| /* $PostgreSQL: pgsql/src/tutorial/funcs.c,v 1.17 2007/02/27 23:48:10 tgl Exp $ */ |
| |
| /****************************************************************************** |
| 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 "old style" function call conventions. |
| See funcs_new.c for examples of "new style". |
| *****************************************************************************/ |
| |
| #include "postgres.h" /* general Postgres declarations */ |
| |
| #include "executor/executor.h" /* for GetAttributeByName() */ |
| #include "utils/geo_decls.h" /* for point type */ |
| |
| PG_MODULE_MAGIC; |
| |
| |
| /* 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(HeapTupleHeader t, /* the current instance of EMP */ |
| int32 limit); |
| |
| |
| /* By Value */ |
| |
| int |
| add_one(int arg) |
| { |
| 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)); |
| |
| 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)); |
| |
| SET_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; |
| } |
| |
| text * |
| concat_text(text *arg1, text *arg2) |
| { |
| int32 arg1_size = VARSIZE(arg1) - VARHDRSZ; |
| int32 arg2_size = VARSIZE(arg2) - VARHDRSZ; |
| 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(arg1), arg1_size); |
| memcpy(VARDATA(new_text) + arg1_size, VARDATA(arg2), arg2_size); |
| return new_text; |
| } |
| |
| /* Composite types */ |
| |
| bool |
| c_overpaid(HeapTupleHeader t, /* the current instance of EMP */ |
| int32 limit) |
| { |
| bool isnull; |
| int32 salary; |
| |
| salary = DatumGetInt32(GetAttributeByName(t, "salary", &isnull)); |
| if (isnull) |
| return false; |
| return salary > limit; |
| } |