NAME
cdb.h - accessing constant databases
SYNOPSIS
#include <limb/cdb.h>
DESCRIPTION
The header defines the needed functions to access constant databases, known as .cdb files.
This header is a complement to skalibs' own header, intended to be used as a "replacement". However, instead of re-inventing the wheel, it depends/includes skalibs' header, and some of the functions below are actually implemented in skalibs, or macros to such functions.
Structures
The following structures are defined :
struct cdb_data_s
A structure to hold information about an element in a cdb, defined as such :
struct cdb_data_s {
const char *s;
u32 len;
}
Member s points to the data, of length len bytes. (cdb database must be
under 4 GiB, therefore any length can fit within a 32bit value.)
Types
The following types are defined :
cdb
An opaque structure representing a cdb.
cdb_data
A struct cdb_data_s, usually given to a cdb-reading function for it to be
filled with information about the wanted element. Pointers set in such a
cdb_data are read-only (hence the const) and remain valid until the cdb
is closed.
cdb_find_state
An opaque structure used when searching inside a cdb, notably to find all elements stored with the same key.
cdb_traverse
An opaque structure used when iterating over a cdb.
Macros
The following macros are defined :
CDB_ZERO
Value to initialize a stack-allocated cdb.
CDB_FIND_STATE_ZERO
Value to initialize a stack-allocated cdb_find_state.
CDB_TRAVERSE_ZERO
Value to initialize a stack-allocated cdb_traverse.
Objects
The following objects are defined :
cdb_zero
An empty cdb, which can be used for (re-)initialization.
Functions
The following functions are defined :
Initialize a cdb_find_state.
Similar to cdb_find(3) except that it takes a cdb_find_state argument, allowing to find all elements with the same key.
Find the first element for the given key in a cdb.
Free memory associated with a cdb from a file (descriptor).
Initialize a cdb from a file.
Similar to cdb_init(3) except for relative path, relative to the given file descriptor.
Similar to cdb_init(3) but taking a file descriptor instead of a file name.
Similar to cdb_init(3) but taking a pointer to a memory area, which must contain a valid CDB file.
Initialize a cdb_traverse.
Find the next element when iterating over a cdb.