www.pudn.com > freetype.rar > ftsysio.h

#ifndef __FT_SYSTEM_IO_H__ 
#define __FT_SYSTEM_IO_H__ 
 
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 /*****    NOTE: THE CONTENT OF THIS DMFILE IS NOT CURRENTLY USED      *****/ 
 /*****          IN NORMAL BUILDS.  CONSIDER IT EXPERIMENTAL.        *****/ 
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 /******************************************************************** 
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#include "ft2build.h" 
#include "freetype/internal/ftobject.h" 
 
FT_BEGIN_HEADER 
 
 /*@******************************************************************* 
  * 
  * @type: FT_Stream 
  * 
  * @description: 
  *   handle to an input stream object. These are also @FT_Object handles 
  */ 
  #ifndef cDef_FT_Stream 
  # define cDef_FT_Stream 
  typedef struct FT_StreamRec_*    FT_Stream; 
  #endif 
 
 
 /*@******************************************************************* 
  * 
  * @type: FT_Stream_Class 
  * 
  * @description: 
  *   opaque handle to a @FT_Stream_ClassRec class structure describing 
  *   the methods of input streams 
  */ 
  typedef const struct FT_Stream_ClassRec_*   FT_Stream_Class; 
 
 
 /*@******************************************************************* 
  * 
  * @functype: FT_Stream_ReadFunc 
  * 
  * @description: 
  *   a method used to read bytes from an input stream into memory 
  * 
  * @input: 
  *   stream  :: target stream handle 
  *   buffer  :: target buffer address 
  *   size    :: number of bytes to read 
  * 
  * @return: 
  *   number of bytes effectively read. Must be <= 'size'. 
  */ 
  typedef FT_ULong  (*FT_Stream_ReadFunc)( FT_Stream   stream, 
                                           FT_Byte*    buffer, 
                                           FT_ULong    size ); 
 
 
 /*@******************************************************************* 
  * 
  * @functype: FT_Stream_SeekFunc 
  * 
  * @description: 
  *   a method used to seek to a new position within a stream 
  * 
  * @input: 
  *   stream  :: target stream handle 
  *   pos     :: new read position, from start of stream 
  * 
  * @return: 
  *   error code. 0 means success 
  */ 
  typedef FT_Error  (*FT_Stream_SeekFunc)( FT_Stream   stream, 
                                           FT_ULong    pos ); 
 
 
 /*@******************************************************************* 
  * 
  * @struct: FT_Stream_ClassRec 
  * 
  * @description: 
  *   a structure used to describe an input stream class 
  * 
  * @input: 
  *   clazz       :: root @FT_ClassRec fields 
  *   stream_read :: stream byte read method 
  *   stream_seek :: stream seek method 
  */ 
  typedef struct FT_Stream_ClassRec_ 
  { 
    FT_ClassRec          clazz; 
    FT_Stream_ReadFunc   stream_read; 
    FT_Stream_SeekFunc   stream_seek; 
 
  } FT_Stream_ClassRec; 
 
 /* */ 
 
#define  FT_STREAM_CLASS(x)        ((FT_Stream_Class)(x)) 
#define  FT_STREAM_CLASS__READ(x)  FT_STREAM_CLASS(x)->stream_read 
#define  FT_STREAM_CLASS__SEEK(x)  FT_STREAM_CLASS(x)->stream_seek; 
 
 /*@******************************************************************* 
  * 
  * @struct: FT_StreamRec 
  * 
  * @description: 
  *   the input stream object structure. See @FT_Stream_ClassRec for 
  *   its class descriptor 
  * 
  * @fields: 
  *   object      :: root @FT_ObjectRec fields 
  *   size        :: size of stream in bytes (0 if unknown) 
  *   pos         :: current position within stream 
  *   base        :: for memory-based streams, the address of the stream's 
  *                  first data byte in memory. NULL otherwise 
  * 
  *   cursor      :: the current cursor position within an input stream 
  *                  frame. Only valid within a FT_FRAME_ENTER .. FT_FRAME_EXIT 
  *                  block; NULL otherwise 
  * 
  *   limit       :: the current frame limit within a FT_FRAME_ENTER .. 
  *                  FT_FRAME_EXIT block. NULL otherwise 
  */ 
  typedef struct FT_StreamRec_ 
  { 
    FT_ObjectRec        object; 
    FT_ULong            size; 
    FT_ULong            pos; 
    const FT_Byte*      base; 
    const FT_Byte*      cursor; 
    const FT_Byte*      limit; 
 
  } FT_StreamRec; 
 
 /* some useful macros */ 
#define  FT_STREAM(x)    ((FT_Stream)(x)) 
#define  FT_STREAM_P(x)  ((FT_Stream*)(x)) 
 
#define  FT_STREAM__READ(x)  FT_STREAM_CLASS__READ(FT_OBJECT__CLASS(x)) 
#define  FT_STREAM__SEEK(x)  FT_STREAM_CLASS__SEEK(FT_OBJECT__CLASS(x)) 
 
#define  FT_STREAM_IS_BASED(x)  ( FT_STREAM(x)->base != NULL ) 
 
 /* */ 
 
 /* create new memory-based stream */ 
  FT_BASE( FT_Error )   ft_stream_new_memory( const FT_Byte*  stream_base, 
                                              FT_ULong        stream_size, 
                                              FT_Memory       memory, 
                                              FT_Stream      *astream ); 
 
  FT_BASE( FT_Error )   ft_stream_new_iso( const char*  pathanme, 
                                           FT_Memory    memory, 
                                           FT_Stream   *astream ); 
 
 
 /* handle to default stream class implementation for a given build */ 
 /* this is used by "FT_New_Face"                                   */ 
 /*                                                                 */ 
  FT_APIVAR( FT_Type )   ft_stream_default_type; 
 
FT_END_HEADER 
 
#endif /* __FT_SYSTEM_STREAM_H__ */