% Copyright (C) 2001-2021 Artifex Software, Inc.
% All Rights Reserved.
%
% This software is provided AS-IS with no warranty, either express or
% implied.
%
% This software is distributed under license and may not be copied,
% modified or distributed except as expressly authorized under the terms
% of the license contained in the file LICENSE in this distribution.
%
% Refer to licensing information at http://www.artifex.com or contact
% Artifex Software, Inc., 1305 Grant Avenue - Suite 200, Novato,
% CA 94945, U.S.A., +1(415)492-9861, for further information.
%
% Implementation of ReusableStreamDecode filter.
% This file must be loaded after gs_lev2.ps and gs_res.ps.
level2dict begin
% ------ ReusableStreamDecode filter ------ %
/.reusablestreamdecode { % <source> <dict> .reusablestreamdecode <file>
% <source> .reusablestreamdecode <file>
% Collect the filter parameters.
dup type /dicttype eq { 2 copy } { dup 0 dict } ifelse
dup .rsdparams
% Construct the filter pipeline.
% The very first filter should use the value of CloseSource
% from the RSD dictionary; all the others should have
% CloseSource = true.
% Stack: source dict filters parms
2 index /CloseSource .knownget not { //false } if 5 -1 roll
% Stack: dict filters parms CloseSource source
0 1 5 index length 1 sub {
4 index 1 index get
% Stack: dict filters parms CloseSource source index filtname
4 index //null eq {
0 dict
} {
4 index 2 index get dup //null eq { pop 0 dict} if
} ifelse
3 -1 roll pop exch filter
exch pop //true exch % set CloseSource for further filters
} for
% If AsyncRead is true, try to create the filter directly.
% Stack: dict filters parms CloseSource source
4 index /AsyncRead .knownget not { //false } if {
1 index { .reusablestream } //.internalstopped exec
} {
//null //true
} ifelse {
pop
% No luck. Read the entire contents of the stream now.
dup type /filetype ne {
% Make a stream from a procedure or string data source.
0 () .subfiledecode
} if
% We must allocate the string in the same VM space as its
% source, since the reusable stream must be allocated there.
.currentglobal 1 index gcheck .setglobal exch
currentpacking //false setpacking exch
2 dict begin /filelen 0 def % scratch dict for filelen and pos (below).
% Stack: dict filters parms CloseSource oldglobal oldpacking file
[ exch {
dup 40000 string readstring
/filelen 2 index length filelen add def % accumulate filelen
not { exit } if exch
} loop
exch pop
]
{ filelen string } stopped { % try allocating a single string
pop % couldn't make a string - discard filelen value
} {
% transfer the array-of-strings to the single string.
% stack: ... [() ...] string
/pos 0 def exch {
1 index exch pos exch putinterval /pos pos 40000 add def
} forall
} ifelse
% top of stack is either array of strings or one string == stream_data
end % done with scratch dict
% Stack: dict filters parms CloseSource oldglobal oldpacking stream_data
3 1 roll setpacking setglobal
% Stack: dict filters parms CloseSource stream_data
1 index .reusablestream
} if
% We created the stream successfully: clean up.
4 { exch pop } repeat
1 index type /dicttype eq { exch pop } if exch pop
} odef
filterdict /ReusableStreamDecode /.reusablestreamdecode load put
end % level2dict
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