pgbitmap.h File Reference

Define bitmap datatypes. More...

#include "postgres.h"
#include "funcapi.h"

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Data Structures
struct	Bitmap

Macros
#define	BITMAP_DATATYPES   1
#define	USE_64_BIT   1
#define	ELEMBITS   64
#define	DBG_ELEMS   0
#define	SETCANARY(b)
#define	CHKCANARY(b)   true
#define	CANARYELEM
#define	BITZERO(x)   ((x) & 0xffffffffffffffc0)
#define	BITSET_ELEM(x)   ((x) >> 6)
#define	BITSET_BIT(x)   (x & 0x3f)
#define	ARRAYELEMS(min, max)   (((max - BITZERO(min)) >> 6) + 1)
#define	MIN(a, b)   ((a < b)? a: b)
#define	MAX(a, b)   ((a > b)? a: b)
#define	DatumGetBitmap(x)   ((Bitmap *) PG_DETOAST_DATUM(DatumGetPointer(x)))
#define	PG_GETARG_BITMAP(x)
#define	PG_RETURN_BITMAP(x)   PG_RETURN_POINTER(x)

Typedefs
typedef uint64	bm_int
typedef struct Bitmap	Bitmap
typedef unsigned char	boolean

Functions
bool	bitmapTestbit (Bitmap *bitmap, int32 bit)
Bitmap *	bitmapCopy (Bitmap *bitmap)
Datum	bitmap_in (FunctionCallInfo fcinfo)
Datum	bitmap_out (FunctionCallInfo fcinfo)
Datum	bitmap_is_empty (FunctionCallInfo fcinfo)
Datum	bitmap_bits (FunctionCallInfo fcinfo)
Datum	bitmap_new_empty (FunctionCallInfo fcinfo)
Datum	bitmap_new (FunctionCallInfo fcinfo)
Datum	bitmap_bitmin (FunctionCallInfo fcinfo)
Datum	bitmap_bitmax (FunctionCallInfo fcinfo)
Datum	bitmap_setbit (FunctionCallInfo fcinfo)
Datum	bitmap_testbit (FunctionCallInfo fcinfo)
Datum	bitmap_setmin (FunctionCallInfo fcinfo)
Datum	bitmap_setmax (FunctionCallInfo fcinfo)
Datum	bitmap_equal (FunctionCallInfo fcinfo)
Datum	bitmap_nequal (FunctionCallInfo fcinfo)
Datum	bitmap_union (FunctionCallInfo fcinfo)
Datum	bitmap_clearbit (FunctionCallInfo fcinfo)
Datum	bitmap_intersection (FunctionCallInfo fcinfo)
Datum	bitmap_minus (FunctionCallInfo fcinfo)
Datum	bitmap_lt (FunctionCallInfo fcinfo)
Datum	bitmap_le (FunctionCallInfo fcinfo)
Datum	bitmap_gt (FunctionCallInfo fcinfo)
Datum	bitmap_ge (FunctionCallInfo fcinfo)
Datum	bitmap_cmp (FunctionCallInfo fcinfo)

Detailed Description

Define bitmap datatypes.

Author:       Marc Munro
Copyright (c) 2020 Marc Munro
License:      BSD

Macro Definition Documentation

ARRAYELEMS

#define ARRAYELEMS	(		min,
			max
	)		(((max - BITZERO(min)) >> 6) + 1)

Gives the number of array elements in a Bitmap that runs from element min to element max.

Parameters

min
max

Returns

The number of elements in the bitmap.

BITMAP_DATATYPES

#define BITMAP_DATATYPES   1

Prevent this header from being included multiple times.

BITSET_BIT

#define BITSET_BIT

(

x

)

(x & 0x3f)

Gives the index into bitmasks for the bit specified in x.

Parameters

x	The bit in question

Returns

The bitmask index

BITSET_ELEM

#define BITSET_ELEM

(

x

)

((x) >> 6)

Gives the index of the word for a given bit, assuming bitmin is zero.

Parameters

x	The bit in question

Returns

The array index of the bit.

BITZERO

#define BITZERO

(

x

)

((x) & 0xffffffffffffffc0)

Gives the bitmask index for the bitzero value of a Bitmap. This is part of the "normalisation" process for bitmap ranges. This process allows unlike bitmaps to be more easily compared by forcing bitmap indexes to be normalised around 32 or 64 bit word boundaries.

Parameters

x	The bitzero value of a bitmap

Returns

The bitmask index representing x.

DatumGetBitmap

#define DatumGetBitmap

(

x

)

((Bitmap *) PG_DETOAST_DATUM(DatumGetPointer(x)))

Provide a macro for getting a bitmap datum.

ELEMBITS

#define ELEMBITS   64

Use 64-bit words.

MAX

#define MAX	(		a,
			b
	)		((a > b)? a: b)

Return the larger of a or b. Note that expressions a and b may be evaluated more than once.

Parameters

a
b

Returns

The smaller value of a or b.

MIN

#define MIN	(		a,
			b
	)		((a < b)? a: b)

Return the smaller of a or b. Note that expressions a and b may be evaluated more than once.

Parameters

a
b

Returns

The smaller value of a or b.

PG_GETARG_BITMAP

#define PG_GETARG_BITMAP

(

x

)

Value:

DatumGetBitmap(     \
        PG_DETOAST_DATUM(PG_GETARG_DATUM(x)))

Provide a macro for dealing with bitmap arguments.

PG_RETURN_BITMAP

#define PG_RETURN_BITMAP

(

x

)

PG_RETURN_POINTER(x)

Provide a macro for returning bitmap results.

USE_64_BIT

#define USE_64_BIT   1

Use 64-bit word definitions throughout.

Typedef Documentation

Bitmap

typedef struct Bitmap Bitmap

A bitmap is stored as an array of integer values. Note that the size of a Bitmap structure is determined dynamically at run time as the size of the array is only known then.

bm_int

typedef uint64 bm_int

bm_int is the bitmap integer type (a 64-bit value).

boolean

typedef unsigned char boolean

Defines a boolean type to make our code more readable.

Function Documentation

bitmap_bitmax()

Datum bitmap_bitmax

(

FunctionCallInfo

fcinfo

)

bitmap_bitmax(bitmap bitmap) returns boolean Return the highest bit set in the bitmap, or NULL if none are set. This relies on bitmap->bitmax always identifying the highest numbered bit in the bitset, unless the bitmap is empty.

Parameters

fcinfo

Params as described_below bitmap bitmap The bitmap being examined.

Returns

integer The lowest bit set in the bitmap or NULL if there are no bits set.

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bitmap_bitmin()

Datum bitmap_bitmin

(

FunctionCallInfo

fcinfo

)

bitmap_bitmin(bitmap bitmap) returns boolean Return the lowest bit set in the bitmap, or NULL if none are set. This relies on bitmap->bitmin always identifying the lowest numbered bit in the bitset, unless the bitmap is empty.

Parameters

fcinfo

Params as described_below bitmap bitmap The bitmap being examined.

Returns

integer The lowest bit set in the bitmap or NULL if there are no bits set.

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bitmap_bits()

Datum bitmap_bits

(

FunctionCallInfo

fcinfo

)

bitmap_bits(name text) returns setof int4 Return the set of all bits set in the specified Bitmap.

Parameters

fcinfo

name text The name of the bitmap.

Returns

setof int4The set of bits that are set in the bitmap.

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bitmap_clearbit()

Datum bitmap_clearbit

(

FunctionCallInfo

fcinfo

)

bitmap_clearbit(bitmap bitmap, bit int4) returns bool Clear the given bit in the bitmap, returning FALSE.

Parameters

fcinfo

Params as described_below bitmap bitmap The bitmap to be manipulated. bitno int4 The bitnumber to be set.

Returns

bool TRUE

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bitmap_cmp()

Datum bitmap_cmp

(

FunctionCallInfo

fcinfo

)

bitmap_cmp(bitmap1 bitmap, bitmap2 bitmap) returns bool Return result of comparison of bitmap1's string representation with bitmap2's.

Parameters

fcinfo

Params as described_below bitmap1 bitmap The first bitmap bitmap2 bitmap The second bitmap

Returns

int4 result of comparison

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bitmap_equal()

Datum bitmap_equal

(

FunctionCallInfo

fcinfo

)

bitmap_equal(bitmap1 bitmap, bitmap2 bitmap) returns bool Return true if the bitmaps are equivalent,

Parameters

fcinfo

Params as described_below bitmap1 bitmap The first bitmap bitmap2 bitmap The second bitmap

Returns

bool true if the bitmaps contain the same bits.

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bitmap_ge()

Datum bitmap_ge

(

FunctionCallInfo

fcinfo

)

bitmap_ge(bitmap1 bitmap, bitmap2 bitmap) returns bool Return true if bitmap1's string representation should be sorted later than, or the same as, bitmap2's.

Parameters

fcinfo

Params as described_below bitmap1 bitmap The first bitmap bitmap2 bitmap The second bitmap

Returns

bool true unless the bitmaps contain the same bits.

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bitmap_gt()

Datum bitmap_gt

(

FunctionCallInfo

fcinfo

)

bitmap_gt(bitmap1 bitmap, bitmap2 bitmap) returns bool Return true if bitmap1's string representation should be sorted later than bitmap2's.

Parameters

fcinfo

Params as described_below bitmap1 bitmap The first bitmap bitmap2 bitmap The second bitmap

Returns

bool true unless the bitmaps contain the same bits.

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bitmap_in()

Datum bitmap_in

(

FunctionCallInfo

fcinfo

)

bitmap_in(serialised_bitmap text) returns bitmap Create a Bitmap initialised from a (base64) text value.

Parameters

fcinfo

Params as described_below serialised_bitmap text A base64 serialiastion of a bitmap value.

Returns

Bitmap the newly created bitmap

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bitmap_intersection()

Datum bitmap_intersection

(

FunctionCallInfo

fcinfo

)

bitmap_intersection(bitmap1 bitmap, bitmap2 bitmap) returns bitmap Return the intersection of 2 bitmaps. This can be used as an aggregate function in which case the bitmap1 parameter will be null for the first call. In this case simply return the second argument.

Parameters

fcinfo

Params as described_below bitmap1 bitmap The first bitmap bitmap2 bitmap The second bitmap

Returns

bitmap the intersection of the two bitmaps.

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bitmap_is_empty()

Datum bitmap_is_empty

(

FunctionCallInfo

fcinfo

)

bitmap_is_empty(bitmap bitmap) returns boolean Predicate to identify whether a bitmap is empty or not.

Parameters

fcinfo

Params as described_below bitmap bitmap The bitmap being examined. bitmap value.

Returns

boolean true, if the bitmap has no bits.

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bitmap_le()

Datum bitmap_le

(

FunctionCallInfo

fcinfo

)

bitmap_le(bitmap1 bitmap, bitmap2 bitmap) returns bool Return true if bitmap1's string representation should be sorted earlier than, or the same as, bitmap2's.

Parameters

fcinfo

Params as described_below bitmap1 bitmap The first bitmap bitmap2 bitmap The second bitmap

Returns

bool true unless the bitmaps contain the same bits.

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bitmap_lt()

Datum bitmap_lt

(

FunctionCallInfo

fcinfo

)

bitmap_lt(bitmap1 bitmap, bitmap2 bitmap) returns bool Return true if bitmap1's string representation should be sorted earlier than bitmap2's.

Parameters

fcinfo

Params as described_below bitmap1 bitmap The first bitmap bitmap2 bitmap The second bitmap

Returns

bool true unless the bitmaps contain the same bits.

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bitmap_minus()

Datum bitmap_minus

(

FunctionCallInfo

fcinfo

)

bitmap_minus(bitmap1 bitmap, bitmap2 bitmap) returns bitmap Return the bitmap1 with all bits from bitmap2 subtracted (cleared) from it.

Parameters

fcinfo

Params as described_below bitmap1 bitmap The first bitmap bitmap2 bitmap The second bitmap

Returns

bitmap the subtraction of the two bitmaps.

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bitmap_nequal()

Datum bitmap_nequal

(

FunctionCallInfo

fcinfo

)

bitmap_nequal(bitmap1 bitmap, bitmap2 bitmap) returns bool Return true if the bitmaps are not equivalent,

Parameters

fcinfo

Params as described_below bitmap1 bitmap The first bitmap bitmap2 bitmap The second bitmap

Returns

bool true unless the bitmaps contain the same bits.

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bitmap_new()

Datum bitmap_new

(

FunctionCallInfo

fcinfo

)

bitmap_new() returns bitmap; Create or re-initialise a Bitmap, for dealing with a named range of values.

Parameters

fcinfo

Params as described_below bitno int32 The first integer value to be recorded in the bitmap

Returns

Bitmap the newly allocated bitmap

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bitmap_new_empty()

Datum bitmap_new_empty

(

FunctionCallInfo

fcinfo

)

bitmap_new_empty() returns bitmap; Create an empty Bitmap, for dealing with a named range of values.

Parameters

fcinfo

Params as described_below

Returns

Bitmap the newly allocated bitmap

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bitmap_out()

Datum bitmap_out

(

FunctionCallInfo

fcinfo

)

bitmap_out(bitmap bitmap) returns text Create a (base64) text representation of a bitmap.

Parameters

fcinfo

Params as described_below bitmap bitmap A base64 serialiastion of a bitmap value.

Returns

cstring the newly serialised text stream.

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bitmap_setbit()

Datum bitmap_setbit

(

FunctionCallInfo

fcinfo

)

bitmap_setbit(bitmap bitmap, bit int4) returns bool Set the given bit in the bitmap, returning TRUE. This can be used as an aggregate function in which case the bitmap parameter will be null for the first call. In this case simply create a bitmap from the second argument.

Parameters

fcinfo

Params as described_below bitmap bitmap The bitmap to be manipulated. bitno int4 The bitnumber to be set.

Returns

bitmap The result.

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bitmap_setmax()

Datum bitmap_setmax

(

FunctionCallInfo

fcinfo

)

bitmap_setmax(bitmap bitmap, bitmax int4) returns bitmap Return a new bitmap having no bits greater than bitmax

Parameters

fcinfo

Params as described_below bitmap bitmap The bitmap to be manipulated. bitmax int4 The new maximum bit.

Returns

bitmap The new bitmap.

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bitmap_setmin()

Datum bitmap_setmin

(

FunctionCallInfo

fcinfo

)

bitmap_setmin(bitmap bitmap, bitmin int4) returns bitmap Return a new bitmap having no bits less than bitmin

Parameters

fcinfo

Params as described_below bitmap bitmap The bitmap to be manipulated. bitmin int4 The new minimum bit.

Returns

bitmap The new bitmap.

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bitmap_testbit()

Datum bitmap_testbit

(

FunctionCallInfo

fcinfo

)

bitmap_testbit(bitmap bitmap, bit int4) returns bool Test the given bit in the bitmap, returning TRUE if it is 1.

Parameters

fcinfo

Params as described_below bitmap bitmap The bitmap to be manipulated. bitno int4 The bitnumber to be tested.

Returns

bool the truth value of the bit.

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bitmap_union()

Datum bitmap_union

(

FunctionCallInfo

fcinfo

)

bitmap_union(bitmap1 bitmap, bitmap2 bitmap) returns bitmap Return the union of 2 bitmaps. This can be used as an aggregate function in which case the bitmap1 parameter will be null for the first call. In this case simply return the second argument.

Parameters

fcinfo

Params as described_below bitmap1 bitmap The first bitmap bitmap2 bitmap The second bitmap

Returns

bitmap the union of the two bitmaps.

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bitmapCopy()

Bitmap* bitmapCopy

(

Bitmap *

bitmap

)

Create a copy of a bitmap.

Parameters

bitmap

The original bitmap

Returns

Copy of bitmap.

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bitmapTestbit()

bool bitmapTestbit	(	Bitmap *	bitmap,
		int32	bit
	)

Test a bit within a Bitmap. If the bit is outside of the acceptable range return false.

Parameters

bitmap	The Bitmap within which the bit is to be set.
bit	The bit to be tested.

Returns

True if the bit is set, false otherwise.