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133 | --------------------------------------------------------------------------
-- file : multiecho.adb [$Revision: 110555 $]
--------------------------------------------------------------------------
-- This is a modification of "echoserver.adb", to allow multiple
-- connections, using Ada tasks.
-- waits for a client to attach to port 8189, then
-- reads input from the client, a line at a time, and echos it.
-- To run this program, type "java EchoServer",
-- then put the job in the background
-- or switch to another window, and type
-- "telnet <hostname> <portnumber>",
-- replacing <hostname> by the name of
-- the host on which you are running the echo-server
-- and <portnumber> by the port number that the server printed
-- out when it started up.
-- This will connect you to the server.
-- The server should be able to handle up to 4 concurrent connections.
-- Use control-C to kill the server.
with ada.characters.latin_1;
with ada.exceptions;
with ada.task_identification;
with ada.text_io;
with sockets;
with sockets.internet;
procedure multiecho is
type connection_id is range 1..4;
connections : array (connection_id) of sockets.stream_socket;
procedure shut_down (e : ada.exceptions.exception_occurrence);
main_task : constant ada.task_identification.task_id :=
ada.task_identification.current_task;
-- used to shut down the entire program
task type server_task;
servers : array (connections'range) of server_task;
lf : constant character := ada.characters.latin_1.lf;
-- line-feed
cr : constant character := ada.characters.latin_1.cr;
-- carriage-return
protected server_pool is
entry await_turn;
procedure next_turn;
private
turn : boolean := false;
end server_pool;
protected body server_pool is
entry await_turn when turn is
begin
turn := false;
end await_turn;
procedure next_turn is
begin
turn := true;
end next_turn;
end server_pool;
procedure writeln (outs : sockets.output_stream_ptr; s : string) is
begin
string'write (outs, s);
character'write (outs, cr);
character'write (outs, lf);
end writeln;
function readln (ins : sockets.input_stream_ptr) return string is
buf : string (1 .. 1024);
i : integer := 1;
begin
loop
character'read (ins, buf (i));
exit when buf (i) = lf;
i := i + 1;
end loop;
return buf (1 .. i-2);
end readln;
peer : sockets.internet.internet_socket_address;
s : sockets.server_socket;
task body server_task is
connection : sockets.stream_socket;
ins : sockets.input_stream_ptr;
outs : sockets.output_stream_ptr;
begin
loop
server_pool.await_turn;
sockets.accept_connection (s, connection, peer);
server_pool.next_turn;
ins := sockets.get_input_stream (connection);
outs := sockets.get_output_stream (connection);
writeln (outs, "Hello! Enter BYE to exit.");
loop
declare
str : constant string := readln (ins);
begin
exit when str (1..3) = "BYE";
writeln (outs, "Echo: """ & str & '"');
end;
end loop;
sockets.close(connection);
end loop;
exception when e : others => shut_down (e);
end server_task;
procedure shut_down (e : ada.exceptions.exception_occurrence) is
begin
ada.text_io.put_line ("main: " & ada.exceptions.exception_name (e)
& ": " & ada.exceptions.exception_message (e));
sockets.close (s);
ada.task_identification.abort_task (main_task);
end shut_down;
begin
sockets.open (s, sockets.internet.new_address
(sockets.internet.any_port, sockets.internet.all_local_addresses));
ada.text_io.put_line ("serving at: "
& sockets.internet.get_addressstring (
-- & sockets.internet.get_hostbyaddr (
sockets.internet.get_internet_address (
sockets.internet.get_address (s)))
& " port "
& sockets.internet.port_number'image (
sockets.internet.get_port (
sockets.internet.get_address (s))));
server_pool.next_turn;
exception when e : others => shut_down (e);
end multiecho;
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