
DIRECTORY
IO USING [Backup, CharsAvail, Close, CreateStream, CreateStreamProcs, EndOf, EndOfStream, EraseChar, Flush, GetBlock, GetChar, PeekChar, PutBlock, PutChar, Reset, SP, STREAM, StreamProcs, UnsafeBlock, UnsafeGetBlock, UnsafePutBlock],
IOClasses USING [],
IOUtils USING [closedStreamProcs],
RefText USING [ObtainScratch, ReleaseScratch];

IOClassesImpl: CEDAR PROGRAM  
IMPORTS IO, IOUtils, RefText
EXPORTS IOClasses
SHARES IO --for representation of StreamProcs
= BEGIN

STREAM: TYPE = IO.STREAM;
StreamProcs: TYPE = IO.StreamProcs;
UnsafeBlock: TYPE = IO.UnsafeBlock;


Copy: PUBLIC PROC [from, to: STREAM, closeFrom, closeTo: BOOL, bufferByteCount: NAT] = {
scratchLen: NAT = MAX[bufferByteCount, 1];
buffer: REF TEXT м RefText.ObtainScratch[scratchLen];
DO
nBytes: NAT м IO.GetBlock[from, buffer, 0, scratchLen ! IO.EndOfStream => EXIT];
IO.PutBlock[to, buffer, 0, nBytes];
IF nBytes # scratchLen THEN EXIT;
ENDLOOP;
IF closeFrom THEN IO.Close[from];
IF closeTo THEN IO.Close[to];
RefText.ReleaseScratch[buffer];
};


FilterCommentsStreamData: TYPE = REF FilterCommentsStreamRecord; 
FilterCommentsStreamRecord: TYPE = RECORD [
inStringLiteral: BOOL м FALSE,
inCharLiteral: BOOL м FALSE,
inExtendedChar: BOOL м FALSE
];
FilterCommentsStreamProcs: REF IO.StreamProcs = IO.CreateStreamProcs[
variety: $input, class: $CommentFilter,
getChar: FilterCommentsStreamGetChar
];

CreateCommentFilterStream: PUBLIC PROC [input: STREAM] RETURNS [STREAM] = { 
RETURN[IO.CreateStream[
streamProcs: FilterCommentsStreamProcs, backingStream: input,
streamData: NEW[FilterCommentsStreamRecord м []]]];
};

FilterCommentsStreamGetChar: PROC [self: STREAM] RETURNS [char: CHAR] = {
data: FilterCommentsStreamData = NARROW[self.streamData];
char м self.backingStream.GetChar[];
SELECT TRUE FROM
data.inExtendedChar => {
data.inExtendedChar м FALSE; -- not really, but rest of extended char can't contain '"
};
data.inCharLiteral => {
data.inCharLiteral м FALSE;
IF char = '\\ THEN data.inExtendedChar м TRUE;
};
data.inStringLiteral => {
SELECT char FROM
'\\ => data.inExtendedChar м TRUE;
'\" => data.inStringLiteral м FALSE; -- not really, but if following char is '" it will look like a new string literal, which is ok
ENDCASE;
};
ENDCASE =>
SELECT char FROM
'\" => data.inStringLiteral м TRUE;
'\' => data.inCharLiteral м TRUE;
'<, '\253 => {
nest: INT м 1;
IF char = '< THEN {
IF self.backingStream.EndOf[] THEN GO TO notComment;
IF self.backingStream.PeekChar[] # '< THEN GO TO notComment;
char м self.backingStream.GetChar[];
};
DO
char м self.backingStream.GetChar[];
SELECT char FROM
'< =>
IF self.backingStream.PeekChar[] = '< THEN {
char м self.backingStream.GetChar[];
nest м nest + 1;
};
'> =>
IF self.backingStream.PeekChar[] = '> THEN {
char м self.backingStream.GetChar[];
nest м nest - 1;
IF nest <= 0 THEN GO TO endComment;
};
'\253 => nest м nest + 1;
'\273 => {nest м nest - 1; IF nest <= 0 THEN GO TO endComment};
ENDCASE;
ENDLOOP;
EXITS
notComment => {};
endComment => {char м IO.SP};
};
'- => IF NOT self.backingStream.EndOf[]
AND self.backingStream.PeekChar[] = '- THEN {
[] м self.backingStream.GetChar[];
DO
SELECT (char м self.backingStream.GetChar[]) FROM
'\l, '\r => EXIT;
'- => IF self.backingStream.GetChar[] = '- THEN {
char м IO.SP; EXIT };
ENDCASE;
ENDLOOP;
}
ENDCASE;
};


CatInputStreamData: TYPE = REF CatInputStreamRecord; 
CatInputStreamRecord: TYPE = RECORD [
input1, input2: STREAM,
state: CatInputStreamState];
CatInputStreamState: TYPE = { initial, swapped, closed };
CatInputStreamProcs: REF IO.StreamProcs = IO.CreateStreamProcs[
variety: $input, class: $Concatenated,
getChar: CatInputStreamGetChar,
getBlock: CatInputStreamGetBlock,
unsafeGetBlock: CatInputStreamUnsafeGetBlock,
charsAvail: CatInputStreamCharsAvail,
backup: CatInputStreamBackup,
endOf: CatInputStreamEndOf,
reset: CatInputStreamReset,
close: CatInputStreamClose
];

CreateCatInputStream: PUBLIC PROC [input1, input2: STREAM] RETURNS [STREAM] = {
RETURN[IO.CreateStream[streamProcs: CatInputStreamProcs, streamData: NEW[CatInputStreamRecord м [input1: input1, input2: input2, state: $initial]]]];
};

CatInputStreamGetChar: PROC [self: STREAM] RETURNS [CHAR] = {
data: CatInputStreamData = NARROW[self.streamData];
{
ENABLE IO.EndOfStream => IF data.state = $initial THEN GOTO nextStream;
RETURN[data.input1.GetChar[]];
EXITS nextStream => {
SwapStreams[data];
RETURN[data.input1.GetChar[]];
}
}
};

SwapStreams: PROC [data: CatInputStreamData] = {
temp: STREAM м data.input1;
IF data.state # $initial THEN ERROR;
data.input1 м data.input2;
data.input2 м temp;
data.state м $swapped;
};

CatInputStreamGetBlock: PROC [self: STREAM, block: REF TEXT, startIndex: NAT, count: NAT] RETURNS [nBytesRead: NAT] = {
data: CatInputStreamData = NARROW[self.streamData];
nBytesRead м data.input1.GetBlock[block, startIndex, count];
IF nBytesRead > 0 OR data.state = $swapped THEN RETURN [nBytesRead];
SwapStreams[data];
RETURN[data.input1.GetBlock[block, startIndex, count]];
};

CatInputStreamUnsafeGetBlock: PROC [self: STREAM, block: UnsafeBlock] RETURNS [nBytesRead: INT] = TRUSTED {
data: CatInputStreamData = NARROW[self.streamData];
nBytesRead м data.input1.UnsafeGetBlock[block];
IF nBytesRead > 0 OR data.state = $swapped THEN RETURN [nBytesRead];
SwapStreams[data];
RETURN[data.input1.UnsafeGetBlock[block]];
};

CatInputStreamEndOf: PROC [self: STREAM] RETURNS [BOOL] = {
data: CatInputStreamData = NARROW[self.streamData];
IF NOT data.input1.EndOf[] THEN RETURN [FALSE];
IF data.state = $swapped THEN RETURN [TRUE];
SwapStreams[data];
RETURN [data.input1.EndOf[]];
};

CatInputStreamCharsAvail: PROC [self: STREAM, wait: BOOL] RETURNS [INT] = {
data: CatInputStreamData = NARROW[self.streamData];
RETURN[data.input1.CharsAvail[wait]];
};

CatInputStreamBackup: PROC [self: STREAM, char: CHAR] = {
data: CatInputStreamData = NARROW[self.streamData];
data.input1.Backup[char];
};

CatInputStreamReset: PROC [self: STREAM] = {
data: CatInputStreamData = NARROW[self.streamData];
data.input1.Reset[];
data.input2.Reset[];
};

CatInputStreamClose: PROC [self: STREAM, abort: BOOL] = {
data: CatInputStreamData = NARROW[self.streamData];
data.input1.Close[];
data.input2.Close[];
data.state м $closed;
self.streamProcs м IOUtils.closedStreamProcs;
};


DribbleStreamData: TYPE = REF DribbleStreamRecord;
DribbleStreamRecord: TYPE = RECORD [outputStream: STREAM];
DribbleStreamProcs: REF StreamProcs м IO.CreateStreamProcs[
variety: $output, class: $Dribble,
putChar: DribbleStreamPutChar,
putBlock: DribbleStreamPutBlock,
unsafePutBlock: DribbleStreamUnsafePutBlock,
flush: DribbleStreamFlush,
eraseChar: DribbleStreamEraseChar,
reset: DribbleStreamReset,
close: DribbleStreamClose
];

CreateDribbleOutputStream: PUBLIC PROC [output1, output2: STREAM] RETURNS [STREAM] = {
RETURN[IO.CreateStream[
streamProcs: DribbleStreamProcs,
streamData: NEW[DribbleStreamRecord м [outputStream: output2]],
backingStream: output1]];
};

DribbleStreamPutChar: PROC [self: STREAM, char: CHAR] = {
data: DribbleStreamData = NARROW[self.streamData];
self.backingStream.PutChar[char];
data.outputStream.PutChar[char];
};

DribbleStreamPutBlock: PROC [self: STREAM, block: REF READONLY TEXT, startIndex: NAT, count: NAT] = {
data: DribbleStreamData = NARROW[self.streamData];
self.backingStream.PutBlock[block, startIndex, count];
data.outputStream.PutBlock[block, startIndex, count];
};

DribbleStreamUnsafePutBlock: PROC [self: STREAM, block: IO.UnsafeBlock] = {
data: DribbleStreamData = NARROW[self.streamData];
self.backingStream.UnsafePutBlock[block];
data.outputStream.UnsafePutBlock[block];
};

DribbleStreamFlush: PROC [self: STREAM] = {
data: DribbleStreamData = NARROW[self.streamData];
self.backingStream.Flush[];
data.outputStream.Flush[];
};

DribbleStreamEraseChar: PROC [self: STREAM, char: CHAR] = {
data: DribbleStreamData = NARROW[self.streamData];
self.backingStream.EraseChar[char];
data.outputStream.EraseChar[char];
};

DribbleStreamReset: PROC [self: STREAM] = {
data: DribbleStreamData = NARROW[self.streamData];
self.backingStream.Reset[];
data.outputStream.Reset[];
};

DribbleStreamClose: PROC [self: STREAM, abort: BOOL] = {
data: DribbleStreamData = NARROW[self.streamData];
self.backingStream.Close[abort];
data.outputStream.Close[abort];
};

END.
   ┤  
IOClassesImpl.mesa
Copyright ╙ 1985, 1986, 1988, 1990, 1991 by Xerox Corporation.  All rights reserved.
MBrown on January 13, 1984 1:32 pm
Russ Atkinson (RRA) May 10, 1985 4:24:56 pm PDT
Eduardo Pelegri-Llopart December 5, 1988 2:29:20 pm PST
Willie-sue, April 6, 1990 5:12 pm PDT
Copy
scratchLen: NAT = 128;
Comment-filtered Input Stream
May raise IO.EndOfStream.
Skip over the comment.  Return ending CR, LF, or SP if ends without CR, or raise IO.EndOfStream if comment ends with end of input.
Concatenated Input Stream
we preserve the information for debugging purposes
Dribble Output Stream 
Eduardo Pelegri-Llopart December 5, 1988 2:28:45 pm PST
Treats CR and LFs identically.

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