Add re-entrant versions of the hash functions based on the GNU api.
While testing this I found a conformance issue in hdestroy() that will be fixed in a subsequent commit. Obtained from: NetBSD (hcreate.c, CVS Rev. 1.7)
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pfg
parent
428b45aa53
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@ -1,8 +1,8 @@
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/*-
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* Written by J.T. Conklin <jtc@netbsd.org>
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* Written by J.T. Conklin <jtc@NetBSD.org>
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* Public domain.
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*
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* $NetBSD: search.h,v 1.12 1999/02/22 10:34:28 christos Exp $
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* $NetBSD: search.h,v 1.16 2005/02/03 04:39:32 perry Exp $
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* $FreeBSD$
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*/
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@ -45,6 +45,15 @@ struct que_elem {
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};
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#endif
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#if __BSD_VISIBLE
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struct _ENTRY;
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struct hsearch_data {
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struct _ENTRY *table;
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size_t size;
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size_t filled;
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};
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#endif
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__BEGIN_DECLS
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int hcreate(size_t);
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void hdestroy(void);
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@ -61,6 +70,13 @@ void *tfind(const void *, void * const *,
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int (*)(const void *, const void *));
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void *tsearch(const void *, void **, int (*)(const void *, const void *));
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void twalk(const void *, void (*)(const void *, VISIT, int));
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#if __BSD_VISIBLE
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int hcreate_r(size_t, struct hsearch_data *);
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void hdestroy_r(struct hsearch_data *);
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int hsearch_r(ENTRY, ACTION, ENTRY **, struct hsearch_data *);
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#endif
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__END_DECLS
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#endif /* !_SEARCH_H_ */
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@ -35,6 +35,7 @@ MLINKS+=exit.3 _Exit.3
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MLINKS+=getenv.3 putenv.3 getenv.3 setenv.3 getenv.3 unsetenv.3
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MLINKS+=getopt_long.3 getopt_long_only.3
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MLINKS+=hcreate.3 hdestroy.3 hcreate.3 hsearch.3
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MLINKS+=hcreate.3 hcreate_r.3 hcreate.3 hdestroy_r.3 hcreate.3 hsearch_r.3
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MLINKS+=insque.3 remque.3
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MLINKS+=lsearch.3 lfind.3
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MLINKS+=ptsname.3 grantpt.3 ptsname.3 unlockpt.3
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@ -109,6 +109,9 @@ FBSD_1.4 {
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heapsort_b;
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mergesort_b;
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qsort_b;
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hcreate_r;
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hdestroy_r;
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hsearch_r;
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};
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FBSDprivate_1.0 {
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@ -28,11 +28,16 @@
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.\"
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.\" $FreeBSD$
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.\"
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.Dd July 6, 2008
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.Dd July 21, 2014
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.Dt HCREATE 3
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.Os
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.Sh NAME
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.Nm hcreate , hdestroy , hsearch
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.Nm hcreate ,
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.Nm hcreate_r ,
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.Nm hdestroy ,
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.Nm hdestroy_r ,
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.Nm hsearch ,
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.Nm hsearch_r
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.Nd manage hash search table
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.Sh LIBRARY
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.Lb libc
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@ -40,16 +45,25 @@
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.In search.h
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.Ft int
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.Fn hcreate "size_t nel"
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.Ft int
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.Fn hcreate_r "size_t nel" "struct hsearch_data *table"
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.Ft void
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.Fn hdestroy void
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.Fn hdestroy "void"
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.Ft void
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.Fn hdestroy_r "struct hsearch_data *table"
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.Ft ENTRY *
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.Fn hsearch "ENTRY item" "ACTION action"
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.Ft int
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.Fn hsearch_r "ENTRY item" "ACTION action" "ENTRY ** itemp" "struct hsearch_data *table"
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.Sh DESCRIPTION
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The
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.Fn hcreate ,
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.Fn hcreate_r ,
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.Fn hdestroy ,
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.Fn hdestroy_r
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.Fn hsearch ,
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and
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.Fn hsearch
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.Fn hsearch_r
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functions manage hash search tables.
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.Pp
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The
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@ -90,7 +104,7 @@ argument is a structure of type
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.Vt ENTRY
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(defined in the
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.In search.h
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header) containing two pointers:
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header) that contains two pointers:
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.Fa item.key
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points to the comparison key (a
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.Vt "char *" ) ,
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@ -136,21 +150,50 @@ is
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and
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.Fn hdestroy
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is called.
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.Pp
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The
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.Fn hcreate_r ,
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.Fn hdestroy_r ,
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and
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.Fn hsearch_r
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functions are re-entrant versions of the above functions that can
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operate on a table supplied by the user.
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The
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.Fn hsearch_r
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function returns
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.Dv 0
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if the action is
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.Dv ENTER
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and the element cannot be created,
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.Dv 1
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otherwise.
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If the element exists or can be created, it will be placed in
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.Fa itemp ,
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otherwise
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.Fa itemp
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will be set to
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.Dv NULL .
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.Sh RETURN VALUES
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The
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.Fn hcreate
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function returns 0 if the table creation failed and the global variable
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and
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.Fn hcreate_r
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functions return 0 if the table creation failed and the global variable
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.Va errno
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is set to indicate the error;
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otherwise, a non-zero value is returned.
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.Pp
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The
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.Fn hdestroy
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function does not return a value.
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and
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.Fn hdestroy_r
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functions return no value.
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.Pp
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The
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.Fn hsearch
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function returns a
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and
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.Fn hsearch_r
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functions return a
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.Dv NULL
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pointer if either the
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.Fa action
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@ -223,15 +266,31 @@ main(void)
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.Sh ERRORS
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The
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.Fn hcreate
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and
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.Fn hcreate_r ,
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.Fn hsearch
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functions may fail if:
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and
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.Fn hsearch_r
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functions will fail if:
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.Bl -tag -width Er
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.It Bq Er ENOMEM
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Insufficient storage space is available.
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Insufficient memory is available.
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.It Bq Er EINVAL
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A table already exists.
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.El
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.Pp
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The
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.Fn hsearch
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and
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.Fn hsearch_r
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functions will also fail if the action is
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.Dv SEARCH
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and the element is not found:
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.Bl -tag -width Er
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.It Bq Er ESRCH
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The
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.Fa item
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given is not found.
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.El
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.Sh SEE ALSO
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.Xr bsearch 3 ,
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.Xr lsearch 3 ,
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@ -254,5 +313,15 @@ and
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.Fn hsearch
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functions first appeared in
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.At V .
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The
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.Fn hcreate_r ,
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.Fn hdestroy_r
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and
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.Fn hsearch_r
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functions are
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.Tn GNU
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extensions.
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.Sh BUGS
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The interface permits the use of only one hash table at a time.
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The original,
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.Pf non- Tn GNU
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interface permits the use of only one hash table at a time.
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@ -1,4 +1,4 @@
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/* $NetBSD: hcreate.c,v 1.6 2008/07/21 12:05:43 lukem Exp $ */
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/* $NetBSD: hcreate.c,v 1.7 2011/09/14 23:33:51 christos Exp $ */
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/*
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* Copyright (c) 2001 Christopher G. Demetriou
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@ -49,7 +49,7 @@
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#include <sys/cdefs.h>
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#if 0
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#if defined(LIBC_SCCS) && !defined(lint)
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__RCSID("$NetBSD: hcreate.c,v 1.6 2008/07/21 12:05:43 lukem Exp $");
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__RCSID("$NetBSD: hcreate.c,v 1.7 2011/09/14 23:33:51 christos Exp $");
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#endif /* LIBC_SCCS and not lint */
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#endif
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__FBSDID("$FreeBSD$");
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@ -84,20 +84,27 @@ SLIST_HEAD(internal_head, internal_entry);
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/* Default hash function, from db/hash/hash_func.c */
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extern u_int32_t (*__default_hash)(const void *, size_t);
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static struct internal_head *htable;
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static size_t htablesize;
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static struct hsearch_data htable;
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int
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hcreate(size_t nel)
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{
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size_t idx;
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unsigned int p2;
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/* Make sure this is not called when a table already exists. */
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if (htable != NULL) {
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if (htable.table != NULL) {
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errno = EINVAL;
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return 0;
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}
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return hcreate_r(nel, &htable);
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}
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int
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hcreate_r(size_t nel, struct hsearch_data *head)
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{
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struct internal_head *table;
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size_t idx;
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unsigned int p2;
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void *p;
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/* If nel is too small, make it min sized. */
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if (nel < MIN_BUCKETS)
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@ -115,71 +122,103 @@ hcreate(size_t nel)
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}
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/* Allocate the table. */
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htablesize = nel;
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htable = malloc(htablesize * sizeof htable[0]);
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if (htable == NULL) {
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head->size = nel;
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head->filled = 0;
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p = malloc(nel * sizeof table[0]);
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if (p == NULL) {
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errno = ENOMEM;
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return 0;
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}
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head->table = p;
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table = p;
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/* Initialize it. */
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for (idx = 0; idx < htablesize; idx++)
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SLIST_INIT(&htable[idx]);
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for (idx = 0; idx < nel; idx++)
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SLIST_INIT(&table[idx]);
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return 1;
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}
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void
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hdestroy(void)
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{
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hdestroy_r(&htable);
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}
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void
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hdestroy_r(struct hsearch_data *head)
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{
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struct internal_entry *ie;
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size_t idx;
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void *p;
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struct internal_head *table;
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if (htable == NULL)
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if (head == NULL)
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return;
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for (idx = 0; idx < htablesize; idx++) {
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while (!SLIST_EMPTY(&htable[idx])) {
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ie = SLIST_FIRST(&htable[idx]);
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SLIST_REMOVE_HEAD(&htable[idx], link);
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p = head->table;
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head->table = NULL;
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table = p;
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for (idx = 0; idx < head->size; idx++) {
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while (!SLIST_EMPTY(&table[idx])) {
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ie = SLIST_FIRST(&table[idx]);
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SLIST_REMOVE_HEAD(&table[idx], link);
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free(ie->ent.key);
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free(ie);
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}
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}
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free(htable);
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htable = NULL;
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free(table);
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}
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ENTRY *
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hsearch(ENTRY item, ACTION action)
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{
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struct internal_head *head;
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ENTRY *ep;
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(void)hsearch_r(item, action, &ep, &htable);
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return ep;
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}
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int
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hsearch_r(ENTRY item, ACTION action, ENTRY **itemp, struct hsearch_data *head)
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{
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struct internal_head *table, *chain;
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struct internal_entry *ie;
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uint32_t hashval;
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size_t len;
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void *p;
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p = head->table;
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table = p;
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len = strlen(item.key);
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hashval = (*__default_hash)(item.key, len);
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head = &htable[hashval & (htablesize - 1)];
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ie = SLIST_FIRST(head);
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chain = &table[hashval & (head->size - 1)];
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ie = SLIST_FIRST(chain);
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while (ie != NULL) {
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if (strcmp(ie->ent.key, item.key) == 0)
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break;
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ie = SLIST_NEXT(ie, link);
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}
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if (ie != NULL)
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return &ie->ent;
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else if (action == FIND)
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return NULL;
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if (ie != NULL) {
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*itemp = &ie->ent;
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return 1;
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} else if (action == FIND) {
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*itemp = NULL;
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errno = ESRCH;
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return 1;
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}
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ie = malloc(sizeof *ie);
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if (ie == NULL)
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return NULL;
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return 0;
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ie->ent.key = item.key;
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ie->ent.data = item.data;
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SLIST_INSERT_HEAD(head, ie, link);
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return &ie->ent;
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SLIST_INSERT_HEAD(chain, ie, link);
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*itemp = &ie->ent;
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head->filled++;
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return 1;
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}
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