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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-04 12:15:05 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-04 12:15:05 +0000 |
commit | 46651ce6fe013220ed397add242004d764fc0153 (patch) | |
tree | 6e5299f990f88e60174a1d3ae6e48eedd2688b2b /src/tutorial/funcs.c | |
parent | Initial commit. (diff) | |
download | postgresql-14-46651ce6fe013220ed397add242004d764fc0153.tar.xz postgresql-14-46651ce6fe013220ed397add242004d764fc0153.zip |
Adding upstream version 14.5.upstream/14.5upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/tutorial/funcs.c')
-rw-r--r-- | src/tutorial/funcs.c | 126 |
1 files changed, 126 insertions, 0 deletions
diff --git a/src/tutorial/funcs.c b/src/tutorial/funcs.c new file mode 100644 index 0000000..cdd155e --- /dev/null +++ b/src/tutorial/funcs.c @@ -0,0 +1,126 @@ +/* src/tutorial/funcs.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. +*****************************************************************************/ + +#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); +} |