ftsystem.h

一个Xpdf应用的例子

/***************************************************************************/
/*                                                                         */
/*  ftsystem.h                                                             */
/*                                                                         */
/*    FreeType low-level system interface definition (specification).      */
/*                                                                         */
/*  Copyright 1996-2001 by                                                 */
/*  David Turner, Robert Wilhelm, and Werner Lemberg.                      */
/*                                                                         */
/*  This file is part of the FreeType project, and may only be used,       */
/*  modified, and distributed under the terms of the FreeType project      */
/*  license, LICENSE.TXT.  By continuing to use, modify, or distribute     */
/*  this file you indicate that you have read the license and              */
/*  understand and accept it fully.                                        */
/*                                                                         */
/***************************************************************************/


#ifndef __FTSYSTEM_H__
#define __FTSYSTEM_H__


#include <ft2build.h>


FT_BEGIN_HEADER

  /*************************************************************************/
  /*                                                                       */
  /* <Section>                                                             */
  /*    system_interface                                                   */
  /*                                                                       */
  /* <Title>                                                               */
  /*    System Interface                                                   */
  /*                                                                       */
  /* <Abstract>                                                            */
  /*    How FreeType manages memory and i/o.                               */
  /*                                                                       */
  /* <Description>                                                         */
  /*    This section contains various definitions related to memory        */
  /*    management and i/o access.  You need to understand this            */
  /*    information if you want to use a custom memory manager or you own  */
  /*    input i/o streams.                                                 */
  /*                                                                       */
  /*************************************************************************/


  /*************************************************************************/
  /*                                                                       */
  /*                  M E M O R Y   M A N A G E M E N T                    */
  /*                                                                       */
  /*************************************************************************/


  /*************************************************************************/
  /*                                                                       */
  /* @type:                                                                */
  /*    FT_Memory                                                          */
  /*                                                                       */
  /* @description:                                                         */
  /*    A handle to a given memory manager object, defined with a          */
  /*    @FT_MemoryRec structure.                                           */
  /*                                                                       */
  typedef struct FT_MemoryRec_*  FT_Memory;


  /*************************************************************************/
  /*                                                                       */
  /* @functype:                                                            */
  /*    FT_Alloc_Func                                                      */
  /*                                                                       */
  /* @description:                                                         */
  /*    A function used to allocate `size' bytes from `memory'.            */
  /*                                                                       */
  /* @input:                                                               */
  /*    memory :: A handle to the source memory manager.                   */
  /*                                                                       */
  /*    size   :: The size in bytes to allocate.                           */
  /*                                                                       */
  /* @return:                                                              */
  /*    Address of new memory block.  0 in case of failure.                */
  /*                                                                       */
  typedef void*
  (*FT_Alloc_Func)( FT_Memory  memory,
                    long       size );


  /*************************************************************************/
  /*                                                                       */
  /* @functype:                                                            */
  /*    FT_Free_Func                                                       */
  /*                                                                       */
  /* @description:                                                         */
  /*    A function used to release a given block of memory.                */
  /*                                                                       */
  /* @input:                                                               */
  /*    memory :: A handle to the source memory manager.                   */
  /*                                                                       */
  /*    block  :: The address of the target memory block.                  */
  /*                                                                       */
  typedef void
  (*FT_Free_Func)( FT_Memory  memory,
                   void*      block );


  /*************************************************************************/
  /*                                                                       */
  /* @functype:                                                            */
  /*    FT_Realloc_Func                                                    */
  /*                                                                       */
  /* @description:                                                         */
  /*    a function used to re-allocate a given block of memory.            */
  /*                                                                       */
  /* @input:                                                               */
  /*    memory   :: A handle to the source memory manager.                 */
  /*                                                                       */
  /*    cur_size :: The block's current size in bytes.                     */
  /*                                                                       */
  /*    new_size :: The block's requested new size.                        */
  /*                                                                       */
  /*    block    :: The block's current address.                           */
  /*                                                                       */
  /* @return:                                                              */
  /*    New block address.  0 in case of memory shortage.                  */
  /*                                                                       */
  /* @note:                                                                */
  /*   In case of error, the old block must still be available.            */
  /*                                                                       */
  typedef void*
  (*FT_Realloc_Func)( FT_Memory  memory,
                      long       cur_size,
                      long       new_size,
                      void*      block );


  /*************************************************************************/
  /*                                                                       */
  /* @struct:                                                              */
  /*    FT_MemoryRec                                                       */
  /*                                                                       */
  /* @description:                                                         */
  /*    A structure used to describe a given memory manager to FreeType 2. */
  /*                                                                       */
  /* @fields:                                                              */
  /*    user    :: A generic typeless pointer for user data.               */
  /*                                                                       */
  /*    alloc   :: A pointer type to an allocation function.               */
  /*                                                                       */
  /*    free    :: A pointer type to an memory freeing function.           */
  /*                                                                       */
  /*    realloc :: A pointer type to a reallocation function.              */
  /*                                                                       */
  struct  FT_MemoryRec_
  {