mirror of
https://github.com/postgres/postgres.git
synced 2025-05-25 00:04:05 -04:00
9d7726c2ba
When commit 3e23b68dac006e8deb0afa327e855258df8de064 introduced single-byte varlena headers, its fmgr.h changes presented PG_GETARG_TEXT_PP() and PG_GETARG_TEXT_P() as equals. Its postgres.h changes presented PG_DETOAST_DATUM_PACKED() and VARDATA_ANY() as the exceptional case. Now, instead, firmly recommend PG_GETARG_TEXT_PP() over PG_GETARG_TEXT_P(); likewise for other ...PP() macros. This shaves cycles and invites consistency of style.
130 lines
3.1 KiB
C
130 lines
3.1 KiB
C
/* src/tutorial/funcs_new.c */
|
|
|
|
/******************************************************************************
|
|
These are user-defined functions that can be bound to a Postgres backend
|
|
and called by Postgres to execute SQL functions of the same name.
|
|
|
|
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 "new style" function call conventions.
|
|
See funcs.c for examples of "old style".
|
|
*****************************************************************************/
|
|
|
|
#include "postgres.h" /* general Postgres declarations */
|
|
|
|
#include "executor/executor.h" /* for GetAttributeByName() */
|
|
#include "utils/geo_decls.h" /* for point type */
|
|
|
|
PG_MODULE_MAGIC;
|
|
|
|
|
|
/* By Value */
|
|
|
|
PG_FUNCTION_INFO_V1(add_one);
|
|
|
|
Datum
|
|
add_one(PG_FUNCTION_ARGS)
|
|
{
|
|
int32 arg = PG_GETARG_INT32(0);
|
|
|
|
PG_RETURN_INT32(arg + 1);
|
|
}
|
|
|
|
/* By Reference, Fixed Length */
|
|
|
|
PG_FUNCTION_INFO_V1(add_one_float8);
|
|
|
|
Datum
|
|
add_one_float8(PG_FUNCTION_ARGS)
|
|
{
|
|
/* The macros for FLOAT8 hide its pass-by-reference nature */
|
|
float8 arg = PG_GETARG_FLOAT8(0);
|
|
|
|
PG_RETURN_FLOAT8(arg + 1.0);
|
|
}
|
|
|
|
PG_FUNCTION_INFO_V1(makepoint);
|
|
|
|
Datum
|
|
makepoint(PG_FUNCTION_ARGS)
|
|
{
|
|
Point *pointx = PG_GETARG_POINT_P(0);
|
|
Point *pointy = PG_GETARG_POINT_P(1);
|
|
Point *new_point = (Point *) palloc(sizeof(Point));
|
|
|
|
new_point->x = pointx->x;
|
|
new_point->y = pointy->y;
|
|
|
|
PG_RETURN_POINT_P(new_point);
|
|
}
|
|
|
|
/* By Reference, Variable Length */
|
|
|
|
PG_FUNCTION_INFO_V1(copytext);
|
|
|
|
Datum
|
|
copytext(PG_FUNCTION_ARGS)
|
|
{
|
|
text *t = PG_GETARG_TEXT_PP(0);
|
|
|
|
/*
|
|
* VARSIZE_ANY_EXHDR is the size of the struct in bytes, minus the
|
|
* VARHDRSZ or VARHDRSZ_SHORT of its header. Construct the copy with a
|
|
* full-length header.
|
|
*/
|
|
text *new_t = (text *) palloc(VARSIZE_ANY_EXHDR(t) + VARHDRSZ);
|
|
|
|
SET_VARSIZE(new_t, VARSIZE_ANY_EXHDR(t) + VARHDRSZ);
|
|
|
|
/*
|
|
* VARDATA is a pointer to the data region of the new struct. The source
|
|
* could be a short datum, so retrieve its data through VARDATA_ANY.
|
|
*/
|
|
memcpy((void *) VARDATA(new_t), /* destination */
|
|
(void *) VARDATA_ANY(t), /* source */
|
|
VARSIZE_ANY_EXHDR(t)); /* how many bytes */
|
|
PG_RETURN_TEXT_P(new_t);
|
|
}
|
|
|
|
PG_FUNCTION_INFO_V1(concat_text);
|
|
|
|
Datum
|
|
concat_text(PG_FUNCTION_ARGS)
|
|
{
|
|
text *arg1 = PG_GETARG_TEXT_PP(0);
|
|
text *arg2 = PG_GETARG_TEXT_PP(1);
|
|
int32 arg1_size = VARSIZE_ANY_EXHDR(arg1);
|
|
int32 arg2_size = VARSIZE_ANY_EXHDR(arg2);
|
|
int32 new_text_size = arg1_size + arg2_size + VARHDRSZ;
|
|
text *new_text = (text *) palloc(new_text_size);
|
|
|
|
SET_VARSIZE(new_text, new_text_size);
|
|
memcpy(VARDATA(new_text), VARDATA_ANY(arg1), arg1_size);
|
|
memcpy(VARDATA(new_text) + arg1_size, VARDATA_ANY(arg2), arg2_size);
|
|
PG_RETURN_TEXT_P(new_text);
|
|
}
|
|
|
|
/* Composite types */
|
|
|
|
PG_FUNCTION_INFO_V1(c_overpaid);
|
|
|
|
Datum
|
|
c_overpaid(PG_FUNCTION_ARGS)
|
|
{
|
|
HeapTupleHeader t = PG_GETARG_HEAPTUPLEHEADER(0);
|
|
int32 limit = PG_GETARG_INT32(1);
|
|
bool isnull;
|
|
int32 salary;
|
|
|
|
salary = DatumGetInt32(GetAttributeByName(t, "salary", &isnull));
|
|
if (isnull)
|
|
PG_RETURN_BOOL(false);
|
|
|
|
/*
|
|
* Alternatively, we might prefer to do PG_RETURN_NULL() for null salary
|
|
*/
|
|
|
|
PG_RETURN_BOOL(salary > limit);
|
|
}
|