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1 /***************************************************************************/
2 /*                                                                         */
3 /*  ttinterp.h                                                             */
4 /*                                                                         */
5 /*    TrueType bytecode interpreter (specification).                       */
6 /*                                                                         */
7 /*  Copyright 1996-2001, 2002, 2003, 2004, 2005, 2006, 2007, 2010 by       */
8 /*  David Turner, Robert Wilhelm, and Werner Lemberg.                      */
9 /*                                                                         */
10 /*  This file is part of the FreeType project, and may only be used,       */
11 /*  modified, and distributed under the terms of the FreeType project      */
12 /*  license, LICENSE.TXT.  By continuing to use, modify, or distribute     */
13 /*  this file you indicate that you have read the license and              */
14 /*  understand and accept it fully.                                        */
15 /*                                                                         */
16 /***************************************************************************/
17 
18 
19 #ifndef __TTINTERP_H__
20 #define __TTINTERP_H__
21 
22 #include <ft2build.h>
23 #include "ttobjs.h"
24 
25 
26 FT_BEGIN_HEADER
27 
28 
29 #ifndef TT_CONFIG_OPTION_STATIC_INTERPRETER /* indirect implementation */
30 
31 #define EXEC_OP_   TT_ExecContext  exc,
32 #define EXEC_OP    TT_ExecContext  exc
33 #define EXEC_ARG_  exc,
34 #define EXEC_ARG   exc
35 
36 #else                                       /* static implementation */
37 
38 #define EXEC_OP_   /* void */
39 #define EXEC_OP    /* void */
40 #define EXEC_ARG_  /* void */
41 #define EXEC_ARG   /* void */
42 
43 #endif /* TT_CONFIG_OPTION_STATIC_INTERPRETER */
44 
45 
46   /*************************************************************************/
47   /*                                                                       */
48   /* Rounding mode constants.                                              */
49   /*                                                                       */
50 #define TT_Round_Off             5
51 #define TT_Round_To_Half_Grid    0
52 #define TT_Round_To_Grid         1
53 #define TT_Round_To_Double_Grid  2
54 #define TT_Round_Up_To_Grid      4
55 #define TT_Round_Down_To_Grid    3
56 #define TT_Round_Super           6
57 #define TT_Round_Super_45        7
58 
59 
60   /*************************************************************************/
61   /*                                                                       */
62   /* Function types used by the interpreter, depending on various modes    */
63   /* (e.g. the rounding mode, whether to render a vertical or horizontal   */
64   /* line etc).                                                            */
65   /*                                                                       */
66   /*************************************************************************/
67 
68   /* Rounding function */
69   typedef FT_F26Dot6
70   (*TT_Round_Func)( EXEC_OP_ FT_F26Dot6  distance,
71                              FT_F26Dot6  compensation );
72 
73   /* Point displacement along the freedom vector routine */
74   typedef void
75   (*TT_Move_Func)( EXEC_OP_ TT_GlyphZone  zone,
76                             FT_UShort     point,
77                             FT_F26Dot6    distance );
78 
79   /* Distance projection along one of the projection vectors */
80   typedef FT_F26Dot6
81   (*TT_Project_Func)( EXEC_OP_ FT_Pos   dx,
82                                FT_Pos   dy );
83 
84   /* reading a cvt value.  Take care of non-square pixels if necessary */
85   typedef FT_F26Dot6
86   (*TT_Get_CVT_Func)( EXEC_OP_ FT_ULong  idx );
87 
88   /* setting or moving a cvt value.  Take care of non-square pixels  */
89   /* if necessary                                                    */
90   typedef void
91   (*TT_Set_CVT_Func)( EXEC_OP_ FT_ULong    idx,
92                                FT_F26Dot6  value );
93 
94 
95   /*************************************************************************/
96   /*                                                                       */
97   /* This structure defines a call record, used to manage function calls.  */
98   /*                                                                       */
99   typedef struct  TT_CallRec_
100   {
101     FT_Int   Caller_Range;
102     FT_Long  Caller_IP;
103     FT_Long  Cur_Count;
104     FT_Long  Cur_Restart;
105 
106   } TT_CallRec, *TT_CallStack;
107 
108 
109   /*************************************************************************/
110   /*                                                                       */
111   /* The main structure for the interpreter which collects all necessary   */
112   /* variables and states.                                                 */
113   /*                                                                       */
114   typedef struct  TT_ExecContextRec_
115   {
116     TT_Face            face;
117     TT_Size            size;
118     FT_Memory          memory;
119 
120     /* instructions state */
121 
122     FT_Error           error;      /* last execution error */
123 
124     FT_Long            top;        /* top of exec. stack   */
125 
126     FT_UInt            stackSize;  /* size of exec. stack  */
127     FT_Long*           stack;      /* current exec. stack  */
128 
129     FT_Long            args;
130     FT_UInt            new_top;    /* new top after exec.  */
131 
132     TT_GlyphZoneRec    zp0,        /* zone records */
133                        zp1,
134                        zp2,
135                        pts,
136                        twilight;
137 
138     FT_Size_Metrics    metrics;
139     TT_Size_Metrics    tt_metrics; /* size metrics */
140 
141     TT_GraphicsState   GS;         /* current graphics state */
142 
143     FT_Int             curRange;  /* current code range number   */
144     FT_Byte*           code;      /* current code range          */
145     FT_Long            IP;        /* current instruction pointer */
146     FT_Long            codeSize;  /* size of current range       */
147 
148     FT_Byte            opcode;    /* current opcode              */
149     FT_Int             length;    /* length of current opcode    */
150 
151     FT_Bool            step_ins;  /* true if the interpreter must */
152                                   /* increment IP after ins. exec */
153     FT_ULong           cvtSize;
154     FT_Long*           cvt;
155 
156     FT_UInt            glyphSize; /* glyph instructions buffer size */
157     FT_Byte*           glyphIns;  /* glyph instructions buffer */
158 
159     FT_UInt            numFDefs;  /* number of function defs         */
160     FT_UInt            maxFDefs;  /* maximum number of function defs */
161     TT_DefArray        FDefs;     /* table of FDefs entries          */
162 
163     FT_UInt            numIDefs;  /* number of instruction defs */
164     FT_UInt            maxIDefs;  /* maximum number of ins defs */
165     TT_DefArray        IDefs;     /* table of IDefs entries     */
166 
167     FT_UInt            maxFunc;   /* maximum function index     */
168     FT_UInt            maxIns;    /* maximum instruction index  */
169 
170     FT_Int             callTop,    /* top of call stack during execution */
171                        callSize;   /* size of call stack */
172     TT_CallStack       callStack;  /* call stack */
173 
174     FT_UShort          maxPoints;    /* capacity of this context's `pts' */
175     FT_Short           maxContours;  /* record, expressed in points and  */
176                                      /* contours.                        */
177 
178     TT_CodeRangeTable  codeRangeTable;  /* table of valid code ranges */
179                                         /* useful for the debugger   */
180 
181     FT_UShort          storeSize;  /* size of current storage */
182     FT_Long*           storage;    /* storage area            */
183 
184     FT_F26Dot6         period;     /* values used for the */
185     FT_F26Dot6         phase;      /* `SuperRounding'     */
186     FT_F26Dot6         threshold;
187 
188 #if 0
189     /* this seems to be unused */
190     FT_Int             cur_ppem;   /* ppem along the current proj vector */
191 #endif
192 
193     FT_Bool            instruction_trap; /* If `True', the interpreter will */
194                                          /* exit after each instruction     */
195 
196     TT_GraphicsState   default_GS;       /* graphics state resulting from   */
197                                          /* the prep program                */
198     FT_Bool            is_composite;     /* true if the glyph is composite  */
199     FT_Bool            pedantic_hinting; /* true if pedantic interpretation */
200 
201     /* latest interpreter additions */
202 
203     FT_Long            F_dot_P;    /* dot product of freedom and projection */
204                                    /* vectors                               */
205     TT_Round_Func      func_round; /* current rounding function             */
206 
207     TT_Project_Func    func_project,   /* current projection function */
208                        func_dualproj,  /* current dual proj. function */
209                        func_freeProj;  /* current freedom proj. func  */
210 
211     TT_Move_Func       func_move;      /* current point move function */
212     TT_Move_Func       func_move_orig; /* move original position function */
213 
214     TT_Get_CVT_Func    func_read_cvt;  /* read a cvt entry              */
215     TT_Set_CVT_Func    func_write_cvt; /* write a cvt entry (in pixels) */
216     TT_Set_CVT_Func    func_move_cvt;  /* incr a cvt entry (in pixels)  */
217 
218     FT_Bool            grayscale;      /* are we hinting for grayscale? */
219 
220   } TT_ExecContextRec;
221 
222 
223   extern const TT_GraphicsState  tt_default_graphics_state;
224 
225 
226   FT_LOCAL( FT_Error )
227   TT_Goto_CodeRange( TT_ExecContext  exec,
228                      FT_Int          range,
229                      FT_Long         IP );
230 
231   FT_LOCAL( FT_Error )
232   TT_Set_CodeRange( TT_ExecContext  exec,
233                     FT_Int          range,
234                     void*           base,
235                     FT_Long         length );
236 
237   FT_LOCAL( FT_Error )
238   TT_Clear_CodeRange( TT_ExecContext  exec,
239                       FT_Int          range );
240 
241 
242   FT_LOCAL( FT_Error )
243   Update_Max( FT_Memory  memory,
244               FT_ULong*  size,
245               FT_Long    multiplier,
246               void*      _pbuff,
247               FT_ULong   new_max );
248 
249 
250   /*************************************************************************/
251   /*                                                                       */
252   /* <Function>                                                            */
253   /*    TT_New_Context                                                     */
254   /*                                                                       */
255   /* <Description>                                                         */
256   /*    Queries the face context for a given font.  Note that there is     */
257   /*    now a _single_ execution context in the TrueType driver which is   */
258   /*    shared among faces.                                                */
259   /*                                                                       */
260   /* <Input>                                                               */
261   /*    face :: A handle to the source face object.                        */
262   /*                                                                       */
263   /* <Return>                                                              */
264   /*    A handle to the execution context.  Initialized for `face'.        */
265   /*                                                                       */
266   /* <Note>                                                                */
267   /*    Only the glyph loader and debugger should call this function.      */
268   /*                                                                       */
269   FT_EXPORT( TT_ExecContext )
270   TT_New_Context( TT_Driver  driver );
271 
272   FT_LOCAL( FT_Error )
273   TT_Done_Context( TT_ExecContext  exec );
274 
275   FT_LOCAL( FT_Error )
276   TT_Load_Context( TT_ExecContext  exec,
277                    TT_Face         face,
278                    TT_Size         size );
279 
280   FT_LOCAL( FT_Error )
281   TT_Save_Context( TT_ExecContext  exec,
282                    TT_Size         ins );
283 
284   FT_LOCAL( FT_Error )
285   TT_Run_Context( TT_ExecContext  exec,
286                   FT_Bool         debug );
287 
288 
289   /*************************************************************************/
290   /*                                                                       */
291   /* <Function>                                                            */
292   /*    TT_RunIns                                                          */
293   /*                                                                       */
294   /* <Description>                                                         */
295   /*    Executes one or more instruction in the execution context.  This   */
296   /*    is the main function of the TrueType opcode interpreter.           */
297   /*                                                                       */
298   /* <Input>                                                               */
299   /*    exec :: A handle to the target execution context.                  */
300   /*                                                                       */
301   /* <Return>                                                              */
302   /*    FreeType error code.  0 means success.                             */
303   /*                                                                       */
304   /* <Note>                                                                */
305   /*    Only the object manager and debugger should call this function.    */
306   /*                                                                       */
307   /*    This function is publicly exported because it is directly          */
308   /*    invoked by the TrueType debugger.                                  */
309   /*                                                                       */
310   FT_EXPORT( FT_Error )
311   TT_RunIns( TT_ExecContext  exec );
312 
313 
314 FT_END_HEADER
315 
316 #endif /* __TTINTERP_H__ */
317 
318 
319 /* END */
320