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/*-------------------------------------------------------------------------
*
* array.h
* Declarations for Postgres arrays.
*
* A standard varlena array has the following internal structure:
* <vl_len_> - standard varlena header word
* <ndim> - number of dimensions of the array
* <dataoffset> - offset to stored data, or 0 if no nulls bitmap
* <elemtype> - element type OID
* <dimensions> - length of each array axis (C array of int)
* <lower bnds> - lower boundary of each dimension (C array of int)
* <null bitmap> - bitmap showing locations of nulls (OPTIONAL)
* <actual data> - whatever is the stored data
*
* The <dimensions> and <lower bnds> arrays each have ndim elements.
*
* The <null bitmap> may be omitted if the array contains no NULL elements.
* If it is absent, the <dataoffset> field is zero and the offset to the
* stored data must be computed on-the-fly. If the bitmap is present,
* <dataoffset> is nonzero and is equal to the offset from the array start
* to the first data element (including any alignment padding). The bitmap
* follows the same conventions as tuple null bitmaps, ie, a 1 indicates
* a non-null entry and the LSB of each bitmap byte is used first.
*
* The actual data starts on a MAXALIGN boundary. Individual items in the
* array are aligned as specified by the array element type. They are
* stored in row-major order (last subscript varies most rapidly).
*
* NOTE: it is important that array elements of toastable datatypes NOT be
* toasted, since the tupletoaster won't know they are there. (We could
* support compressed toasted items; only out-of-line items are dangerous.
* However, it seems preferable to store such items uncompressed and allow
* the toaster to compress the whole array as one input.)
*
*
* The OIDVECTOR and INT2VECTOR datatypes are storage-compatible with
* generic arrays, but they support only one-dimensional arrays with no
* nulls (and no null bitmap). They don't support being toasted, either.
*
* There are also some "fixed-length array" datatypes, such as NAME and
* POINT. These are simply a sequence of a fixed number of items each
* of a fixed-length datatype, with no overhead; the item size must be
* a multiple of its alignment requirement, because we do no padding.
* We support subscripting on these types, but array_in() and array_out()
* only work with varlena arrays.
*
* In addition, arrays are a major user of the "expanded object" TOAST
* infrastructure. This allows a varlena array to be converted to a
* separate representation that may include "deconstructed" Datum/isnull
* arrays holding the elements.
*
*
* Portions Copyright (c) 1996-2018, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* src/include/utils/array.h
*
*-------------------------------------------------------------------------
*/
#ifndef ARRAY_H
#define ARRAY_H
#include "fmgr.h"
#include "utils/expandeddatum.h"
/* avoid including execnodes.h here */
struct ExprState;
struct ExprContext;
/*
* Maximum number of elements in an array. We limit this to at most about a
* quarter billion elements, so that it's not necessary to check for overflow
* in quite so many places --- for instance when palloc'ing Datum arrays.
*/
#define MaxArraySize ((Size) (MaxAllocSize / sizeof(Datum)))
/*
* Arrays are varlena objects, so must meet the varlena convention that
* the first int32 of the object contains the total object size in bytes.
* Be sure to use VARSIZE() and SET_VARSIZE() to access it, though!
*
* CAUTION: if you change the header for ordinary arrays you will also
* need to change the headers for oidvector and int2vector!
*/
typedef struct
{
int32 vl_len_; /* varlena header (do not touch directly!) */
int ndim; /* # of dimensions */
int32 dataoffset; /* offset to data, or 0 if no bitmap */
Oid elemtype; /* element type OID */
} ArrayType;
/*
* An expanded array is contained within a private memory context (as
* all expanded objects must be) and has a control structure as below.
*
* The expanded array might contain a regular "flat" array if that was the
* original input and we've not modified it significantly. Otherwise, the
* contents are represented by Datum/isnull arrays plus dimensionality and
* type information. We could also have both forms, if we've deconstructed
* the original array for access purposes but not yet changed it. For pass-
* by-reference element types, the Datums would point into the flat array in
* this situation. Once we start modifying array elements, new pass-by-ref
* elements are separately palloc'd within the memory context.
*/
#define EA_MAGIC 689375833 /* ID for debugging crosschecks */
typedef struct ExpandedArrayHeader
{
/* Standard header for expanded objects */
ExpandedObjectHeader hdr;
/* Magic value identifying an expanded array (for debugging only) */
int ea_magic;
/* Dimensionality info (always valid) */
int ndims; /* # of dimensions */
int *dims; /* array dimensions */
int *lbound; /* index lower bounds for each dimension */
/* Element type info (always valid) */
Oid element_type; /* element type OID */
int16 typlen; /* needed info about element datatype */
bool typbyval;
char typalign;
/*
* If we have a Datum-array representation of the array, it's kept here;
* else dvalues/dnulls are NULL. The dvalues and dnulls arrays are always
* palloc'd within the object private context, but may change size from
* time to time. For pass-by-ref element types, dvalues entries might
* point either into the fstartptr..fendptr area, or to separately
* palloc'd chunks. Elements should always be fully detoasted, as they
* are in the standard flat representation.
*
* Even when dvalues is valid, dnulls can be NULL if there are no null
* elements.
*/
Datum *dvalues; /* array of Datums */
bool *dnulls; /* array of is-null flags for Datums */
int dvalueslen; /* allocated length of above arrays */
int nelems; /* number of valid entries in above arrays */
/*
* flat_size is the current space requirement for the flat equivalent of
* the expanded array, if known; otherwise it's 0. We store this to make
* consecutive calls of get_flat_size cheap.
*/
Size flat_size;
/*
* fvalue points to the flat representation if it is valid, else it is
* NULL. If we have or ever had a flat representation then
* fstartptr/fendptr point to the start and end+1 of its data area; this
* is so that we can tell which Datum pointers point into the flat
* representation rather than being pointers to separately palloc'd data.
*/
ArrayType *fvalue; /* must be a fully detoasted array */
char *fstartptr; /* start of its data area */
char *fendptr; /* end+1 of its data area */
} ExpandedArrayHeader;
/*
* Functions that can handle either a "flat" varlena array or an expanded
* array use this union to work with their input. Don't refer to "flt";
* instead, cast to ArrayType. This struct nominally requires 8-byte
* alignment on 64-bit, but it's often used for an ArrayType having 4-byte
* alignment. UBSan complains about referencing "flt" in such cases.
*/
typedef union AnyArrayType
{
ArrayType flt;
ExpandedArrayHeader xpn;
} AnyArrayType;
/*
* working state for accumArrayResult() and friends
* note that the input must be scalars (legal array elements)
*/
typedef struct ArrayBuildState
{
MemoryContext mcontext; /* where all the temp stuff is kept */
Datum *dvalues; /* array of accumulated Datums */
bool *dnulls; /* array of is-null flags for Datums */
int alen; /* allocated length of above arrays */
int nelems; /* number of valid entries in above arrays */
Oid element_type; /* data type of the Datums */
int16 typlen; /* needed info about datatype */
bool typbyval;
char typalign;
bool private_cxt; /* use private memory context */
} ArrayBuildState;
/*
* working state for accumArrayResultArr() and friends
* note that the input must be arrays, and the same array type is returned
*/
typedef struct ArrayBuildStateArr
{
MemoryContext mcontext; /* where all the temp stuff is kept */
char *data; /* accumulated data */
bits8 *nullbitmap; /* bitmap of is-null flags, or NULL if none */
int abytes; /* allocated length of "data" */
int nbytes; /* number of bytes used so far */
int aitems; /* allocated length of bitmap (in elements) */
int nitems; /* total number of elements in result */
int ndims; /* current dimensions of result */
int dims[MAXDIM];
int lbs[MAXDIM];
Oid array_type; /* data type of the arrays */
Oid element_type; /* data type of the array elements */
bool private_cxt; /* use private memory context */
} ArrayBuildStateArr;
/*
* working state for accumArrayResultAny() and friends
* these functions handle both cases
*/
typedef struct ArrayBuildStateAny
{
/* Exactly one of these is not NULL: */
ArrayBuildState *scalarstate;
ArrayBuildStateArr *arraystate;
} ArrayBuildStateAny;
/*
* structure to cache type metadata needed for array manipulation
*/
typedef struct ArrayMetaState
{
Oid element_type;
int16 typlen;
bool typbyval;
char typalign;
char typdelim;
Oid typioparam;
Oid typiofunc;
FmgrInfo proc;
} ArrayMetaState;
/*
* private state needed by array_map (here because caller must provide it)
*/
typedef struct ArrayMapState
{
ArrayMetaState inp_extra;
ArrayMetaState ret_extra;
} ArrayMapState;
/* ArrayIteratorData is private in arrayfuncs.c */
typedef struct ArrayIteratorData *ArrayIterator;
/* fmgr macros for regular varlena array objects */
#define DatumGetArrayTypeP(X) ((ArrayType *) PG_DETOAST_DATUM(X))
#define DatumGetArrayTypePCopy(X) ((ArrayType *) PG_DETOAST_DATUM_COPY(X))
#define PG_GETARG_ARRAYTYPE_P(n) DatumGetArrayTypeP(PG_GETARG_DATUM(n))
#define PG_GETARG_ARRAYTYPE_P_COPY(n) DatumGetArrayTypePCopy(PG_GETARG_DATUM(n))
#define PG_RETURN_ARRAYTYPE_P(x) PG_RETURN_POINTER(x)
/* fmgr macros for expanded array objects */
#define PG_GETARG_EXPANDED_ARRAY(n) DatumGetExpandedArray(PG_GETARG_DATUM(n))
#define PG_GETARG_EXPANDED_ARRAYX(n, metacache) \
DatumGetExpandedArrayX(PG_GETARG_DATUM(n), metacache)
#define PG_RETURN_EXPANDED_ARRAY(x) PG_RETURN_DATUM(EOHPGetRWDatum(&(x)->hdr))
/* fmgr macros for AnyArrayType (ie, get either varlena or expanded form) */
#define PG_GETARG_ANY_ARRAY_P(n) DatumGetAnyArrayP(PG_GETARG_DATUM(n))
/*
* Access macros for varlena array header fields.
*
* ARR_DIMS returns a pointer to an array of array dimensions (number of
* elements along the various array axes).
*
* ARR_LBOUND returns a pointer to an array of array lower bounds.
*
* That is: if the third axis of an array has elements 5 through 8, then
* ARR_DIMS(a)[2] == 4 and ARR_LBOUND(a)[2] == 5.
*
* Unlike C, the default lower bound is 1.
*/
#define ARR_SIZE(a) VARSIZE(a)
#define ARR_NDIM(a) ((a)->ndim)
#define ARR_HASNULL(a) ((a)->dataoffset != 0)
#define ARR_ELEMTYPE(a) ((a)->elemtype)
#define ARR_DIMS(a) \
((int *) (((char *) (a)) + sizeof(ArrayType)))
#define ARR_LBOUND(a) \
((int *) (((char *) (a)) + sizeof(ArrayType) + \
sizeof(int) * ARR_NDIM(a)))
#define ARR_NULLBITMAP(a) \
(ARR_HASNULL(a) ? \
(bits8 *) (((char *) (a)) + sizeof(ArrayType) + \
2 * sizeof(int) * ARR_NDIM(a)) \
: (bits8 *) NULL)
/*
* The total array header size (in bytes) for an array with the specified
* number of dimensions and total number of items.
*/
#define ARR_OVERHEAD_NONULLS(ndims) \
MAXALIGN(sizeof(ArrayType) + 2 * sizeof(int) * (ndims))
#define ARR_OVERHEAD_WITHNULLS(ndims, nitems) \
MAXALIGN(sizeof(ArrayType) + 2 * sizeof(int) * (ndims) + \
((nitems) + 7) / 8)
#define ARR_DATA_OFFSET(a) \
(ARR_HASNULL(a) ? (a)->dataoffset : ARR_OVERHEAD_NONULLS(ARR_NDIM(a)))
/*
* Returns a pointer to the actual array data.
*/
#define ARR_DATA_PTR(a) \
(((char *) (a)) + ARR_DATA_OFFSET(a))
/*
* Macros for working with AnyArrayType inputs. Beware multiple references!
*/
#define AARR_NDIM(a) \
(VARATT_IS_EXPANDED_HEADER(a) ? \
(a)->xpn.ndims : ARR_NDIM((ArrayType *) (a)))
#define AARR_HASNULL(a) \
(VARATT_IS_EXPANDED_HEADER(a) ? \
((a)->xpn.dvalues != NULL ? (a)->xpn.dnulls != NULL : ARR_HASNULL((a)->xpn.fvalue)) : \
ARR_HASNULL((ArrayType *) (a)))
#define AARR_ELEMTYPE(a) \
(VARATT_IS_EXPANDED_HEADER(a) ? \
(a)->xpn.element_type : ARR_ELEMTYPE((ArrayType *) (a)))
#define AARR_DIMS(a) \
(VARATT_IS_EXPANDED_HEADER(a) ? \
(a)->xpn.dims : ARR_DIMS((ArrayType *) (a)))
#define AARR_LBOUND(a) \
(VARATT_IS_EXPANDED_HEADER(a) ? \
(a)->xpn.lbound : ARR_LBOUND((ArrayType *) (a)))
/*
* GUC parameter
*/
extern bool Array_nulls;
/*
* prototypes for functions defined in arrayfuncs.c
*/
extern void CopyArrayEls(ArrayType *array,
Datum *values,
bool *nulls,
int nitems,
int typlen,
bool typbyval,
char typalign,
bool freedata);
extern Datum array_get_element(Datum arraydatum, int nSubscripts, int *indx,
int arraytyplen, int elmlen, bool elmbyval, char elmalign,
bool *isNull);
extern Datum array_set_element(Datum arraydatum, int nSubscripts, int *indx,
Datum dataValue, bool isNull,
int arraytyplen, int elmlen, bool elmbyval, char elmalign);
extern Datum array_get_slice(Datum arraydatum, int nSubscripts,
int *upperIndx, int *lowerIndx,
bool *upperProvided, bool *lowerProvided,
int arraytyplen, int elmlen, bool elmbyval, char elmalign);
extern Datum array_set_slice(Datum arraydatum, int nSubscripts,
int *upperIndx, int *lowerIndx,
bool *upperProvided, bool *lowerProvided,
Datum srcArrayDatum, bool isNull,
int arraytyplen, int elmlen, bool elmbyval, char elmalign);
extern Datum array_ref(ArrayType *array, int nSubscripts, int *indx,
int arraytyplen, int elmlen, bool elmbyval, char elmalign,
bool *isNull);
extern ArrayType *array_set(ArrayType *array, int nSubscripts, int *indx,
Datum dataValue, bool isNull,
int arraytyplen, int elmlen, bool elmbyval, char elmalign);
extern Datum array_map(Datum arrayd,
struct ExprState *exprstate, struct ExprContext *econtext,
Oid retType, ArrayMapState *amstate);
extern void array_bitmap_copy(bits8 *destbitmap, int destoffset,
const bits8 *srcbitmap, int srcoffset,
int nitems);
extern ArrayType *construct_array(Datum *elems, int nelems,
Oid elmtype,
int elmlen, bool elmbyval, char elmalign);
extern ArrayType *construct_md_array(Datum *elems,
bool *nulls,
int ndims,
int *dims,
int *lbs,
Oid elmtype, int elmlen, bool elmbyval, char elmalign);
extern ArrayType *construct_empty_array(Oid elmtype);
extern ExpandedArrayHeader *construct_empty_expanded_array(Oid element_type,
MemoryContext parentcontext,
ArrayMetaState *metacache);
extern void deconstruct_array(ArrayType *array,
Oid elmtype,
int elmlen, bool elmbyval, char elmalign,
Datum **elemsp, bool **nullsp, int *nelemsp);
extern bool array_contains_nulls(ArrayType *array);
extern ArrayBuildState *initArrayResult(Oid element_type,
MemoryContext rcontext, bool subcontext);
extern ArrayBuildState *accumArrayResult(ArrayBuildState *astate,
Datum dvalue, bool disnull,
Oid element_type,
MemoryContext rcontext);
extern Datum makeArrayResult(ArrayBuildState *astate,
MemoryContext rcontext);
extern Datum makeMdArrayResult(ArrayBuildState *astate, int ndims,
int *dims, int *lbs, MemoryContext rcontext, bool release);
extern ArrayBuildStateArr *initArrayResultArr(Oid array_type, Oid element_type,
MemoryContext rcontext, bool subcontext);
extern ArrayBuildStateArr *accumArrayResultArr(ArrayBuildStateArr *astate,
Datum dvalue, bool disnull,
Oid array_type,
MemoryContext rcontext);
extern Datum makeArrayResultArr(ArrayBuildStateArr *astate,
MemoryContext rcontext, bool release);
extern ArrayBuildStateAny *initArrayResultAny(Oid input_type,
MemoryContext rcontext, bool subcontext);
extern ArrayBuildStateAny *accumArrayResultAny(ArrayBuildStateAny *astate,
Datum dvalue, bool disnull,
Oid input_type,
MemoryContext rcontext);
extern Datum makeArrayResultAny(ArrayBuildStateAny *astate,
MemoryContext rcontext, bool release);
extern ArrayIterator array_create_iterator(ArrayType *arr, int slice_ndim, ArrayMetaState *mstate);
extern bool array_iterate(ArrayIterator iterator, Datum *value, bool *isnull);
extern void array_free_iterator(ArrayIterator iterator);
/*
* prototypes for functions defined in arrayutils.c
*/
extern int ArrayGetOffset(int n, const int *dim, const int *lb, const int *indx);
extern int ArrayGetOffset0(int n, const int *tup, const int *scale);
extern int ArrayGetNItems(int ndim, const int *dims);
extern void ArrayCheckBounds(int ndim, const int *dims, const int *lb);
extern void mda_get_range(int n, int *span, const int *st, const int *endp);
extern void mda_get_prod(int n, const int *range, int *prod);
extern void mda_get_offset_values(int n, int *dist, const int *prod, const int *span);
extern int mda_next_tuple(int n, int *curr, const int *span);
extern int32 *ArrayGetIntegerTypmods(ArrayType *arr, int *n);
/*
* prototypes for functions defined in array_expanded.c
*/
extern Datum expand_array(Datum arraydatum, MemoryContext parentcontext,
ArrayMetaState *metacache);
extern ExpandedArrayHeader *DatumGetExpandedArray(Datum d);
extern ExpandedArrayHeader *DatumGetExpandedArrayX(Datum d,
ArrayMetaState *metacache);
extern AnyArrayType *DatumGetAnyArrayP(Datum d);
extern void deconstruct_expanded_array(ExpandedArrayHeader *eah);
#endif /* ARRAY_H */
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