| /*------------------------------------------------------------------------- | |
| * | |
| * datum.h | |
| * POSTGRES Datum (abstract data type) manipulation routines. | |
| * | |
| * These routines are driven by the 'typbyval' and 'typlen' information, | |
| * which must previously have been obtained by the caller for the datatype | |
| * of the Datum. (We do it this way because in most situations the caller | |
| * can look up the info just once and use it for many per-datum operations.) | |
| * | |
| * Portions Copyright (c) 1996-2024, PostgreSQL Global Development Group | |
| * Portions Copyright (c) 1994, Regents of the University of California | |
| * | |
| * src/include/utils/datum.h | |
| * | |
| *------------------------------------------------------------------------- | |
| */ | |
| /* | |
| * datumGetSize - find the "real" length of a datum | |
| */ | |
| extern Size datumGetSize(Datum value, bool typByVal, int typLen); | |
| /* | |
| * datumCopy - make a copy of a non-NULL datum. | |
| * | |
| * If the datatype is pass-by-reference, memory is obtained with palloc(). | |
| */ | |
| extern Datum datumCopy(Datum value, bool typByVal, int typLen); | |
| /* | |
| * datumTransfer - transfer a non-NULL datum into the current memory context. | |
| * | |
| * Differs from datumCopy() in its handling of read-write expanded objects. | |
| */ | |
| extern Datum datumTransfer(Datum value, bool typByVal, int typLen); | |
| /* | |
| * datumIsEqual | |
| * return true if two datums of the same type are equal, false otherwise. | |
| * | |
| * XXX : See comments in the code for restrictions! | |
| */ | |
| extern bool datumIsEqual(Datum value1, Datum value2, | |
| bool typByVal, int typLen); | |
| /* | |
| * datum_image_eq | |
| * | |
| * Compares two datums for identical contents, based on byte images. Return | |
| * true if the two datums are equal, false otherwise. | |
| */ | |
| extern bool datum_image_eq(Datum value1, Datum value2, | |
| bool typByVal, int typLen); | |
| /* | |
| * datum_image_hash | |
| * | |
| * Generates hash value for 'value' based on its bits rather than logical | |
| * value. | |
| */ | |
| extern uint32 datum_image_hash(Datum value, bool typByVal, int typLen); | |
| /* | |
| * Serialize and restore datums so that we can transfer them to parallel | |
| * workers. | |
| */ | |
| extern Size datumEstimateSpace(Datum value, bool isnull, bool typByVal, | |
| int typLen); | |
| extern void datumSerialize(Datum value, bool isnull, bool typByVal, | |
| int typLen, char **start_address); | |
| extern Datum datumRestore(char **start_address, bool *isnull); | |