%%s 0/0/0
%%d D 1.1 25-Mar-82 12:02:57 v1.1 1 0
%%c Version 1.1 is the Spring 1982 Distribution of the LBL/Hughes release
%%c of the Software Tools Virtual Operating System software and documentation.
%%T
%%I 1
#-h- cprsym           244  asc  25-mar-82 07:28:52  v1.1 (sw-tools v1.1)
 # symbols for compress and expand tools
 # put on a file called 'cprsym'
 # Used only by compress and expand
 
 #must have RCODE > (MAXCHUNK + BLANK) or RCODE = 0
 define(RCODE,125)
 define(MAXCHUNK,arith(RCODE,-,incr(' ')))
 define(THRESH,4)
#-h- cpress.r        1915  asc  25-mar-82 07:28:55  v1.1 (sw-tools v1.1)
#-h- main             524  asc  25-mar-82 07:28:25  v1.1 (sw-tools v1.1)
 ## cpress - compress input files

 include cprsym

 DRIVER(cpress)
 
 character buf(MAXLINE)
 integer getarg, open
 integer i
 #must have RCODE > (MAXCHUNK + ' ') or RCODE = 0
 
 call query("usage:  cpress [file] ...")
 for (i=1; ; i=i+1)
	{
	if (getarg(i,buf,MAXLINE) == EOF)
		{
		if (i != 1)
			break
		int = STDIN
		}
	else if (buf(1) == '-' & buf(2) == EOS)
		int = STDIN
	else
		{
		int = open(buf,READ)
		if (int == ERR)
			call cant(buf)
		}
	call press (int)
	if (int != STDIN)
		call close(int)
	}

 DRETURN
 end
#-h- press            702  asc  25-mar-82 07:28:27  v1.1 (sw-tools v1.1)
 ## press - compress file -int-
 subroutine press (int)
 character getch
 character buf(MAXCHUNK), c, lastc
 integer int, nrep, nsave
 #must have RCODE > (MAXCHUNK + ' ') or RCODE = 0
 
 nsave = 0
 for (lastc=getch(lastc,int); lastc != EOF; lastc = c)
	{
	for (nrep=1; getch(c,int) == lastc; nrep = nrep + 1)
		if (nrep >= MAXCHUNK)	#count repetitions
			break
	if (nrep < THRESH)		#append short string
		for (; nrep > 0; nrep = nrep - 1)
			{
			nsave = nsave + 1
			buf(nsave) = lastc
			if (nsave >= MAXCHUNK)
				call putbuf(buf, nsave)
			}
	else
		{
		call putbuf(buf, nsave)
		call putc(RCODE)
		call putc(lastc)
		call putcnt(nrep)
		}
	}
 call putbuf(buf, nsave)		#put last chunk
 return
 end
#-h- putbuf           246  asc  25-mar-82 07:28:28  v1.1 (sw-tools v1.1)
 ## putbuf - output buf(1) ... buf(nsave),  clear nsave
 subroutine putbuf(buf, nsave)
 character buf(MAXCHUNK)
 integer i, nsave
 
 if (nsave > 0)
	{
	call putcnt(nsave)
	for (i=1; i<=nsave; i=i+1)
		call putc(buf(i))
	}
 nsave = 0
 return
 end
#-h- putcnt           151  asc  25-mar-82 07:28:30  v1.1 (sw-tools v1.1)
## putcnt - output integer offset by ' ' as a character
 subroutine putcnt(int)

 integer int
 character c

 c = int + ' '
 call putc(c)

 return
 end
#-h- cpress.fmt       526  asc  25-mar-82 07:28:58  v1.1 (sw-tools v1.1)
.so ~bin/manhdr
.hd Cpress (1) 15-Jan-79
compress input files
.sy
cpress [file] ...
.ds
cpress compresses runs of repeated characters in the input files.
The output file can eventually be expanded with the tool 'expand'.
 
If no input files are given, or the filename '-' appears, input will
be from the standard input.
.fl
none
.sa
expand
.di
A message is printed if an input file cannot be opened; further processing
is terminated.
.au
From Kernighan & Plauger's 'Software Tools', with modifications by
Debbie Scherrer.
.bu
%%E 1