TOPIC:

USING System.Text   
USING System.IO

FUNCTION Start() AS VOID 
LOCAL cPath, cFile1, cFile2, cFile3 AS STRING 
   
	cPath := "D:\test\"	
	
	cFile1 := cPath + "unicode.txt"
	cFile2 := cPath + "utf8.txt"
	cFile3 := cPath + "Ansi.txt"		
		
	? StrToFile( "Content of unicode file starts with: 'FF FE' " + Time() , cFile1 , 2 ) 
	? StrToFile( "Append Text1" , cFile1 , 3 ) // This not allowed !
	? StrToFile( "Append Text2" , cFile1 , 5 ) // This not allowed !
	?
	
	? StrToFile( "Content of utf-8 file starts with: 'EF BB BF' " + Time() , cFile2 , 4 ) 
	? StrToFile( "Append Text1" , cFile2 , 3 )  // This not allowed !
	? StrToFile( "Append Text2" , cFile2 , 5 )  // This not allowed !
	?
    
	? StrToFile( "Text Ansi codepage " + Time() , cFile3 ) 
	? StrToFile( "Append Text1" , cFile3 , TRUE ) 
	? StrToFile( "Append Text2" , cFile3 , 1 ) 
	? StrToFile( "Append Text3" , cFile3 , 1 ) 
	?	

	RETURN 

FUNCTION StrToFile(cExpression, cFileName ) AS DWORD 
RETURN	StrToFile(cExpression, cFileName , 0 )  

FUNCTION StrToFile(cExpression AS STRING, cFileName AS STRING , lAdditive AS LOGIC) AS DWORD 
RETURN	StrToFile(cExpression, cFileName  , IIF ( lAdditive , 1 , 0 ) )  

FUNCTION StrToFile(cExpression AS STRING, cFileName AS STRING , nFlag AS DWORD ) AS DWORD 
LOCAL enc AS System.Text.Encoding
LOCAL lAdditive AS LOGIC
LOCAL dwWritten AS DWORD
 
    	
	IF nFlag == 3 .OR. nFlag > 4 
		
		// allowed flags are 0,1,2 or 4
		// 
  		//  if the param nFlag value is not valid 
		// What does VFP do ?  
		
		RETURN 0 

	ENDIF		

	
	DO CASE 
	CASE nFlag == 0 .OR. nFlag == 1 
		
		enc := RuntimeState.WinEncoding 
		
		IF nFlag == 1
			lAdditive := TRUE 
		ENDIF				
		
	CASE nFlag == 2
		
		// ensures that the first two bytes of the file  
		// are "FF FE"
		enc := System.Text.Encoding.Unicode
		
	CASE nFlag == 4
		
		// ensures that the first three bytes of the file  
		// are "EF BB BF"
		enc := System.Text.Encoding.UTF8
		
	ENDCASE  
	

	// The same can be done using a FileStream and a StreamWriter,
	// instead of File.AppendAllText() and File.WriteAllText()
	// Is there any reason to do it not the way i did ? 
	
	IF lAdditive
		// If the file doesn´t exist it´s automatically created. 
		File.AppendAllText(  cFileName, cExpression + Environment.NewLine, enc )
		
		dwWritten := (DWORD) cExpression:Length	
	
	ELSE 

		// This depends on the SET SAFETY setting 
		IF File.Exists( cFileName ) 
			
			// File already exists, ask the user to overwrite the file.
			// What does VFP do ?	
		
			//	RETURN 0  			
				
		ENDIF		
		
		// if the file already exists, it will be overwritten.	
		File.WriteAllText(cFileName  , cExpression + Environment.NewLine , enc ) 
		
		dwWritten := (DWORD) cExpression:Length	
			
	ENDIF 
	
	
	RETURN dwWritten

IF File.Exists( cFileName ) // .AND. SetSafety() <-- doesn´t exist yet
			
	// File already exists - ask the user to overwrite the file. 
		
	IF XSharp.VFP.Functions.MessageBox ( "File " + cFileName +" already exits." + Environment.NewLine + ;
			"Should the file be overwritten ?" , MB_YESNO  + MB_ICONQUESTION ) != IDYES
					
		RETURN 0  			
	ENDIF 	
				
ENDIF	

		//  VFP Dll
				
		PUBLIC STATIC METHOD SetSafety() AS LOGIC
		RETURN RuntimeState.GetValue<LOGIC>(@@Set.Safety)

		PUBLIC STATIC METHOD SetSafety(lSet AS LOGIC ) AS LOGIC
		RETURN RuntimeState.SetValue(@@Set.Safety, lSet)
		
		
		// part of a vh file
 
		#command  SET SAFETY <x:ON,OFF,&>    =>  SetSafety( Upper(<(x)>)=="ON")
		#command  SET SAFETY (<x>)           =>  SetSafety(  <x> )

		

STRTOFILE("Bouvard et Pécuchet", "t1.txt", 0)
STRTOFILE(e"Bouvard et P\xC3\xA9cuchet", "t2.txt", 4)

FUNCTION StrToFile (Expression AS String, Filename AS String, Flags AS Int) AS Int
    
    LOCAL Additive = .F. AS Boolean
    LOCAL BOM = "" AS String
    LOCAL Result = 0 AS Int
    LOCAL FHandle AS Int

    DO CASE
        CASE Flags = 1
            Additive = .T.
            
        CASE Flags = 2
            BOM = e"\xFF\xFE"
            
        CASE Flags = 4
            BOM = e"\xEF\xBB\xBF"
            
        CASE Flags != 0
            RETURN 0
    ENDCASE

    IF Additive

        FHandle = FOpen(Filename, FO_READWRITE + FO_SHARED)
        IF FHandle != F_ERROR
            FSeek3(FHandle, 0, FS_END)
            Result = FWrite(FHandle, Expression)
            FClose(FHandle)
        ENDIF

    ELSE
        
        FHandle = FCreate(Filename)
        IF FHandle != F_ERROR
            IF ! (BOM == "")
                Result = FWrite(FHandle, BOM)
            ENDIF
            Result += FWrite(FHandle, Expression)
            FClose(FHandle)
        ENDIF

    ENDIF

    RETURN Result

ENDFUNC

FUNCTION FileToStr (Filename AS String) AS String
    
    LOCAL FHandle AS Int
    LOCAL StrLen AS Int
    LOCAL Result = .NULL. AS String
    
    FHandle = FOpen(Filename, FO_READ + FO_SHARED)
    IF FHandle != F_ERROR
        StrLen = FSize(FHandle)
        IF StrLen > 0
            Result = SPACE(StrLen)
            IF FRead(FHandle, @Result, StrLen) != StrLen
                Result = .NULL.
            ENDIF
        ELSE
            Result = ""
        ENDIF
    ENDIF
    
    RETURN Result
    
ENDFUNC

IF Flag == 3 .OR. Flag > 4 
		
	// valid Flag values are 0,1,2 or 4

	THROW ArgumentException { String.Format("Param value is {0}, but it must be either 0,1,2 or 4", Flag ) , NAMEOF ( Flag )  }

ENDIF 

pngFileName = "<some PNG file>"
    pngImage = FILETOSTR(pngFilename)
    STRTOFILE(pngImage, JUSTPATH(pngFilename) + "\Copy of " + JUSTFNAME(pngFilename), 0)

Local gnFileHandle,nSize,cString
gnFileHandle = FOPEN("test.txt")
* Seek to end of file to determine number of bytes in the file.
nSize =  FSEEK(gnFileHandle, 0, 2)     && Move pointer to EOF
IF nSize <= 0
 * If file is empty, display an error message.
 WAIT WINDOW "This file is empty!" NOWAIT
ELSE
 * If file is not empty, store the file's contents in memory
 * and display the text in the main Visual FoxPro window.
 = FSEEK(gnFileHandle, 0, 0)      && Move pointer to BOF
 cString = FREAD(gnFileHandle, nSize)
 ? cString
ENDIF
= FCLOSE(gnFileHandle)         && Close the file

* VFP standard flags
#DEFINE S2F_FLAG_OVERWRITE          0x0000
#DEFINE S2F_FLAG_APPEND             0x0001
#DEFINE S2F_FLAG_UNICODE_LE         0x0002
#DEFINE S2F_FLAG_UTF8               0x0004
* X# extension flags
#DEFINE S2F_FLAG_UNICODE_BE         0x0008
#define S2F_FLAG_UNICODE_FORMATS    (S2F_FLAG_UNICODE_LE | S2F_FLAG_UTF8 | S2F_FLAG_UNICODE_BE)
#DEFINE S2F_FLAG_UNICODE_TEXT       0x0100

FUNCTION StrToFile (Expression AS String, Filename AS String, Flags AS Int) AS Int
    
    LOCAL Additive = .F. AS Boolean
    LOCAL BOM = "" AS String
    LOCAL Result = 0 AS Int
    LOCAL FHandle AS Int
    LOCAL VFPBehavior = .T. AS Boolean      // it means the string must hold an already prepared buffer, or it is binary
    LOCAL UnicodeEncoding AS System.Text.Encoding

    DO CASE
        CASE Flags = S2F_FLAG_APPEND
            Additive = .T.
            
        CASE Flags = S2F_FLAG_UNICODE_LE
            BOM = e"\xFF\xFE"

        CASE Flags = S2F_FLAG_UTF8
            BOM = e"\xEF\xBB\xBF"

        CASE Flags = S2F_FLAG_UNICODE_BE
            BOM = e"\xFE\xFF"
            
        CASE Flags != S2F_FLAG_OVERWRITE

            IF (Flags & S2F_FLAG_UNICODE_TEXT) != 0

                VFPBehavior = .F.
                
                Additive = (Flags & S2F_FLAG_APPEND) != 0
            
                SWITCH Flags & S2F_FLAG_UNICODE_FORMATS
                    CASE S2F_FLAG_UNICODE_LE
                        UnicodeEncoding = System.Text.Encoding.Unicode
                        
                    CASE S2F_FLAG_UTF8
                        UnicodeEncoding = System.Text.Encoding.UTF8
                        
                    CASE S2F_FLAG_UNICODE_BE
                        UnicodeEncoding = System.Text.Encoding.BigEndianUnicode
                        
                    OTHERWISE
                        THROW ArgumentException {}
                        
                END SWITCH
            ELSE
                THROW ArgumentException {}
            ENDIF
    END CASE
    
    IF Additive

        IF VFPBehavior

            FHandle = FOpen(Filename, FO_READWRITE + FO_SHARED)
            IF FHandle != F_ERROR
                FSeek3(FHandle, 0, FS_END)
                Result = FWrite(FHandle, Expression)
                FClose(FHandle)
            ENDIF
            
        ELSE
            
            TRY
                File.AppendAllText(Filename, Expression, UnicodeEncoding)
            CATCH
                THROW
            ENDTRY
                
            Result = Expression:Length
            
        ENDIF

    ELSE
        
        IF VFPBehavior
        
            FHandle = FCreate(Filename)
            IF FHandle != F_ERROR
                IF ! (BOM == "")
                    Result = FWrite(FHandle, BOM)
                ENDIF
                Result += FWrite(FHandle, Expression)
                FClose(FHandle)
            ENDIF
 
        ELSE
            
            TRY
                File.WriteAllText(Filename, Expression, UnicodeEncoding)
            CATCH
                THROW
            ENDTRY
            
            Result = Expression:Length
            
        ENDIF

    ENDIF

    RETURN Result

ENDFUNC

FUNCTION FileToStr (Filename AS String) AS String
    RETURN FileToStr(Filename, 0)

FUNCTION FileToStr (Filename AS String, Flags AS Int) AS String
    
    LOCAL FHandle AS Int
    LOCAL StrLen AS Int
    LOCAL Result = .NULL. AS String

    IF (Flags & S2F_FLAG_UNICODE_TEXT) = 0      // VFP behavior, read file as binary, even if it is a Unicode text

        FHandle = FOpen(Filename, FO_READ + FO_SHARED)
        IF FHandle != F_ERROR
            StrLen = FSize(FHandle)
            IF StrLen > 0
                Result = SPACE(StrLen)
                IF FRead(FHandle, @Result, StrLen) != StrLen
                    Result = .NULL.
                ENDIF
            ELSE
                Result = ""
            ENDIF
        ENDIF

    ELSE
        
        TRY
            Result = File.ReadAllText(Filename)     // read a text file
        CATCH
            THROW
        ENDTRY
        
    ENDIF

    RETURN Result
    
ENDFUNC

* VFP standard flags
DEFINE S2F_FLAG_OVERWRITE       = 0x0000 
DEFINE S2F_FLAG_APPEND          = 0x0001 
DEFINE S2F_FLAG_UNICODE_LE      = 0x0002 
DEFINE S2F_FLAG_UTF8            = 0x0004 
* X# extension flags
DEFINE S2F_FLAG_UNICODE_BE      =  0x0008 
DEFINE S2F_FLAG_UNICODE_FORMATS  = (S2F_FLAG_UNICODE_LE | S2F_FLAG_UTF8 | S2F_FLAG_UNICODE_BE) 
DEFINE S2F_FLAG_UNICODE_TEXT     =  0x0100  

THROW ArgumentException { String.Format("Param value {0} is invalid" , Flags ) , NAMEOF ( Flags ) }

TRY

  File.AppendAllText(Filename, Expression, UnicodeEncoding)

CATCH e AS Exception 

  THROW e

ENDTRY

? StrToFile ( "Drive 'P' doesn´t exist !" , "P:\test.txt" , S2F_FLAG_UTF8  )  

IF RuntimeState.FileError > 0
	? RuntimeState.FileError , DosErrString ( RuntimeState.FileError )	
    ?
	IF RuntimeState.FileException != NULL
		THROW RuntimeState.FileException
	ENDIF	
ENDIF 

...
       FHandle = FCreate(Filename)
           IF FHandle != F_ERROR
               IF ! (BOM == "")
                   Result = FWrite(FHandle, BOM)
               ENDIF
               Result += FWrite(FHandle, Expression)
               FClose(FHandle)
           ENDIF

	   IF RuntimeState.FileError > 0 .AND. RuntimeState.FileException != NULL 
		THROW RuntimeState.FileException
	   ENDIF 	
...									

DEFINE FC_READONLY   := 0x00000001