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1 : /*-------------------------------------------------------------------------
2 : *
3 : * tupmacs.h
4 : * Tuple macros used by both index tuples and heap tuples.
5 : *
6 : *
7 : * Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group
8 : * Portions Copyright (c) 1994, Regents of the University of California
9 : *
10 : * src/include/access/tupmacs.h
11 : *
12 : *-------------------------------------------------------------------------
13 : */
14 : #ifndef TUPMACS_H
15 : #define TUPMACS_H
16 :
17 : #include "catalog/pg_type_d.h" /* for TYPALIGN macros */
18 :
19 :
20 : /*
21 : * Check a tuple's null bitmap to determine whether the attribute is null.
22 : * Note that a 0 in the null bitmap indicates a null, while 1 indicates
23 : * non-null.
24 : */
25 : static inline bool
26 619743940 : att_isnull(int ATT, const bits8 *BITS)
27 : {
28 619743940 : return !(BITS[ATT >> 3] & (1 << (ATT & 0x07)));
29 : }
30 :
31 : #ifndef FRONTEND
32 : /*
33 : * Given an attbyval and an attlen from either a Form_pg_attribute or
34 : * CompactAttribute and a pointer into a tuple's data area, return the
35 : * correct value or pointer.
36 : *
37 : * We return a Datum value in all cases. If attbyval is false, we return the
38 : * same pointer into the tuple data area that we're passed. Otherwise, we
39 : * return the correct number of bytes fetched from the data area and extended
40 : * to Datum form.
41 : *
42 : * On machines where Datum is 8 bytes, we support fetching 8-byte byval
43 : * attributes; otherwise, only 1, 2, and 4-byte values are supported.
44 : *
45 : * Note that T must already be properly aligned for this to work correctly.
46 : */
47 : #define fetchatt(A,T) fetch_att(T, (A)->attbyval, (A)->attlen)
48 :
49 : /*
50 : * Same, but work from byval/len parameters rather than Form_pg_attribute.
51 : */
52 : static inline Datum
53 1419383540 : fetch_att(const void *T, bool attbyval, int attlen)
54 : {
55 1419383540 : if (attbyval)
56 : {
57 1160667210 : switch (attlen)
58 : {
59 112737578 : case sizeof(char):
60 112737578 : return CharGetDatum(*((const char *) T));
61 64858480 : case sizeof(int16):
62 64858480 : return Int16GetDatum(*((const int16 *) T));
63 941879004 : case sizeof(int32):
64 941879004 : return Int32GetDatum(*((const int32 *) T));
65 : #if SIZEOF_DATUM == 8
66 41192148 : case sizeof(Datum):
67 41192148 : return *((const Datum *) T);
68 : #endif
69 0 : default:
70 0 : elog(ERROR, "unsupported byval length: %d", attlen);
71 : return 0;
72 : }
73 : }
74 : else
75 258716330 : return PointerGetDatum(T);
76 : }
77 : #endif /* FRONTEND */
78 :
79 : /*
80 : * att_align_datum aligns the given offset as needed for a datum of alignment
81 : * requirement attalign and typlen attlen. attdatum is the Datum variable
82 : * we intend to pack into a tuple (it's only accessed if we are dealing with
83 : * a varlena type). Note that this assumes the Datum will be stored as-is;
84 : * callers that are intending to convert non-short varlena datums to short
85 : * format have to account for that themselves.
86 : */
87 : #define att_align_datum(cur_offset, attalign, attlen, attdatum) \
88 : ( \
89 : ((attlen) == -1 && VARATT_IS_SHORT(DatumGetPointer(attdatum))) ? \
90 : (uintptr_t) (cur_offset) : \
91 : att_align_nominal(cur_offset, attalign) \
92 : )
93 :
94 : /*
95 : * Similar to att_align_datum, but accepts a number of bytes, typically from
96 : * CompactAttribute.attalignby to align the Datum by.
97 : */
98 : #define att_datum_alignby(cur_offset, attalignby, attlen, attdatum) \
99 : ( \
100 : ((attlen) == -1 && VARATT_IS_SHORT(DatumGetPointer(attdatum))) ? \
101 : (uintptr_t) (cur_offset) : \
102 : TYPEALIGN(attalignby, cur_offset))
103 :
104 : /*
105 : * att_align_pointer performs the same calculation as att_align_datum,
106 : * but is used when walking a tuple. attptr is the current actual data
107 : * pointer; when accessing a varlena field we have to "peek" to see if we
108 : * are looking at a pad byte or the first byte of a 1-byte-header datum.
109 : * (A zero byte must be either a pad byte, or the first byte of a correctly
110 : * aligned 4-byte length word; in either case we can align safely. A non-zero
111 : * byte must be either a 1-byte length word, or the first byte of a correctly
112 : * aligned 4-byte length word; in either case we need not align.)
113 : *
114 : * Note: some callers pass a "char *" pointer for cur_offset. This is
115 : * a bit of a hack but should work all right as long as uintptr_t is the
116 : * correct width.
117 : */
118 : #define att_align_pointer(cur_offset, attalign, attlen, attptr) \
119 : ( \
120 : ((attlen) == -1 && VARATT_NOT_PAD_BYTE(attptr)) ? \
121 : (uintptr_t) (cur_offset) : \
122 : att_align_nominal(cur_offset, attalign) \
123 : )
124 :
125 : /*
126 : * Similar to att_align_pointer, but accepts a number of bytes, typically from
127 : * CompactAttribute.attalignby to align the pointer by.
128 : */
129 : #define att_pointer_alignby(cur_offset, attalignby, attlen, attptr) \
130 : ( \
131 : ((attlen) == -1 && VARATT_NOT_PAD_BYTE(attptr)) ? \
132 : (uintptr_t) (cur_offset) : \
133 : TYPEALIGN(attalignby, cur_offset))
134 :
135 : /*
136 : * att_align_nominal aligns the given offset as needed for a datum of alignment
137 : * requirement attalign, ignoring any consideration of packed varlena datums.
138 : * There are three main use cases for using this macro directly:
139 : * * we know that the att in question is not varlena (attlen != -1);
140 : * in this case it is cheaper than the above macros and just as good.
141 : * * we need to estimate alignment padding cost abstractly, ie without
142 : * reference to a real tuple. We must assume the worst case that
143 : * all varlenas are aligned.
144 : * * within arrays and multiranges, we unconditionally align varlenas (XXX this
145 : * should be revisited, probably).
146 : *
147 : * The attalign cases are tested in what is hopefully something like their
148 : * frequency of occurrence.
149 : */
150 : #define att_align_nominal(cur_offset, attalign) \
151 : ( \
152 : ((attalign) == TYPALIGN_INT) ? INTALIGN(cur_offset) : \
153 : (((attalign) == TYPALIGN_CHAR) ? (uintptr_t) (cur_offset) : \
154 : (((attalign) == TYPALIGN_DOUBLE) ? DOUBLEALIGN(cur_offset) : \
155 : ( \
156 : AssertMacro((attalign) == TYPALIGN_SHORT), \
157 : SHORTALIGN(cur_offset) \
158 : ))) \
159 : )
160 :
161 : /*
162 : * Similar to att_align_nominal, but accepts a number of bytes, typically from
163 : * CompactAttribute.attalignby to align the offset by.
164 : */
165 : #define att_nominal_alignby(cur_offset, attalignby) \
166 : TYPEALIGN(attalignby, cur_offset)
167 :
168 : /*
169 : * att_addlength_datum increments the given offset by the space needed for
170 : * the given Datum variable. attdatum is only accessed if we are dealing
171 : * with a variable-length attribute.
172 : */
173 : #define att_addlength_datum(cur_offset, attlen, attdatum) \
174 : att_addlength_pointer(cur_offset, attlen, DatumGetPointer(attdatum))
175 :
176 : /*
177 : * att_addlength_pointer performs the same calculation as att_addlength_datum,
178 : * but is used when walking a tuple --- attptr is the pointer to the field
179 : * within the tuple.
180 : *
181 : * Note: some callers pass a "char *" pointer for cur_offset. This is
182 : * actually perfectly OK, but probably should be cleaned up along with
183 : * the same practice for att_align_pointer.
184 : */
185 : #define att_addlength_pointer(cur_offset, attlen, attptr) \
186 : ( \
187 : ((attlen) > 0) ? \
188 : ( \
189 : (cur_offset) + (attlen) \
190 : ) \
191 : : (((attlen) == -1) ? \
192 : ( \
193 : (cur_offset) + VARSIZE_ANY(attptr) \
194 : ) \
195 : : \
196 : ( \
197 : AssertMacro((attlen) == -2), \
198 : (cur_offset) + (strlen((char *) (attptr)) + 1) \
199 : )) \
200 : )
201 :
202 : #ifndef FRONTEND
203 : /*
204 : * store_att_byval is a partial inverse of fetch_att: store a given Datum
205 : * value into a tuple data area at the specified address. However, it only
206 : * handles the byval case, because in typical usage the caller needs to
207 : * distinguish by-val and by-ref cases anyway, and so a do-it-all function
208 : * wouldn't be convenient.
209 : */
210 : static inline void
211 174823922 : store_att_byval(void *T, Datum newdatum, int attlen)
212 : {
213 174823922 : switch (attlen)
214 : {
215 23615916 : case sizeof(char):
216 23615916 : *(char *) T = DatumGetChar(newdatum);
217 23615916 : break;
218 8863134 : case sizeof(int16):
219 8863134 : *(int16 *) T = DatumGetInt16(newdatum);
220 8863134 : break;
221 123996846 : case sizeof(int32):
222 123996846 : *(int32 *) T = DatumGetInt32(newdatum);
223 123996846 : break;
224 : #if SIZEOF_DATUM == 8
225 18348026 : case sizeof(Datum):
226 18348026 : *(Datum *) T = newdatum;
227 18348026 : break;
228 : #endif
229 0 : default:
230 0 : elog(ERROR, "unsupported byval length: %d", attlen);
231 : }
232 174823922 : }
233 : #endif /* FRONTEND */
234 :
235 : #endif /* TUPMACS_H */
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