Lianja

Write Text at a 64-bit Offset in a Remote SFTP File

Demonstrates the Chilkat SFtp.WriteFileText64 method, which encodes text and writes it at a specific 64-bit byte offset in an open handle. The arguments are the handle, the offset, the charset, and the text. The 64-bit offset supports very large files.

Background: A 32-bit offset tops out at about 4 GB, so files larger than that require the 64-bit form to address positions beyond that boundary. The behavior is otherwise identical to the 32-bit version — the only difference is the width of the offset argument, chosen to match the size of the file you are working with.

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llSuccess = .F.

//  Demonstrates the SFtp.WriteFileText64 method, which encodes text and writes it at a specific
//  64-bit byte offset in an open handle.  The 1st argument is the handle, the 2nd is the offset,
//  the 3rd is the charset, and the 4th is the text.  The 64-bit offset supports very large files.

loSftp = createobject("CkSFtp")

//  Connect, authenticate, and initialize the SFTP subsystem.
lnPort = 22
llSuccess = loSftp.Connect("sftp.example.com",lnPort)
if (llSuccess = .F.) then
    ? loSftp.LastErrorText
    release loSftp
    return
endif

//  Normally you would not hard-code the password in source.  You should instead obtain it
//  from an interactive prompt, environment variable, or a secrets vault.
lcPassword = "mySshPassword"

llSuccess = loSftp.AuthenticatePw("mySshLogin",lcPassword)
if (llSuccess = .F.) then
    ? loSftp.LastErrorText
    release loSftp
    return
endif

llSuccess = loSftp.InitializeSftp()
if (llSuccess = .F.) then
    ? loSftp.LastErrorText
    release loSftp
    return
endif

lcHandle = loSftp.OpenFile("subdir/hugefile.dat","readWrite","openOrCreate")
if (loSftp.LastMethodSuccess = .F.) then
    ? loSftp.LastErrorText
    release loSftp
    return
endif

//  Write at a byte offset beyond the 32-bit (4 GB) range.
lnOffset = 5000000000
llSuccess = loSftp.WriteFileText64(lcHandle,lnOffset,"utf-8","MARKER")
if (llSuccess = .F.) then
    ? loSftp.LastErrorText
    release loSftp
    return
endif

llSuccess = loSftp.CloseHandle(lcHandle)
if (llSuccess = .F.) then
    ? loSftp.LastErrorText
    release loSftp
    return
endif

? "Wrote at the 64-bit offset."

loSftp.Disconnect()


release loSftp