[bb] Random Access File Utilities by TygerWulf [ 1+ years ago ]

Started by BlitzBot, June 29, 2017, 00:28:40

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June 29, 2017, 00:28:40
Title : Random Access File Utilities
Author : TygerWulf
Posted : 1+ years ago

Description : Allows you to randomly access a file by using identifiers to locate data in a file.  It needs an encryption code or some other such to be truly effective, though, but it operates well the way it is.  If you don't mind people being able to read the files, then go ahead and use it.

Code :
Code (blitzbasic) Select
Type Datafile
Field FName$
Field Size
Field ID
End Type

;FWriteS(File.DataFile, Key$, KeyVal$)
;File.DataFile--A file opened with FOpen
;Key$--The identifier that will be used to retrieve the data later
;KeyVal$--The Value to be stored for retrieval later
;Writes a string to a file or updates a string value in the file.

Function FWriteS(File.DataFile, Key$,KeyVal$)
Key$ = "$" +Key$
If FileSize = 0 Then
X$ = Key$+"="+KeyVal
WriteLine(FileID,X$)
QSFile(File)
Return 2
End If
P = KeyExists(File, Key$)
If P <> -1 Then

SeekFile(FileID,P)
X$ = ReadLine(FileID)
SeekFile(FileID,P)
L = Len(X$)
X$ = Key$+"="+KeyVal
If Len(X$) < L Then X$ = LSet$(X$,L)
WriteLine(FileID, X$)
QSFile(File)
Return 1 ;Updated an existing value
Else
SeekFile(FileID,FileSize)
X$ = Key$+"="+KeyVal
WriteLine(FileID,X$)
QSFile(File)
Return 2 ;Created a new value
End If

Return 0

End Function


;FReadS$(File.DataFile, Key$)
;File.DataFile--A File Opened with FOpen
;Key$--The identifier to look for in the file, where the information is stored
;Returns the string value found at identifier Key$ or "" if Key$ was not found

Function FReadS$(File.DataFile, Key$)
Key$ = "$" +Key$
P = KeyExists(File, Key$)
If P <> -1 Then
SeekFile(FileID,P)
X$ = ReadLine(FileID)
L = Instr(X$, "=")
If L = 0 Then Return 0
L = Len(X$) - (L)
Return Right$(X$, L)

End If
Return ""

End Function


;FWriteI(File.DataFile, Key$, KeyVal%)
;File.DataFile--A file opened with FOpen
;Key$--The identifier that will be used to retrieve the data later
;KeyVal%--The Value to be stored for retrieval later
;Writes an integer to a file or updates an integer value in the file.

Function FWriteI(File.DataFile, Key$,KeyVal%)
Key$ = "%" +Key$
If FileSize = 0 Then
X$ = Key$+"="+Str(KeyVal)
WriteLine(FileID,X$)
QSFile(File)
Return 2
End If
P = KeyExists(File, Key$)
If P <> -1 Then
SeekFile(FileID,P)
X$ = ReadLine(FileID)
SeekFile(FileID,P)
L = Len(X$)
X$ = Key$+"="+Str(KeyVal)
If Len(X$) < L Then X$ = LSet$(X$,L)
WriteLine(FileID, X$)
QSFile(File)
Return 1 ;Updated an existing value
Else
SeekFile(FileID,FileSize)
X$ = Key$+"="+Str(KeyVal)
WriteLine(FileID,X$)
QSFile(File)
Return 2 ;Created a new value
End If

Return 0

End Function


;FReadI%(File.DataFile, Key$)
;File.DataFile--A File Opened with FOpen
;Key$--The identifier to look for in the file, where the information is stored
;Returns the intiger value found at identifier Key$ or 0 if Key$ was not found

Function FReadI%(File.DataFile, Key$)

Key$ = "%" +Key$
P = KeyExists(File, Key$)
If P <> -1 Then
SeekFile(FileID,P)
X$ = ReadLine(FileID)
L = Instr(X$, "=")
If L = 0 Then Return 0
L = Len(X$) - (L)
X$ = Right$(X$, L)
L = X$
Return L

End If
Return 0

End Function


;FWriteF(File.DataFile, Key$, KeyVal#)
;File.DataFile--A file opened with FOpen
;Key$--The identifier that will be used to retrieve the data later
;KeyVal#--The Value to be stored for retrieval later
;Writes a float to a file or updates a float value in the file.

Function FWriteF(File.DataFile, Key$,KeyVal#)
Key$ = "#" +Key$
If FileSize = 0 Then
X$ = Key$+"="+Str(KeyVal)
WriteLine(FileID,X$)
QSFile(File)
Return 2
End If
P = KeyExists(File, Key$)
If P <> -1 Then
SeekFile(FileID,P)
X$ = ReadLine(FileID)
SeekFile(FileID,P)
L = Len(X$)
X$ = Key$+"="+Str(KeyVal)
If Len(X$) < L Then X$ = LSet$(X$,L)
WriteLine(FileID, X$)
QSFile(File)
Return 1 ;Updated an existing value
Else
SeekFile(FileID,FileSize)
X$ = Key$+"="+Str(KeyVal)
WriteLine(FileID,X$)
QSFile(File)
Return 2 ;Created a new value
End If

Return 0

End Function


;FReadF#(File.DataFile, Key#)
;File.DataFile--A File Opened with FOpen
;Key$--The identifier to look for in the file, where the information is stored
;Returns the float value found at identifier Key$ or 0.0 if Key$ was not found

Function FReadF#(File.DataFile, Key$)

Key$ = "#" +Key$
P = KeyExists(File, Key$)
If P <> -1 Then
SeekFile(FileID,P)
X$ = ReadLine(FileID)
L = Instr(X$, "=")
If L = 0 Then Return 0
L = Len(X$) - (L)
X$ = Right$(X$, L)
L = X$
Return L

End If
Return 0

End Function


;KeyExists(File.DataFile, Key$)
;File.DataFile--A File opened with FOpen
;Key$--The identifier to search for.
;Returns the location in the file where Key$ is found, or -1 if Key$ was not found

Function KeyExists(File.DataFile, Key$)

L = Len(Key$)
SeekFile(FileID,0)
While Not Eof(FileID)
N = FilePos(FileID)
X$ = ReadLine(FileID)
If Lower$(Key$) = Lower$(Left$(X$,L)) Then
Return N
End If
Wend
Return -1

End Function


;QSFile(File.DataFile)
;File.Datafile--A file opened with FOpen
;Closes and reopens a file to save data changes to disk.

Function QSFile(File.DataFile)

CloseFile(FileID)
FileID = OpenFile(FileFName$)
UpdateFile(File)
Return

End Function


;UpdateFile(File.DataFile)
;File.Datafile--A file opened with FOpen
;Updates the information of a Datafile type.  Currently only updates size.

Function UpdateFile(File.DataFile)

FileSize = FileSize(FileFName$)
Return

End Function

;FOpen.DataFile(Filename$,RC)
;Filename$--a string containing the file you want to open
;RC--a flag indicating if the file should be created when not found
;Opens a file and returns a Datafile custom type with information and a
;pointer to the file in its fields.

Function FOpen.DataFile(Filename$,RC)

File.DataFile = New DataFile
Select RC
Case 0 ;Read/Write, create if not found
If ff_is_file(Filename$) <> True Then
CurFile = WriteFile(FileName$)  ;Creating Unfound File
CloseFile(CurFile)
End If
FileID = OpenFile(Filename$)
FileFName$ = Filename$
FileSize = FileSize(Filename$)
Return File


Case 1 ;Read/Write, Return Error on no file found
If ff_is_file(Filename$) <> True Then
Return Null ;File not found
End If
FileID = OpenFile(Filename$)
FileFName$ = Filename$
FileSize = FileSize(Filename$)
Return File

Default
Delete File
Return Null ;Unexpected error

End Select

End Function


;FClose(File.DataFile)
;File.DataFile--A File opened with FOpen
;Closes a file previously opened with FOpen

Function FClose(File.DataFile)

CloseFile(FileID)
Delete File

End Function

;A function to check if a file exists
;Not mine.

Function ff_is_file(file$)
If FileType(file$) = 1 Then Return True
End Function

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