ranhash.3x

<B>Digital的Unix操作系统VAX 4.2源码</B>

.TH ranhash 3x RISC
.SH Name
ranhashinit, ranhash, ranlookup \- access routine for the symbol table
definition file in archives
.SH Syntax
.B #include <ar.h>
.PP
.B int ranhashinit(pran, pstr, size)
.br
.B struct ranlib *pran;
.br
.B char *pstr;
.br
.B int size;
.PP
.B ranhash(name)
.br
.B char *name;
.PP
.B struct ranlib *ranhash(name)
.br
.B char *name;
.SH Description
The function
.PN ranhashinit
initializes static information for future use by
.PN ranhash
and
.PN ranlookup .
The argument
.IR pran
points to an array of ranlib structures.
The argument
.IR pstr
points to the corresponding ranlib string table (these are only used by 
.PN ranlookup ).
The argument size
.IR size
is the size of the hash table and should be a power of 2. If the size is not
a power of 2,
a 1 is returned; otherwise, a 0 is returned.
.PP
The function
.PN ranhash
returns a hash number given a name. It uses a multiplicative
hashing algorithm
and the
.IR size
argument to
.PN ranhashinit .
.PP
The
.PN ranlookup
function 
looks up
.IR name
in the ranlib table specified by
.IR ranhashinit.
It uses the
.PN ranhash
routine as a starting point. Then, it does a rehash from there.
This routine returns a pointer to a valid ranlib entry on a match. 
If no matches are found (the "emptiness" can be
inferred if the ran_off field is zero), the empty ranlib structure 
hash table should be sparse.  This routine does not expect to run out
of places to look in the table.  For example, if you collide on all entries in
the table, an error is printed tostderr and a zero is returned.
.SH See Also
ar(1), ar(5)