mirror of
https://git.postgresql.org/git/postgresql.git
synced 2024-10-06 19:06:54 +02:00
134 lines
3.5 KiB
C
134 lines
3.5 KiB
C
|
/*-------------------------------------------------------------------------
|
||
|
*
|
||
|
* arrayaccess.h
|
||
|
* Declarations for element-by-element access to Postgres arrays.
|
||
|
*
|
||
|
*
|
||
|
* Portions Copyright (c) 1996-2015, PostgreSQL Global Development Group
|
||
|
* Portions Copyright (c) 1994, Regents of the University of California
|
||
|
*
|
||
|
* src/include/utils/arrayaccess.h
|
||
|
*
|
||
|
*-------------------------------------------------------------------------
|
||
|
*/
|
||
|
#ifndef ARRAYACCESS_H
|
||
|
#define ARRAYACCESS_H
|
||
|
|
||
|
#include "access/tupmacs.h"
|
||
|
#include "utils/array.h"
|
||
|
|
||
|
|
||
|
/*
|
||
|
* Functions for iterating through elements of a flat or expanded array.
|
||
|
* These require a state struct "array_iter iter".
|
||
|
*
|
||
|
* Use "array_iter_setup(&iter, arrayptr);" to prepare to iterate, and
|
||
|
* "datumvar = array_iter_next(&iter, &isnullvar, index, ...);" to fetch
|
||
|
* the next element into datumvar/isnullvar.
|
||
|
* "index" must be the zero-origin element number; we make caller provide
|
||
|
* this since caller is generally counting the elements anyway. Despite
|
||
|
* that, these functions can only fetch elements sequentially.
|
||
|
*/
|
||
|
|
||
|
typedef struct array_iter
|
||
|
{
|
||
|
/* datumptr being NULL or not tells if we have flat or expanded array */
|
||
|
|
||
|
/* Fields used when we have an expanded array */
|
||
|
Datum *datumptr; /* Pointer to Datum array */
|
||
|
bool *isnullptr; /* Pointer to isnull array */
|
||
|
|
||
|
/* Fields used when we have a flat array */
|
||
|
char *dataptr; /* Current spot in the data area */
|
||
|
bits8 *bitmapptr; /* Current byte of the nulls bitmap, or NULL */
|
||
|
int bitmask; /* mask for current bit in nulls bitmap */
|
||
|
} array_iter;
|
||
|
|
||
|
/*
|
||
|
* We want the functions below to be inline; but if the compiler doesn't
|
||
|
* support that, fall back on providing them as regular functions. See
|
||
|
* STATIC_IF_INLINE in c.h.
|
||
|
*/
|
||
|
#ifndef PG_USE_INLINE
|
||
|
extern void array_iter_setup(array_iter *it, AnyArrayType *a);
|
||
|
extern Datum array_iter_next(array_iter *it, bool *isnull, int i,
|
||
|
int elmlen, bool elmbyval, char elmalign);
|
||
|
#endif /* !PG_USE_INLINE */
|
||
|
|
||
|
#if defined(PG_USE_INLINE) || defined(ARRAYACCESS_INCLUDE_DEFINITIONS)
|
||
|
|
||
|
STATIC_IF_INLINE void
|
||
|
array_iter_setup(array_iter *it, AnyArrayType *a)
|
||
|
{
|
||
|
if (VARATT_IS_EXPANDED_HEADER(a))
|
||
|
{
|
||
|
if (a->xpn.dvalues)
|
||
|
{
|
||
|
it->datumptr = a->xpn.dvalues;
|
||
|
it->isnullptr = a->xpn.dnulls;
|
||
|
/* we must fill all fields to prevent compiler warnings */
|
||
|
it->dataptr = NULL;
|
||
|
it->bitmapptr = NULL;
|
||
|
}
|
||
|
else
|
||
|
{
|
||
|
/* Work with flat array embedded in the expanded datum */
|
||
|
it->datumptr = NULL;
|
||
|
it->isnullptr = NULL;
|
||
|
it->dataptr = ARR_DATA_PTR(a->xpn.fvalue);
|
||
|
it->bitmapptr = ARR_NULLBITMAP(a->xpn.fvalue);
|
||
|
}
|
||
|
}
|
||
|
else
|
||
|
{
|
||
|
it->datumptr = NULL;
|
||
|
it->isnullptr = NULL;
|
||
|
it->dataptr = ARR_DATA_PTR(&a->flt);
|
||
|
it->bitmapptr = ARR_NULLBITMAP(&a->flt);
|
||
|
}
|
||
|
it->bitmask = 1;
|
||
|
}
|
||
|
|
||
|
STATIC_IF_INLINE Datum
|
||
|
array_iter_next(array_iter *it, bool *isnull, int i,
|
||
|
int elmlen, bool elmbyval, char elmalign)
|
||
|
{
|
||
|
Datum ret;
|
||
|
|
||
|
if (it->datumptr)
|
||
|
{
|
||
|
ret = it->datumptr[i];
|
||
|
*isnull = it->isnullptr ? it->isnullptr[i] : false;
|
||
|
}
|
||
|
else
|
||
|
{
|
||
|
if (it->bitmapptr && (*(it->bitmapptr) & it->bitmask) == 0)
|
||
|
{
|
||
|
*isnull = true;
|
||
|
ret = (Datum) 0;
|
||
|
}
|
||
|
else
|
||
|
{
|
||
|
*isnull = false;
|
||
|
ret = fetch_att(it->dataptr, elmbyval, elmlen);
|
||
|
it->dataptr = att_addlength_pointer(it->dataptr, elmlen,
|
||
|
it->dataptr);
|
||
|
it->dataptr = (char *) att_align_nominal(it->dataptr, elmalign);
|
||
|
}
|
||
|
it->bitmask <<= 1;
|
||
|
if (it->bitmask == 0x100)
|
||
|
{
|
||
|
if (it->bitmapptr)
|
||
|
it->bitmapptr++;
|
||
|
it->bitmask = 1;
|
||
|
}
|
||
|
}
|
||
|
|
||
|
return ret;
|
||
|
}
|
||
|
|
||
|
#endif /* defined(PG_USE_INLINE) ||
|
||
|
* defined(ARRAYACCESS_INCLUDE_DEFINITIONS) */
|
||
|
|
||
|
#endif /* ARRAYACCESS_H */
|