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NAME

       tcadb - the abstract database API

DESCRIPTION

       Abstract  database  is  a set of interfaces to use on-memory hash database, on-memory tree
       database, hash database, B+ tree database, fixed-length database, and table database  with
       the same API.

       To  use  the  abstract  database  API, include `tcutil.h', `tcadb.h', and related standard
       header files.  Usually, write the following description near the front of a source file.

              #include <tcutil.h>
              #include <tcadb.h>
              #include <stdlib.h>
              #include <stdbool.h>
              #include <stdint.h>

       Objects whose type is pointer to `TCADB'  are  used  to  handle  abstract  databases.   An
       abstract  database  object is created with the function `tcadbnew' and is deleted with the
       function `tcadbdel'.  To avoid memory leak, it is important to delete every object when it
       is no longer in use.

       Before  operations  to  store or retrieve records, it is necessary to connect the abstract
       database object to the concrete one.  The function `tcadbopen' is used to open a  concrete
       database  and  the  function  `tcadbclose'  is  used to close the database.  To avoid data
       missing or corruption, it is important to close every database  instance  when  it  is  no
       longer  in  use.   It  is forbidden for multible database objects in a process to open the
       same database at the same time.

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.

SEE ALSO

       tcatest(1), tcamttest(1), tcamgr(1), tokyocabinet(3)