475 lines
25 KiB
C
475 lines
25 KiB
C
/***************************************************************************/
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/* */
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/* ttinterp.h */
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/* */
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/* TrueType bytecode intepreter (specification). */
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/* */
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/* Copyright 1996-1999 by */
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/* David Turner, Robert Wilhelm, and Werner Lemberg. */
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/* */
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/* This file is part of the FreeType project, and may only be used */
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/* modified and distributed under the terms of the FreeType project */
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/* license, LICENSE.TXT. By continuing to use, modify, or distribute */
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/* this file you indicate that you have read the license and */
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/* understand and accept it fully. */
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/* */
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/***************************************************************************/
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#ifndef TTINTERP_H
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#define TTINTERP_H
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#include <ttobjs.h>
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#ifdef __cplusplus
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extern "C" {
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#endif
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#ifndef TT_STATIC_INTEPRETER /* indirect implementation */
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#define EXEC_OP_ TT_ExecContext exc,
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#define EXEC_OP TT_ExecContext exc
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#define EXEC_ARG_ exc,
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#define EXEC_ARG exc
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#else /* static implementation */
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#define EXEC_OP_ /* void */
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#define EXEC_OP /* void */
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#define EXEC_ARG_ /* void */
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#define EXEC_ARG /* void */
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#endif /* TT_STATIC_INTERPRETER */
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/*************************************************************************/
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/* */
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/* Rounding mode constants. */
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/* */
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#define TT_Round_Off 5
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#define TT_Round_To_Half_Grid 0
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#define TT_Round_To_Grid 1
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#define TT_Round_To_Double_Grid 2
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#define TT_Round_Up_To_Grid 4
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#define TT_Round_Down_To_Grid 3
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#define TT_Round_Super 6
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#define TT_Round_Super_45 7
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/*************************************************************************/
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/* */
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/* Function types used by the interpreter, depending on various modes */
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/* (e.g. the rounding mode, whether to render a vertical or horizontal */
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/* line etc). */
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/* */
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/*************************************************************************/
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/* Rounding function */
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typedef TT_F26Dot6 (*TT_Round_Func)( EXEC_OP_ TT_F26Dot6 distance,
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TT_F26Dot6 compensation );
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/* Point displacement along the freedom vector routine */
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typedef void (*TT_Move_Func)( EXEC_OP_ FT_GlyphZone* zone,
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TT_UInt point,
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TT_F26Dot6 distance );
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/* Distance projection along one of the projection vectors */
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typedef TT_F26Dot6 (*TT_Project_Func)( EXEC_OP_ TT_Vector* v1,
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TT_Vector* v2 );
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/* reading a cvt value. Take care of non-square pixels if necessary */
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typedef TT_F26Dot6 (*TT_Get_CVT_Func)( EXEC_OP_ TT_ULong index );
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/* setting or moving a cvt value. Take care of non-square pixels */
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/* if necessary */
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typedef void (*TT_Set_CVT_Func)( EXEC_OP_ TT_ULong index,
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TT_F26Dot6 value );
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/*************************************************************************/
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/* */
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/* This structure defines a call record, used to manage function calls. */
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/* */
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typedef struct TT_CallRec_
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{
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TT_Int Caller_Range;
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TT_Long Caller_IP;
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TT_Long Cur_Count;
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TT_Long Cur_Restart;
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} TT_CallRec, *TT_CallStack;
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/*************************************************************************/
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/* */
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/* The main structure for the interpreter which collects all necessary */
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/* variables and states. */
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/* */
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typedef struct TT_ExecContextRec_
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{
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TT_Face face;
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TT_Size size;
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FT_Memory memory;
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/* instructions state */
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TT_Error error; /* last execution error */
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TT_Long top; /* top of exec. stack */
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TT_UInt stackSize; /* size of exec. stack */
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TT_Long* stack; /* current exec. stack */
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TT_Long args;
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TT_UInt new_top; /* new top after exec. */
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FT_GlyphZone zp0, /* zone records */
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zp1,
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zp2,
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pts,
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twilight;
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FT_Size_Metrics metrics;
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TT_Size_Metrics tt_metrics; /* size metrics */
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TT_GraphicsState GS; /* current graphics state */
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TT_Int curRange; /* current code range number */
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TT_Byte* code; /* current code range */
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TT_Long IP; /* current instruction pointer */
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TT_Long codeSize; /* size of current range */
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TT_Byte opcode; /* current opcode */
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TT_Int length; /* length of current opcode */
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TT_Bool step_ins; /* true if the interpreter must */
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/* increment IP after ins. exec */
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TT_Long cvtSize;
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TT_Long* cvt;
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TT_UInt glyphSize; /* glyph instructions buffer size */
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TT_Byte* glyphIns; /* glyph instructions buffer */
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TT_UInt numFDefs; /* number of function defs */
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TT_UInt maxFDefs; /* maximum number of function defs */
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TT_DefArray FDefs; /* table of FDefs entries */
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TT_UInt numIDefs; /* number of instruction defs */
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TT_UInt maxIDefs; /* maximum number of ins defs */
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TT_DefArray IDefs; /* table of IDefs entries */
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TT_UInt maxFunc; /* maximum function index */
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TT_UInt maxIns; /* maximum instruction index */
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TT_Int callTop, /* top of call stack during execution */
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callSize; /* size of call stack */
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TT_CallStack callStack; /* call stack */
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TT_UShort maxPoints; /* capacity of this context's `pts' */
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TT_Short maxContours; /* record, expressed in points and */
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/* contours. */
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TT_CodeRangeTable codeRangeTable; /* table of valid code ranges */
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/* useful for the debugger */
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TT_UShort storeSize; /* size of current storage */
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TT_Long* storage; /* storage area */
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TT_F26Dot6 period; /* values used for the */
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TT_F26Dot6 phase; /* `SuperRounding' */
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TT_F26Dot6 threshold;
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/* this seems to be unused */
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#if 0
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TT_Int cur_ppem; /* ppem along the current proj vector */
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#endif
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TT_Bool instruction_trap; /* If `True', the interpreter will */
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/* exit after each instruction */
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TT_GraphicsState default_GS; /* graphics state resulting from */
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/* the prep program */
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TT_Bool is_composite; /* true if the glyph is composite */
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TT_Bool pedantic_hinting; /* true for pedantic interpretation */
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/* latest interpreter additions */
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TT_Long F_dot_P; /* dot product of freedom and projection */
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/* vectors */
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TT_Round_Func func_round; /* current rounding function */
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TT_Project_Func func_project, /* current projection function */
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func_dualproj, /* current dual proj. function */
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func_freeProj; /* current freedom proj. func */
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TT_Move_Func func_move; /* current point move function */
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TT_Get_CVT_Func func_read_cvt; /* read a cvt entry */
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TT_Set_CVT_Func func_write_cvt; /* write a cvt entry (in pixels) */
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TT_Set_CVT_Func func_move_cvt; /* incr a cvt entry (in pixels) */
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TT_ULong loadSize;
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TT_SubGlyph_Stack loadStack; /* loading subglyph stack */
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} TT_ExecContextRec;
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LOCAL_DEF
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const TT_GraphicsState tt_default_graphics_state;
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/*************************************************************************/
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/* */
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/* <Function> */
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/* TT_Goto_CodeRange */
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/* */
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/* <Description> */
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/* Switches to a new code range (updates the code related elements in */
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/* `exec', and `IP'). */
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/* */
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/* <Input> */
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/* range :: The new execution code range. */
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/* IP :: The new IP in the new code range. */
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/* */
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/* <InOut> */
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/* exec :: The target execution context. */
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/* */
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/* <Return> */
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/* TrueType error code. 0 means success. */
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/* */
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LOCAL_DEF
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TT_Error TT_Goto_CodeRange( TT_ExecContext exec,
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TT_Int range,
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TT_Long IP );
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/*************************************************************************/
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/* */
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/* <Function> */
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/* TT_Set_CodeRange */
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/* */
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/* <Description> */
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/* Sets a code range. */
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/* */
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/* <Input> */
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/* range :: The code range index. */
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/* base :: The new code base. */
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/* length :: The range size in bytes. */
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/* */
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/* <InOut> */
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/* exec :: The target execution context. */
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/* */
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/* <Return> */
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/* TrueType error code. 0 means success. */
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/* */
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LOCAL_DEF
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TT_Error TT_Set_CodeRange( TT_ExecContext exec,
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TT_Int range,
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void* base,
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TT_Long length );
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/*************************************************************************/
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/* */
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/* <Function> */
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/* TT_Clear_CodeRange */
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/* */
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/* <Description> */
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/* Clears a code range. */
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/* */
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/* <Input> */
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/* range :: The code range index. */
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/* */
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/* <InOut> */
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/* exec :: The target execution context. */
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/* */
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/* <Return> */
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/* TrueType error code. 0 means success. */
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/* */
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/* <Note> */
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/* Does not set the Error variable. */
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/* */
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LOCAL_DEF
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TT_Error TT_Clear_CodeRange( TT_ExecContext exec,
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TT_Int range );
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/*************************************************************************/
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/* */
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/* <Function> */
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/* TT_New_Context */
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/* */
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/* <Description> */
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/* Queries the face context for a given font. Note that there is */
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/* now a _single_ execution context in the TrueType driver which is */
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/* shared among faces. */
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/* */
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/* <Input> */
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/* face :: A handle to the source face object. */
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/* */
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/* <Return> */
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/* A handle to the execution context. Initialized for `face'. */
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/* */
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/* <Note> */
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/* Only the glyph loader and debugger should call this function. */
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/* */
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/* This function is publicly exported because it is directly */
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/* invoked by the TrueType debugger.. */
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/* */
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FT_EXPORT_DEF(TT_ExecContext) TT_New_Context( TT_Face face );
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/*************************************************************************/
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/* */
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/* <Function> */
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/* TT_Done_Context */
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/* */
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/* <Description> */
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/* Discards an execution context. */
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/* */
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/* <Input> */
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/* exec :: A handle to the target execution context. */
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/* */
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/* <Return> */
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/* TrueType error code. 0 means success. */
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/* */
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/* <Note> */
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/* Only the glyph loader and debugger should call this function. */
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/* */
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LOCAL_DEF
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TT_Error TT_Done_Context( TT_ExecContext exec );
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/*************************************************************************/
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/* */
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/* <Function> */
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/* TT_Destroy_Context */
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/* */
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/* <Description> */
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/* Destroys a given context. */
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/* */
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/* <Input> */
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/* exec :: A handle to the target execution context. */
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/* memory :: A handle to the parent memory object. */
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/* */
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/* <Return> */
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/* TrueType error code. 0 means success. */
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/* */
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/* <Note> */
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/* Only the glyph loader and debugger should call this function. */
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/* */
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LOCAL_DEF
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TT_Error TT_Destroy_Context( TT_ExecContext exec,
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FT_Memory memory );
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/*************************************************************************/
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/* */
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/* <Function> */
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/* TT_Load_Context */
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/* */
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/* <Description> */
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/* Prepare an execution context for glyph hinting. */
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/* */
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/* <Input> */
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/* exec :: A handle to the target execution context. */
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/* face :: A handle to the source face object. */
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/* size :: A handle to the source size object. */
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/* */
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/* <Return> */
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/* TrueType error code. 0 means success. */
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/* */
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/* <Note> */
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/* Only the glyph loader and debugger should call this function. */
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/* */
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LOCAL_DEF
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TT_Error TT_Load_Context( TT_ExecContext exec,
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TT_Face face,
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TT_Size size );
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/*************************************************************************/
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/* */
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/* <Function> */
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/* TT_Save_Context */
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/* */
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/* <Description> */
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/* Saves the code ranges in a `size' object. */
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/* */
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/* <Input> */
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/* exec :: A handle to the source execution context. */
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/* */
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/* <Output> */
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/* ins :: A handle to the target size object. */
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/* */
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/* <Return> */
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/* TrueType error code. 0 means success. */
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/* */
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/* <Note> */
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/* Only the glyph loader and debugger should call this function. */
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/* */
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LOCAL_DEF
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TT_Error TT_Save_Context( TT_ExecContext exec,
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TT_Size ins );
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/*************************************************************************/
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/* */
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/* <Function> */
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/* TT_Run_Context */
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/* */
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/* <Description> */
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/* Executes one or more instructions in the execution context. */
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/* */
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/* <Input> */
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/* exec :: A handle to the target execution context. */
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/* */
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/* debug :: A Boolean flag. If set, the function sets some internal */
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/* variables and returns immediately, otherwise TT_RunIns() */
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/* is called. */
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/* */
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/* <Return> */
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/* TrueTyoe error code. 0 means success. */
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/* */
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/* <Note> */
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/* Only the glyph loader and debugger should call this function. */
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/* */
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LOCAL_DEF
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TT_Error TT_Run_Context( TT_ExecContext exec,
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TT_Bool debug );
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/*************************************************************************/
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/* */
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/* <Function> */
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/* TT_RunIns */
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/* */
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/* <Description> */
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/* Executes one or more instruction in the execution context. This */
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/* is the main function of the TrueType opcode interpreter. */
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/* */
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/* <Input> */
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/* exec :: A handle to the target execution context. */
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/* */
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/* <Return> */
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/* TrueType error code. 0 means success. */
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/* */
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/* <Note> */
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/* Only object manager and debugger should call this function. */
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/* */
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/* This function is publicly exported because it is directly */
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/* invoked by the TrueType debugger.. */
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/* */
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FT_EXPORT_DEF(TT_Error) TT_RunIns( TT_ExecContext exec );
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#ifdef __cplusplus
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}
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#endif
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#endif /* TTINTERP_H */
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/* END */
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