ftsystem.h
上传用户:yisoukefu
上传日期:2020-08-09
资源大小:39506k
文件大小:10k
- /***************************************************************************/
- /* */
- /* ftsystem.h */
- /* */
- /* FreeType low-level system interface definition (specification). */
- /* */
- /* Copyright 1996-2001, 2002, 2005 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 */
- /* 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 an
- * @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_
- {
- void* user;
- FT_Alloc_Func alloc;
- FT_Free_Func free;
- FT_Realloc_Func realloc;
- };
- /*************************************************************************/
- /* */
- /* I / O M A N A G E M E N T */
- /* */
- /*************************************************************************/
- /*************************************************************************
- *
- * @type:
- * FT_Stream
- *
- * @description:
- * A handle to an input stream.
- *
- */
- typedef struct FT_StreamRec_* FT_Stream;
- /*************************************************************************
- *
- * @struct:
- * FT_StreamDesc
- *
- * @description:
- * A union type used to store either a long or a pointer. This is used
- * to store a file descriptor or a `FILE*' in an input stream.
- *
- */
- typedef union FT_StreamDesc_
- {
- long value;
- void* pointer;
- } FT_StreamDesc;
- /*************************************************************************
- *
- * @functype:
- * FT_Stream_IoFunc
- *
- * @description:
- * A function used to seek and read data from a given input stream.
- *
- * @input:
- * stream ::
- * A handle to the source stream.
- *
- * offset ::
- * The offset of read in stream (always from start).
- *
- * buffer ::
- * The address of the read buffer.
- *
- * count ::
- * The number of bytes to read from the stream.
- *
- * @return:
- * The number of bytes effectively read by the stream.
- *
- * @note:
- * This function might be called to perform a seek or skip operation
- * with a `count' of 0.
- *
- */
- typedef unsigned long
- (*FT_Stream_IoFunc)( FT_Stream stream,
- unsigned long offset,
- unsigned char* buffer,
- unsigned long count );
- /*************************************************************************
- *
- * @functype:
- * FT_Stream_CloseFunc
- *
- * @description:
- * A function used to close a given input stream.
- *
- * @input:
- * stream ::
- * A handle to the target stream.
- *
- */
- typedef void
- (*FT_Stream_CloseFunc)( FT_Stream stream );
- /*************************************************************************
- *
- * @struct:
- * FT_StreamRec
- *
- * @description:
- * A structure used to describe an input stream.
- *
- * @input:
- * base ::
- * For memory-based streams, this is the address of the first stream
- * byte in memory. This field should always be set to NULL for
- * disk-based streams.
- *
- * size ::
- * The stream size in bytes.
- *
- * pos ::
- * The current position within the stream.
- *
- * descriptor ::
- * This field is a union that can hold an integer or a pointer. It is
- * used by stream implementations to store file descriptors or `FILE*'
- * pointers.
- *
- * pathname ::
- * This field is completely ignored by FreeType. However, it is often
- * useful during debugging to use it to store the stream's filename
- * (where available).
- *
- * read ::
- * The stream's input function.
- *
- * close ::
- * The stream;s close function.
- *
- * memory ::
- * The memory manager to use to preload frames. This is set
- * internally by FreeType and shouldn't be touched by stream
- * implementations.
- *
- * cursor ::
- * This field is set and used internally by FreeType when parsing
- * frames.
- *
- * limit ::
- * This field is set and used internally by FreeType when parsing
- * frames.
- *
- */
- typedef struct FT_StreamRec_
- {
- unsigned char* base;
- unsigned long size;
- unsigned long pos;
- FT_StreamDesc descriptor;
- FT_StreamDesc pathname;
- FT_Stream_IoFunc read;
- FT_Stream_CloseFunc close;
- FT_Memory memory;
- unsigned char* cursor;
- unsigned char* limit;
- } FT_StreamRec;
- /* */
- FT_END_HEADER
- #endif /* __FTSYSTEM_H__ */
- /* END */