Hyper Stacks 1994 May/Hyper Stacks (Pacific HiTech)(1994)[Mac].iso/HyperTalk/Serial Port Toolkit v.2.5/Source Code/recvUpTo.p

Text File | 1988-04-18 | 8.1 KB | 279 lines | [TEXT/MPS ]

(*
    recvUpTo(termination character, waitTime,oldString) -- Return a string from the
        serial port; return everything available, up to the termination character (if any). Pass an empty
        termination character to receive everything available. WaitTime is the amount of time to wait
        for the input, in ticks (60ths of a second). oldString is what was read the last call (presumably
        terminated due to a time-out).

    To compile and link this file using Macintosh Programmer's Workshop,

        pascal -w recvUpTo.p
        link -m ENTRYPOINT -o HyperCommands -rt XFCN=7032 -sn Main=recvUpTo ∂
            recvUpTo.p.o "{MPW}"Libraries:interface.o

    © Copyright 1987,88 by Apple Computer, Inc.

    Initial coding 9/87 by Harry R. Chesley.
*)

{$R-}

{$S recvUpTo }     { Segment name must be the same as the command name. }

unit DummyUnit;

interface

uses MemTypes, QuickDraw, OSIntf, ToolIntf, HyperXCmd;

procedure EntryPoint(paramPtr: XCmdPtr);

implementation

const

return = 13;                { Carriage return. }
linefeed = 10;            { Line feed. }
bs = 8;                        { Back space. }
delete = 127;            { Delete. }
space = ord(' ');        { Space. }
tab = 9;                    { Horizontal tab. }

type

Str31 = String[31];

procedure recvUpTo(paramPtr: XCmdPtr); forward;

procedure EntryPoint(paramPtr: XCmdPtr);

    begin
        recvUpTo(paramPtr);
    end;

procedure recvUpTo(paramPtr: XCmdPtr);

    var str: Str255;
        l: longInt;
        waitForChars: longInt;        { Ticks to wait until for characters (compated to TickCount). }
        lookForTerm: boolean;        { True if we're looking for a terminator character. }
        termChar: signedByte;        { The terminator character we're looking for. }
        resultHand: Handle;            { A handle to the result string. }
        resultSize: longInt;            { The size of the result string (minus the zero termination tacked on last). }
        theChar: signedByte;
        p, p2: Ptr;
        col: integer;                        { The current column. }
        i,j: integer;

    {$I XCmdGlue.inc}

    procedure Fail(errMsg: Str255); { set theResult and quit }
        begin
            paramPtr^.returnValue := PasToZero(errMsg);
            exit(recvUpTo);
        end;

    {$I SPortUtil.inc}

    procedure sendByte(b: SignedByte);
        { Send one byte out the port. }

        var l: longInt;

        begin
            l := 1;
            if FSWrite(ThisSPort.portOutDev,l,@b) <> noErr then Fail('FSWrite failed');
        end;

    procedure sendCRLF;
        { Send a carriage return/linefeed out the port. }

        begin
            sendByte(return); sendByte(linefeed);
        end;

    procedure sendBS;
        { Backspace on a terminal attached to the port: backspace, then space to erase any character in the
            previous position, then backspace again to get the cursor in the right place. }

        begin
            sendByte(bs); sendByte(space); sendByte(bs);
        end;

    procedure disposAndFail(err: str255);
        { Fail routine used after the result handle has been allocated. }

        begin
            DisposHandle(resultHand);
            Fail(err);
        end;

    begin
        if paramPtr^.paramCount <> 3 then Fail('parameter count is not 3');

        SetUpSPortGlobals;
        EnsureOpenPort;

        GetStrParm(1,str);                                        { First parameter is termination character. }
        if length(str) = 0 then lookForTerm := false
        else
            begin
                lookForTerm := true;
                termChar := SignedByte(str[1]);
            end;
        waitForChars := GetLongParm(2);                    { Second parameter is whether to wait. }
        resultHand := paramPtr^.params[3];                { Third parameter is the old string. }

        { If there's anything in the "previous" string, copy it. }
        if resultHand <> NIL then
            begin
                p := resultHand^;
                resultSize := 0;
                while p^ <> 0 do
                    begin
                        resultSize := resultSize + 1;
                        p := Ptr(ord4(p)+1);
                    end;
                if resultSize < 0 then Fail('Input string size too small!');
                if HandToHand(resultHand) <> noErr then Fail('HandToHand failed!');
                SetHandleSize(resultHand,resultSize);
            end
        { On the other hand, if the previous string is empty, make a new, empty one. }
        else
            begin
                resultHand := NewHandle(0);
                resultSize := 0;
            end;

        { Get our current idea of where the other side's cursor is. }
        col := ThisSPort.currentColumn;

        { Figure out when to stop trying (timeout). }
        waitForChars := waitForChars + TickCount;

        { Cycle until the timeout happens or we see the termintor character. }
        while true do
            begin
                { Check if there's any input from the port. }
                if SerGetBuf(ThisSPort.portInDev,l) <> noErr then disposAndFail('SerGetBuf failed');
                { If not, do another round or get out, depending on the timeout condition. }
                if l = 0 then
                    begin
                        if TickCount > waitForChars then leave
                        else cycle;
                    end;

                { Expand the result handle and read in the first character that's waiting. }
                resultSize := resultSize+1;
                SetHandleSize(resultHand,resultSize);
                if MemError <> noErr then disposAndFail('SetHandleSize failed!');
                HLock(resultHand);
                l := 1;
                if FSRead(ThisSPort.portInDev,l,Ptr(ord4(resultHand^)+resultSize-1)) <> noErr then
                    disposAndFail('FSRead failed');
                HUnlock(resultHand);

                { Strip the character, if appropriate, and then get it into theChar. }
                p := Ptr(ord4(resultHand^)+resultSize-1);
                if ThisSPort.stripIncoming then p^ := BAND(p^,$7F);
                theChar := p^;

                { Weed out control characters, if appropriate. }
                if ThisSPort.stripControls then
                    if (theChar < space) and (theChar <> tab) and (theChar <> return) and (theChar <> bs) then
                        begin
                            resultSize := resultSize-1;
                            SetHandleSize(resultHand,resultSize);
                            cycle;
                        end;

                { If we're echoing... }
                if ThisSPort.doEcho then
                    begin
                        { If this is a backspace... }
                        if ThisSPort.doEdit and ((theChar = bs) or (theChar = delete)) then
                            begin
                                if (col > 1) and (resultSize > 1) then
                                    begin
                                        sendBS;
                                        col := col-1;
                                    end;
                            end
                        { If it's a carriage return... }
                        else if theChar = return then
                            begin
                                sendCRLF;
                                col := 1;
                            end
                        { If it's a normal, non-wrapped character... }
                        else if (col < WRAPCOLUMN) or (not ThisSPort.autoWrap) then
                            begin
                                sendByte(theChar);
                                col := col+1;
                            end
                        { If it's a space in the wrap column (which only allows spaces)... }
                        else if (theChar = space) and (col = WRAPCOLUMN) then
                            begin
                                sendByte(space);
                                col := col+1;
                            end
                        { Otherwise, wrap the last word of the line onto the next line... }
                        else
                            begin
                                { Figure out how many characters will wrap... }
                                p := pointer(ord4(resultHand^)+resultSize);
                                i := 0;
                                while p <> resultHand^ do
                                    begin
                                        p := pointer(ord4(p)-1);
                                        if (p^ = space) or (p^ = return) then leave;
                                        i := i+1;
                                    end;
                                { If it's the entire line, forget it. }
                                if i >= MAXWRAP then i := 1;
                                { If there's nothing to wrap, then just send a carriage return/linefeed. }
                                if i = 0 then i := 1
                                { Otherwise, backspace thru the characters being wrapped, then go to the next
                                    line, then send the wrapping characters. }
                                else
                                    begin
                                        if i > 1 then for j := 1 to i-1 do sendBS;
                                        sendCRLF;
                                        for j := resultSize-i to resultSize-1 do
                                            sendByte(Ptr(ord4(resultHand^)+j)^);
                                    end;
                                col := i+1;
                            end;
                    end;

                { If we're editing this line and this is the edit character... }
                if ThisSPort.doEdit and (theChar = bs) or (theChar = delete) then
                    begin
                        { Eliminate the backspace character. }
                        resultSize := resultSize-1;
                        { If we're allowed to edit it (i.e., it isn't on the previous line on the screen),
                            eliminate the erased character. }
                        if (col >= 1) or (not ThisSPort.doEcho) then resultSize := resultSize-1;
                        { Make sure we're not deleting more than there is. }
                        if resultSize < 0 then resultSize := 0;
                        { Delete it. }
                        SetHandleSize(resultHand,resultSize);
                    end;
                if lookForTerm and (theChar = termChar) then leave;
                if resultSize > 30000 then leave;
            end;

        { Add in the zero termination for the string. }
        SetHandleSize(resultHand,resultSize+1);
        p := ptr(ord4(resultHand^)+resultSize);
        p^ := 0;

        { Return the handle. }
        paramPtr^.returnValue := resultHand;

        { Remember where we think the cursor column is. }
        Globals^^.ports[Globals^^.selectedPort].currentColumn := col;
    end;

end.