with System; use System;

Package body C_String_Pkg is


function C_String_Length(
  C_Str              : in C_String;
  Include_Terminator : in boolean := FALSE) return natural is

  Length: natural := 0;
  Start : System.Address;
  Char  : character;

begin
  if (C_Str = NULL) then
    return ( 0 );
  end if;

  Start := C_Str.all'ADDRESS;
  loop
    -- Get the next char by calculating its position relative to the start
    Char := Fetch_Char(Start + OFFSET(Length));
    exit when Char = Ascii.NUL;
    Length := Length + 1;
  end loop;
  if Include_Terminator then
    Length := Length + 1;
  end if;
  return ( Length );
end C_String_Length;


function C_to_Ada_String(
  C_Str              : in C_String;
  Include_Terminator : in boolean := FALSE) return Ada_String is

  Ada_Str : Ada_String := NULL;
  Length  : natural := 0;
  C_Start : System.Address;
  Char    : character;

begin
  Length := C_String_Length(C_Str, Include_Terminator);
  if (Length = 0) then
    return ( NULL );
  end if;

  Ada_Str := new string(1 .. Length);
  C_Start := C_Str.all'ADDRESS;
  for Pos in 0 .. (Length - 1)
  loop
    Char := Fetch_Char(C_Start + OFFSET(Pos));
    Ada_Str.all(Pos + 1) := Char;
  end loop;
  return ( Ada_Str );
  
  exception
    when STORAGE_ERROR => return NULL;
end C_to_Ada_String;


procedure C_to_Ada_String(
  C_Str        : in     C_String;
  The_String   :    out string;
  Include_Term : in     boolean := FALSE) is

  Length : natural := 0;

begin
  Length := C_String_Length(C_Str, Include_Term);
  if Length > The_String'LENGTH then
    Length := The_String'LENGTH;
  end if;
  if Length > 0 then
    Length := Length - 1;
    for Index in 0 .. Length
    loop
      The_String(Index+1) := Get_Char(C_Str, Index);
    end loop;
  end if;
end C_to_Ada_String;

function Get_Char(
  C_Str    : in C_String;
  Position : in natural) return character is

  C_Start : System.Address;
  Char    : character;

begin
  if (Position > C_String_Length(C_Str, FALSE)) then
    return ( Ascii.NUL );
  end if;
  C_Start := C_Str.all'ADDRESS;
  Char := Fetch_Char(C_Start + OFFSET(Position));
  return ( Char );
end Get_Char;

end C_String_Pkg;