ref: a557c515c8c9c01fdb4f6cc850665be05accd84c
dir: /sys/lib/ghostscript/gs_diskf.ps/
% Copyright (C) 1996 Aladdin Enterprises. 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.
%
% For more information about licensing, please refer to
% http://www.ghostscript.com/licensing/. For information on
% commercial licensing, go to http://www.artifex.com/licensing/ or
% contact Artifex Software, Inc., 101 Lucas Valley Road #110,
% San Rafael, CA 94903, U.S.A., +1(415)492-9861.
% $Id: gs_diskf.ps,v 1.4 2002/02/21 21:49:28 giles Exp $
% Support for converting Type 1 fonts without eexec encryption to
% Type 4 fonts that load individual character outlines on demand.
% If DISKFONTS is true, we load individual CharStrings as they are needed.
% (This is intended primarily for machines with very small memories.)
% Initially, the character definition is the file position of the definition;
% this gets replaced with the actual CharString.
% Note that if we are loading characters lazily, CharStrings is writable.
% _Cstring must be long enough to hold the longest CharString for
% a character defined using seac. This is lenIV + 4 * 5 (for the operands
% of sbw, assuming div is not used) + 2 (for sbw) + 3 * 5 (for the operands
% of seac other than the character codes) + 2 * 2 (for the character codes)
% + 2 (for seac), i.e., lenIV + 43.
/_Cstring 60 string def
% When we initially load the font, we call
% <index|charname> <length> <readproc> cskip_C
% to skip over each character definition and return the file position instead.
% This substitutes for the procedure
% <index|charname> <length> string currentfile exch read[hex]string pop
% [encrypt]
% What we actually store in the CharString is fileposition * 1000 + length,
% negated if the string is stored in binary form.
/cskip_C
{ exch dup 1000 ge 3 index type /nametype ne or
{ % This is a Subrs string, or the string is so long we can't represent
% its length. Load it now.
exch exec
}
{ % Record the position and length, and skip the string.
dup currentfile fileposition 1000 mul add
2 index 3 get /readstring cvx eq { neg } if
3 1 roll
dup _Cstring length idiv
{ currentfile _Cstring 3 index 3 get exec pop pop
} repeat
_Cstring length mod _Cstring exch 0 exch getinterval
currentfile exch 3 -1 roll 3 get exec pop pop
}
ifelse
} bind def
% Load a CharString from the file. The font is the top entry
% on the dictionary stack.
/load_C % <charname> <fileposandlength> load_C -
{ dup abs 1000 idiv FontFile exch setfileposition
CharStrings 3 1 roll
.currentglobal CharStrings .gcheck .setglobal exch
dup 0 lt
{ neg 1000 mod string FontFile exch readstring }
{ 1000 mod string FontFile exch readhexstring }
ifelse pop
exch .setglobal
% If the CharStrings aren't encrypted on the file, encrypt now.
Private /-| get 0 get
dup type /nametype ne
{ dup length 5 sub 5 exch getinterval exec }
{ pop }
ifelse dup 4 1 roll put
% If the character is defined with seac, load its components now.
mark exch seac_C
counttomark
{ StandardEncoding exch get dup CharStrings exch get
dup type /integertype eq { load_C } { pop pop } ifelse
} repeat
pop % the mark
} bind def
/seac_C % <charstring> seac_C <achar> <bchar> ..or nothing..
{ dup length _Cstring length le
{ 4330 exch _Cstring .type1decrypt exch pop
dup dup length 2 sub 2 getinterval <0c06> eq % seac
{ dup length
Private /lenIV known { Private /lenIV get } { 4 } ifelse
exch 1 index sub getinterval
% Parse the string just enough to extract the seac information.
% We assume that the only possible operators are hsbw, sbw, and seac,
% and that there are no 5-byte numbers.
mark 0 3 -1 roll
{ exch
{ { dup 32 lt
{ pop 0 }
{ dup 247 lt
{ 139 sub 0 }
{ dup 251 lt
{ 247 sub 256 mul 108 add 1 1 }
{ 251 sub -256 mul -108 add -1 1 }
ifelse
}
ifelse
}
ifelse
} % 0
{ mul add 0 } % 1
}
exch get exec
}
forall pop
counttomark 1 add 2 roll cleartomark % pop all but achar bchar
}
{ pop % not seac
}
ifelse
}
{ pop % punt
}
ifelse
} bind def
% Define replacement procedures for loading fonts.
% If DISKFONTS is true and the body of the font is not encrypted with eexec:
% - Prevent the CharStrings from being made read-only.
% - Substitute a different CharString-reading procedure.
% (eexec disables this because the implicit 'systemdict begin' hides
% the redefinitions that make the scheme work.)
% We assume that:
% - The magic procedures (-|, -!, |-, and |) are defined with
% executeonly or readonly;
% - The contents of the reading procedures are as defined in bdftops.ps;
% - The font includes the code
% <font> /CharStrings <CharStrings> readonly put
/.loadfontdict 6 dict def mark
/begin % push this dict after systemdict
{ dup begin
//systemdict eq { //.loadfontdict begin } if
} bind
/end % match begin
{ currentdict end
//.loadfontdict eq currentdict //systemdict eq and { end } if
} bind
/dict % leave room for FontFile, BuildChar, BuildGlyph
{ 3 add dict
} bind
/executeonly % for reading procedures
{ readonly
}
/noaccess % for Subrs strings and Private dictionary
{ readonly
}
/readonly % for procedures and CharStrings dictionary
{ % We want to take the following non-standard actions here:
% - If the operand is the CharStrings dictionary, do nothing;
% - If the operand is a number (a file position replacing the
% actual CharString), do nothing;
% - If the operand is either of the reading procedures (-| or -!),
% substitute a different one.
dup type /dicttype eq % CharStrings or Private
count 2 gt and
{ 1 index /CharStrings ne { readonly } if }
{ dup type /arraytype eq % procedure or data array
{ dup length 5 ge 1 index xcheck and
{ dup 0 get /string eq
1 index 1 get /currentfile eq and
1 index 2 get /exch eq and
1 index 3 get dup /readstring eq exch /readhexstring eq or and
1 index 4 get /pop eq and
{ /cskip_C cvx 2 packedarray cvx
}
{ readonly
}
ifelse
}
{ readonly
}
ifelse
}
{ dup type /stringtype eq % must be a Subr string
{ readonly }
if
}
ifelse
}
ifelse
} bind
/definefont % to insert BuildChar/Glyph and change FontType
{ dup /FontType get 1 eq
{ dup /FontType 4 put
dup /BuildChar /build_C load put
dup /BuildGlyph /build_C load put
}
if definefont
} bind
counttomark 2 idiv { .loadfontdict 3 1 roll put } repeat pop
.loadfontdict readonly pop
% Define the BuildChar and BuildGlyph procedures for modified fonts.
% A single procedure serves for both.
/build_C % <font> <code|name> build_C -
{ 1 index begin
dup dup type /integertype eq { Encoding exch get } if
% Stack: font code|name name
dup CharStrings exch .knownget not
{ 2 copy eq { exch pop /.notdef exch } if
QUIET not
{ (Substituting .notdef for ) print = flush }
{ pop }
ifelse
/.notdef CharStrings /.notdef get
} if
% Stack: font code|name name charstring
dup type /integertype eq
{ load_C end build_C }
{ end .type1execchar }
ifelse
} bind def