58 lines
1.7 KiB
C
58 lines
1.7 KiB
C
/* -------------------------------------------------------------------------
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*
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* datum.h
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* openGauss Datum (abstract data type) manipulation routines.
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*
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* These routines are driven by the 'typbyval' and 'typlen' information,
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* which must previously have been obtained by the caller for the datatype
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* of the Datum. (We do it this way because in most situations the caller
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* can look up the info just once and use it for many per-datum operations.)
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*
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* Portions Copyright (c) 1996-2012, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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* src/include/utils/datum.h
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*
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* -------------------------------------------------------------------------
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*/
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#ifndef DATUM_H
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#define DATUM_H
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/*
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* datumGetSize - find the "real" length of a datum
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*/
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extern Size datumGetSize(Datum value, bool typByVal, int typLen);
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/*
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* datumCopy - make a copy of a datum.
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*
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* If the datatype is pass-by-reference, memory is obtained with palloc().
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*/
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extern Datum datumCopy(Datum value, bool typByVal, int typLen);
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/*
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* datumFree - free a datum previously allocated by datumCopy, if any.
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*
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* Does nothing if datatype is pass-by-value.
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*/
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extern void datumFree(Datum value, bool typByVal, int typLen);
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/*
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* datumIsEqual
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* return true if two datums of the same type are equal, false otherwise.
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*
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* XXX : See comments in the code for restrictions!
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*/
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extern bool datumIsEqual(Datum value1, Datum value2, bool typByVal, int typLen);
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/*
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* DatumImageEq
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*
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* Compares two datums for identical contents, based on byte images. Return
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* true if the two datums are equal, false otherwise.
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*/
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extern bool DatumImageEq(Datum value1, Datum value2,
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bool typByVal, int typLen);
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#endif /* DATUM_H */
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