ID List Management

Data Structures
struct	MDB_ID2

Macros
#define	MDB_IDL_LOGN   16 /* DB_SIZE is 2^16, UM_SIZE is 2^17 */
#define	MDB_IDL_DB_SIZE   (1<<MDB_IDL_LOGN)
#define	MDB_IDL_UM_SIZE   (1<<(MDB_IDL_LOGN+1))
#define	MDB_IDL_DB_MAX   (MDB_IDL_DB_SIZE-1)
#define	MDB_IDL_UM_MAX   (MDB_IDL_UM_SIZE-1)
#define	MDB_IDL_SIZEOF(ids)   (((ids)[0]+1) * sizeof(MDB_ID))
#define	MDB_IDL_IS_ZERO(ids)   ( (ids)[0] == 0 )
#define	MDB_IDL_CPY(dst, src)   (memcpy( dst, src, MDB_IDL_SIZEOF( src ) ))
#define	MDB_IDL_FIRST(ids)   ( (ids)[1] )
#define	MDB_IDL_LAST(ids)   ( (ids)[(ids)[0]] )
#define	MDB_IDL_ALLOCLEN(ids)   ( (ids)[-1] )
#define	mdb_midl_xappend(idl, id)
#define	CMP(x, y)   ( (x) < (y) ? -1 : (x) > (y) )
#define	SMALL   8
#define	MIDL_SWAP(a, b)   { itmp=(a); (a)=(b); (b)=itmp; }

Typedefs
typedef size_t	MDB_ID
typedef MDB_ID *	MDB_IDL
typedef MDB_ID2 *	MDB_ID2L

Functions
unsigned	mdb_midl_search (MDB_IDL ids, MDB_ID id)
MDB_IDL	mdb_midl_alloc (int num)
void	mdb_midl_free (MDB_IDL ids)
int	mdb_midl_shrink (MDB_IDL *idp)
int	mdb_midl_need (MDB_IDL *idp, unsigned num)
int	mdb_midl_append (MDB_IDL *idp, MDB_ID id)
int	mdb_midl_append_list (MDB_IDL *idp, MDB_IDL app)
int	mdb_midl_append_range (MDB_IDL *idp, MDB_ID id, unsigned n)
void	mdb_midl_xmerge (MDB_IDL idl, MDB_IDL merge)
void	mdb_midl_sort (MDB_IDL ids)
unsigned	mdb_mid2l_search (MDB_ID2L ids, MDB_ID id)
int	mdb_mid2l_insert (MDB_ID2L ids, MDB_ID2 *id)
int	mdb_mid2l_append (MDB_ID2L ids, MDB_ID2 *id)
static int	mdb_midl_grow (MDB_IDL *idp, int num)

Detailed Description

---

Data Structure Documentation

struct MDB_ID2

An ID2 is an ID/pointer pair.

Data Fields
MDB_ID	mid
void *	mptr

Field Documentation

MDB_ID MDB_ID2::mid

The ID

void* MDB_ID2::mptr

The pointer

Macro Definition Documentation

#define MDB_IDL_ALLOCLEN

(

ids

)

( (ids)[-1] )

Current max length of an mdb_midl_alloc()ed IDL

#define mdb_midl_xappend	(		idl,
			id
	)

Value:

do { \
		MDB_ID *xidl = (idl), xlen = ++(xidl[0]); \
        xidl[xlen] = (id); \
    } while (0)

Append ID to IDL. The IDL must be big enough.

Typedef Documentation

typedef size_t MDB_ID

A generic unsigned ID number. These were entryIDs in back-bdb. Preferably it should have the same size as a pointer.

typedef MDB_ID* MDB_IDL

An IDL is an ID List, a sorted array of IDs. The first element of the array is a counter for how many actual IDs are in the list. In the original back-bdb code, IDLs are sorted in ascending order. For libmdb IDLs are sorted in descending order.

typedef MDB_ID2* MDB_ID2L

An ID2L is an ID2 List, a sorted array of ID2s. The first element's mid member is a count of how many actual elements are in the array. The mptr member of the first element is unused. The array is sorted in ascending order by mid.

Function Documentation

unsigned mdb_midl_search	(	MDB_IDL	ids,
		MDB_ID	id
	)

Search for an ID in an IDL.

Parameters

[in]	ids	The IDL to search.
[in]	id	The ID to search for.

Returns

The index of the first ID greater than or equal to id.

MDB_IDL mdb_midl_alloc

(

int

num

)

Allocate an IDL. Allocates memory for an IDL of the given size.

Returns

IDL on success, NULL on failure.

void mdb_midl_free

(

MDB_IDL

ids

)

Free an IDL.

Parameters

[in]

ids

The IDL to free.

int mdb_midl_shrink

(

MDB_IDL *

idp

)

Shrink an IDL. Return the IDL to the default size if it has grown larger.

Parameters

[in,out]

idp

Address of the IDL to shrink.

Returns

0 on no change, non-zero if shrunk.

int mdb_midl_need	(	MDB_IDL *	idp,
		unsigned	num
	)

Make room for num additional elements in an IDL.

Parameters

[in,out]	idp	Address of the IDL.
[in]	num	Number of elements to make room for.

Returns

0 on success, ENOMEM on failure.

int mdb_midl_append	(	MDB_IDL *	idp,
		MDB_ID	id
	)

Append an ID onto an IDL.

Parameters

[in,out]	idp	Address of the IDL to append to.
[in]	id	The ID to append.

Returns

0 on success, ENOMEM if the IDL is too large.

int mdb_midl_append_list	(	MDB_IDL *	idp,
		MDB_IDL	app
	)

Append an IDL onto an IDL.

Parameters

[in,out]	idp	Address of the IDL to append to.
[in]	app	The IDL to append.

Returns

0 on success, ENOMEM if the IDL is too large.

int mdb_midl_append_range	(	MDB_IDL *	idp,
		MDB_ID	id,
		unsigned	n
	)

Append an ID range onto an IDL.

Parameters

[in,out]	idp	Address of the IDL to append to.
[in]	id	The lowest ID to append.
[in]	n	Number of IDs to append.

Returns

0 on success, ENOMEM if the IDL is too large.

void mdb_midl_xmerge	(	MDB_IDL	idl,
		MDB_IDL	merge
	)

Merge an IDL onto an IDL. The destination IDL must be big enough.

Parameters

[in]	idl	The IDL to merge into.
[in]	merge	The IDL to merge.

void mdb_midl_sort

(

MDB_IDL

ids

)

Sort an IDL.

Parameters

[in,out]

ids

The IDL to sort.

unsigned mdb_mid2l_search	(	MDB_ID2L	ids,
		MDB_ID	id
	)

Search for an ID in an ID2L.

Parameters

[in]	ids	The ID2L to search.
[in]	id	The ID to search for.

Returns

The index of the first ID2 whose mid member is greater than or equal to id.

int mdb_mid2l_insert	(	MDB_ID2L	ids,
		MDB_ID2 *	id
	)

Insert an ID2 into a ID2L.

Parameters

[in,out]	ids	The ID2L to insert into.
[in]	id	The ID2 to insert.

Returns

0 on success, -1 if the ID was already present in the ID2L.

int mdb_mid2l_append	(	MDB_ID2L	ids,
		MDB_ID2 *	id
	)

Append an ID2 into a ID2L.

Parameters

[in,out]	ids	The ID2L to append into.
[in]	id	The ID2 to append.

Returns

0 on success, -2 if the ID2L is too big.