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Update funcs tutorial for new function manager.

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This commit is contained in:
Tom Lane
2000-08-24 23:32:43 +00:00
parent 782c16c6a1
commit d9eb7d8fa1
2 changed files with 184 additions and 39 deletions
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107
src/tutorial/funcs.c
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@ -4,75 +4,104 @@
The calling format for these functions is defined by the CREATE FUNCTION
SQL statement that binds them to the backend.
NOTE: this file shows examples of "old style" function call conventions.
See funcs_new.c for examples of "new style".
*****************************************************************************/
#include "postgres.h" /* for variable length type */
#include <string.h>
#include "postgres.h" /* general Postgres declarations */
#include "executor/executor.h" /* for GetAttributeByName() */
#include "utils/geo_decls.h" /* for point type */
/* The following prototypes declare what we assume the user declares to
Postgres in his CREATE FUNCTION statement.
*/
/* These prototypes just prevent possible warnings from gcc. */
int add_one(int arg);
float8 *add_one_float8(float8 *arg);
Point *makepoint(Point *pointx, Point *pointy);
text *copytext(text *t);
text *concat_text(text *arg1, text *arg2);
bool c_overpaid(TupleTableSlot *t, /* the current instance of EMP */
int4 limit);
int32 limit);
/* By Value */
int
add_one(int arg)
{
return arg + 1;
return arg + 1;
}
/* By Reference, Fixed Length */
float8 *
add_one_float8(float8 *arg)
{
float8 *result = (float8 *) palloc(sizeof(float8));
*result = *arg + 1.0;
return result;
}
Point *
makepoint(Point *pointx, Point *pointy)
{
Point *new_point = (Point *) palloc(sizeof(Point));
Point *new_point = (Point *) palloc(sizeof(Point));
new_point->x = pointx->x;
new_point->y = pointy->y;
return new_point;
new_point->x = pointx->x;
new_point->y = pointy->y;
return new_point;
}
/* By Reference, Variable Length */
text *
copytext(text *t)
{
/*
* VARSIZE is the total size of the struct in bytes.
*/
text *new_t = (text *) palloc(VARSIZE(t));
MemSet(new_t, 0, VARSIZE(t));
VARSIZE(new_t) = VARSIZE(t);
/*
* VARDATA is a pointer to the data region of the struct.
*/
memcpy((void *) VARDATA(new_t), /* destination */
(void *) VARDATA(t), /* source */
VARSIZE(t) - VARHDRSZ); /* how many bytes */
return new_t;
/*
* VARSIZE is the total size of the struct in bytes.
*/
text *new_t = (text *) palloc(VARSIZE(t));
VARATT_SIZEP(new_t) = VARSIZE(t);
/*
* VARDATA is a pointer to the data region of the struct.
*/
memcpy((void *) VARDATA(new_t), /* destination */
(void *) VARDATA(t), /* source */
VARSIZE(t)-VARHDRSZ); /* how many bytes */
return new_t;
}
text *
concat_text(text *arg1, text *arg2)
{
int32 new_text_size = VARSIZE(arg1) + VARSIZE(arg2) - VARHDRSZ;
text *new_text = (text *) palloc(new_text_size);
memset((void *) new_text, 0, new_text_size);
VARATT_SIZEP(new_text) = new_text_size;
strncpy(VARDATA(new_text), VARDATA(arg1), VARSIZE(arg1)-VARHDRSZ);
strncat(VARDATA(new_text), VARDATA(arg2), VARSIZE(arg2)-VARHDRSZ);
return new_text;
}
/* Composite types */
bool
c_overpaid(TupleTableSlot *t, /* the current instance of EMP */
int4 limit)
int32 limit)
{
bool isnull = false;
int4 salary;
bool isnull;
int32 salary;
salary = (int4) GetAttributeByName(t, "salary", &isnull);
if (isnull)
return false;
return salary > limit;
salary = DatumGetInt32(GetAttributeByName(t, "salary", &isnull));
if (isnull)
return (false);
return salary > limit;
}