#!/usr/bin/env raku
# PopUpTest4.pl6

# read the computer's name from Kernel32.dll as a pointer
# and use the pointer to test memcpy_s


use lib 'C:/NtUtil', 'K:/Windows/NtUtil', '/home/CDs/Windows/NtUtil';
use NativeCall;
use NativeConvert :c-utf8-to-raku-str;


constant BYTE     := uint8;
constant LPDWORD  := uint64;        # long pointer to a DWORD
constant LPSTR    = CArray[BYTE];   # long pointer to a string
constant DWORD    := uint32;
constant HANDLE   = Pointer[void];
constant WTS_CURRENT_SERVER_HANDLE = 0;  # Current (local) server


sub memcpy_s(
   #`{
       errno_t memcpy_s(
          void *dest,
          size_t destSize,
          const void *src,
          size_t count
       );
       Returns zero if successful; an error code on failure.

       $RtnCode = memcpy_s $SessionArray, $Length , $SessionPtr, $Length ;
   }
      CArray[BYTE] $dest,       # [in,out] New buffer (target)
      DWORD $numberOfElements,  # [in] Maximum size of $dest
      Pointer $src is rw,       # [in] Pointer to the source to be copied
      DWORD $count              # [out] number of bytes to copy from the source
   )
   is native("ucrtbase.dll")
   is symbol("memcpy_s")
   returns DWORD                 # [out] Zero if successful; an error code on failure
   { * };


sub GetComputerName(
   #`{
       https://learn.microsoft.com/en-us/windows/win32/api/winbase/nf-winbase-getcomputernamea
       C++

       BOOL GetComputerNameA(
          [out]     LPSTR   lpBuffer,
          [in, out] LPDWORD nSize
       );
       [out] lpBuffer:  A pointer to a buffer that receives the computer name or
                        the cluster virtual server name. The buffer size should be large
                        enough to contain MAX_COMPUTERNAME_LENGTH + 1 characters.

                        The maximum number of characters for a Netbios computer name is 15.
                        The buffer passed to GetComputerName should be at least 16 characters
                        to account for the nul at the end.

       [in, out] nSize  On input, specifies the size of the buffer, in TCHARs. On output,
                        the number of TCHARs copied to the destination buffer, not including
                        the terminating null character.
   }
   Pointer   $lpBuffer is rw,
   LPDWORD  $nSize is rw
   )
   is native("Kernel32.dll")
   is symbol("GetComputerNameA")
   returns DWORD    # If no error occurs, gethostname returns zero
   { * };

# NetBios names are 15 characters plus 1 nul long maximum
my LPDWORD $nSize = 16;

my $NamePrt = NativeCall::Types::Pointer.new();
my $RtnCode = GetComputerName $NamePrt, $nSize;

my $SessionArray = CArray[BYTE].new( 0xFF xx $nSize );

$RtnCode = memcpy_s $SessionArray, $nSize , $NamePrt, $nSize ;

print "Computer Name = <";
for $SessionArray -> $i  { print Buf.new( $i ).decode("utf8-c8"); }
print ">\n\n";