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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 738412734 : att_isnull(int ATT, const bits8 *BITS)
27 : {
28 738412734 : 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 : * Note that T must already be properly aligned for this to work correctly.
43 : */
44 : #define fetchatt(A,T) fetch_att(T, (A)->attbyval, (A)->attlen)
45 :
46 : /*
47 : * Same, but work from byval/len parameters rather than Form_pg_attribute.
48 : */
49 : static inline Datum
50 1618568944 : fetch_att(const void *T, bool attbyval, int attlen)
51 : {
52 1618568944 : if (attbyval)
53 : {
54 1342266668 : switch (attlen)
55 : {
56 149657606 : case sizeof(char):
57 149657606 : return CharGetDatum(*((const char *) T));
58 77518966 : case sizeof(int16):
59 77518966 : return Int16GetDatum(*((const int16 *) T));
60 1073279276 : case sizeof(int32):
61 1073279276 : return Int32GetDatum(*((const int32 *) T));
62 41810820 : case sizeof(int64):
63 41810820 : return Int64GetDatum(*((const int64 *) T));
64 0 : default:
65 0 : elog(ERROR, "unsupported byval length: %d", attlen);
66 : return 0;
67 : }
68 : }
69 : else
70 276302276 : return PointerGetDatum(T);
71 : }
72 : #endif /* FRONTEND */
73 :
74 : /*
75 : * att_align_datum aligns the given offset as needed for a datum of alignment
76 : * requirement attalign and typlen attlen. attdatum is the Datum variable
77 : * we intend to pack into a tuple (it's only accessed if we are dealing with
78 : * a varlena type). Note that this assumes the Datum will be stored as-is;
79 : * callers that are intending to convert non-short varlena datums to short
80 : * format have to account for that themselves.
81 : */
82 : #define att_align_datum(cur_offset, attalign, attlen, attdatum) \
83 : ( \
84 : ((attlen) == -1 && VARATT_IS_SHORT(DatumGetPointer(attdatum))) ? \
85 : (uintptr_t) (cur_offset) : \
86 : att_align_nominal(cur_offset, attalign) \
87 : )
88 :
89 : /*
90 : * Similar to att_align_datum, but accepts a number of bytes, typically from
91 : * CompactAttribute.attalignby to align the Datum by.
92 : */
93 : #define att_datum_alignby(cur_offset, attalignby, attlen, attdatum) \
94 : ( \
95 : ((attlen) == -1 && VARATT_IS_SHORT(DatumGetPointer(attdatum))) ? \
96 : (uintptr_t) (cur_offset) : \
97 : TYPEALIGN(attalignby, cur_offset))
98 :
99 : /*
100 : * att_align_pointer performs the same calculation as att_align_datum,
101 : * but is used when walking a tuple. attptr is the current actual data
102 : * pointer; when accessing a varlena field we have to "peek" to see if we
103 : * are looking at a pad byte or the first byte of a 1-byte-header datum.
104 : * (A zero byte must be either a pad byte, or the first byte of a correctly
105 : * aligned 4-byte length word; in either case we can align safely. A non-zero
106 : * byte must be either a 1-byte length word, or the first byte of a correctly
107 : * aligned 4-byte length word; in either case we need not align.)
108 : *
109 : * Note: some callers pass a "char *" pointer for cur_offset. This is
110 : * a bit of a hack but should work all right as long as uintptr_t is the
111 : * correct width.
112 : */
113 : #define att_align_pointer(cur_offset, attalign, attlen, attptr) \
114 : ( \
115 : ((attlen) == -1 && VARATT_NOT_PAD_BYTE(attptr)) ? \
116 : (uintptr_t) (cur_offset) : \
117 : att_align_nominal(cur_offset, attalign) \
118 : )
119 :
120 : /*
121 : * Similar to att_align_pointer, but accepts a number of bytes, typically from
122 : * CompactAttribute.attalignby to align the pointer by.
123 : */
124 : #define att_pointer_alignby(cur_offset, attalignby, attlen, attptr) \
125 : ( \
126 : ((attlen) == -1 && VARATT_NOT_PAD_BYTE(attptr)) ? \
127 : (uintptr_t) (cur_offset) : \
128 : TYPEALIGN(attalignby, cur_offset))
129 :
130 : /*
131 : * att_align_nominal aligns the given offset as needed for a datum of alignment
132 : * requirement attalign, ignoring any consideration of packed varlena datums.
133 : * There are three main use cases for using this macro directly:
134 : * * we know that the att in question is not varlena (attlen != -1);
135 : * in this case it is cheaper than the above macros and just as good.
136 : * * we need to estimate alignment padding cost abstractly, ie without
137 : * reference to a real tuple. We must assume the worst case that
138 : * all varlenas are aligned.
139 : * * within arrays and multiranges, we unconditionally align varlenas (XXX this
140 : * should be revisited, probably).
141 : *
142 : * The attalign cases are tested in what is hopefully something like their
143 : * frequency of occurrence.
144 : */
145 : #define att_align_nominal(cur_offset, attalign) \
146 : ( \
147 : ((attalign) == TYPALIGN_INT) ? INTALIGN(cur_offset) : \
148 : (((attalign) == TYPALIGN_CHAR) ? (uintptr_t) (cur_offset) : \
149 : (((attalign) == TYPALIGN_DOUBLE) ? DOUBLEALIGN(cur_offset) : \
150 : ( \
151 : AssertMacro((attalign) == TYPALIGN_SHORT), \
152 : SHORTALIGN(cur_offset) \
153 : ))) \
154 : )
155 :
156 : /*
157 : * Similar to att_align_nominal, but accepts a number of bytes, typically from
158 : * CompactAttribute.attalignby to align the offset by.
159 : */
160 : #define att_nominal_alignby(cur_offset, attalignby) \
161 : TYPEALIGN(attalignby, cur_offset)
162 :
163 : /*
164 : * att_addlength_datum increments the given offset by the space needed for
165 : * the given Datum variable. attdatum is only accessed if we are dealing
166 : * with a variable-length attribute.
167 : */
168 : #define att_addlength_datum(cur_offset, attlen, attdatum) \
169 : att_addlength_pointer(cur_offset, attlen, DatumGetPointer(attdatum))
170 :
171 : /*
172 : * att_addlength_pointer performs the same calculation as att_addlength_datum,
173 : * but is used when walking a tuple --- attptr is the pointer to the field
174 : * within the tuple.
175 : *
176 : * Note: some callers pass a "char *" pointer for cur_offset. This is
177 : * actually perfectly OK, but probably should be cleaned up along with
178 : * the same practice for att_align_pointer.
179 : */
180 : #define att_addlength_pointer(cur_offset, attlen, attptr) \
181 : ( \
182 : ((attlen) > 0) ? \
183 : ( \
184 : (cur_offset) + (attlen) \
185 : ) \
186 : : (((attlen) == -1) ? \
187 : ( \
188 : (cur_offset) + VARSIZE_ANY(attptr) \
189 : ) \
190 : : \
191 : ( \
192 : AssertMacro((attlen) == -2), \
193 : (cur_offset) + (strlen((char *) (attptr)) + 1) \
194 : )) \
195 : )
196 :
197 : #ifndef FRONTEND
198 : /*
199 : * store_att_byval is a partial inverse of fetch_att: store a given Datum
200 : * value into a tuple data area at the specified address. However, it only
201 : * handles the byval case, because in typical usage the caller needs to
202 : * distinguish by-val and by-ref cases anyway, and so a do-it-all function
203 : * wouldn't be convenient.
204 : */
205 : static inline void
206 192851074 : store_att_byval(void *T, Datum newdatum, int attlen)
207 : {
208 192851074 : switch (attlen)
209 : {
210 25743826 : case sizeof(char):
211 25743826 : *(char *) T = DatumGetChar(newdatum);
212 25743826 : break;
213 9532108 : case sizeof(int16):
214 9532108 : *(int16 *) T = DatumGetInt16(newdatum);
215 9532108 : break;
216 136719354 : case sizeof(int32):
217 136719354 : *(int32 *) T = DatumGetInt32(newdatum);
218 136719354 : break;
219 20855786 : case sizeof(int64):
220 20855786 : *(int64 *) T = DatumGetInt64(newdatum);
221 20855786 : break;
222 0 : default:
223 0 : elog(ERROR, "unsupported byval length: %d", attlen);
224 : }
225 192851074 : }
226 : #endif /* FRONTEND */
227 :
228 : #endif /* TUPMACS_H */
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