1dbh_sweep(3)           DBHashTables Programmers' Manual           dbh_sweep(3)
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NAME

8       dbh_sweep,     dbh_fanout,    dbh_foreach_sweep,    dbh_foreach_fanout,
9       dbh_exit_sweep, dbh_exit_fanout - apply a function to all  or  part  of
10       the DBHashtable
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SYNOPSIS

14       #include <dbh.h>
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16       int dbh_foreach_sweep (DBHashTable *dbh, DBHashFunc operate);
17       int dbh_foreach_fanout (DBHashTable *dbh, DBHashFunc operate);
18       int  dbh_sweep  (DBHashTable  *dbh,  DBHashFunc  operate, unsigned char
19       *key1, unsigned char *key2, unsigned char ignore_portion);
20       int dbh_fanout (DBHashTable *dbh,  DBHashFunc  operate,  unsigned  char
21       *key1, unsigned char *key2, unsigned char ignore_portion);
22       void dbh_exit_sweep (DBHashTable *dbh);
23       void dbh_exit_fanout (DBHashTable *dbh);
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DESCRIPTION

26       dbh_foreach_sweep  applies function operate to each member of the hash,
27       following  a  sweep  trajectory.   Sweep  is  done  by  traversing  the
28       DBHashTable in a vertical direction through all branches.
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31       dbh_foreach_fanout  applies  a  function  operate to each member of the
32       hash, following a fanout trajectory. Fanout is done by  traversing  the
33       DBHashTable in a horizontal direction through all records.
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35       dbh_sweep  and  dbh_fanout  apply  a function to subtree members of the
36       hash, where dbh_sweep follows a sweep  trajectory  (vertically  through
37       branches)  and  dbh_fanout  follows  a  fanout trajectory (horizontally
38       through branches).
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40       key1 is the key from which to start the sweep or NULL if you don't care
41       and  want  to start at the top.  If you decide to define key1 make sure
42       it is a top level node of a subtree. This is done with dbh_find
43       key2 is the key which will trigger an exit condition, or NULL if  don't
44       care and want to continue until the end of the DBHashTable
45       ignore_portion  allows you to define the ignored trailing bytes of key1
46       which will define the size of the subtree to be sweeped, or zero if you
47       don't care and want to process all branches.
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49       In  these  functions, operate ( void (*operate) (DBHashTable *dbh) ) is
50       the function to apply to each selected member of the DBHashTable
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52       dbh_exit_sweep and dbh_exit_fanout within  the  operate  function  will
53       cause the exit of a currently running sweep or fanout.
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RETURN VALUE

56       0 on error, 1 otherwise.
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NOTES

59       In  order  for  sweep/fanout functions to be extremely fast, you should
60       prepare the DBHashTable for the  trajectory  you  intend  to  use  with
61       dbh_regen_sweep  or  dbh_regen_fanout  first. This allows for extremely
62       efficient use of hardware and operating system caches.
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SEE ALSO

65       dbh (0),  dbh_regen_sweep  (3),  dbh_regen_fanout  (3),  dbh_find  (3),
66       dbh_settempdir (3)
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Author

69       Edscott Wilson Garcia <edscott@xfce.org>
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73DBHashTables                          DBH                         dbh_sweep(3)
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