datum.c File Reference

#include "postgres.h"
#include "utils/datum.h"

Include dependency graph for datum.c:

Go to the source code of this file.

Functions
Size	datumGetSize (Datum value, bool typByVal, int typLen)
Datum	datumCopy (Datum value, bool typByVal, int typLen)
bool	datumIsEqual (Datum value1, Datum value2, bool typByVal, int typLen)

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Function Documentation

Datum datumCopy	(	Datum	value,
		bool	typByVal,
		int	typLen
	)

Definition at line 115 of file datum.c.

References DatumGetPointer, datumGetSize(), NULL, palloc(), and PointerGetDatum.

Referenced by _copyConst(), accumArrayResult(), advance_transition_function(), advance_windowaggregate(), collectMatchBitmap(), compute_array_stats(), compute_index_stats(), compute_minimal_stats(), compute_scalar_stats(), copyParamList(), eval_const_expressions_mutator(), eval_windowaggregates(), eval_windowfunction(), evaluate_expr(), exec_assign_value(), exec_eval_using_params(), exec_stmt_block(), ExecWindowAgg(), finalize_aggregate(), finalize_windowaggregate(), get_actual_variable_range(), get_attstatsslot(), get_variable_range(), getDatumCopy(), initialize_aggregates(), initialize_windowaggregate(), postquel_get_single_result(), spg_text_inner_consistent(), spgWalk(), tuplesort_getdatum(), and tuplesort_putdatum().

{
    Datum       res;

    if (typByVal)
        res = value;
    else
    {
        Size        realSize;
        char       *s;

        if (DatumGetPointer(value) == NULL)
            return PointerGetDatum(NULL);

        realSize = datumGetSize(value, typByVal, typLen);

        s = (char *) palloc(realSize);
        memcpy(s, DatumGetPointer(value), realSize);
        res = PointerGetDatum(s);
    }
    return res;
}

Size datumGetSize	(	Datum	value,
		bool	typByVal,
		int	typLen
	)

Definition at line 55 of file datum.c.

References Assert, DatumGetPointer, elog, ereport, errcode(), errmsg(), ERROR, PointerIsValid, and VARSIZE_ANY.

Referenced by _outDatum(), datumCopy(), datumIsEqual(), plpgsql_exec_function(), and writetup_datum().

{
    Size        size;

    if (typByVal)
    {
        /* Pass-by-value types are always fixed-length */
        Assert(typLen > 0 && typLen <= sizeof(Datum));
        size = (Size) typLen;
    }
    else
    {
        if (typLen > 0)
        {
            /* Fixed-length pass-by-ref type */
            size = (Size) typLen;
        }
        else if (typLen == -1)
        {
            /* It is a varlena datatype */
            struct varlena *s = (struct varlena *) DatumGetPointer(value);

            if (!PointerIsValid(s))
                ereport(ERROR,
                        (errcode(ERRCODE_DATA_EXCEPTION),
                         errmsg("invalid Datum pointer")));

            size = (Size) VARSIZE_ANY(s);
        }
        else if (typLen == -2)
        {
            /* It is a cstring datatype */
            char       *s = (char *) DatumGetPointer(value);

            if (!PointerIsValid(s))
                ereport(ERROR,
                        (errcode(ERRCODE_DATA_EXCEPTION),
                         errmsg("invalid Datum pointer")));

            size = (Size) (strlen(s) + 1);
        }
        else
        {
            elog(ERROR, "invalid typLen: %d", typLen);
            size = 0;           /* keep compiler quiet */
        }
    }

    return size;
}

bool datumIsEqual	(	Datum	value1,
		Datum	value2,
		bool	typByVal,
		int	typLen
	)

Definition at line 175 of file datum.c.

References DatumGetPointer, datumGetSize(), memcmp(), s1, and s2.

Referenced by _equalConst(), heap_tuple_attr_equals(), and stringTypeDatum().

{
    bool        res;

    if (typByVal)
    {
        /*
         * just compare the two datums. NOTE: just comparing "len" bytes will
         * not do the work, because we do not know how these bytes are aligned
         * inside the "Datum".  We assume instead that any given datatype is
         * consistent about how it fills extraneous bits in the Datum.
         */
        res = (value1 == value2);
    }
    else
    {
        Size        size1,
                    size2;
        char       *s1,
                   *s2;

        /*
         * Compare the bytes pointed by the pointers stored in the datums.
         */
        size1 = datumGetSize(value1, typByVal, typLen);
        size2 = datumGetSize(value2, typByVal, typLen);
        if (size1 != size2)
            return false;
        s1 = (char *) DatumGetPointer(value1);
        s2 = (char *) DatumGetPointer(value2);
        res = (memcmp(s1, s2, size1) == 0);
    }
    return res;
}