bm_pat
*
bm_comp(
u_char *pattern
, size_t patlen
, u_char freq[256]
)
u_char
*
bm_exec(
bm_pat *pdesc
, u_char *text
, size_t len
)
void
bm_free(
bm_pat *pdesc
)
bm_comp()
evaluates the
patlen
bytes starting at
pattern
,
and returns a pointer to a structure describing them.
The bytes referenced by
pattern
may be of any value.
The search takes advantage of the frequency distribution of the
bytes in the text to be searched.
If specified,
freq
should be an array of 256 values,
with higher values indicating that the corresponding character occurs
more frequently.
(A less than optimal frequency distribution can only result in less
than optimal performance, not incorrect results.)
If
freq
is
NULL
,
a system default table is used.
bm_exec()
returns a pointer to the leftmost occurrence of the string given to
bm_comp(
)
within
text
,
or
NULL
if none occurs.
The number of bytes in
text
must be specified by
len
.
Space allocated for the returned description is discarded
by calling
bm_free()
with the returned description as an argument.
The asymptotic speed of
bm_exec()
is O(len/patlen).