API
The function `tcwdberrmsg' is used in order to get the message
string corresponding to an error code.
const char *tcwdberrmsg(int ecode);
`ecode' specifies the error code.
The return value is the message string of the error
code.
The function `tcwdbnew' is used in order to create a word database
object.
TCWDB *tcwdbnew(void);
The return value is the new word database object.
The function `tcwdbdel' is used in order to delete a word database
object.
void tcwdbdel(TCWDB *wdb);
`wdb' specifies the word database object.
If the database is not closed, it is closed implicitly.
Note that the deleted object and its derivatives can not be used
anymore.
The function `tcwdbecode' is used in order to get the last
happened error code of a word database object.
int tcwdbecode(TCWDB *wdb);
`wdb' specifies the word database object.
The return value is the last happened error code.
The following error code is defined: `TCESUCCESS' for
success, `TCETHREAD' for threading error, `TCEINVALID' for invalid operation,
`TCENOFILE' for file not found, `TCENOPERM' for no permission, `TCEMETA' for
invalid meta data, `TCERHEAD' for invalid record header, `TCEOPEN' for open
error, `TCECLOSE' for close error, `TCETRUNC' for trunc error, `TCESYNC' for
sync error, `TCESTAT' for stat error, `TCESEEK' for seek error, `TCEREAD' for
read error, `TCEWRITE' for write error, `TCEMMAP' for mmap error, `TCELOCK'
for lock error, `TCEUNLINK' for unlink error, `TCERENAME' for rename error,
`TCEMKDIR' for mkdir error, `TCERMDIR' for rmdir error, `TCEKEEP' for existing
record, `TCENOREC' for no record found, and `TCEMISC' for miscellaneous
error.
The function `tcwdbtune' is used in order to set the tuning
parameters of a word database object.
bool tcwdbtune(TCWDB *wdb, int64_t etnum, uint8_t
opts);
`wdb' specifies the word database object which is
not opened.
`etnum' specifies the expected number of tokens to
be stored. If it is not more than 0, the default value is specified. The
default value is 1000000.
`opts' specifies options by bitwise-or:
`WDBTLARGE' specifies that the size of the database can be larger than 2GB by
using 64-bit bucket array, `WDBTDEFLATE' specifies that each page is
compressed with Deflate encoding, `WDBTBZIP' specifies that each page is
compressed with BZIP2 encoding, `WDBTTCBS' specifies that each page is
compressed with TCBS encoding.
If successful, the return value is true, else, it is
false.
Note that the tuning parameters should be set before the
database is opened.
The function `tcwdbsetcache' is used in order to set the caching
parameters of a word database object.
bool tcwdbsetcache(TCWDB *wdb, int64_t icsiz,
int32_t lcnum);
`wdb' specifies the word database object which is
not opened.
`icsiz' specifies the capacity size of the token
cache. If it is not more than 0, the default value is specified. The default
value is 134217728.
`lcnum' specifies the maximum number of cached
leaf nodes of B+ tree. If it is not more than 0, the default value is
specified. The default value is 64 for writer or 1024 for reader.
If successful, the return value is true, else, it is
false.
Note that the caching parameters should be set before the
database is opened.
The function `tcwdbsetfwmmax' is used in order to set the maximum
number of forward matching expansion of a word database object.
bool tcwdbsetfwmmax(TCWDB *wdb, uint32_t
fwmmax);
`wdb' specifies the word database object.
`fwmmax' specifies the maximum number of forward
matching expansion.
If successful, the return value is true, else, it is
false.
Note that the matching parameters should be set before
the database is opened.
The function `tcwdbopen' is used in order to open a word database
object.
bool tcwdbopen(TCWDB *wdb, const char *path, int
omode);
`wdb' specifies the word database object.
`path' specifies the path of the database
file.
`omode' specifies the connection mode:
`WDBOWRITER' as a writer, `WDBOREADER' as a reader. If the mode is
`WDBOWRITER', the following may be added by bitwise-or: `WDBOCREAT', which
means it creates a new database if not exist, `WDBOTRUNC', which means it
creates a new database regardless if one exists. Both of `WDBOREADER' and
`WDBOWRITER' can be added to by bitwise-or: `WDBONOLCK', which means it opens
the database file without file locking, or `WDBOLCKNB', which means locking is
performed without blocking.
If successful, the return value is true, else, it is
false.
The function `tcwdbclose' is used in order to close a word
database object.
bool tcwdbclose(TCWDB *wdb);
`wdb' specifies the word 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 `tcwdbput' is used in order to store a record into a
word database object.
bool tcwdbput(TCWDB *wdb, int64_t id, const
TCLIST *words);
`wdb' specifies the word database object connected
as a writer.
`id' specifies the ID number of the record. It
should be positive.
`words' specifies a list object contains the words
of the record, whose encoding should be UTF-8.
If successful, the return value is true, else, it is
false.
The function `tcwdbput2' is used in order to store a record with a
text string into a word database object.
bool tcwdbput2(TCWDB *wdb, int64_t id, const char
*text, const char *delims);
`wdb' specifies the word database object connected
as a writer.
`id' specifies the ID number of the record. It
should be positive.
`text' specifies the string of the record, whose
encoding should be UTF-8.
`delims' specifies a string containing delimiting
characters of the text. If it is `NULL', space characters are specified.
If successful, the return value is true, else, it is
false.
The function `tcwdbout' is used in order to remove a record of a
word database object.
bool tcwdbout(TCWDB *wdb, int64_t id, const
TCLIST *words);
`wdb' specifies the word database object connected
as a writer.
`id' specifies the ID number of the record. It
should be positive.
`words' specifies a list object contains the words
of the record, which should be same as the stored ones.
If successful, the return value is true, else, it is
false.
The function `tcwdbout2' is used in order to remove a record with
a text string of a word database object.
bool tcwdbout2(TCWDB *wdb, int64_t id, const char
*text, const char *delims);
`wdb' specifies the word database object connected
as a writer.
`id' specifies the ID number of the record. It
should be positive.
`text' specifies the string of the record, which
should be same as the stored one.
`delims' specifies a string containing delimiting
characters of the text. If it is `NULL', space characters are specified.
If successful, the return value is true, else, it is
false.
The function `tcwdbsearch' is used in order to search a word
database.
uint64_t *tcwdbsearch(TCWDB *wdb, const char
*word, int *np);
`wdb' specifies the word database object.
`word' specifies the string of the word to be
matched to.
`np' specifies the pointer to the variable into
which the number of elements of the return value is assigned.
If successful, the return value is the pointer to an
array of ID numbers of the corresponding records. `NULL' is returned on
failure.
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 `tcwdbsync' is used in order to synchronize updated
contents of a word database object with the file and the device.
bool tcwdbsync(TCWDB *wdb);
`wdb' specifies the word database object connected
as a writer.
If successful, the return value is true, else, it is
false.
This function is useful when another process connects the
same database file.
The function `tcwdboptimize' is used in order to optimize the file
of a word database object.
bool tcwdboptimize(TCWDB *wdb);
`wdb' specifies the word database object connected
as a writer.
If successful, the return value is true, else, it is
false.
This function is useful to reduce the size of the
database file with data fragmentation by successive updating.
The function `tcwdbvanish' is used in order to remove all records
of a word database object.
bool tcwdbvanish(TCWDB *wdb);
`wdb' specifies the word database object connected
as a writer.
If successful, the return value is true, else, it is
false.
The function `tcwdbcopy' is used in order to copy the database
file of a word database object.
bool tcwdbcopy(TCWDB *wdb, const char *path);
`wdb' specifies the word 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 `tcwdbpath' is used in order to get the file path of
a word database object.
const char *tcwdbpath(TCWDB *wdb);
`wdb' specifies the word database object.
The return value is the path of the database file or
`NULL' if the object does not connect to any database file.
The function `tcwdbtnum' is used in order to get the number of
tokens of a word database object.
uint64_t tcwdbtnum(TCWDB *wdb);
`wdb' specifies the word database object.
The return value is the number of tokens or 0 if the
object does not connect to any database file.
The function `tcwdbfsiz' is used in order to get the size of the
database file of a word database object.
uint64_t tcwdbfsiz(TCWDB *wdb);
`wdb' specifies the word database object.
The return value is the size of the database file or 0 if
the object does not connect to any database file.
