
231 : */
232 : int32 *
233 8164 : ArrayGetIntegerTypmods(ArrayType *arr, int *n)
234 : {
235 : int32 *result;
236 : Datum *elem_values;
237 : int i;
238 :
239 8164 : if (ARR_ELEMTYPE(arr) != CSTRINGOID)
240 0 : ereport(ERROR,
241 : (errcode(ERRCODE_ARRAY_ELEMENT_ERROR),
242 : errmsg("typmod array must be type cstring[]")));
243 :
244 8164 : if (ARR_NDIM(arr) != 1)
245 0 : ereport(ERROR,
246 : (errcode(ERRCODE_ARRAY_SUBSCRIPT_ERROR),
247 : errmsg("typmod array must be one-dimensional")));
248 :
249 8164 : if (array_contains_nulls(arr))
250 0 : ereport(ERROR,
251 : (errcode(ERRCODE_NULL_VALUE_NOT_ALLOWED),
252 : errmsg("typmod array must not contain nulls")));
253 :
254 8164 : deconstruct_array_builtin(arr, CSTRINGOID, &elem_values, NULL, n);
255 :
256 8164 : result = (int32 *) palloc(*n * sizeof(int32));
257 :
258 18360 : for (i = 0; i < *n; i++)
259 10196 : result[i] = pg_strtoint32(DatumGetCString(elem_values[i]));
260 :
261 8164 : pfree(elem_values);
262 :
263 8164 : return result;
264 : }
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