Final Specifications

Code from MP4 and other example code that was not written during the time spent on the final project is marked in red.

:Client

Constants

DOWNARROW EQU 80
RIGHTARROW EQU 77
LEFTARROW EQU 75
UPARROW EQU 72

CANVAS_X EQU 106
CANVAS_Y EQU 30
TOOL_X EQU 0
TOOL_Y EQU 30
TOOL_W EQU 106
TOOL_H EQU 283

NUM_MENU_ITEMS EQU 11

BKSP EQU 8
ESC EQU 1
ENTERKEY EQU 13
SPACE EQU 57
LSHIFT EQU 42
RSHIFT EQU 54

;--Packet masks (get them out of the ASCII char range)
CONTROL_MASK EQU 0FCh               ; control packet
MESSAGE_MASK EQU 0FEh                ; message packet
DRAW_MASK EQU 0FDh                      ; draw packet

;-------Second byte of the packet  (subtype)
;--Draw
DRAW_PIXEL_M EQU 0F0h                 ; draw circle
DRAW_LINE_M EQU 0F1h                   ; draw line
DRAW_RECT_M EQU 0F2h                  ; draw rect
DRAW_CIRCLE_M EQU 0F3h              ; draw circle
DRAW_TEXT_M EQU 0F4h                  ; draw text
DRAW_FILL_M EQU 0F5h
;--Control
CHANGE_NAME EQU 0FBh                 ; user is trying to change name
SIGNON EQU 0F6h                                ; sent on connect
SIGNOFF EQU 0F7h                              ; send on disconnect
USERLIST EQU 0F8h                             ;new user list coming in

TB EQU 0FFh                                          ;text break, used to terminate text data

;----SOUND
DMASIZE EQU 1024*64                        ;DMA SIZE MAX: 64 KB

RECFILESIZE EQU 396                         ;incoming message
REC2FILESIZE EQU 1332                     ;alternate incoming message
SIGNONFILESIZE EQU 4730               ;change in the user list
DRAWFILESIZE EQU 4366                  ; incoming draw

Variables

DMASel resw 1                                       ;DMA selector
DMAAddr resd 1                                    ;DMA linear address
DMAChan resb 1                                    ;DMA channel

FileOffset resd 1                                     ; Pointer to beginning of wav data
FileBufferSize resd 1                               ; Size of data in the buffer

_GraphicsMode resw 1                          ; Graphics mode #

_kbINT resb 1                                       ; Keyboard interrupt #
_kbIRQ resb 1                                       ; Keyboard IRQ
_kbPort resw 1                                      ; Keyboard port

_MouseSeg resw 1                                 ; real mode segment for MouseCallback
_MouseOff resw 1                                  ; real mode offset for MouseCallback
_MouseX resw 1                                    ; X coordinate position of mouse on screen
_MouseY resw 1                                    ; Y coordinate position of mouse on screen

_ScreenOff resd 1                                  ; Screen image offset
_CanvasOff resd 1                                 ; Canvas image offset
_OverlayOff resd 1                                ; Overlay image offset
_SmallFontOff resd 1                             ; Font image offset
_Font2Off resd 1
_MenuOff resd 1                                   ; Menu image offset
_UsersOff resd 1                                   ; Users list offset
_ToolsOff resd 1                                   ; Tools offset
_DividerOff resd 1                                 ; divider bar
_TextDispOff resd 1                              ; Chat window
_TextEnterOff resd 1                             ; Text bar
_Net_ErrOff resd 1                               ; Network error dialog
_hosterrOff resd 1                                 ; hostname failed message
_connerrOff resd 1                                ; connect failed message
_recverrOff resd 1                                 ; receive error message
_senderrOff resd 1                                ; send error message
_connOff resd 1                                    ; connected icon 
_notconnOff resd 1                               ; disconnected icon
_guideOff resd 1                                   ; user guide

_TextMessage resb 96                          ;text message buffer

_MPFlags resb 1 ; program flags
; Bit 0 - Exit program
; Bit 1 - Left mouse button (LMB) status: set if down, cleared if up
; Bit 2 - Change in LMB status: set if button status
; moves from pressed->released or vice-versa
; Bit 3 - Right shift key status: set if down, cleared if up
; Bit 4 - Left shift key status: set if down, cleared if up
; Bit 5 - Key other than shift was pressed
; Bit 6 - Not Used Anymore
; Bit 7 - Not Used 

_MenuItem resb 1 ; selected menu item
                            ; -1 - none
                            ; 1 - pencil
                            ; 2 - flood
                            ; 3 - rect empty
                            ; 4 - rect fill
                            ; 5 - circle empty
                            ; 6 - circle fill
                            ; 7 - line
                            ; 8 - text
                            ; 9 - color
                            ; 10 - text box

; Line algorithm variables 
_x resw 1
_y resw 1
_dx resw 1
_dy resw 1
_lineerror resw 1
_xhorizinc resw 1
_xdiaginc resw 1
_yvertinc resw 1
_ydiaginc resw 1
_errordiaginc resw 1
_errornodiaginc resw 1

; Circle algorithm variables
_radius resw 1
_circleerror resw 1
_xdist resw 1
_ydist resw 1

; flood fill variables
_PointQueue resd 1
_QueueHead resd 1
_QueueTail resd 1

_key resb 1

_Numpixels resw 1

_SelectedUser resd 1                             ;pointer to beginning of selected user name in _UserList
_UserLength resb 1                                ;length of users current user name
_UserList resb 320                                 ;current list of connected users
_errorMsg resd 1                                   ;pointer to network error message

_socket resd 1                                       ;pointer to outgoing socket
_address resb SOCKADDR_size          ; SOCKADDR structures
recvbuf_len equ 96                                
_recvbuf resb recvbuf_len                      ;buffer for incoming data  
_buf resb 96                                          ;scratch buffer for outgoing data

_listensock resd 1                                  ;pointer to listening socket
_connsocket resd 1                               ;socket connected from server
_listenaddr resb SOCKADDR_size      ;address structure for listening socket

_gotaccept db 0                                     ;set by socket handler on waiting connection

;SOUND files
SoundRec db "rec.wav",0
SoundRec2 db "rec2.wav",0
SoundSignOn db "signon.wav",0
SoundDraw db "draw.wav",0

DMAFlag dd 0

; Required image files
_SmallFontFN db 'small.png',0            ;8x16 font used by DrawSmallText
_Font2FN db 'font3.png',0                  ;12x24 font used by DrawText
_MenuFN db 'menu.png',0                  ;menu/title bar
_UsersFN db 'users.png',0                  ;user list
_ToolsFN db 'tools.png',0                   ;drawing toolbox
_DrawFN db 'draw.png',0                  ;canvas area
_DividerFN db 'divider.png',0             ;divider between canvas and messages
_T_DispFN db 't_disp.png',0              ;message area
_T_EnterFN db 't_enter.png',0            ;text entry box
_Net_ErrFN db 'net_err.png',0           ;network error dialog
_hosterrFN db 'hosterr.png',0             ;hostname failed message
_connerrFN db 'connerr.png',0           ;connect failed message
_senderrFN db 'senderr.png',0            ;receive error message
_recverrFN db 'recverr.png',0            ;send error message
_connFN db 'conn.png',0                   ;connected icon 
_notconnFN db 'notconn.png',0         ;disconnected icon
_guideFN db 'guide.png', 0                ;user guide
_ssFN db 'ss_test.bmp',0                  ;screen shot test file name


; Defined color values
_CurrentColor dd 0ffff0000h             ; current color (initially red)
_ColorBlue dd 0ff0033ffh                
_ColorWhite dd 0ffffffffh
_ColorBlack dd 0ff000000h
_ColorHalfBlack dd 0cc000000h
_ColorRed dd 0ffe00f0fh

_buffer db ' ','$'

_ColorString1 db 'Enter numerical values for','$'
_ColorString2 db 'each channel (ARGB), and','$'
_ColorString3 db 'separate each number by a','$'
_ColorString4 db 'space (ex. 127 255 255 0).','$'

_QwertyNames
db 0 ; filler
db 0,'1','2','3','4','5','6','7','8','9','0','-','=',BKSP
db 0, 'q','w','e','r','t','y','u','i','o','p','[',']',ENTERKEY
db 0,'a','s','d','f','g','h','j','k','l',';',"'","`"
db 0,'\','z','x','c','v','b','n','m',",",'.','/',0,'*'
db 0, ' ', 0, 0,0,0,0,0,0,0,0,0,0 ; F1-F10
db 0,0 ; numlock, scroll lock
db 0, 0, 0, '-'
db 0, 0, 0, '+'
db 0, 0, 0, 0
db 0, 0; sysrq
_QwertyNames_end resb 0

_QwertyShift
db 0 ; filler
db 0,'!','@','#','$','%','^','&','*','(',')','_','+',BKSP
db 0, 'Q','W','E','R','T','Y','U','I','O','P','{','}',ENTERKEY
db 0,'A','S','D','F','G','H','J','K','L',':','"','~'
db 0,'|','Z','X','C','V','B','N','M',"<",'>','?',0,'*'
db 0, ' ', 0, 0,0,0,0,0,0,0,0,0,0 ; F1-F10
db 0,0 ; numlock, scroll lock
db 0, 0, 0, '-'
db 0, 0, 0, '+'
db 0, 0, 0, 0
db 0, 0; sysrq
_QwertyShift_end resb 0

_TextInputString times 80 db 0,'$'                     ;max message length plus room for user name at end
_ColorInputString times 15 db 0,'$'                   

_RoundingFactor dd 000800080h, 00000080h


_UserName times 9 db 0                                 ;8 char max
_FileName times 13 db 0                                 ;8 char max entry, +4 extension

;NETWORK VARIABLES
_connected db 0                                             ;set whenever connected to a server
_listenconnected db 0                                     ;set when server has connected back

;Various text prompts
_UserString1 db 'Enter a user name to', '$'            
_UserString2 db 'display to others','$'
_FileString1 db 'Enter a file name:','$'
_FileString2 db '(.bmp extension is assumed)','$'

_ServerString1 db 'Enter hostname or IP of', '$'
_ServerString2 db 'server to connect to', '$'
_InitString db 'CONNECT FROM CLIENT',10,13

_Server times 24 db 0                                     ;IP address buffer, 23 char max server name/ip
_port dw 12345                                             ; outgoing port

:Server

Constants

;-------Packet masks (out of the ASCII char range)
CONTROL_MASK EQU 0FCh     ; control packet
MESSAGE_MASK EQU 0FEh      ; message packet
DRAW_MASK EQU 0FDh            ; draw packet

;-------Second envelope of the packet 
;--Draw
DRAW_PIXEL_M EQU 0F0h     ; draw circle
DRAW_LINE_M EQU 0F1h       ; draw line
DRAW_RECT_M EQU 0F2h      ; draw rect
DRAW_CIRCLE_M EQU 0F3h  ; draw circle
DRAW_TEXT_M EQU 0F4h      ; draw text
DRAW_FILL_M EQU 0F5h
;--Control
CHANGE_NAME EQU 0FBh    ; user is trying to change name
SIGNON EQU 0F6h                   ; when user signs in
SIGNOFF EQU 0F7h                 ; when user closes the client
USERLIST EQU 0F8h                ; for a username list

TB EQU 0FFh                             ;text break, used to terminate/separate text data

Variables

_port dw 12345                           ; port number to listen on
_numusers db 0                            ; number of users connected (0-30)
lim_users equ 30
_usernames resb lim_users*9+4     ;array of user names/pointers to sockets (9 bytes for user name, 4 for pointer to socket)
_usersockets resd lim_users           ;array of pointers to socket user is connected on
_socket resd 1 ; listening socket
_connsockets resd lim_users          ;array of connection sockets back to users
_gotaccept resb 1
_address resb SOCKADDR_size ; SOCKADDR structure
_clientaddress resb SOCKADDR_size
_currentuser resd 1                        ;holds a pointer to the current socket (as we traverse the arrays)
buf_len equ 16*1024
_buf resb buf_len                           ;incoming/scratch buffer

Procedures/Subroutines

:Client

.init                                                             --Will Snodgrass--
    ;pseudocode :
    call _LibInit
    Allocate image buffers
    Load image files into buffers
    Initialize graphics
    Install keyboard and mouse ISR's
    Initialize socket library
    Create outgoing socket
    Create & bind listening socket
    Install socket handler
    Start listening on listen socket
    Copy image buffers to main screen buffer
    Display user guide until ESC press
    call _GetUserName
    call _GetServer

.mainLoop                                                    --Will Snodgrass--
    Check flags to determine if the server is ready to connect to client
        Call AcceptConnection to accept incoming connection if necessary
    Fill current color box with the current color
    Check the connection status and display either connected or disconnected icon
    Call Recv_and_Update to check for incoming data
    Check for mouse press, call .MouseEvent if true
    Check if in draw text or change color mode, jump to their handler if so
    Check for data on the socket from server, pass it to PacketDecode if it exists
    .endloop
      

.MouseEvent                                                --Will Snodgrass--
   Called from main loop when mouse button is pressed.  Handles all mouse clicks while in 
    drawing mode.  Checks for and handles Server, User Name and Close button clicks. 
    Also handles selection of drawing tools, and entry into text messaging mode.  If a tool
    was clicked, sets [_MenuItem] to the corresponding integer value and jumps to the associated
    handler loop for that tool if applicable. Otherwise returns to beginning of main loop.  Draws red
    rectangle around selected object if applicable.
    Inputs:
        _MouseX, _MouseY - coordinates of mouse when pressed
    Outputs:
        [_MenuItem] - number that corresponds to mode of operation
        [_MPFlags] - updated to reflect handling of mouse event
        Highlight rectangle cleared and drawn in new location
    Calls: _DrawRect, _CopyBuffer, _CopyToScreen, _PointInBox, _GetUserName, 
            _GetServer, _ScreenShot

.HandleTextBox                                        --Will Snodgrass--
   Loop to control entering of text message:
    Displays text entry into box as it is typed and sends entered text to server when ENTER is pressed.
    Checks for new incoming data on each iteration to prevent blocking.  Checks for clicks within the 
    user list to handle user selection.  Returns to drawing mode (main loop) when ESC is pressed.
    Inputs:
        [_key] -- ASCII value of current keypress
        [_connected] -- flag set when connected to server
        [_MPFlags]  -- identifies mouse events and ESC presses
        [_MouseX], [_MouseY] -- coordinates of a mouse click
        *_UserName - ptr to current user name string, to add to text entered before transmittal
    Outputs:
        _TextMessage - message that was entered + $ + user name + $
    Calls: _Packet_Encode, _DrawSmallText, _ClearBuffer, _CopyBuffer, _ComposeBuffers, _CopyToScreen,
            _PointInBox, _UpdateUsers

void    AcceptConnection                           --Will Snodgrass--
    Accepts a waiting connection on the listening socket and saves a reference to the socket.
    Sets flags to reflect status.
    Inputs:
        [_listensocket] - incoming socket with ready connection
    Outputs:
        [_connsocket] - reference to accepted connection
        [_gotaccept] - cleared to indicate waiting connection was handled
        [_listenconnected] - set to indicate we have an active incoming connection
    Calls:
        _Socket_accept

void _SocketHandler                                --Will Snodgrass--
    Ran when a new connection is incoming on the listening socket.  Sets a flag that will be seen
    by the main loop.
    Inputs:
        [_listensocket] - socket we're listening on
    Outputs:
        [_gotaccept] - flag set if we have a new connection ready
    Calls:
        none

void _GetUserName (word flag)                --Will Snodgrass--
   Prompts user for username to be displayed to other users.  Transmits username to server if being
    called to change current user name.
    Inputs:
        flag -- 0 if initial call, 1 if calling to change user name
        Text entered to prompt
    Outputs:
        [_UserName] - text stored here, terminated by $
    Calls: _ClearBuffer, _CopyBuffer, _DrawRect, _ComposeBuffers, _DrawText, _CopyToScreen, _PacketEncode

void _GetServer (word flag)                    --Will Snodgrass--
   Prompts user for server URL or IP to connect to.  Disconnects from current server if required,
    and connects to entered server.  Transmits signon packet with username when connected.
    Inputs:
        flag -- for future features
        [_connected] - status flag to determine if we need to disconnect first
        [_socket] - connection socket
        *_address - pointer to address structure for connection socket
        Text entered to prompt
    Outputs:
        [_Server] - text stored here, terminated by 0
        [_listenconnected] - cleared if disconnect is executed
        
    Calls:   _ClearBuffer, _CopyBuffer, _DrawRect, _ComposeBuffers, _DrawText, _CopyToScreen, _PacketEncode,
                _Socket_close, _Socket_create, _Socket_getbyhostname, _Socket_connect

void NetworkError (dword [_errorMsg])    --Will Snodgrass--
   Displays network error message who's image buffer is pointed to by _errorMsg.  Waits for
    ESC press before clearing dialog box.
    Inputs:
        *[_errorMsg] - pointer to error message image buffer
        *[_Net_ErrOff] - pointer to dialog box image buffer
    Outputs:
        [_connected] - flag is set to 0
        Prompt displayed
    Calls: DrawText, DrawRect ClearBuffer, CopyBuffer, ComposeBuffers, CopyToScreen

void _MessageUpdate(dword *buf)        --Will Snodgrass--
   Updates the messaging window with new text message that was received.  The data pointed to by
    buf will have a $ terminated message followed by a $ terminated user name followed by a TB byte
    Inputs:
       *buf    - pointer to packet data
    Outputs:
        Messaging text rotated upwards, new message inserted at bottom of message window
    Calls: _DrawSmallText, _ClearBuffer, _CopyBuffer, _ComposeBuffers, _CopyToScreen

void _UpdateUsers(dword *buf, word userselect)        --Will Snodgrass--
   Updates the list of online users when a userlist packet is received from server and highlights
    the user at index userselect if it is valid for the current number of users.  Also saves a pointer
    to the selected username
    Inputs:
        *buf    - pointer to packet data
        userselect - index of user to highlight and save
    Outputs:
        _UserList - new user list written to this buffer
        [_SelectedUser] - pointer to the selected user in _UserList
    Calls: _DrawSmallText, _ClearBuffer, _CopyBuffer, _ComposeBuffers, _CopyToScreen

void _Recv_and_Update                    --Will Snodgrass--
    Checks incoming socket for waiting data.  Processes data based on its header information.
    Handles drawing of image data to canvas.  Plays notification sound based on data type.
    Inputs:
        [_connsocket] - incoming socket to receive data from
        *_recvbuf - pointer to scratch buffer for incoming data
    Outputs:
        none
    Calls:
        _ClearBuffer, _CopyBuffer, _ComposeBuffers, _CopyToScreen,
        _DrawLine, _DrawRect,_DrawCircle,_DrawText,_FloodFill,
        _ReadInFile, _MessageUpdate, _UpdateUsers

void _ScreenShot                            --Will Snodgrass--
    Prompts for user entered file name then saves screen image data to a bitmap file in the
    program directory.
    Inputs:    
        none
    Outputs:
        bitmap file written
    Calls:
        _ClearBuffer, _CopyBuffer, _DrawRect, _ComposeBuffers, _DrawText, _CopyToScreen, _SaveBMP,

void _DrawSmallText(dword *StringOff, dword *DestOff, word DestWidth, word DestHeight, word X, word Y, dword Color)            --Will Snodgrass--
Draws a text string pointed to by StringOff with color Color at point (X,Y) in the buffer pointed to by DestOff using small font file
Inputs:
    StringOff - offset of string to draw
    DestOff -  offset of an image buffer in memory
    DestWidth - width of the buffer
    DestHeight - height of the buffer
    X - x coordinate of start point
    Y - y coordinate of start point
    Color - color of the string to draw
    [_FontOff] - offset of font image data
Outputs: String drawn to buffer
Calls: _PointInBox

void _SoundISR                           --Josh Kim--
    Triggered when a sound completes
    Inputs: none
    Outputs: [DMAFlag] set when run
    Calls: none

void _InitSound                           --Josh Kim--
    Purpose: Initialize everything that has to do with sound, including the DMA buffer
    Inputs: None
    Outputs: None
    Calls:     DMA_Allocate_Mem
                 DMA_Lock_Mem
                 LockArea
                 SB16_Init
                 SB16_GetChannel
                 SB16_SetFormat
                 SB16_SetMixers
    Comments: Sets _DMAChannel, _DMASelector, and _DMAAddress

void ReadinFile (dword FileName, dword Size)                        --Josh Kim--
    Reads the file, and sets up a Buffer and BufferSize.  Plays the loaded file.
    Inputs:  .Filename: Name of the file
                .Size: Size of the file
    Outputs: None
    Calls: AllocMem
             OpenFile
             ReadFile
             CloseFile
             DMA_Start
             SB16_Start
    Comments: The main for the sound stuff

void StopSound                        --Josh Kim--
    Purpose: Kill everything that has to do with sound and DMA
    Inputs: [DMAChan], dma channel we were using
    Outputs: None
    Calls: DMA_Stop
             SB16_Stop
             SB16_SetMixers
             SB16_Exit
    Comments: Ends the sound insanity

***All draw handlers modified to call PacketEncode with appropriate data when release event occurs***

.HandlePen
   Loop, handles drawing w/ pen tool

.HandleRect
    Loop, handles rectangle tool

.HandleCircle
    Loop, handles circle tool

.HandleLine
    Loop, handles line tool

.HandleFill
    Loop, handles fill tool

.HandleText
        Loop, handles text tool

.HandleColor
    Loop, handles color changes

dword _PointInBox(word PointX, word PointY, word BoxULCornerX, word BoxULCornerY, word BoxLRCornerX, word BoxLRCornerY)

• Determines if the point (X,Y) is located in the box formed by the points (BoxULCornerX,BoxULCornerY) and (BoxLRCornerX,BoxLRCornerY) 
• Inputs:
  • X - x coordinate of point in question
  • Y - y coordinate of point in question
  • BoxULCornerX - x coordinate of upper-left hand corner of box
  • BoxULCornerY - y coordinate of upper-left hand corner of box
  • BoxLRCornerX - x coordinate of lower-right hand corner of box
  • BoxLRCornerY - y coordinate of lower-right hand corner of box
• Outputs:
• Calls: None
• Returns: 1 if BoxULCornerX <= X <= BoxLRCornerX and BoxULCornerY <= Y <= BoxLRCornerY, 0 otherwise

void _DrawPixel(dword *DestOff, word DestWidth, word DestHeight, word X, word Y, dword Color)

• Draws a pixel with color Color at point (X,Y) in the buffer pointed to by DestOff 
• Inputs:
  • DestOff - offset of an image buffer in memory
  • DestWidth - width of the buffer
  • DestHeight - height of the buffer
  • X - x coordinate of point
  • Y - y coordinate of point
  • Color - color of pixel to draw
• Outputs: Pixel drawn to buffer
• Calls: _PointInBox
• Returns: None

void _DrawLine(dword *DestOff, word DestWidth, word DestHeight, word X1, word Y1, word X2, word Y2, dword Color)

• Draws a line with color Color from point (X1,Y1) to (X2,Y2) in the buffer pointed to by DestOff 
• Inputs:
  • DestOff - offset of an image buffer in memory
  • DestWidth - width of the buffer
  • DestHeight - height of the buffer
  • X1 - x coordinate of start point
  • Y1 - y coordinate of start point
  • X2 - x coordinate of end point
  • Y2 - y coordinate of end point
  • Color - color of line to draw
• Outputs: Line drawn to buffer
• Calls: _DrawPixel
• Returns: None

void _DrawRect(dword *DestOff, word DestWidth, word DestHeight, word DestX1, word DestY1, word DestX2, word DestY2, dword Color, dword FillRectFlag)

• Draws a rectangle with color Color from point (X1,Y1) to (X2,Y2) in the buffer pointed to by DestOff 
• Inputs:
  • DestOff - offset of an image buffer in memory
  • DestWidth - width of the buffer
  • DestHeight - height of the buffer
  • X1 - x coordinate of start point
  • Y1 - y coordinate of start point
  • X2 - x coordinate of end point
  • Y2 - y coordinate of end point
  • Color - color of rectangle to draw
  • FillRectFlag - flag to determine whether or not to fill the rectangle
• Outputs: Rectangle drawn to buffer, filled if necessary
• Calls: _DrawLine, _FloodFill
• Returns: None

void _DrawCircle(dword *DestOff, word DestWidth, word DestHeight, word X, word Y, word Radius, dword Color, dword FillCircleFlag)

• Draws a circle with center (X,Y), color Color, and radius Radius in the buffer pointed to by DestOff 
• Inputs:
  • DestOff - offset of an image buffer in memory
  • DestWidth - width of the buffer
  • DestHeight - height of the buffer
  • X - x coordinate of center
  • Y - y coordinate of center
  • Color - color of line to draw
  • FillCircleFlag - flag to determine whether or not to fill the circle
• Outputs: Circle drawn to buffer, filled if necessary
• Calls: _DrawPixel, _FloodFill
• Returns: None

void _DrawText(dword *StringOff, dword *DestOff, word DestWidth, word DestHeight, word X, word Y, dword Color)

• Draws a text string pointed to by StringOff with color Color at point (X,Y) in the buffer pointed to by DestOff
• Inputs:
  • StringOff - offset of string to draw
  • DestOff -  offset of an image buffer in memory
  • DestWidth - width of the buffer
  • DestHeight - height of the buffer
  • X - x coordinate of start point
  • Y - y coordinate of start point
  • Color - color of the string to draw
  • [_FontOff] - offset of font image data
• Outputs: String drawn to buffer
• Calls: _PointInBox

void _ClearBuffer(dword *DestOff, word DestWidth, word DestHeight, dword Color)

• Clears a buffer pointed to by DestOff by filling it with color Color
• Inputs:
  • DestOff -  offset of an image buffer in memory
  • DestWidth - width of the buffer
  • DestHeight - height of the buffer
  • Color - color to make buffer
• Outputs: Color copied to buffer
• Calls: None

void _CopyBuffer(dword *SrcOff, word SrcWidth, word SrcHeight, dword *DestOff, word DestWidth, word DestHeight, word X, word Y)

• Copies a source buffer pointed to by SrcOff to a location (X,Y) in a destination buffer pointed to by DestOff
• Inputs:
  • SrcOff - offset of source buffer
  • SrcWidth - width of source buffer
  • SrcHeight - height of source buffer
  • DestOff -  offset of destination buffer
  • DestWidth - width of destination buffer
  • DestHeight - height of destination buffer
  • X - x coordinate of start point in destination buffer
  • Y - y coordinate of start point in destination buffer
• Outputs: Source buffer copied onto destination buffer
• Calls: None

void _ComposeBuffers(dword *SrcOff, word SrcWidth, word SrcHeight, dword *DestOff, word DestWidth, word DestHeight, word X, word Y)

• Alpha composes a source buffer pointed to by SrcOff onto a destination buffer pointed to by DestOff at location (X,Y)
• Inputs:
  • SrcOff - offset of source buffer
  • SrcWidth - width of source buffer
  • SrcHeight - height of source buffer
  • DestOff -  offset of destination buffer
  • DestWidth - width of destination buffer
  • DestHeight - height of destination buffer
  • X - x coordinate of start point in destination buffer
  • Y - y coordinate of start point in destination buffer
• Outputs: Source buffer alpha composed onto destination buffer
• Calls: None

dword _InstallKeyboard(void)

• Installs the keyboard ISR
• Inputs: None
• Outputs: None
• Calls: _LockArea
• Returns: 1 on error, 0 otherwise

void _RemoveKeyboard(void)

• Uninstalls the keyboard ISR
• Inputs: None
• Outputs: None

void _KeyboardISR(void)

• Handles keyboard input from the user
• Inputs: Keypress waiting at port [_kbPort], [_kbIRQ]
• Outputs: [_key], [_MPFlags]
• Calls: None

dword _InstallMouse(void)

• Installs the mouse callback
• Inputs: None
• Outputs: [_MouseSeg], [_MouseOff]
• Returns: 1 on error, 0 otherwise
• Calls: _LockArea, _Get_RMCB, DPMI_Int

void _RemoveMouse(void)

• Removes the mouse callback
• Inputs: [_MouseSeg], [_MouseOff]
• Outputs: None
• Calls: _Free_RMCB, DPMI_Int

void _MouseCallback(dword *DPMIRegsPtr)

• Handles mouse input from the user
• Inputs:
  • DPMIRegsPtr - pointer to DPMI register structure
  • [_MouseX], [_MouseY], [_MPFlags]
• Outputs: [_MouseX], [_MouseY], [_MPFlags]
• Calls: None

:Server

.init                                                                                    --Alessandro Bellina, Will Snodgrass--
    ;pseudocode:
    call _LibInit
    Create _socket, the listen socket
    Create _usersockets, an array of 30 outgoing sockets
    Initialize _usernames array with header bytes and fill with TB bytes
    Initialize _connsockets, the array of connected incoming sockets to 0's
    Bind listening socket, install handler, and start listening 

.mainLoop                                                                         --Alessandro Bellina--
    Check for keypress, exit on true
    Check for new incoming connection, jump to .gotconn on true
    Attempt receive on incoming array of sockets.
        On successful receive from any socket:
            Dump packet data to screen
            If control packet:
                call _Packet_Decode
                Transmit user list to all clients
            If other type of packet:
                Loop through outgoing sockets and broadcast received data to each
    .endloop

void _Packet_Decode (dword *buf, word index)                    --Alessandro Bellina--
   Called when a control packet is received (Change in users)
    Updates the usernames array to reflect the changes, and clears
    socket data for a user if they sent a SIGNOFF packet
    Inputs:
        *buf - pointer to packet data
        index - the index in the arrays of the user even came from
    Outputs:
        _usernames - new name written at index, or name cleared (EEh written)
    Calls:
       none

void  _SocketHandler
    This callback procedure will be executed when a new connection
    is received. Will set a flag to signify the main loop that it should
    accept a new socket.
    Inputs:
        Socket to socket responsible for the event thrown
        Event the event that was received
    Outputs:
        [_gotaccept] set to 1, since a new connection should be ready