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{File_stream}


(including protected members)



CLASS {File_stream}
, BYTES, DESTRUCTORS,
	NATIVE, TESTED(76) :



 Class to work with files via streams.





IMPORT : 
{Stream}
, 
{File_path}
 .


BASE CLASS 
{Stream} .




--------------------------------------------------------- 'fields for read'


INT 
Handle|_of_file_stream_object
 , READ


 A file opened descriptor.






STR 
Path|_of_file
 , READ
 , INIT


 Path of the file opened.






{mode_file} 
Mode|_file_opened
 , READ
 , INIT


 A mode used to open the file.





 





ENUMERATION {mode_file|_stream} : 

        'READ|_FILE'
 ,

        'WRITE|_FILE'
 ,

        'READ_WRITE'
 ,

        'READ_ANYWAY|_even_if_file_already_opened_in_another_process'
 .






 The enumeration of possible modes to open a file.










FUNCTION 
Read_file_stream

(

     STR 
Path|_to_file
)
 ==> {File_stream} 
 , NEW






 Creating a stream to read a file.










FUNCTION 
Anyway_read_file_stream

(

     STR 
Path|_to_file
)
 ==> {File_stream} 
 , NEW












FUNCTION 
Write_file_stream

(

     STR 
Path|_to_file
, 

     BOOL 
Can_read
)
 ==> {File_stream} 
 , NEW






 Creating a stream to write a file. In case when Can_read = TRUE, an existing
 file is opened not truncated, but with the position set to 0, and it is
 possible to move current position to any other position and read / write
 bytes there.






---------------------------------------------------------- 'size, position'

   






OVERRIDE 
Size

 ==> {Long_int}.{long} 






 The size of the stream is the size of the file opened.










FUN 
get_Size

(

     INT 
Handle|_of_file_stream
, 

     BOOL 
Is_closed|_stream
, 

     INT 
lo_hi|_values
[]
)
 , NATIVE











OVERRIDE 
Position

 ==> {long} 






 The position in the stream is the position in the file opened.










FUN 
get_Position

(

     INT 
Handle|_of_file_stream
, 

     BOOL 
Is_closed|_stream
, 

     INT 
lo_hi|_values
[]
)
 , NATIVE











OVERRIDE 
Set_pos

(

     {long} 
New|_position
, 

     {Stream}.{disp} 
Disp|osition_from
)






 Moving current position in the file.










FUN 
do_Set_pos

(

     INT 
Handle|_of_file_stream
, 

     INT 
New_lo|_position
, 

     INT 
New_hi|_position
, 

     {disp} 
Disp|osition_from
)
 , NATIVE











OVERRIDE 
Ended

 ==> BOOL 






 TRUE, if the current position is out of the file.






----------------------------------------------------------------- 'closing'

 






OVERRIDE 
Close

 , REPLACE






 Closing the file and the stream.










FUN 
do_Close

(
INT 
Handle|_of_file_stream
)
 , NATIVE











OVERRIDE 
Closed

 ==> BOOL 






 TRUE, if the file is already closed. It is not possible to do any operations
 with a closed stream.






-------------------------------------------------------- 'read/write bytes'

  






OVERRIDE 
Load_bytes

(

     BYTE 
Dest|ination
[]
, 

     INT 
Count|_bytes_read
)
 ==> BOOL 






 Implementing Load_bytes operation for a file stream. Maximum Count bytes are
 loaded into the buffer Dest (which first is cleared anyway). TRUE is returned
 if any bytes are loaded. Usually amount of bytes loaded can be smaller then
 the Count only if the position was near to the end of the file. But actually
 other reasons are possible.









OVERRIDE 
Read_bytes

(
BYTE 
Dest|ination
[*]
)
 ==> INT 






 Implementing Read_bytes operation for a file stream, reading bytes to the
 fixed array Dest[] and returning amount of bytes which were read.










FUN 
do_Read_bytes

(

     INT 
Handle|_of_file_stream
, 

     BYTE 
Dest|ination
[*]
)
 ==> INT 
 , NATIVE











OVERRIDE 
Save_bytes

(
BYTE 
Source|_bytes
[*]
)
 ==> INT 






 Implementing Save_bytes operation for a file stream, writing entire fixed
 array Source[] and returning amount of bytes written.










FUN 
do_Write_bytes

(

     INT 
Handle|_of_file_stream
, 

     BYTE 
Source|_bytes
[*]
)
 ==> INT 
 , NATIVE







END