Artifact db63c63deeb9993c6e375f944fce0d62f727aef58572e0003e36e1b7126208a0:

• File psl-1983/emode/move-strings.red — 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: 2674) [annotate] [blame] [check-ins using] [more...]

%
% MOVE-STRINGS.RED - "Fast" string copying utilities.
% 
% Author:      William F. Galway
%              Symbolic Computation Group
%              Computer Science Dept.
%              University of Utah
% Date:        8 June 1982
% Copyright (c) 1982 University of Utah
%


% Utilities for moving subranges of strings around (and other related
% operations).  Written in SysLisp for speed.  (Modeled after
% PI:STRING-OPS.RED and PI:COPIERS.RED.)  

% Equivalent routines for vectors should be added (one of these days).

on SysLisp;

syslsp procedure MoveSubstringToFrom(DestString, SourceString,
                                     DestIndex, SourceIndex,
                                     SubrangeLength);
% Quite a few arguments there, but should be clear enough?  Returns the
% modified destination string.
% WARNING--this version screws up when destination and source overlap
% (movement of one subrange of a string to another subrange of the same
% string.)
begin scalar rawsrc, rawdst, isrc, idst, maxindx, len, i;
    isrc := IntInf SourceIndex;
    idst := IntInf DestIndex;
    rawsrc := StrInf SourceString;
    rawdst := StrInf DestString;
    len := IntInf SubrangeLength;

    % Get upper bound on how far to copy--don't go past end of destination
    % or source, or subrange.
    % We want (i + idst) <= StrLen rawdst AND (i + isrc) <= StrLen rawsrc
    % AND i < SubrangeLength.  (Strictly less than SubrangeLength, since i
    % starts at 0.)   maxindx is the appropriate bound on i.

    maxindx := (StrLen rawdst) - idst;

    if maxindx >= len then
        maxindx := len-1;

    if maxindx > (StrLen rawsrc) - isrc then
        maxindx := (StrLen rawsrc) - isrc;

    i := 0;
loop:
        % if we've run out of stuff, quit.
        if i > maxindx then
            goto loopex;

        % Otherwise, copy the string.
        StrByt(rawdst, i + idst) := StrByt(rawsrc, i + isrc);

        i := i+1;
        goto loop;

loopex:

    return DestString;
end;

syslsp procedure FillSubstring(DestString, DestIndex, SubrangeLength, chr);
% Fill a subrange of a string with a character code.
begin scalar rawdst, rawchr, idst,len, maxindx, i;
    idst := IntInf DestIndex;
    rawdst := StrInf DestString;
    rawchr := IntInf chr;
    len := IntInf SubrangeLength;

    maxindx := StrLen rawdst;
    if maxindx >= len then
        maxindx := len-1;

    i := 0;
loop:
        % if we've run out of stuff, quit.
        if i > maxindx then
            goto loopex;

        % Copy the character into the destination.
        StrByt(rawdst, i + idst) := rawchr;

        i := i+1;
        goto loop;

loopex:

    return DestString;
end;

off SysLisp;