Boyer-Moore string search: Difference between revisions
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=={{header|Fortran}}==
module bm_str
implicit none
private
public :: bmstr
!
! PARAMETER definitions
!
integer , private , parameter :: NO_OF_CHARS = 256, SIZEX=256
contains
pure subroutine badcharheuristic(Str,M,Badchar)
implicit none
! Dummy arguments
!
integer :: M
integer , dimension(NO_OF_CHARS) :: Badchar
character(1) , dimension(M) :: Str
intent (in) M , Str
intent (out) Badchar
!
! Local variables
!
integer :: i
! Code starts here
Badchar(NO_OF_CHARS) = -1
do i = 1 , M
Badchar(iachar(Str(i))) = i
enddo
return
end subroutine badcharheuristic
function bmstr(Pat,M,Str,N) result(found)
implicit none
!
! Dummy arguments
!
integer :: M
integer :: N
character(len=m) :: Pat
character(len=n) :: Str
intent (in) M , N , Pat , Str
!
! Local variables
!
integer , dimension(NO_OF_CHARS) :: badchar
integer :: found
integer :: i
integer :: j
integer :: s
! Code starts here
!
found = -1
if ( (M==0) .OR. (N==0) .OR. (M>N) ) return
badchar = 0
call badcharheuristic(Pat,M,badchar)
i = 0
s = 0
do while ( s<=(N-M) )
j = M
do j = m,1,-1
if((Pat(j:j) /= Str(s+j:s+j)) )exit ! Leave, the pattern doesn't match.
enddo
if ( j < 1 ) then ! Found, let's leave
found = s + 1
return
endif
i = badchar(iachar(Str(s+j:s+j)))
s = s + MAX(1,j-i)
enddo
found = -1
return
end function bmstr
end module bm_str</pre>
</pre>
=={{header|J}}==
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