140865Sbostic /*-
2*62092Sbostic * Copyright (c) 1979, 1993
3*62092Sbostic * The Regents of the University of California. All rights reserved.
440865Sbostic *
540865Sbostic * %sccs.include.redist.c%
640865Sbostic */
71669Smckusick
840865Sbostic #ifndef lint
9*62092Sbostic static char sccsid[] = "@(#)PACK.c 8.1 (Berkeley) 06/06/93";
1040865Sbostic #endif /* not lint */
111669Smckusick
121669Smckusick /*
131669Smckusick * pack(a,i,z)
141669Smckusick *
151669Smckusick * with: a: array[m..n] of t
161669Smckusick * z: packed array[u..v] of t
171669Smckusick *
181669Smckusick * semantics: for j := u to v do
191669Smckusick * z[j] := a[j-u+i];
201669Smckusick *
211669Smckusick * need to check:
221669Smckusick * 1. i >= m
231669Smckusick * 2. i+(v-u) <= n (i.e. i-m <= (n-m)-(v-u))
241669Smckusick *
251669Smckusick * on stack: lv(z), lv(a), rv(i) (len 4)
261669Smckusick *
271669Smckusick * move w(t)*(v-u+1) bytes from lv(a)+w(t)*(i-m) to lv(z)
281669Smckusick */
291669Smckusick
PACK(i,a,z,size_a,lb_a,ub_a,size_z)301669Smckusick PACK(i, a, z, size_a, lb_a, ub_a, size_z)
311669Smckusick
323015Smckusic long i; /* subscript into a to begin packing */
331669Smckusick char *a; /* pointer to structure a */
341669Smckusick char *z; /* pointer to structure z */
353015Smckusic long size_a; /* sizeof(a_type) */
363015Smckusic long lb_a; /* lower bound of structure a */
373015Smckusic long ub_a; /* (upper bound of a) - (lb_a + sizeof(z_type)) */
383015Smckusic long size_z; /* sizeof(z_type) */
391669Smckusick {
401669Smckusick int subscr;
411669Smckusick register char *cp;
421669Smckusick register char *zp = z;
431669Smckusick register char *limit;
441669Smckusick
451669Smckusick subscr = i - lb_a;
461669Smckusick if (subscr < 0 || subscr > ub_a) {
473868Smckusic ERROR("i = %D: Bad i to pack(a,i,z)\n", i);
481669Smckusick return;
491669Smckusick }
501669Smckusick cp = &a[subscr * size_a];
511669Smckusick limit = cp + size_z;
521669Smckusick do {
531669Smckusick *zp++ = *cp++;
541669Smckusick } while (cp < limit);
551669Smckusick }
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