Artifact 143a9308fcd1b882e9d923fd8b78623d0f59ba1916df781b449833e29a595b13:

• File psl-1983/3-1/util/string-search.sl — part of check-in [eb17ceb7f6] at 2020-04-21 19:40:01 on branch master — Add Reduce 3.0 to the historical section of the archive, and some more
  files relating to version sof PSL from the early 1980s. Thanks are due to
  Paul McJones and Nelson Beebe for these, as well as to all the original
  authors.

  git-svn-id: https://svn.code.sf.net/p/reduce-algebra/code/historical@5328 2bfe0521-f11c-4a00-b80e-6202646ff360 (user: arthurcnorman@users.sourceforge.net, size: 2130) [annotate] [blame] [check-ins using] [more...]

• File psl-1983/util/string-search.sl — part of check-in [eb17ceb7f6] at 2020-04-21 19:40:01 on branch master — Add Reduce 3.0 to the historical section of the archive, and some more
  files relating to version sof PSL from the early 1980s. Thanks are due to
  Paul McJones and Nelson Beebe for these, as well as to all the original
  authors.

  git-svn-id: https://svn.code.sf.net/p/reduce-algebra/code/historical@5328 2bfe0521-f11c-4a00-b80e-6202646ff360 (user: arthurcnorman@users.sourceforge.net, size: 2130) [annotate] [blame] [check-ins using]

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%% STRING-SEARCH
%%%
%%% Author: Cris Perdue
%%% 11/23/82
%%% 
%%% General-purpose searches for substring.  Case is important.
%%% If the target is found, the index in the domain of the
%%% leftmost character of the leftmost match is returned,
%%% otherwise NIL.
%%%
%%% (STRING-SEARCH TARGET DOMAIN).
%%% 
%%% If passed two strings, Common LISP "search" will give the
%%% same results.
%%%
%%% (STRING-SEARCH-FROM TARGET DOMAIN START)
%%%
%%% Like string-search, but the search effectively starts at index
%%% START in the domain.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

%%% Implementation note: In both of these, the value of the first
%%% character of the target is precomputed and it is tested against
%%% characters of the domain separately from the other characters of
%%% the target.

(compiletime (load fast-int if))

(defun string-search (target domain)
  (if (not (and (stringp target) (stringp domain))) then
      (error 0 "Arg to string-search not a string"))
  (let* ((s (isizes target))
	 (m (- (isizes domain) s)))
    (if (= s -1) then 0
	else
	(let ((c (igets target 0)))
	  (for (from i 0 m)
	       (do (if (eq (igets domain i) c) then
		       (if
			(for (from u 1 s)
			     (from v (+ i 1))
			     (do (if (neq (igets target u)
					  (igets domain v)) then
				     (return nil)))
			     (finally (return t))) then
			(return i)))))))))

%%% Like string-search, but takes an explicit starting index
%%% in the domain string.

(defun string-search-from (target domain start)
  (if (not (and (stringp target) (stringp domain))) then
      (error 0 "Arg to substring-search not a string"))
  (let* ((s (isizes target))
	 (m (- (isizes domain) s)))
    (if (= s -1) then start
	else
	(let ((c (igets target 0)))
	  (for (from i start m)
	       (do (if (eq (igets domain i) c) then
		       (if
			(for (from u 1 s)
			     (from v (+ i 1))
			     (do (if (neq (igets target u)
					  (igets domain v)) then
				     (return nil)))
			     (finally (return t))) then
			(return i)))))))))