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