| BM(3) | Library Functions Manual | BM(3) | 
bm_comp, bm_exec,
  bm_free —
#include <sys/types.h>
#include <bm.h>
bm_pat *
  
  bm_comp(unsigned
    char *pattern, size_t
    patlen, unsigned char
    freq[256]);
unsigned char *
  
  bm_exec(bm_pat
    *pdesc, unsigned 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).
Hume and Sunday, Fast String Searching, Software Practice and Experience, Vol. 21, 11, pp. 1221-48, November 1991.
| April 8, 2001 | NetBSD 10.0 |