459 lines
17 KiB
C
459 lines
17 KiB
C
/*-------------------------------------------------------------------------
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*
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* array.h
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* Declarations for Postgres arrays.
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*
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* A standard varlena array has the following internal structure:
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* <vl_len_> - standard varlena header word
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* <ndim> - number of dimensions of the array
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* <dataoffset> - offset to stored data, or 0 if no nulls bitmap
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* <elemtype> - element type OID
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* <dimensions> - length of each array axis (C array of int)
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* <lower bnds> - lower boundary of each dimension (C array of int)
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* <null bitmap> - bitmap showing locations of nulls (OPTIONAL)
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* <actual data> - whatever is the stored data
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*
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* The <dimensions> and <lower bnds> arrays each have ndim elements.
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*
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* The <null bitmap> may be omitted if the array contains no NULL elements.
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* If it is absent, the <dataoffset> field is zero and the offset to the
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* stored data must be computed on-the-fly. If the bitmap is present,
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* <dataoffset> is nonzero and is equal to the offset from the array start
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* to the first data element (including any alignment padding). The bitmap
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* follows the same conventions as tuple null bitmaps, ie, a 1 indicates
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* a non-null entry and the LSB of each bitmap byte is used first.
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*
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* The actual data starts on a MAXALIGN boundary. Individual items in the
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* array are aligned as specified by the array element type. They are
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* stored in row-major order (last subscript varies most rapidly).
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*
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* NOTE: it is important that array elements of toastable datatypes NOT be
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* toasted, since the tupletoaster won't know they are there. (We could
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* support compressed toasted items; only out-of-line items are dangerous.
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* However, it seems preferable to store such items uncompressed and allow
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* the toaster to compress the whole array as one input.)
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*
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*
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* The OIDVECTOR and INT2VECTOR datatypes are storage-compatible with
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* generic arrays, but they support only one-dimensional arrays with no
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* nulls (and no null bitmap). They don't support being toasted, either.
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*
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* There are also some "fixed-length array" datatypes, such as NAME and
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* POINT. These are simply a sequence of a fixed number of items each
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* of a fixed-length datatype, with no overhead; the item size must be
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* a multiple of its alignment requirement, because we do no padding.
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* We support subscripting on these types, but array_in() and array_out()
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* only work with varlena arrays.
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*
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* In addition, arrays are a major user of the "expanded object" TOAST
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* infrastructure. This allows a varlena array to be converted to a
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* separate representation that may include "deconstructed" Datum/isnull
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* arrays holding the elements.
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*
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*
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* Portions Copyright (c) 1996-2019, 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/array.h
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*
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*-------------------------------------------------------------------------
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*/
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#ifndef ARRAY_H
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#define ARRAY_H
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#include "fmgr.h"
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#include "utils/expandeddatum.h"
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/* avoid including execnodes.h here */
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struct ExprState;
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struct ExprContext;
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/*
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* Arrays are varlena objects, so must meet the varlena convention that
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* the first int32 of the object contains the total object size in bytes.
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* Be sure to use VARSIZE() and SET_VARSIZE() to access it, though!
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*
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* CAUTION: if you change the header for ordinary arrays you will also
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* need to change the headers for oidvector and int2vector!
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*/
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typedef struct ArrayType
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{
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int32 vl_len_; /* varlena header (do not touch directly!) */
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int ndim; /* # of dimensions */
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int32 dataoffset; /* offset to data, or 0 if no bitmap */
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Oid elemtype; /* element type OID */
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} ArrayType;
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/*
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* An expanded array is contained within a private memory context (as
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* all expanded objects must be) and has a control structure as below.
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*
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* The expanded array might contain a regular "flat" array if that was the
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* original input and we've not modified it significantly. Otherwise, the
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* contents are represented by Datum/isnull arrays plus dimensionality and
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* type information. We could also have both forms, if we've deconstructed
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* the original array for access purposes but not yet changed it. For pass-
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* by-reference element types, the Datums would point into the flat array in
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* this situation. Once we start modifying array elements, new pass-by-ref
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* elements are separately palloc'd within the memory context.
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*/
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#define EA_MAGIC 689375833 /* ID for debugging crosschecks */
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typedef struct ExpandedArrayHeader
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{
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/* Standard header for expanded objects */
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ExpandedObjectHeader hdr;
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/* Magic value identifying an expanded array (for debugging only) */
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int ea_magic;
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/* Dimensionality info (always valid) */
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int ndims; /* # of dimensions */
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int *dims; /* array dimensions */
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int *lbound; /* index lower bounds for each dimension */
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/* Element type info (always valid) */
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Oid element_type; /* element type OID */
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int16 typlen; /* needed info about element datatype */
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bool typbyval;
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char typalign;
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/*
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* If we have a Datum-array representation of the array, it's kept here;
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* else dvalues/dnulls are NULL. The dvalues and dnulls arrays are always
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* palloc'd within the object private context, but may change size from
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* time to time. For pass-by-ref element types, dvalues entries might
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* point either into the fstartptr..fendptr area, or to separately
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* palloc'd chunks. Elements should always be fully detoasted, as they
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* are in the standard flat representation.
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*
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* Even when dvalues is valid, dnulls can be NULL if there are no null
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* elements.
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*/
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Datum *dvalues; /* array of Datums */
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bool *dnulls; /* array of is-null flags for Datums */
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int dvalueslen; /* allocated length of above arrays */
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int nelems; /* number of valid entries in above arrays */
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/*
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* flat_size is the current space requirement for the flat equivalent of
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* the expanded array, if known; otherwise it's 0. We store this to make
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* consecutive calls of get_flat_size cheap.
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*/
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Size flat_size;
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/*
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* fvalue points to the flat representation if it is valid, else it is
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* NULL. If we have or ever had a flat representation then
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* fstartptr/fendptr point to the start and end+1 of its data area; this
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* is so that we can tell which Datum pointers point into the flat
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* representation rather than being pointers to separately palloc'd data.
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*/
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ArrayType *fvalue; /* must be a fully detoasted array */
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char *fstartptr; /* start of its data area */
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char *fendptr; /* end+1 of its data area */
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} ExpandedArrayHeader;
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/*
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* Functions that can handle either a "flat" varlena array or an expanded
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* array use this union to work with their input. Don't refer to "flt";
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* instead, cast to ArrayType. This struct nominally requires 8-byte
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* alignment on 64-bit, but it's often used for an ArrayType having 4-byte
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* alignment. UBSan complains about referencing "flt" in such cases.
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*/
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typedef union AnyArrayType
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{
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ArrayType flt;
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ExpandedArrayHeader xpn;
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} AnyArrayType;
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/*
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* working state for accumArrayResult() and friends
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* note that the input must be scalars (legal array elements)
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*/
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typedef struct ArrayBuildState
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{
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MemoryContext mcontext; /* where all the temp stuff is kept */
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Datum *dvalues; /* array of accumulated Datums */
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bool *dnulls; /* array of is-null flags for Datums */
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int alen; /* allocated length of above arrays */
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int nelems; /* number of valid entries in above arrays */
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Oid element_type; /* data type of the Datums */
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int16 typlen; /* needed info about datatype */
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bool typbyval;
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char typalign;
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bool private_cxt; /* use private memory context */
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} ArrayBuildState;
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/*
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* working state for accumArrayResultArr() and friends
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* note that the input must be arrays, and the same array type is returned
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*/
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typedef struct ArrayBuildStateArr
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{
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MemoryContext mcontext; /* where all the temp stuff is kept */
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char *data; /* accumulated data */
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bits8 *nullbitmap; /* bitmap of is-null flags, or NULL if none */
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int abytes; /* allocated length of "data" */
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int nbytes; /* number of bytes used so far */
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int aitems; /* allocated length of bitmap (in elements) */
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int nitems; /* total number of elements in result */
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int ndims; /* current dimensions of result */
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int dims[MAXDIM];
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int lbs[MAXDIM];
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Oid array_type; /* data type of the arrays */
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Oid element_type; /* data type of the array elements */
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bool private_cxt; /* use private memory context */
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} ArrayBuildStateArr;
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/*
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* working state for accumArrayResultAny() and friends
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* these functions handle both cases
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*/
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typedef struct ArrayBuildStateAny
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{
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/* Exactly one of these is not NULL: */
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ArrayBuildState *scalarstate;
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ArrayBuildStateArr *arraystate;
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} ArrayBuildStateAny;
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/*
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* structure to cache type metadata needed for array manipulation
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*/
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typedef struct ArrayMetaState
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{
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Oid element_type;
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int16 typlen;
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bool typbyval;
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char typalign;
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char typdelim;
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Oid typioparam;
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Oid typiofunc;
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FmgrInfo proc;
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} ArrayMetaState;
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/*
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* private state needed by array_map (here because caller must provide it)
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*/
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typedef struct ArrayMapState
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{
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ArrayMetaState inp_extra;
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ArrayMetaState ret_extra;
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} ArrayMapState;
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/* ArrayIteratorData is private in arrayfuncs.c */
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typedef struct ArrayIteratorData *ArrayIterator;
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/* fmgr macros for regular varlena array objects */
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#define DatumGetArrayTypeP(X) ((ArrayType *) PG_DETOAST_DATUM(X))
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#define DatumGetArrayTypePCopy(X) ((ArrayType *) PG_DETOAST_DATUM_COPY(X))
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#define PG_GETARG_ARRAYTYPE_P(n) DatumGetArrayTypeP(PG_GETARG_DATUM(n))
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#define PG_GETARG_ARRAYTYPE_P_COPY(n) DatumGetArrayTypePCopy(PG_GETARG_DATUM(n))
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#define PG_RETURN_ARRAYTYPE_P(x) PG_RETURN_POINTER(x)
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/* fmgr macros for expanded array objects */
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#define PG_GETARG_EXPANDED_ARRAY(n) DatumGetExpandedArray(PG_GETARG_DATUM(n))
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#define PG_GETARG_EXPANDED_ARRAYX(n, metacache) \
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DatumGetExpandedArrayX(PG_GETARG_DATUM(n), metacache)
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#define PG_RETURN_EXPANDED_ARRAY(x) PG_RETURN_DATUM(EOHPGetRWDatum(&(x)->hdr))
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/* fmgr macros for AnyArrayType (ie, get either varlena or expanded form) */
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#define PG_GETARG_ANY_ARRAY_P(n) DatumGetAnyArrayP(PG_GETARG_DATUM(n))
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/*
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* Access macros for varlena array header fields.
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*
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* ARR_DIMS returns a pointer to an array of array dimensions (number of
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* elements along the various array axes).
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*
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* ARR_LBOUND returns a pointer to an array of array lower bounds.
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*
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* That is: if the third axis of an array has elements 5 through 8, then
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* ARR_DIMS(a)[2] == 4 and ARR_LBOUND(a)[2] == 5.
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*
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* Unlike C, the default lower bound is 1.
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*/
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#define ARR_SIZE(a) VARSIZE(a)
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#define ARR_NDIM(a) ((a)->ndim)
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#define ARR_HASNULL(a) ((a)->dataoffset != 0)
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#define ARR_ELEMTYPE(a) ((a)->elemtype)
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#define ARR_DIMS(a) \
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((int *) (((char *) (a)) + sizeof(ArrayType)))
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#define ARR_LBOUND(a) \
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((int *) (((char *) (a)) + sizeof(ArrayType) + \
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sizeof(int) * ARR_NDIM(a)))
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#define ARR_NULLBITMAP(a) \
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(ARR_HASNULL(a) ? \
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(bits8 *) (((char *) (a)) + sizeof(ArrayType) + \
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2 * sizeof(int) * ARR_NDIM(a)) \
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: (bits8 *) NULL)
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/*
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* The total array header size (in bytes) for an array with the specified
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* number of dimensions and total number of items.
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*/
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#define ARR_OVERHEAD_NONULLS(ndims) \
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MAXALIGN(sizeof(ArrayType) + 2 * sizeof(int) * (ndims))
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#define ARR_OVERHEAD_WITHNULLS(ndims, nitems) \
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MAXALIGN(sizeof(ArrayType) + 2 * sizeof(int) * (ndims) + \
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((nitems) + 7) / 8)
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#define ARR_DATA_OFFSET(a) \
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(ARR_HASNULL(a) ? (a)->dataoffset : ARR_OVERHEAD_NONULLS(ARR_NDIM(a)))
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/*
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* Returns a pointer to the actual array data.
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*/
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#define ARR_DATA_PTR(a) \
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(((char *) (a)) + ARR_DATA_OFFSET(a))
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/*
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* Macros for working with AnyArrayType inputs. Beware multiple references!
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*/
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#define AARR_NDIM(a) \
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(VARATT_IS_EXPANDED_HEADER(a) ? \
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(a)->xpn.ndims : ARR_NDIM((ArrayType *) (a)))
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#define AARR_HASNULL(a) \
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(VARATT_IS_EXPANDED_HEADER(a) ? \
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((a)->xpn.dvalues != NULL ? (a)->xpn.dnulls != NULL : ARR_HASNULL((a)->xpn.fvalue)) : \
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ARR_HASNULL((ArrayType *) (a)))
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#define AARR_ELEMTYPE(a) \
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(VARATT_IS_EXPANDED_HEADER(a) ? \
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(a)->xpn.element_type : ARR_ELEMTYPE((ArrayType *) (a)))
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#define AARR_DIMS(a) \
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(VARATT_IS_EXPANDED_HEADER(a) ? \
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(a)->xpn.dims : ARR_DIMS((ArrayType *) (a)))
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#define AARR_LBOUND(a) \
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(VARATT_IS_EXPANDED_HEADER(a) ? \
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(a)->xpn.lbound : ARR_LBOUND((ArrayType *) (a)))
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/*
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* GUC parameter
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*/
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extern bool Array_nulls;
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/*
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* prototypes for functions defined in arrayfuncs.c
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*/
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extern void CopyArrayEls(ArrayType *array,
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Datum *values,
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bool *nulls,
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int nitems,
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int typlen,
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bool typbyval,
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char typalign,
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bool freedata);
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extern Datum array_get_element(Datum arraydatum, int nSubscripts, int *indx,
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int arraytyplen, int elmlen, bool elmbyval, char elmalign,
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bool *isNull);
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extern Datum array_set_element(Datum arraydatum, int nSubscripts, int *indx,
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Datum dataValue, bool isNull,
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int arraytyplen, int elmlen, bool elmbyval, char elmalign);
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extern Datum array_get_slice(Datum arraydatum, int nSubscripts,
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int *upperIndx, int *lowerIndx,
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bool *upperProvided, bool *lowerProvided,
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int arraytyplen, int elmlen, bool elmbyval, char elmalign);
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extern Datum array_set_slice(Datum arraydatum, int nSubscripts,
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int *upperIndx, int *lowerIndx,
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bool *upperProvided, bool *lowerProvided,
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Datum srcArrayDatum, bool isNull,
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int arraytyplen, int elmlen, bool elmbyval, char elmalign);
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extern Datum array_ref(ArrayType *array, int nSubscripts, int *indx,
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int arraytyplen, int elmlen, bool elmbyval, char elmalign,
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bool *isNull);
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extern ArrayType *array_set(ArrayType *array, int nSubscripts, int *indx,
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Datum dataValue, bool isNull,
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int arraytyplen, int elmlen, bool elmbyval, char elmalign);
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extern Datum array_map(Datum arrayd,
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struct ExprState *exprstate, struct ExprContext *econtext,
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Oid retType, ArrayMapState *amstate);
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extern void array_bitmap_copy(bits8 *destbitmap, int destoffset,
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const bits8 *srcbitmap, int srcoffset,
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int nitems);
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extern ArrayType *construct_array(Datum *elems, int nelems,
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Oid elmtype,
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int elmlen, bool elmbyval, char elmalign);
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extern ArrayType *construct_md_array(Datum *elems,
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bool *nulls,
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int ndims,
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int *dims,
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int *lbs,
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Oid elmtype, int elmlen, bool elmbyval, char elmalign);
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extern ArrayType *construct_empty_array(Oid elmtype);
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extern ExpandedArrayHeader *construct_empty_expanded_array(Oid element_type,
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MemoryContext parentcontext,
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ArrayMetaState *metacache);
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extern void deconstruct_array(ArrayType *array,
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Oid elmtype,
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int elmlen, bool elmbyval, char elmalign,
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Datum **elemsp, bool **nullsp, int *nelemsp);
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extern bool array_contains_nulls(ArrayType *array);
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extern ArrayBuildState *initArrayResult(Oid element_type,
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MemoryContext rcontext, bool subcontext);
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extern ArrayBuildState *accumArrayResult(ArrayBuildState *astate,
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Datum dvalue, bool disnull,
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Oid element_type,
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MemoryContext rcontext);
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extern Datum makeArrayResult(ArrayBuildState *astate,
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MemoryContext rcontext);
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extern Datum makeMdArrayResult(ArrayBuildState *astate, int ndims,
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int *dims, int *lbs, MemoryContext rcontext, bool release);
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extern ArrayBuildStateArr *initArrayResultArr(Oid array_type, Oid element_type,
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MemoryContext rcontext, bool subcontext);
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extern ArrayBuildStateArr *accumArrayResultArr(ArrayBuildStateArr *astate,
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Datum dvalue, bool disnull,
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Oid array_type,
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MemoryContext rcontext);
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extern Datum makeArrayResultArr(ArrayBuildStateArr *astate,
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MemoryContext rcontext, bool release);
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extern ArrayBuildStateAny *initArrayResultAny(Oid input_type,
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MemoryContext rcontext, bool subcontext);
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extern ArrayBuildStateAny *accumArrayResultAny(ArrayBuildStateAny *astate,
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Datum dvalue, bool disnull,
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Oid input_type,
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MemoryContext rcontext);
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extern Datum makeArrayResultAny(ArrayBuildStateAny *astate,
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MemoryContext rcontext, bool release);
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extern ArrayIterator array_create_iterator(ArrayType *arr, int slice_ndim, ArrayMetaState *mstate);
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extern bool array_iterate(ArrayIterator iterator, Datum *value, bool *isnull);
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extern void array_free_iterator(ArrayIterator iterator);
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/*
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* prototypes for functions defined in arrayutils.c
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*/
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extern int ArrayGetOffset(int n, const int *dim, const int *lb, const int *indx);
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extern int ArrayGetOffset0(int n, const int *tup, const int *scale);
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extern int ArrayGetNItems(int ndim, const int *dims);
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extern void mda_get_range(int n, int *span, const int *st, const int *endp);
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extern void mda_get_prod(int n, const int *range, int *prod);
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extern void mda_get_offset_values(int n, int *dist, const int *prod, const int *span);
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extern int mda_next_tuple(int n, int *curr, const int *span);
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extern int32 *ArrayGetIntegerTypmods(ArrayType *arr, int *n);
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/*
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* prototypes for functions defined in array_expanded.c
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*/
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extern Datum expand_array(Datum arraydatum, MemoryContext parentcontext,
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ArrayMetaState *metacache);
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extern ExpandedArrayHeader *DatumGetExpandedArray(Datum d);
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extern ExpandedArrayHeader *DatumGetExpandedArrayX(Datum d,
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ArrayMetaState *metacache);
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extern AnyArrayType *DatumGetAnyArrayP(Datum d);
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extern void deconstruct_expanded_array(ExpandedArrayHeader *eah);
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#endif /* ARRAY_H */
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