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Commitd9eb7d8

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Update funcs tutorial for new function manager.
1 parent782c16c commitd9eb7d8

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2 files changed

+183
-38
lines changed

2 files changed

+183
-38
lines changed

‎src/tutorial/funcs.c

Lines changed: 67 additions & 38 deletions
Original file line numberDiff line numberDiff line change
@@ -4,75 +4,104 @@
44
55
The calling format for these functions is defined by the CREATE FUNCTION
66
SQL statement that binds them to the backend.
7+
8+
NOTE: this file shows examples of "old style" function call conventions.
9+
See funcs_new.c for examples of "new style".
710
*****************************************************************************/
811

9-
#include"postgres.h"/* for variable length type */
12+
#include<string.h>
13+
14+
#include"postgres.h"/* general Postgres declarations */
15+
1016
#include"executor/executor.h"/* for GetAttributeByName() */
1117
#include"utils/geo_decls.h"/* for point type */
1218

13-
/* The following prototypes declare what we assume the user declares to
14-
Postgres in his CREATE FUNCTION statement.
15-
*/
19+
20+
/* These prototypes just prevent possible warnings from gcc. */
1621

1722
intadd_one(intarg);
23+
float8*add_one_float8(float8*arg);
1824
Point*makepoint(Point*pointx,Point*pointy);
1925
text*copytext(text*t);
20-
26+
text*concat_text(text*arg1,text*arg2);
2127
boolc_overpaid(TupleTableSlot*t,/* the current instance of EMP */
22-
int4limit);
23-
28+
int32limit);
2429

2530

31+
/* By Value */
32+
2633
int
2734
add_one(intarg)
2835
{
29-
returnarg+1;
36+
returnarg+1;
37+
}
38+
39+
/* By Reference, Fixed Length */
40+
41+
float8*
42+
add_one_float8(float8*arg)
43+
{
44+
float8*result= (float8*)palloc(sizeof(float8));
45+
46+
*result=*arg+1.0;
47+
48+
returnresult;
3049
}
3150

3251
Point*
3352
makepoint(Point*pointx,Point*pointy)
3453
{
35-
Point*new_point= (Point*)palloc(sizeof(Point));
54+
Point*new_point= (Point*)palloc(sizeof(Point));
3655

37-
new_point->x=pointx->x;
38-
new_point->y=pointy->y;
39-
40-
returnnew_point;
56+
new_point->x=pointx->x;
57+
new_point->y=pointy->y;
58+
59+
returnnew_point;
4160
}
4261

62+
/* By Reference, Variable Length */
63+
4364
text*
4465
copytext(text*t)
4566
{
67+
/*
68+
* VARSIZE is the total size of the struct in bytes.
69+
*/
70+
text*new_t= (text*)palloc(VARSIZE(t));
71+
VARATT_SIZEP(new_t)=VARSIZE(t);
72+
/*
73+
* VARDATA is a pointer to the data region of the struct.
74+
*/
75+
memcpy((void*)VARDATA(new_t),/* destination */
76+
(void*)VARDATA(t),/* source */
77+
VARSIZE(t)-VARHDRSZ);/* how many bytes */
78+
returnnew_t;
79+
}
4680

47-
/*
48-
* VARSIZE is the total size of the struct in bytes.
49-
*/
50-
text*new_t= (text*)palloc(VARSIZE(t));
51-
52-
MemSet(new_t,0,VARSIZE(t));
53-
54-
VARSIZE(new_t)=VARSIZE(t);
55-
56-
/*
57-
* VARDATA is a pointer to the data region of the struct.
58-
*/
59-
memcpy((void*)VARDATA(new_t),/* destination */
60-
(void*)VARDATA(t),/* source */
61-
VARSIZE(t)-VARHDRSZ);/* how many bytes */
62-
63-
returnnew_t;
81+
text*
82+
concat_text(text*arg1,text*arg2)
83+
{
84+
int32new_text_size=VARSIZE(arg1)+VARSIZE(arg2)-VARHDRSZ;
85+
text*new_text= (text*)palloc(new_text_size);
86+
87+
memset((void*)new_text,0,new_text_size);
88+
VARATT_SIZEP(new_text)=new_text_size;
89+
strncpy(VARDATA(new_text),VARDATA(arg1),VARSIZE(arg1)-VARHDRSZ);
90+
strncat(VARDATA(new_text),VARDATA(arg2),VARSIZE(arg2)-VARHDRSZ);
91+
returnnew_text;
6492
}
6593

94+
/* Composite types */
95+
6696
bool
6797
c_overpaid(TupleTableSlot*t,/* the current instance of EMP */
68-
int4limit)
98+
int32limit)
6999
{
70-
boolisnull= false;
71-
int4salary;
72-
73-
salary= (int4)GetAttributeByName(t,"salary",&isnull);
100+
boolisnull;
101+
int32salary;
74102

75-
if (isnull)
76-
return false;
77-
returnsalary>limit;
103+
salary=DatumGetInt32(GetAttributeByName(t,"salary",&isnull));
104+
if (isnull)
105+
return (false);
106+
returnsalary>limit;
78107
}

‎src/tutorial/funcs_new.c

Lines changed: 116 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,116 @@
1+
/******************************************************************************
2+
These are user-defined functions that can be bound to a Postgres backend
3+
and called by Postgres to execute SQL functions of the same name.
4+
5+
The calling format for these functions is defined by the CREATE FUNCTION
6+
SQL statement that binds them to the backend.
7+
8+
NOTE: this file shows examples of "new style" function call conventions.
9+
See funcs.c for examples of "old style".
10+
*****************************************************************************/
11+
12+
#include<string.h>
13+
14+
#include"postgres.h"/* general Postgres declarations */
15+
16+
#include"fmgr.h"/* for argument/result macros */
17+
#include"executor/executor.h"/* for GetAttributeByName() */
18+
#include"utils/geo_decls.h"/* for point type */
19+
20+
21+
/* These prototypes just prevent possible warnings from gcc. */
22+
23+
Datumadd_one(PG_FUNCTION_ARGS);
24+
Datumadd_one_float8(PG_FUNCTION_ARGS);
25+
Datummakepoint(PG_FUNCTION_ARGS);
26+
Datumcopytext(PG_FUNCTION_ARGS);
27+
Datumconcat_text(PG_FUNCTION_ARGS);
28+
Datumc_overpaid(PG_FUNCTION_ARGS);
29+
30+
31+
/* By Value */
32+
33+
Datum
34+
add_one(PG_FUNCTION_ARGS)
35+
{
36+
int32arg=PG_GETARG_INT32(0);
37+
38+
PG_RETURN_INT32(arg+1);
39+
}
40+
41+
/* By Reference, Fixed Length */
42+
43+
Datum
44+
add_one_float8(PG_FUNCTION_ARGS)
45+
{
46+
/* The macros for FLOAT8 hide its pass-by-reference nature */
47+
float8arg=PG_GETARG_FLOAT8(0);
48+
49+
PG_RETURN_FLOAT8(arg+1.0);
50+
}
51+
52+
Datum
53+
makepoint(PG_FUNCTION_ARGS)
54+
{
55+
Point*pointx=PG_GETARG_POINT_P(0);
56+
Point*pointy=PG_GETARG_POINT_P(1);
57+
Point*new_point= (Point*)palloc(sizeof(Point));
58+
59+
new_point->x=pointx->x;
60+
new_point->y=pointy->y;
61+
62+
PG_RETURN_POINT_P(new_point);
63+
}
64+
65+
/* By Reference, Variable Length */
66+
67+
Datum
68+
copytext(PG_FUNCTION_ARGS)
69+
{
70+
text*t=PG_GETARG_TEXT_P(0);
71+
/*
72+
* VARSIZE is the total size of the struct in bytes.
73+
*/
74+
text*new_t= (text*)palloc(VARSIZE(t));
75+
VARATT_SIZEP(new_t)=VARSIZE(t);
76+
/*
77+
* VARDATA is a pointer to the data region of the struct.
78+
*/
79+
memcpy((void*)VARDATA(new_t),/* destination */
80+
(void*)VARDATA(t),/* source */
81+
VARSIZE(t)-VARHDRSZ);/* how many bytes */
82+
PG_RETURN_TEXT_P(new_t);
83+
}
84+
85+
Datum
86+
concat_text(PG_FUNCTION_ARGS)
87+
{
88+
text*arg1=PG_GETARG_TEXT_P(0);
89+
text*arg2=PG_GETARG_TEXT_P(1);
90+
int32new_text_size=VARSIZE(arg1)+VARSIZE(arg2)-VARHDRSZ;
91+
text*new_text= (text*)palloc(new_text_size);
92+
93+
memset((void*)new_text,0,new_text_size);
94+
VARATT_SIZEP(new_text)=new_text_size;
95+
strncpy(VARDATA(new_text),VARDATA(arg1),VARSIZE(arg1)-VARHDRSZ);
96+
strncat(VARDATA(new_text),VARDATA(arg2),VARSIZE(arg2)-VARHDRSZ);
97+
PG_RETURN_TEXT_P(new_text);
98+
}
99+
100+
/* Composite types */
101+
102+
Datum
103+
c_overpaid(PG_FUNCTION_ARGS)
104+
{
105+
TupleTableSlot*t= (TupleTableSlot*)PG_GETARG_POINTER(0);
106+
int32limit=PG_GETARG_INT32(1);
107+
boolisnull;
108+
int32salary;
109+
110+
salary=DatumGetInt32(GetAttributeByName(t,"salary",&isnull));
111+
if (isnull)
112+
PG_RETURN_BOOL(false);
113+
/* Alternatively, we might prefer to do PG_RETURN_NULL() for null salary */
114+
115+
PG_RETURN_BOOL(salary>limit);
116+
}

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