Read Text at a 64-bit Offset from a Remote SFTP File

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Demonstrates the Chilkat SFtp.ReadFileText64 method, which reads up to a number of bytes from a specific 64-bit byte offset of an open handle and decodes them to text. The arguments are the handle, the offset, the maximum number of bytes, and the charset. The 64-bit offset supports very large files.

load ./chilkat.dll

set success 0

#  Demonstrates the SFtp.ReadFileText64 method, which reads up to a number of bytes from a
#  specific 64-bit byte offset of an open handle and decodes them to text.  The 1st argument is
#  the handle, the 2nd is the offset, the 3rd is the maximum number of bytes, and the 4th is the
#  charset.  The 64-bit offset supports very large files.

set sftp [new_CkSFtp]

#  Connect, authenticate, and initialize the SFTP subsystem.
set port 22
set success [CkSFtp_Connect $sftp "sftp.example.com" $port]
if {$success == 0} then {
    puts [CkSFtp_lastErrorText $sftp]
    delete_CkSFtp $sftp
    exit
}

#  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.
set password "mySshPassword"

set success [CkSFtp_AuthenticatePw $sftp "mySshLogin" $password]
if {$success == 0} then {
    puts [CkSFtp_lastErrorText $sftp]
    delete_CkSFtp $sftp
    exit
}

set success [CkSFtp_InitializeSftp $sftp]
if {$success == 0} then {
    puts [CkSFtp_lastErrorText $sftp]
    delete_CkSFtp $sftp
    exit
}

set handle [CkSFtp_openFile $sftp "subdir/hugefile.dat" "readOnly" "openExisting"]
if {[CkSFtp_get_LastMethodSuccess $sftp] == 0} then {
    puts [CkSFtp_lastErrorText $sftp]
    delete_CkSFtp $sftp
    exit
}

#  Read 6 bytes starting at a byte offset beyond the 32-bit (4 GB) range.
set offset 5000000000
set numBytes 6
set text [CkSFtp_readFileText64 $sftp $handle $offset $numBytes "utf-8"]
if {[CkSFtp_get_LastMethodSuccess $sftp] == 0} then {
    puts [CkSFtp_lastErrorText $sftp]
    delete_CkSFtp $sftp
    exit
}

puts "$text"

set success [CkSFtp_CloseHandle $sftp $handle]
if {$success == 0} then {
    puts [CkSFtp_lastErrorText $sftp]
    delete_CkSFtp $sftp
    exit
}

CkSFtp_Disconnect $sftp

delete_CkSFtp $sftp