src/ftglue.h

   1 /* ftglue.c: Glue code for compiling the OpenType code from
   2  *           FreeType 1 using only the public API of FreeType 2
   3  *
   4  * By David Turner, The FreeType Project (www.freetype.org)
   5  *
   6  * This code is explicitely put in the public domain
   7  *
   8  * ==========================================================================
   9  *
  10  * the OpenType parser codes was originally written as an extension to
  11  * FreeType 1.x. As such, its source code was embedded within the library,
  12  * and used many internal FreeType functions to deal with memory and
  13  * stream i/o.
  14  *
  15  * When it was 'salvaged' for Pango and Qt, the code was "ported" to FreeType 2,
  16  * which basically means that some macro tricks were performed in order to
  17  * directly access FT2 _internal_ functions.
  18  *
  19  * these functions were never part of FT2 public API, and _did_ change between
  20  * various releases. This created chaos for many users: when they upgraded the
  21  * FreeType library on their system, they couldn't run Gnome anymore since
  22  * Pango refused to link.
  23  *
  24  * Very fortunately, it's possible to completely avoid this problem because
  25  * the FT_StreamRec and FT_MemoryRec structure types, which describe how
  26  * memory and stream implementations interface with the rest of the font
  27  * library, have always been part of the public API, and never changed.
  28  *
  29  * What we do thus is re-implement, within the OpenType parser, the few
  30  * functions that depend on them. This only adds one or two kilobytes of
  31  * code, and ensures that the parser can work with _any_ version
  32  * of FreeType installed on your system. How sweet... !
  33  *
  34  * Note that we assume that Pango doesn't use any other internal functions
  35  * from FreeType. It used to in old versions, but this should no longer
  36  * be the case. (crossing my fingers).
  37  *
  38  *  - David Turner
  39  *  - The FreeType Project  (www.freetype.org)
  40  *
  41  * PS: This "glue" code is explicitely put in the public domain
  42  */
  43 #ifndef __OPENTYPE_FTGLUE_H__
  44 #define __OPENTYPE_FTGLUE_H__
  45
  46 #include "fcint.h"
  47
  48 #include <ft2build.h>
  49 #include FT_FREETYPE_H
  50
  51 FT_BEGIN_HEADER
  52
  53
  54 /* utility macros */
  55 #define  TT_Err_Ok                   FT_Err_Ok
  56 #define  TT_Err_Invalid_Argument     FT_Err_Invalid_Argument
  57 #define  TT_Err_Invalid_Face_Handle  FT_Err_Invalid_Face_Handle
  58 #define  TT_Err_Table_Missing        FT_Err_Table_Missing
  59
  60 #define  SET_ERR(c)   ( (error = (c)) != 0 )
  61
  62 #ifndef FTGLUE_API
  63 #define FTGLUE_API(x)  extern FcPrivate x
  64 #endif
  65
  66 #ifndef FTGLUE_APIDEF
  67 #define FTGLUE_APIDEF(x)  x
  68 #endif
  69
  70 /* stream macros used by the OpenType parser */
  71 #define  FILE_Pos()      ftglue_stream_pos( stream )
  72 #define  FILE_Seek(pos)  SET_ERR( ftglue_stream_seek( stream, pos ) )
  73 #define  ACCESS_Frame(size)  SET_ERR( ftglue_stream_frame_enter( stream, size ) )
  74 #define  FORGET_Frame()      ftglue_stream_frame_exit( stream )
  75
  76 #define  GET_Byte()      (*stream->cursor++)
  77 #define  GET_Short()     (stream->cursor += 2, (FT_Short)( \
  78                                 (*(((FT_Byte*)stream->cursor)-2) << 8) | \
  79                                  *(((FT_Byte*)stream->cursor)-1) \
  80                          ))
  81 #define  GET_Long()      (stream->cursor += 4, (FT_Long)( \
  82                                 (*(((FT_Byte*)stream->cursor)-4) << 24) | \
  83                                 (*(((FT_Byte*)stream->cursor)-3) << 16) | \
  84                                 (*(((FT_Byte*)stream->cursor)-2) << 8) | \
  85                                  *(((FT_Byte*)stream->cursor)-1) \
  86                          ))
  87
  88 #define  GET_Char()      ((FT_Char)GET_Byte())
  89 #define  GET_UShort()    ((FT_UShort)GET_Short())
  90 #define  GET_ULong()     ((FT_ULong)GET_Long())
  91 #define  GET_Tag4()      GET_ULong()
  92
  93 #define FT_SET_ERROR( expression ) \
  94           ( ( error = (expression) ) != 0 )
  95
  96 FTGLUE_API( FT_Long )
  97 ftglue_stream_pos( FT_Stream   stream );
  98
  99 FTGLUE_API( FT_Error )
 100 ftglue_stream_seek( FT_Stream   stream,
 101                     FT_Long     pos );
 102
 103 FTGLUE_API( FT_Error )
 104 ftglue_stream_frame_enter( FT_Stream   stream,
 105                            FT_ULong    size );
 106
 107 FTGLUE_API( void )
 108 ftglue_stream_frame_exit( FT_Stream  stream );
 109
 110 FTGLUE_API( FT_Byte )
 111 ftglue_stream_get_byte( FT_Stream  stream );
 112
 113 FTGLUE_API( FT_Short )
 114 ftglue_stream_get_short( FT_Stream  stream );
 115
 116 FTGLUE_API( FT_Long )
 117 ftglue_stream_get_long( FT_Stream   stream );
 118
 119 FTGLUE_API( FT_Error )
 120 ftglue_face_goto_table( FT_Face    face,
 121                         FT_ULong   tag,
 122                         FT_Stream  stream );
 123
 124 FTGLUE_API( FT_Pointer )
 125 ftglue_alloc( FT_Memory  memory,
 126               FT_ULong   size,
 127               FT_Error  *perror_ );
 128
 129 FTGLUE_API( FT_Pointer )
 130 ftglue_realloc( FT_Memory   memory,
 131                 FT_Pointer  block,
 132                 FT_ULong    old_size,
 133                 FT_ULong    new_size,
 134                 FT_Error   *perror_ );
 135
 136 FTGLUE_API( void )
 137 ftglue_free( FT_Memory   memory,
 138              FT_Pointer  block );
 139
 140 /* */
 141
 142 FT_END_HEADER
 143
 144 #endif /* __OPENTYPE_FTGLUE_H__ */