API¶
The function `tcadbnew' is used in order to create an abstract
database object.
TCADB *tcadbnew(void);
The return value is the new abstract database
object.
The function `tcadbdel' is used in order to delete an abstract
database object.
void tcadbdel(TCADB *adb);
`adb' specifies the abstract database
object.
The function `tcadbopen' is used in order to open an abstract
database.
bool tcadbopen(TCADB *adb, const char *name);
`adb' specifies the abstract database
object.
`name' specifies the name of the database. If it
is "*", the database will be an on-memory hash database. If it is
"+", the database will be an on-memory tree database. If its suffix
is ".tch", the database will be a hash database. If its suffix is
".tcb", the database will be a B+ tree database. If its suffix is
".tcf", the database will be a fixed-length database. If its suffix
is ".tct", the database will be a table database. Otherwise, this
function fails. Tuning parameters can trail the name, separated by
"#". Each parameter is composed of the name and the value, separated
by "=". On-memory hash database supports "bnum",
"capnum", and "capsiz". On-memory tree database supports
"capnum" and "capsiz". Hash database supports
"mode", "bnum", "apow", "fpow",
"opts", "rcnum", "xmsiz", and
"dfunit". B+ tree database supports "mode",
"lmemb", "nmemb", "bnum", "apow",
"fpow", "opts", "lcnum", "ncnum",
"xmsiz", and "dfunit". Fixed-length database supports
"mode", "width", and "limsiz". Table database
supports "mode", "bnum", "apow",
"fpow", "opts", "rcnum", "lcnum",
"ncnum", "xmsiz", "dfunit", and
"idx".
If successful, the return value is true, else, it is
false.
The tuning parameter "capnum" specifies the
capacity number of records. "capsiz" specifies the capacity size of
using memory. Records spilled the capacity are removed by the storing order.
"mode" can contain "w" of writer, "r" of reader,
"c" of creating, "t" of truncating, "e" of no
locking, and "f" of non-blocking lock. The default mode is relevant
to "wc". "opts" can contains "l" of large
option, "d" of Deflate option, "b" of BZIP2 option, and
"t" of TCBS option. "idx" specifies the column name of an
index and its type separated by ":". For example,
"casket.tch#bnum=1000000#opts=ld" means that the name of the
database file is "casket.tch", and the bucket number is 1000000, and
the options are large and Deflate.
The function `tcadbclose' is used in order to close an abstract
database object.
bool tcadbclose(TCADB *adb);
`adb' specifies the abstract database
object.
If successful, the return value is true, else, it is
false.
Update of a database is assured to be written when the
database is closed. If a writer opens a database but does not close it
appropriately, the database will be broken.
The function `tcadbput' is used in order to store a record into an
abstract database object.
bool tcadbput(TCADB *adb, const void *kbuf, int
ksiz, const void *vbuf, int
vsiz);
`adb' specifies the abstract database
object.
`kbuf' specifies the pointer to the region of the
key.
`ksiz' specifies the size of the region of the
key.
`vbuf' specifies the pointer to the region of the
value.
`vsiz' specifies the size of the region of the
value.
If successful, the return value is true, else, it is
false.
If a record with the same key exists in the database, it
is overwritten.
The function `tcadbput2' is used in order to store a string record
into an abstract object.
bool tcadbput2(TCADB *adb, const char *kstr,
const char *vstr);
`adb' specifies the abstract database
object.
`kstr' specifies the string of the key.
`vstr' specifies the string of the value.
If successful, the return value is true, else, it is
false.
If a record with the same key exists in the database, it
is overwritten.
The function `tcadbputkeep' is used in order to store a new record
into an abstract database object.
bool tcadbputkeep(TCADB *adb, const void *kbuf,
int ksiz, const void *vbuf, int
vsiz);
`adb' specifies the abstract database
object.
`kbuf' specifies the pointer to the region of the
key.
`ksiz' specifies the size of the region of the
key.
`vbuf' specifies the pointer to the region of the
value.
`vsiz' specifies the size of the region of the
value.
If successful, the return value is true, else, it is
false.
If a record with the same key exists in the database,
this function has no effect.
The function `tcadbputkeep2' is used in order to store a new
string record into an abstract database object.
bool tcadbputkeep2(TCADB *adb, const char *kstr,
const char *vstr);
`adb' specifies the abstract database
object.
`kstr' specifies the string of the key.
`vstr' specifies the string of the value.
If successful, the return value is true, else, it is
false.
If a record with the same key exists in the database,
this function has no effect.
The function `tcadbputcat' is used in order to concatenate a value
at the end of the existing record in an abstract database object.
bool tcadbputcat(TCADB *adb, const void *kbuf,
int ksiz, const void *vbuf, int
vsiz);
`adb' specifies the abstract database
object.
`kbuf' specifies the pointer to the region of the
key.
`ksiz' specifies the size of the region of the
key.
`vbuf' specifies the pointer to the region of the
value.
`vsiz' specifies the size of the region of the
value.
If successful, the return value is true, else, it is
false.
If there is no corresponding record, a new record is
created.
The function `tcadbputcat2' is used in order to concatenate a
string value at the end of the existing record in an abstract database
object.
bool tcadbputcat2(TCADB *adb, const char *kstr,
const char *vstr);
`adb' specifies the abstract database
object.
`kstr' specifies the string of the key.
`vstr' specifies the string of the value.
If successful, the return value is true, else, it is
false.
If there is no corresponding record, a new record is
created.
The function `tcadbout' is used in order to remove a record of an
abstract database object.
bool tcadbout(TCADB *adb, const void *kbuf, int
ksiz);
`adb' specifies the abstract database
object.
`kbuf' specifies the pointer to the region of the
key.
`ksiz' specifies the size of the region of the
key.
If successful, the return value is true, else, it is
false.
The function `tcadbout2' is used in order to remove a string
record of an abstract database object.
bool tcadbout2(TCADB *adb, const char *kstr);
`adb' specifies the abstract database
object.
`kstr' specifies the string of the key.
If successful, the return value is true, else, it is
false.
The function `tcadbget' is used in order to retrieve a record in
an abstract database object.
void *tcadbget(TCADB *adb, const void *kbuf, int
ksiz, int *sp);
`adb' specifies the abstract database
object.
`kbuf' specifies the pointer to the region of the
key.
`ksiz' specifies the size of the region of the
key.
`sp' specifies the pointer to the variable into
which the size of the region of the return value is assigned.
If successful, the return value is the pointer to the
region of the value of the corresponding record. `NULL' is returned if no
record corresponds.
Because an additional zero code is appended at the end of
the region of the return value, the return value can be treated as a character
string. Because the region of the return value is allocated with the `malloc'
call, it should be released with the `free' call when it is no longer in
use.
The function `tcadbget2' is used in order to retrieve a string
record in an abstract database object.
char *tcadbget2(TCADB *adb, const char
*kstr);
`adb' specifies the abstract database
object.
`kstr' specifies the string of the key.
If successful, the return value is the string of the
value of the corresponding record. `NULL' is returned if no record
corresponds.
Because the region of the return value is allocated with
the `malloc' call, it should be released with the `free' call when it is no
longer in use.
The function `tcadbvsiz' is used in order to get the size of the
value of a record in an abstract database object.
int tcadbvsiz(TCADB *adb, const void *kbuf, int
ksiz);
`adb' specifies the abstract database
object.
`kbuf' specifies the pointer to the region of the
key.
`ksiz' specifies the size of the region of the
key.
If successful, the return value is the size of the value
of the corresponding record, else, it is -1.
The function `tcadbvsiz2' is used in order to get the size of the
value of a string record in an abstract database object.
int tcadbvsiz2(TCADB *adb, const char *kstr);
`adb' specifies the abstract database
object.
`kstr' specifies the string of the key.
If successful, the return value is the size of the value
of the corresponding record, else, it is -1.
The function `tcadbiterinit' is used in order to initialize the
iterator of an abstract database object.
bool tcadbiterinit(TCADB *adb);
`adb' specifies the abstract database
object.
If successful, the return value is true, else, it is
false.
The iterator is used in order to access the key of every
record stored in a database.
The function `tcadbiternext' is used in order to get the next key
of the iterator of an abstract database object.
void *tcadbiternext(TCADB *adb, int *sp);
`adb' specifies the abstract database
object.
`sp' specifies the pointer to the variable into
which the size of the region of the return value is assigned.
If successful, the return value is the pointer to the
region of the next key, else, it is `NULL'. `NULL' is returned when no record
is to be get out of the iterator.
Because an additional zero code is appended at the end of
the region of the return value, the return value can be treated as a character
string. Because the region of the return value is allocated with the `malloc'
call, it should be released with the `free' call when it is no longer in use.
It is possible to access every record by iteration of calling this function.
It is allowed to update or remove records whose keys are fetched while the
iteration. However, it is not assured if updating the database is occurred
while the iteration. Besides, the order of this traversal access method is
arbitrary, so it is not assured that the order of storing matches the one of
the traversal access.
The function `tcadbiternext2' is used in order to get the next key
string of the iterator of an abstract database object.
char *tcadbiternext2(TCADB *adb);
`adb' specifies the abstract database
object.
If successful, the return value is the string of the next
key, else, it is `NULL'. `NULL' is returned when no record is to be get out of
the iterator.
Because the region of the return value is allocated with
the `malloc' call, it should be released with the `free' call when it is no
longer in use. It is possible to access every record by iteration of calling
this function. However, it is not assured if updating the database is occurred
while the iteration. Besides, the order of this traversal access method is
arbitrary, so it is not assured that the order of storing matches the one of
the traversal access.
The function `tcadbfwmkeys' is used in order to get forward
matching keys in an abstract database object.
TCLIST *tcadbfwmkeys(TCADB *adb, const void
*pbuf, int psiz, int max);
`adb' specifies the abstract database
object.
`pbuf' specifies the pointer to the region of the
prefix.
`psiz' specifies the size of the region of the
prefix.
`max' specifies the maximum number of keys to be
fetched. If it is negative, no limit is specified.
The return value is a list object of the corresponding
keys. This function does never fail. It returns an empty list even if no key
corresponds.
Because the object of the return value is created with
the function `tclistnew', it should be deleted with the function `tclistdel'
when it is no longer in use. Note that this function may be very slow because
every key in the database is scanned.
The function `tcadbfwmkeys2' is used in order to get forward
matching string keys in an abstract database object.
TCLIST *tcadbfwmkeys2(TCADB *adb, const char
*pstr, int max);
`adb' specifies the abstract database
object.
`pstr' specifies the string of the prefix.
`max' specifies the maximum number of keys to be
fetched. If it is negative, no limit is specified.
The return value is a list object of the corresponding
keys. This function does never fail. It returns an empty list even if no key
corresponds.
Because the object of the return value is created with
the function `tclistnew', it should be deleted with the function `tclistdel'
when it is no longer in use. Note that this function may be very slow because
every key in the database is scanned.
The function `tcadbaddint' is used in order to add an integer to a
record in an abstract database object.
int tcadbaddint(TCADB *adb, const void *kbuf, int
ksiz, int num);
`adb' specifies the abstract database
object.
`kbuf' specifies the pointer to the region of the
key.
`ksiz' specifies the size of the region of the
key.
`num' specifies the additional value.
If successful, the return value is the summation value,
else, it is `INT_MIN'.
If the corresponding record exists, the value is treated
as an integer and is added to. If no record corresponds, a new record of the
additional value is stored.
The function `tcadbadddouble' is used in order to add a real
number to a record in an abstract database object.
double tcadbadddouble(TCADB *adb, const void
*kbuf, int ksiz, double num);
`adb' specifies the abstract database
object.
`kbuf' specifies the pointer to the region of the
key.
`ksiz' specifies the size of the region of the
key.
`num' specifies the additional value.
If successful, the return value is the summation value,
else, it is Not-a-Number.
If the corresponding record exists, the value is treated
as a real number and is added to. If no record corresponds, a new record of
the additional value is stored.
The function `tcadbsync' is used in order to synchronize updated
contents of an abstract database object with the file and the device.
bool tcadbsync(TCADB *adb);
`adb' specifies the abstract database
object.
If successful, the return value is true, else, it is
false.
The function `tcadboptimize' is used in order to optimize the
storage of an abstract database object.
bool tcadboptimize(TCADB *adb, const char
*params);
`adb' specifies the abstract database
object.
`params' specifies the string of the tuning
parameters, which works as with the tuning of parameters the function
`tcadbopen'. If it is `NULL', it is not used.
If successful, the return value is true, else, it is
false.
This function is useful to reduce the size of the
database storage with data fragmentation by successive updating.
The function `tcadbvanish' is used in order to remove all records
of an abstract database object.
bool tcadbvanish(TCADB *adb);
`adb' specifies the abstract database
object.
If successful, the return value is true, else, it is
false.
The function `tcadbcopy' is used in order to copy the database
file of an abstract database object.
bool tcadbcopy(TCADB *adb, const char *path);
`adb' specifies the abstract database
object.
`path' specifies the path of the destination file.
If it begins with `@', the trailing substring is executed as a command
line.
If successful, the return value is true, else, it is
false. False is returned if the executed command returns non-zero code.
The database file is assured to be kept synchronized and
not modified while the copying or executing operation is in progress. So, this
function is useful to create a backup file of the database file.
The function `tcadbtranbegin' is used in order to begin the
transaction of an abstract database object.
bool tcadbtranbegin(TCADB *adb);
`adb' specifies the abstract database
object.
If successful, the return value is true, else, it is
false.
The database is locked by the thread while the
transaction so that only one transaction can be activated with a database
object at the same time. Thus, the serializable isolation level is assumed if
every database operation is performed in the transaction. All updated regions
are kept track of by write ahead logging while the transaction. If the
database is closed during transaction, the transaction is aborted
implicitly.
The function `tcadbtrancommit' is used in order to commit the
transaction of an abstract database object.
bool tcadbtrancommit(TCADB *adb);
`adb' specifies the abstract database
object.
If successful, the return value is true, else, it is
false.
Update in the transaction is fixed when it is committed
successfully.
The function `tcadbtranabort' is used in order to abort the
transaction of an abstract database object.
bool tcadbtranabort(TCADB *adb);
`adb' specifies the abstract database
object.
If successful, the return value is true, else, it is
false.
Update in the transaction is discarded when it is
aborted. The state of the database is rollbacked to before transaction.
The function `tcadbpath' is used in order to get the file path of
an abstract database object.
const char *tcadbpath(TCADB *adb);
`adb' specifies the abstract database
object.
The return value is the path of the database file or
`NULL' if the object does not connect to any database. "*" stands
for on-memory hash database. "+" stands for on-memory tree
database.
The function `tcadbrnum' is used in order to get the number of
records of an abstract database object.
uint64_t tcadbrnum(TCADB *adb);
`adb' specifies the abstract database
object.
The return value is the number of records or 0 if the
object does not connect to any database instance.
The function `tcadbsize' is used in order to get the size of the
database of an abstract database object.
uint64_t tcadbsize(TCADB *adb);
`adb' specifies the abstract database
object.
The return value is the size of the database or 0 if the
object does not connect to any database instance.
The function `tcadbmisc' is used in order to call a versatile
function for miscellaneous operations of an abstract database object.
TCLIST *tcadbmisc(TCADB *adb, const char *name,
const TCLIST *args);
`adb' specifies the abstract database
object.
`name' specifies the name of the function. All
databases support "put", "out", "get",
"putlist", "outlist", "getlist", and
"getpart". "put" is to store a record. It receives a key
and a value, and returns an empty list. "out" is to remove a record.
It receives a key, and returns an empty list. "get" is to retrieve a
record. It receives a key, and returns a list of the values.
"putlist" is to store records. It receives keys and values one after
the other, and returns an empty list. "outlist" is to remove
records. It receives keys, and returns an empty list. "getlist" is
to retrieve records. It receives keys, and returns keys and values of
corresponding records one after the other. "getpart" is to retrieve
the partial value of a record. It receives a key, the offset of the region,
and the length of the region.
`args' specifies a list object containing
arguments.
If successful, the return value is a list object of the
result. `NULL' is returned on failure.
Because the object of the return value is created with
the function `tclistnew', it should be deleted with the function `tclistdel'
when it is no longer in use.
