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decuslib10-07
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43,50433/cmpars.pas
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(*$M-,C-,D-*)
program cmpars,cmpars,cmdird;
TYPE
SETOFCHAR = SET OF CHAR;
{a THING is a declaration used for objects that require conversion
between SIXBIT, half words, and fullwords.}
THING=RECORD
CASE INTEGER OF
1:(SIXBIT:PACKED ARRAY[1:6] OF 0..77B);
2:(HALF:PACKED ARRAY[1:2] OF 0..777777B);
3:(FULL:INTEGER)
END;
{this is a string of characters, typically a file spec. Note that the
actual string is variable length. The 150 upper bound is not actually
enforced. See below.}
STRING=PACKED ARRAY[1:150] OF CHAR;
{this is the long form gtjfn block}
gtjfnblock=record
d0,d1:integer;
gjdev:^string;
gjdir:^string;
gjnam:^string;
gjext:^string
end;
{a BLOCK is a file control block, the internal data structure representing
the state of a file. For the structure of this block, see PASUNV.MAC}
BLOCK=ARRAY[0:32B] OF THING;
VAR
DELIMS,OCTALS:SETOFCHAR;
INITPROCEDURE;
BEGIN
DELIMS:=[':','.','[',',',']'];
OCTALS:=['0','1','2','3','4','5','6','7'];
END;
function cmprsl(s:string):integer;
var i:integer;
begin
i := 0;
while (s[i+1] <> chr(0)) do
i := i+1;
cmprsl := i
end;
PROCEDURE CMGSYM(VAR N:STRING;VAR PT:INTEGER;last:integer;var item:alfa;
var done:Boolean);
var ipt:integer;
CH:CHAR;
doingoctal:Boolean;
{GETOCT is a subprocedure used by GETSYM to handle the syntax
#octal digits. As in PIP, we allow this to specify otherwise
untypable names, e.g. #2020000033.UFD. Reads 2 digits and
returns the character (presumably untypable) that they
describe in sixbit. If just one digit there, assume 0 first
digit. The virtual # referred to below is if there are more than
2 digits. Then we assume a # after the first two.}
FUNCTION GETOCT:CHAR;
%CALLED WITH PT POINTING AT # (REAL OR VIRTUAL). GETS UP TO 2
FOLLOWING OCTAL DIGITS. LEAVES PT POINTING AT LAST CHAR GOT\
var oct:integer;
BEGIN
OCT:=0;
IF(PT+1)<=LAST {PT+1 used because PT is the #}
THEN IF N[PT+1] IN OCTALS
THEN BEGIN
OCT := 8 * (ORD(N[PT+1]) - 60B);
PT := PT+1;
IF ((PT+1) <= LAST)
THEN IF (N[PT+1] IN OCTALS)
THEN BEGIN
OCT := OCT + (ORD(N[PT+1]) - 60B);
PT := PT+1;
END
END;
GETOCT := CHR (OCT + 40B);
END;
{GETSYM gets the next atom and puts it in ITEM. An atom is anything
between delimiters, or a delimiter. So each delimiter will be returned
as a separate atom. Updates PT to point to the character after the
last one scanned. This routine truncates at 6 characters, but scans
more if they are there (usual DEC filename syntax).}
BEGIN %GETSYM\
ITEM:=' ';
IPT:=1; {IPT is pointing into ITEM. Where the output is put.}
CH:='A';
DOINGOCTAL:=FALSE;
{skip blanks and nulls}
WHILE(PT<=LAST) AND ((N[PT]=' ') OR (ORD(N[PT])=0))
DO PT:=PT+1;
{scan until come to end of string or a delimiter}
WHILE(PT<=LAST) AND NOT(CH IN DELIMS) DO
BEGIN
%DOINGOCTAL IS ON IF CHAR AT PT SHOULD BE INTERPRETED AS OCTAL\
IF NOT (N[PT] IN OCTALS) THEN DOINGOCTAL := FALSE;
{map lower case to upper, turn ctl characters into blanks}
CH:=N[PT]; IF ORD(CH)>=140B THEN CH:=CHR(ORD(CH)-40B);
IF ORD(CH)=11B THEN CH:= ' ';
{if octal, make sure DOINGOCTAL is on and PT is pointing to
real or virtual #}
IF CH='#'
THEN DOINGOCTAL := TRUE
%GETOCT WILL START LOOKING AT PT+1, LEAVE PT AT LAST IT SAW\
ELSE IF DOINGOCTAL
THEN PT := PT-1;
%GETOCT EXPECT PT IS #, SO THIS MAKES IT START LOOKING AT
PT. WE HAVE VERIFIED PT IS OCTAL (FIRST LINE OF ROUTINE), SO
GETOCT WILL AT LEAST GOBBLE A DIGIT AT PT\
{copy character to ITEM unless already 6}
IF IPT<=6
THEN IF DOINGOCTAL
THEN ITEM[IPT]:=GETOCT
ELSE ITEM[IPT]:=CH;
PT:=PT+1; IPT:=IPT+1;
END;
IF PT>LAST THEN DONE:=TRUE;
{if we have a delimiter and IPT is 2, that means the delimiter
was the first thing we saw. In that case, we want to return
just the delimiter. If IPT > 2, then it is a delimiter that
marks the end of a normal atom, and we save the delimiter
for next time}
IF (CH IN DELIMS) AND (IPT>2)
THEN BEGIN IF IPT<=7 THEN ITEM[IPT-1]:=' '; IPT:=IPT-1; PT:=PT-1; DONE:= FALSE END;
END;
{CVSIX take the item that is in ITEM and puts it in offset INDEX in the
file control block we are building up. SIXBIT conversion is done.}
PROCEDURE CMCVSIX(item:alfa;var dummy:block;INDEX:INTEGER);
var ipt:integer;
BEGIN
FOR IPT:=1 TO 6 DO
BEGIN
DUMMY[INDEX].SIXBIT[IPT]:=ORD(ITEM[IPT])-40B;
END;
END;
{CVINT takes the item that is in ITEM and puts it in the reference
variable I. It assumes ITEM is the character representation of an
octal number.}
function cmcvint(item:alfa;var i:integer):Boolean;
var ipt:integer;
BEGIN
i:=0; cmcvint:= true;
ipt := 1;
repeat
if item[ipt] in octals
then begin i:=i*8 + ord(item[ipt])-60b; ipt := ipt+1 end
until (ipt > 6) or not (item[ipt] in octals);
while ipt <= 6 do
begin
if item[ipt] <> ' '
then cmcvint := false;
ipt := ipt+1
end
END;
function cmdirparse(var n:string;var pt:integer;last:integer;
var dummy:block;var done:Boolean;var olen:integer):Boolean;
var i:integer;bo:boolean;item:alfa;
begin
cmdirparse := false;
CALLI(24B,0,0,I,BO); {get our PPN}
DUMMY[20B].FULL:=I; {supply our PPN as default, in case of [,]}
if done then goto 6;
CMGSYM(N,PT,LAST,ITEM,DONE); {now get an atom. Can be project number or comma if [,]}
IF(ITEM[1]=',') THEN {if no proj number, we already have default}
ELSE IF(ITEM[1] IN DELIMS) THEN GOTO 6 {junk}
ELSE BEGIN
if cmcvint(item,i)
then dummy[20b].half[1]:=i {put proj number where it goes}
else goto 6;
if done then goto 6;
CMGSYM(N,PT,LAST,ITEM,DONE); {comma after proj number - must be there}
IF NOT(ITEM[1] = ',') THEN GOTO 6;
END;
if done then begin olen := last; goto 5 end;
CMGSYM(N,PT,LAST,ITEM,DONE); {we have now seen [proj, This is prgr num
or ] in case of [,], or comma in case of [,,SFD]}
IF(ITEM[1]=',') THEN GOTO 4
ELSE IF(ITEM[1] IN DELIMS) THEN BEGIN OLEN := PT-2; GOTO 5 END
ELSE BEGIN
if cmcvint(item,i) {here if we have a real prgrm nummber - put it away}
then dummy[20b].half[2]:=i
else goto 6;
if done then begin olen := last; goto 5 end;
CMGSYM(N,PT,LAST,ITEM,DONE); {and get delimiter after prgm number - , or ]}
IF ITEM[1]=',' THEN GOTO 4
ELSE IF (ITEM[1] IN DELIMS) THEN BEGIN OLEN := PT-2; GOTO 5 END
ELSE GOTO 6;
END;
{State 4 - we have seen the , after a PPN - scan for SFD's}
4:
FOR I:=1 TO 5 DO
BEGIN
if done then goto 6;
CMGSYM(N,PT,LAST,ITEM,DONE); {this is an SFD}
IF (ITEM[1] IN DELIMS) THEN GOTO 6;
CMCVSIX(item,dummy,20B+I);
IF DONE THEN BEGIN OLEN := LAST; GOTO 5 END;
CMGSYM(N,PT,LAST,ITEM,DONE); {this is comma if more SFD's, or ] if no more}
IF ITEM[1] = ',' THEN
ELSE IF ITEM[1] IN DELIMS THEN BEGIN OLEN := PT-2; GOTO 5 END
END; {normal exit from this loop is finding ] and going to 5}
GOTO 6; {didn't terminate with ]}
5:
cmdirparse := true;
6:
END;
function cmdird(var n:string;SFDOK:Boolean):integer;
type longppn=record
dum1,dum2:integer;
levels:array[20B:25B] of integer;
end;
var dummy:block;
olen,i,last,pt:integer;
done:Boolean;
convert:record case Boolean of
true:(int:integer);
false:(pt:^longppn)
end;
begin
{Initialization}
delims := [chr(0)..chr(177B)] - ['a'..'z','A'..'Z','0'..'9'];
last := cmprsl(n);
done := false;
pt := 2;
for i := 20B to 25B do dummy[i].full := 0;
if (n[1] <> '[') or (n[last] <> ']')
then convert.int := 0
else if not cmdirparse(n,pt,last,dummy,done,olen)
then convert.int := 0
else if olen <> last-1 {did we parse the whole thing?}
then convert.int := 0
else if (dummy[21B].full <> 0) and not SFDOK
then convert.int := 0
else begin
if dummy[21B].full <> 0 {sfd's}
then begin
new(convert.pt);
with convert.pt^ do
begin
dum1 := 0;
dum2 := 0;
for i := 20B to 25B do
levels[i] := dummy[i].full
end
end
else convert.int := dummy[20B].full {simple PPN}
end;
cmdird := convert.int
end;
{PARSE is the main file name parser. It is a finite state machine.
B - file control block. See PASUNV.MAC. In assembly language,
you should pass the address of the control block in AC 2 (REG)
N - file name. This is a string of arbitrary length. Note that
error checking is turned off, so bounds are not checked on
this array. So the code below must be very careful to handle
the bounds properly. This is the only way to handle arbitrary
length strings in Pascal. In assembly language, put the
address of the string in AC 3 (REG1).
COUNT - length of the string N. The compiler supplies this in
AC 4 (REG2) for RESET, REWRITE, etc. Also the pseudo-type
STRING will cause a string to be tranmitted in one AC and
the length in the next. Be very careful not to refer to
anything before N[COUNT], as bounds checking is turned off.
This routine parses a standard DEC10 file spec and puts the resulting
sixbit stuff in the appropriate places in the file control block.
It returns the number of characters gobbled.
}
FUNCTION CMPARS(VAR B:BLOCK; VAR N:STRING; COUNT:INTEGER;
VAR GB:GTJFNBLOCK):INTEGER;
VAR
ITEM:ALFA; {Current atom, returned by GETSYM}
BO,DONE:BOOLEAN;
LASTSEEN,LAST,I,OCT:INTEGER;
DUMMY:BLOCK; {We build up the block in DUMMY. If there is an error,
we do not want to have changed the real thing.}
OLEN,OPT,PT:INTEGER; {PT - next character to be scanned, index into N}
{Beginning of main scanner logic}
BEGIN
{Initialization}
delims := [chr(0)..chr(177B)] - ['a'..'z','A'..'Z','0'..'9'];
DONE:=FALSE;
LAST:=COUNT;
PT:=1;
OLEN := -1;
{These are default values for the file control block}
b[1].full:=1;
DUMMY[14B].FULL:=0;
DUMMY[15B].FULL:=0;
DUMMY[12B].FULL:=0;
FOR I:=20B TO 20B+5 DO
DUMMY[I].FULL:=0;
{Here is the beginning of the finite state machine}
{Note that this code is as careful as possible about syntax errors,
so whenever a name is expected, you have to check to be sure you
didn't get a delimiter instead, or end of string.}
{State 0: parse the first atom, file name or device}
CMGSYM(N,PT,LAST,ITEM,DONE);
if item[1] in delims then begin olen := 0; goto 5 end;
CMCVSIX(item,dummy,14B); {use as file name.}
IF DONE THEN BEGIN OLEN := COUNT; GOTO 5 END;
OLEN := PT-1;
CMGSYM(N,PT,LAST,ITEM,DONE); {get the delimiter}
IF ITEM[1]=':' THEN GOTO 1
ELSE IF ITEM[1]='.' THEN GOTO 2
ELSE IF ITEM[1]='[' THEN GOTO 3
ELSE GOTO 5;
{State 1: a device name has just been parsed. It was
interpreted as a file name, so copy to device
name field. If there is another atom, it is
unambiguously a file name.}
1:
DUMMY[12B]:=DUMMY[14B]; DUMMY[14B].FULL := 0;
IF DONE THEN BEGIN OLEN := COUNT; GOTO 5 END;
OLEN := PT-1;
CMGSYM(N,PT,LAST,ITEM,DONE); {get next atom. If valid, it will be a file name}
IF(ITEM[1] IN DELIMS) THEN GOTO 5;
CMCVSIX(item,dummy,14B);
IF DONE THEN BEGIN OLEN := COUNT; GOTO 5 END;
OLEN := PT-1;
CMGSYM(N,PT,LAST,ITEM,DONE); {this is the delimiter after the file name}
IF ITEM[1]='.' THEN GOTO 2
ELSE IF ITEM[1]='[' THEN GOTO 3
ELSE GOTO 5;
{State 2: here after file name and dot. Can be extension, PPN, or
end of string}
2:
DUMMY[15B].HALF[2] := 777777B; {allow us to detect null ext}
IF DONE THEN BEGIN OLEN := COUNT; GOTO 5 END;
OLEN := PT-1;
CMGSYM(N,PT,LAST,ITEM,DONE); {next atom: PPN, extension, or junk}
IF(ITEM[1]='[') THEN GOTO 3; {PPN}
IF(ITEM[1] IN DELIMS) THEN GOTO 5; {junk}
CMCVSIX(item,dummy,15B); {extension: put it in extension field}
IF DONE THEN BEGIN OLEN := COUNT; GOTO 5 END;
OLEN := PT-1;
CMGSYM(N,PT,LAST,ITEM,DONE); {delimiter after extension}
IF(ITEM[1]='[') THEN GOTO 3
ELSE GOTO 5;
{State 3: here after a [. Had better be a PPN of some sort}
3: if not cmdirparse(n,pt,last,dummy,done,olen)
then goto 6
else if n[olen+1] <> ']'
then goto 6
else begin
olen := olen+1; {gobble the ]}
goto 5
end;
{State 5 - finished valid scan}
5:
{now we can copy the data into the real control block, since we know
it is valid}
if item[1] = chr(33B) {see if recognition is needed}
then begin
{yes - first figure out the last thing we saw, since completion shows
only for fields after that}
lastseen := 0;
if dummy[12B].full <> 0
then lastseen := 12B;
if dummy[14B].full <> 0
then lastseen := 14B;
if dummy[15B].full <> 0
then lastseen := 15B;
if dummy[20B].full <> 0
then lastseen := 20B;
end
else lastseen := 100; {high enough that no field shows}
opt := olen; {place in atom buffer for recognized chars}
if (dummy[12B].full = 0) and (ord(gb.gjdev) <> 0) {default dev?}
then begin
pt := 1;
cmgsym(gb.gjdev^,pt,cmprsl(gb.gjdev^),item,done);
cmcvsix(item,dummy,12B);
if lastseen < 12B
then begin
for i := 1 to pt-1 do
n[opt + i] := gb.gjdev^[i];
n[opt + pt-1 + 1] := ':';
opt := opt + pt-1 + 1
end
end;
if (dummy[14B].full = 0) and (ord(gb.gjnam) <> 0) {default name?}
then begin
pt := 1;
cmgsym(gb.gjnam^,pt,cmprsl(gb.gjnam^),item,done);
cmcvsix(item,dummy,14B);
if lastseen < 14B
then begin
for i := 1 to pt-1 do
n[opt + i] := gb.gjnam^[i];
opt := opt + pt-1
end
end;
if (dummy[15B].full = 0) and (ord(gb.gjext) <> 0) {default ext?}
then begin
pt := 1;
cmgsym(gb.gjext^,pt,cmprsl(gb.gjext^),item,done);
cmcvsix(item,dummy,15B);
if lastseen < 15B
then begin
n[opt + 1] := '.';
for i := 1 to pt-1 do
n[opt+1 + i] := gb.gjext^[i];
opt := opt + pt-1 + 1
end
end;
n[opt+1] := chr(0);
if (dummy[12B].full = 0) and (dummy[14B].full = 0)
then goto 6; {no name given}
if dummy[14B].full = 0 {if no name, use device}
then dummy[14B] := dummy[12B];
if dummy[12B].full = 0
then begin
DUMMY[12B].HALF[1]:=446353B; {DSK}
DUMMY[12B].HALF[2]:=0;
end;
B[12B]:=DUMMY[12B];
B[14B]:=DUMMY[14B];
B[15B]:=DUMMY[15B];
B[15B].HALF[2] := 0;
FOR I:=20B TO 20B+5 DO
B[I]:=DUMMY[I];
b[1].full:=0;
goto 7;
6:
{error - note that going directly here results in an error. The caller
tests EOF to see if this worked. EOF is initialized to true, and is
only set false in 5 above.}
n[pt] := chr(0);
olen := pt-1;
7:
cmpars := olen
END {of cmpars}.