/*
 * tclIO.c --
 *
 *	This file provides the generic portions (those that are the same on
 *	all platforms and for all channel types) of Tcl's IO facilities.
 *
 * Copyright (c) 1998-2000 Ajuba Solutions
 * Copyright (c) 1995-1997 Sun Microsystems, Inc.

 *
 * See the file "license.terms" for information on usage and redistribution of
 * this file, and for a DISCLAIMER OF ALL WARRANTIES.
 */

#include "tclInt.h"
#include "tclIO.h"

			    Channel *chanPtr);
static int		CloseChannel(Tcl_Interp *interp, Channel *chanPtr,
			    int errorCode);
static int		CloseChannelPart(Tcl_Interp *interp, Channel *chanPtr,
			    int errorCode, int flags);
static int		CloseWrite(Tcl_Interp *interp, Channel *chanPtr);
static void		CommonGetsCleanup(Channel *chanPtr);
static int		CopyAndTranslateBuffer(ChannelState *statePtr,
			    char *result, int space);
static int		CopyBuffer(Channel *chanPtr, char *result, int space);
static int		CopyData(CopyState *csPtr, int mask);
static void		CopyEventProc(ClientData clientData, int mask);
static void		CreateScriptRecord(Tcl_Interp *interp,
			    Channel *chanPtr, int mask, Tcl_Obj *scriptPtr);
static void		DeleteChannelTable(ClientData clientData,
			    Tcl_Interp *interp);
static void		DeleteScriptRecord(Tcl_Interp *interp,
			    Channel *chanPtr, int mask);
static int		DetachChannel(Tcl_Interp *interp, Tcl_Channel chan);
static void		DiscardInputQueued(ChannelState *statePtr,
			    int discardSavedBuffers);
static void		DiscardOutputQueued(ChannelState *chanPtr);
static int		DoRead(Channel *chanPtr, char *srcPtr, int slen, int allowShortReads);

static int		DoReadChars(Channel *chan, Tcl_Obj *objPtr, int toRead,
			    int appendFlag);
static int		FilterInputBytes(Channel *chanPtr,
			    GetsState *statePtr);
static int		FlushChannel(Tcl_Interp *interp, Channel *chanPtr,
			    int calledFromAsyncFlush);
static int		TclGetsObjBinary(Tcl_Channel chan, Tcl_Obj *objPtr);
static Tcl_Encoding	GetBinaryEncoding();
static void		FreeBinaryEncoding(ClientData clientData);
static Tcl_HashTable *	GetChannelTable(Tcl_Interp *interp);
static int		GetInput(Channel *chanPtr);
static int		HaveVersion(const Tcl_ChannelType *typePtr,
			    Tcl_ChannelTypeVersion minimumVersion);
static void		PeekAhead(Channel *chanPtr, char **dstEndPtr,
			    GetsState *gsPtr);
static int		ReadBytes(ChannelState *statePtr, Tcl_Obj *objPtr,
			    int charsLeft, int *offsetPtr);
static int		ReadChars(ChannelState *statePtr, Tcl_Obj *objPtr,
			    int charsLeft, int *offsetPtr, int *factorPtr);
static void		RecycleBuffer(ChannelState *statePtr,
			    ChannelBuffer *bufPtr, int mustDiscard);
static int		StackSetBlockMode(Channel *chanPtr, int mode);
static int		SetBlockMode(Tcl_Interp *interp, Channel *chanPtr,
			    int mode);
static void		StopCopy(CopyState *csPtr);
static int		TranslateInputEOL(ChannelState *statePtr, char *dst,
			    const char *src, int *dstLenPtr, int *srcLenPtr);
static void		UpdateInterest(Channel *chanPtr);
static int		Write(Channel *chanPtr, const char *src,
			    int srcLen, Tcl_Encoding encoding);
static Tcl_Obj *	FixLevelCode(Tcl_Obj *msg);
static void		SpliceChannel(Tcl_Channel chan);
static void		CutChannel(Tcl_Channel chan);

     * the channel itself. We use the buffers in the channel below the new
     * transformation to hold the data. In the future this allows us to write
     * transformations which pre-read data and push the unused part back when
     * they are going away.
     */

    if (((mask & TCL_READABLE) != 0) && (statePtr->inQueueHead != NULL)) {

	/*
	 * Remark: It is possible that the channel buffers contain data from
	 * some earlier push-backs.

	 */

	statePtr->inQueueTail->nextPtr = prevChanPtr->inQueueHead;
	prevChanPtr->inQueueHead = statePtr->inQueueHead;

	if (prevChanPtr->inQueueTail == NULL) {
	    prevChanPtr->inQueueTail = statePtr->inQueueTail;
	}

	statePtr->inQueueHead = NULL;
	statePtr->inQueueTail = NULL;
    }

    chanPtr = ckalloc(sizeof(Channel));

    if (mustDiscard) {
	ReleaseChannelBuffer(bufPtr);
	return;
    }

    /*
     * Only save buffers which are at least as big as the requested buffersize
     * for the channel. This is to honor dynamic changes of the buffersize
     * made by the user.
     */

    if ((bufPtr->bufLength - BUFFER_PADDING) < statePtr->bufSize) {
	ReleaseChannelBuffer(bufPtr);
	return;
    }

    /*
     * Only save buffers for the input queue if the channel is readable.
     */

	    }
	
	    result |= Tcl_UtfToExternal(NULL, encoding, nl, nlLen,
		statePtr->outputEncodingFlags,
		&statePtr->outputEncodingState, dst,
		dstLen + BUFFER_PADDING, &srcRead, &dstWrote, NULL);

	    if (srcRead != nlLen) {
		Tcl_Panic("Can This Happen?");
	    }

	    bufPtr->nextAdded += dstWrote;
	    src++;
	    srcLen--;
	    total += dstWrote;
	    dst += dstWrote;
	    dstLen -= dstWrote;

FilterInputBytes(
    Channel *chanPtr,		/* Channel to read. */
    GetsState *gsPtr)		/* Current state of gets operation. */
{
    ChannelState *statePtr = chanPtr->state;
				/* State info for channel */
    ChannelBuffer *bufPtr;
    char *raw, *rawStart, *dst;
    int offset, toRead, dstNeeded, spaceLeft, result, rawLen;
    Tcl_Obj *objPtr;
#define ENCODING_LINESIZE 20	/* Lower bound on how many bytes to convert at
				 * a time. Since we don't know a priori how
				 * many bytes of storage this many source
				 * bytes will use, we actually need at least
				 * ENCODING_LINESIZE * TCL_MAX_UTF bytes of

    /*
     * Convert some of the bytes from the channel buffer to UTF-8. Space in
     * objPtr's string rep is used to hold the UTF-8 characters. Grow the
     * string rep if we need more space.
     */

    rawStart = RemovePoint(bufPtr);
    raw = rawStart;
    rawLen = BytesLeft(bufPtr);

    dst = *gsPtr->dstPtr;
    offset = dst - objPtr->bytes;
    toRead = ENCODING_LINESIZE;
    if (toRead > rawLen) {
	toRead = rawLen;

	    if (GotFlag(statePtr, CHANNEL_BLOCKED)) {
		if (GotFlag(statePtr, CHANNEL_NONBLOCKING)) {
		    goto done;
		}
		ResetFlag(statePtr, CHANNEL_BLOCKED);
	    }

#ifdef TCL_IO_TRACK_OS_FOR_DRIVER_WITH_BAD_BLOCKING
	    /*
	     * [Bug 943274]. Better emulation of non-blocking channels for
	     * channels without BlockModeProc, by keeping track of true
	     * fileevents generated by the OS == Data waiting and reading if
	     * and only if we are sure to have data.
	     */

	    if (GotFlag(statePtr, CHANNEL_NONBLOCKING) &&
		    (Tcl_ChannelBlockModeProc(chanPtr->typePtr) == NULL) &&
		    !GotFlag(statePtr, CHANNEL_HAS_MORE_DATA)) {
		/*
		 * We bypass the driver; it would block as no data is
		 * available.
		 */

		nread = -1;
		result = EWOULDBLOCK;
	    } else
#endif /* TCL_IO_TRACK_OS_FOR_DRIVER_WITH_BAD_BLOCKING */
	    {
		/*
		 * Now go to the driver to get as much as is possible to fill
		 * the remaining request. Do all the error handling by
		 * ourselves. The code was stolen from 'GetInput' and slightly
		 * adapted (different return value here).
		 *
		 * The case of 'bytesToRead == 0' at this point cannot happen.

		 */

		nread = ChanRead(chanPtr, bufPtr + copied,
			bytesToRead - copied, &result);
	    }

	    if (nread > 0) {
		/*
		 * If we get a short read, signal up that we may be BLOCKED.
		 * We should avoid calling the driver because on some
		 * platforms we will block in the low level reading code even
		 * though the channel is set into nonblocking mode.
		 */

		if (nread < (bytesToRead - copied)) {
		    SetFlag(statePtr, CHANNEL_BLOCKED);
		}

#ifdef TCL_IO_TRACK_OS_FOR_DRIVER_WITH_BAD_BLOCKING
		if (nread <= (bytesToRead - copied)) {
		    /*
		     * [Bug 943274] We have read the available data, clear
		     * flag.
		     */

		    ResetFlag(statePtr, CHANNEL_HAS_MORE_DATA);
		}
#endif /* TCL_IO_TRACK_OS_FOR_DRIVER_WITH_BAD_BLOCKING */
	    } else if (nread == 0) {
		SetFlag(statePtr, CHANNEL_EOF);
		statePtr->inputEncodingFlags |= TCL_ENCODING_END;

	    } else if (nread < 0) {
		if ((result == EWOULDBLOCK) || (result == EAGAIN)) {
		    if (copied > 0) {

				 * will be appended to the object. Otherwise,
				 * the data will replace the existing contents
				 * of the object. */
{
    ChannelState *statePtr = chanPtr->state;
				/* State info for channel */
    ChannelBuffer *bufPtr;
    int offset, factor, copied, copiedNow, result;
    Tcl_Encoding encoding;

#define UTF_EXPANSION_FACTOR	1024

    /*
     * This operation should occur at the top of a channel stack.
     */

    chanPtr = statePtr->topChanPtr;
    encoding = statePtr->encoding;
    factor = UTF_EXPANSION_FACTOR;
    Tcl_Preserve(chanPtr);





    if (appendFlag == 0) {
	if (encoding == NULL) {
	    Tcl_SetByteArrayLength(objPtr, 0);
	} else {
	    Tcl_SetObjLength(objPtr, 0);

	    /*
	     * We're going to access objPtr->bytes directly, so we must ensure
	     * that this is actually a string object (otherwise it might have
	     * been pure Unicode).


	     */

	    TclGetString(objPtr);
	}
	offset = 0;
    } else {
	if (encoding == NULL) {
	    Tcl_GetByteArrayFromObj(objPtr, &offset);
	} else {
	    TclGetStringFromObj(objPtr, &offset);
	}
    }

    for (copied = 0; (unsigned) toRead > 0; ) {
	copiedNow = -1;
	if (statePtr->inQueueHead != NULL) {
	    if (encoding == NULL) {
		copiedNow = ReadBytes(statePtr, objPtr, toRead, &offset);
	    } else {
		copiedNow = ReadChars(statePtr, objPtr, toRead, &offset,
			&factor);
	    }

	    /*
	     * If the current buffer is empty recycle it.
	     */

	    bufPtr = statePtr->inQueueHead;

	} else {
	    copied += copiedNow;
	    toRead -= copiedNow;
	}
    }

    ResetFlag(statePtr, CHANNEL_BLOCKED);
    if (encoding == NULL) {
	Tcl_SetByteArrayLength(objPtr, offset);
    } else {
	Tcl_SetObjLength(objPtr, offset);
    }

    /*
     * Update the notifier state so we don't block while there is still data
     * in the buffers.
     */

  done:

 *	are stored in objPtr as a ByteArray object. EOL and EOF translation
 *	are done.
 *
 *	'bytesToRead' can safely be a very large number because space is only
 *	allocated to hold data read from the channel as needed.
 *
 * Results:
 *	The return value is the number of bytes appended to the object and
 *	*offsetPtr is filled with the total number of bytes in the object
 *	(greater than the return value if there were already bytes in the
 *	object).
 *
 * Side effects:
 *	None.

 *
 *---------------------------------------------------------------------------
 */

static int
ReadBytes(
    ChannelState *statePtr,	/* State of the channel to read. */
    Tcl_Obj *objPtr,		/* Input data is appended to this ByteArray
				 * object. Its length is how much space has
				 * been allocated to hold data, not how many
				 * bytes of data have been stored in the
				 * object. */
    int bytesToRead,		/* Maximum number of bytes to store, or < 0 to
				 * get all available bytes. Bytes are obtained
				 * from the first buffer in the queue - even
				 * if this number is larger than the number of
				 * bytes available in the first buffer, only
				 * the bytes from the first buffer are
				 * returned. */
    int *offsetPtr)		/* On input, contains how many bytes of objPtr
				 * have been used to hold data. On output,
				 * filled with how many bytes are now being
				 * used. */
{
    int toRead, srcLen, offset, length, srcRead, dstWrote;
    ChannelBuffer *bufPtr;
    char *src, *dst;

    offset = *offsetPtr;

    bufPtr = statePtr->inQueueHead;
    src = RemovePoint(bufPtr);
    srcLen = BytesLeft(bufPtr);

    toRead = bytesToRead;
    if ((unsigned) toRead > (unsigned) srcLen) {
	toRead = srcLen;
    }

    dst = (char *) Tcl_GetByteArrayFromObj(objPtr, &length);
    if (toRead > length - offset - 1) {
	/*
	 * Double the existing size of the object or make enough room to hold
	 * all the characters we may get from the source buffer, whichever is
	 * larger.
	 */

	length = offset * 2;
	if (offset < toRead) {
	    length = offset + toRead + 1;
	}
	dst = (char *) Tcl_SetByteArrayLength(objPtr, length);
    }
    dst += offset;

    if (GotFlag(statePtr, INPUT_NEED_NL)) {
	ResetFlag(statePtr, INPUT_NEED_NL);
	if ((srcLen == 0) || (*src != '\n')) {
	    *dst = '\r';
	    *offsetPtr += 1;
	    return 1;
	}
	*dst++ = '\n';
	src++;
	srcLen--;
	toRead--;
    }

    srcRead = srcLen;
    dstWrote = toRead;
    if (TranslateInputEOL(statePtr, dst, src, &dstWrote, &srcRead) != 0) {
	if (dstWrote == 0) {
	    return -1;
	}
    }
    bufPtr->nextRemoved += srcRead;
    *offsetPtr += dstWrote;
    return dstWrote;
}

/*
 *---------------------------------------------------------------------------
 *
 * ReadChars --
 *

    int charsToRead,		/* Maximum number of characters to store, or
				 * -1 to get all available characters.
				 * Characters are obtained from the first
				 * buffer in the queue -- even if this number
				 * is larger than the number of characters
				 * available in the first buffer, only the
				 * characters from the first buffer are
				 * returned. */
    int *offsetPtr,		/* On input, contains how many bytes of objPtr
				 * have been used to hold data. On output,
				 * filled with how many bytes are now being
				 * used. */
    int *factorPtr)		/* On input, contains a guess of how many
				 * bytes need to be allocated to hold the
				 * result of converting N source bytes to
				 * UTF-8. On output, contains another guess
				 * based on the data seen so far. */
{
    int toRead, factor, offset, spaceLeft, srcLen, dstNeeded;
    int srcRead, dstWrote, numChars, dstRead;
    ChannelBuffer *bufPtr;
    char *src, *dst;
    Tcl_EncodingState oldState;
    int encEndFlagSuppressed = 0;

    factor = *factorPtr;
    offset = *offsetPtr;

    bufPtr = statePtr->inQueueHead;
    src = RemovePoint(bufPtr);
    srcLen = BytesLeft(bufPtr);




    toRead = charsToRead;
    if ((unsigned) toRead > (unsigned) srcLen) {
	toRead = srcLen;


    }


    /*
     * 'factor' is how much we guess that the bytes in the source buffer will
     * expand when converted to UTF-8 chars. This guess comes from analyzing
     * how many characters were produced by the previous pass.
     */


    dstNeeded = TCL_UTF_MAX - 1 + toRead * factor / UTF_EXPANSION_FACTOR;
    spaceLeft = objPtr->length - offset;









    if (dstNeeded > spaceLeft) {
	/*
	 * Double the existing size of the object or make enough room to hold







	 * all the characters we want from the source buffer, whichever is
	 * larger.





	 */

	int length = offset + ((offset < dstNeeded) ? dstNeeded : offset);

	if (Tcl_AttemptSetObjLength(objPtr, length) == 0) {
	    length = offset + dstNeeded;
	    if (Tcl_AttemptSetObjLength(objPtr, length) == 0) {
		dstNeeded = TCL_UTF_MAX - 1 + toRead;
		length = offset + dstNeeded;
		Tcl_SetObjLength(objPtr, length);
	    }




	}

	spaceLeft = length - offset;


    }
    if (toRead == srcLen) {
	/*
	 * Want to convert the whole buffer in one pass. If we have enough
	 * space, convert it using all available space in object rather than
	 * using the factor.


	 */




	dstNeeded = spaceLeft;

    }





    dst = objPtr->bytes + offset;

    /*
     * [Bug 1462248]: The cause of the crash reported in this bug is this:

     *
     * - ReadChars, called with a single buffer, with a incomplete
     *	 multi-byte character at the end (only the first byte of it).
     * - Encoding translation fails, asks for more data
     * - Data is read, and eof is reached, TCL_ENCODING_END (TEE) is set.
     * - ReadChar is called again, converts the first buffer, but due to TEE
     *	 it does not check for incomplete multi-byte data, and the character
     *	 just after the end of the first buffer is a valid completion of the
     *	 multi-byte header in the actual buffer. The conversion reads more
     *	 characters from the buffer then present. This causes nextRemoved to
     *	 overshoot nextAdded and the next reads compute a negative srcLen,
     *	 cause further translations to fail, causing copying of data into the
     *	 next buffer using bad arguments, causing the mecpy for to eventually
     *	 fail.
     *
     * In the end it is a memory access bug spiraling out of control if the

     * conditions are _just so_. And ultimate cause is that TEE is given to a

     * conversion where it should not. TEE signals that this is the last






     * buffer. Except in our case it is not.
     *
     * My solution is to suppress TEE if the first buffer is not the last. We
     * will eventually need it given that EOF has been reached, but not right
     * now. This is what the new flag "endEncSuppressFlag" is for.
     *
     * The bug in 'Tcl_Utf2UtfProc' where it read from memory behind the



     * actual buffer has been fixed as well, and fixes the problem with the
     * crash too, but this would still allow the generic layer to
     * accidentially break a multi-byte sequence if the conditions are just
     * right, because again the ExternalToUtf would be successful where it
     * should not.
     */



    if ((statePtr->inputEncodingFlags & TCL_ENCODING_END) &&
	    (bufPtr->nextPtr != NULL)) {

	/*
	 * TEE is set for a buffer which is not the last. Squash it for now,
	 * and restore it later, before yielding control to our caller.



	 */



	statePtr->inputEncodingFlags &= ~TCL_ENCODING_END;




	encEndFlagSuppressed = 1;






    }







    oldState = statePtr->inputEncodingState;
    if (GotFlag(statePtr, INPUT_NEED_NL)) {
	/*
	 * We want a '\n' because the last character we saw was '\r'.
	 */


	ResetFlag(statePtr, INPUT_NEED_NL);
	Tcl_ExternalToUtf(NULL, statePtr->encoding, src, srcLen,
		statePtr->inputEncodingFlags, &statePtr->inputEncodingState,


		dst, TCL_UTF_MAX + 1, &srcRead, &dstWrote, &numChars);
	if ((dstWrote > 0) && (*dst == '\n')) {



	    /*
	     * The next char was a '\n'. Consume it and produce a '\n'.



	     */



	    bufPtr->nextRemoved += srcRead;
	} else {
	    /*
	     * The next char was not a '\n'. Produce a '\r'.

	     */


	    *dst = '\r';

	}

	statePtr->inputEncodingFlags &= ~TCL_ENCODING_START;


	*offsetPtr += 1;









	if (encEndFlagSuppressed) {

	    statePtr->inputEncodingFlags |= TCL_ENCODING_END;
	}

	return 1;
    }

    Tcl_ExternalToUtf(NULL, statePtr->encoding, src, srcLen,
	    statePtr->inputEncodingFlags, &statePtr->inputEncodingState, dst,
	    dstNeeded + 1, &srcRead, &dstWrote, &numChars);

    if (encEndFlagSuppressed) {
	statePtr->inputEncodingFlags |= TCL_ENCODING_END;
    }










    if (srcRead == 0) {



	/*
	 * Not enough bytes in src buffer to make a complete char. Copy the
	 * bytes to the next buffer to make a new contiguous string, then tell


	 * the caller to fill the buffer with more bytes.
	 */

	ChannelBuffer *nextPtr;

	nextPtr = bufPtr->nextPtr;
	if (nextPtr == NULL) {
	    if (srcLen > 0) {
		/*



		 * There isn't enough data in the buffers to complete the next
		 * character, so we need to wait for more data before the next
		 * file event can be delivered. [Bug 478856]






		 *
		 * The exception to this is if the input buffer was completely
		 * empty before we tried to convert its contents. Nothing in,


		 * nothing out, and no incomplete character data. The
		 * conversion before the current one was complete.



		 */





		SetFlag(statePtr, CHANNEL_NEED_MORE_DATA);
	    }

	    return -1;
	}

	/*
	 * Space is made at the beginning of the buffer to copy the previous
	 * unused bytes there. Check first if the buffer we are using actually
	 * has enough space at its beginning for the data we are copying.
	 * Because if not we will write over the buffer management
	 * information, especially the 'nextPtr'.
	 *
	 * Note that the BUFFER_PADDING (See AllocChannelBuffer) is used to
	 * prevent exactly this situation. I.e. it should never happen.
	 * Therefore it is ok to panic should it happen despite the
	 * precautions.
	 */

	if (nextPtr->nextRemoved - srcLen < 0) {
	    Tcl_Panic("Buffer Underflow, BUFFER_PADDING not enough");
	}

	nextPtr->nextRemoved -= srcLen;
	memcpy(RemovePoint(nextPtr), src, (size_t) srcLen);
	RecycleBuffer(statePtr, bufPtr, 0);
	statePtr->inQueueHead = nextPtr;

	return ReadChars(statePtr, objPtr, charsToRead, offsetPtr, factorPtr);
    }

    dstRead = dstWrote;
    if (TranslateInputEOL(statePtr, dst, dst, &dstWrote, &dstRead) != 0) {
	/*
	 * Hit EOF char. How many bytes of src correspond to where the EOF was
	 * located in dst? Run the conversion again with an output buffer just
	 * big enough to hold the data so we can get the correct value for
	 * srcRead.
	 */

	if (dstWrote == 0) {
	    return -1;
	}
	statePtr->inputEncodingState = oldState;
	Tcl_ExternalToUtf(NULL, statePtr->encoding, src, srcLen,
		statePtr->inputEncodingFlags, &statePtr->inputEncodingState,
		dst, dstRead + TCL_UTF_MAX, &srcRead, &dstWrote, &numChars);
	TranslateInputEOL(statePtr, dst, dst, &dstWrote, &dstRead);
    }

    /*
     * The number of characters that we got may be less than the number that
     * we started with because "\r\n" sequences may have been turned into just
     * '\n' in dst.
     */

    numChars -= dstRead - dstWrote;

    if ((unsigned) numChars > (unsigned) toRead) {
	/*
	 * Got too many chars.
	 */

	const char *eof = Tcl_UtfAtIndex(dst, toRead);

	statePtr->inputEncodingState = oldState;
	Tcl_ExternalToUtf(NULL, statePtr->encoding, src, srcLen,
		statePtr->inputEncodingFlags, &statePtr->inputEncodingState,
		dst, eof - dst + TCL_UTF_MAX, &srcRead, &dstWrote, &numChars);
	dstRead = dstWrote;
	TranslateInputEOL(statePtr, dst, dst, &dstWrote, &dstRead);
	numChars -= (dstRead - dstWrote);
    }
    statePtr->inputEncodingFlags &= ~TCL_ENCODING_START;

    bufPtr->nextRemoved += srcRead;
    if (dstWrote > srcRead + 1) {
	*factorPtr = dstWrote * UTF_EXPANSION_FACTOR / srcRead;
    }
    *offsetPtr += dstWrote;
    return numChars;

}

/*
 *---------------------------------------------------------------------------
 *
 * TranslateInputEOL --
 *
 *	Perform input EOL and EOF translation on the source buffer, leaving
 *	the translated result in the destination buffer.
 *
 * Results:
 *	The return value is 1 if the EOF character was found when copying
 *	bytes to the destination buffer, 0 otherwise.
 *
 * Side effects:
 *	None.
 *
 *---------------------------------------------------------------------------
 */

static int
TranslateInputEOL(
    ChannelState *statePtr,	/* Channel being read, for EOL translation and
				 * EOF character. */
    char *dstStart,		/* Output buffer filled with chars by applying
				 * appropriate EOL translation to source
				 * characters. */
    const char *srcStart,	/* Source characters. */
    int *dstLenPtr,		/* On entry, the maximum length of output
				 * buffer in bytes; must be <= *srcLenPtr. On
				 * exit, the number of bytes actually used in
				 * output buffer. */
    int *srcLenPtr)		/* On entry, the length of source buffer. On
				 * exit, the number of bytes read from the
				 * source buffer. */
{
    int dstLen, srcLen, inEofChar;
    const char *eof;

    dstLen = *dstLenPtr;

    eof = NULL;
    inEofChar = statePtr->inEofChar;
    if (inEofChar != '\0') {
	/*
	 * Find EOF in translated buffer then compress out the EOL. The source
	 * buffer may be much longer than the destination buffer - we only
	 * want to return EOF if the EOF has been copied to the destination


	 * buffer.
	 */






	const char *src, *srcMax = srcStart + *srcLenPtr;

	for (src = srcStart; src < srcMax; src++) {
	    if (*src == inEofChar) {
		eof = src;
		srcLen = src - srcStart;

		if (srcLen < dstLen) {
		    dstLen = srcLen;
		}
		*srcLenPtr = srcLen;
		break;
	    }
	}





    }





    switch (statePtr->inputTranslation) {
    case TCL_TRANSLATE_LF:

	if (dstStart != srcStart) {
	    memcpy(dstStart, srcStart, (size_t) dstLen);
	}
	srcLen = dstLen;
	break;
    case TCL_TRANSLATE_CR: {
	char *dst, *dstEnd;

	if (dstStart != srcStart) {
	    memcpy(dstStart, srcStart, (size_t) dstLen);
	}
	dstEnd = dstStart + dstLen;
	for (dst = dstStart; dst < dstEnd; dst++) {
	    if (*dst == '\r') {
		*dst = '\n';
	    }
	}
	srcLen = dstLen;
	break;
    }
    case TCL_TRANSLATE_CRLF: {

	char *dst;
	const char *src, *srcEnd, *srcMax;


	dst = dstStart;
	src = srcStart;
	srcEnd = srcStart + dstLen;
	srcMax = srcStart + *srcLenPtr;

	for ( ; src < srcEnd; ) {
	    if (*src == '\r') {
		src++;
		if (src >= srcMax) {
		    SetFlag(statePtr, INPUT_NEED_NL);
		} else if (*src == '\n') {
		    *dst++ = *src++;

		} else {
		    *dst++ = '\r';

		}



	    } else {
		*dst++ = *src++;

	    }


	}

	srcLen = src - srcStart;
	dstLen = dst - dstStart;
	break;
    }
    case TCL_TRANSLATE_AUTO: {
	char *dst;
	const char *src, *srcEnd, *srcMax;

	dst = dstStart;
	src = srcStart;
	srcEnd = srcStart + dstLen;
	srcMax = srcStart + *srcLenPtr;

	if (GotFlag(statePtr, INPUT_SAW_CR) && (src < srcMax)) {
	    if (*src == '\n') {
		src++;
	    }
	    ResetFlag(statePtr, INPUT_SAW_CR);
	}




	for ( ; src < srcEnd; ) {
	    if (*src == '\r') {

		src++;
		if (src >= srcMax) {
		    SetFlag(statePtr, INPUT_SAW_CR);
		} else if (*src == '\n') {
		    if (srcEnd < srcMax) {
			srcEnd++;
		    }
		    src++;
		}
		*dst++ = '\n';
	    } else {
		*dst++ = *src++;
	    }
	}

	srcLen = src - srcStart;
	dstLen = dst - dstStart;
	break;
    }
    default:
	return 0;

    }
    *dstLenPtr = dstLen;


    if ((eof != NULL) && (srcStart + srcLen >= eof)) {
	/*
	 * EOF character was seen in EOL translated range. Leave current file
	 * position pointing at the EOF character, but don't store the EOF
	 * character in the output string.
	 */

	SetFlag(statePtr, CHANNEL_EOF | CHANNEL_STICKY_EOF);
	statePtr->inputEncodingFlags |= TCL_ENCODING_END;
	ResetFlag(statePtr, INPUT_SAW_CR | INPUT_NEED_NL);
	return 1;
    }

    *srcLenPtr = srcLen;
    return 0;
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_Ungets --
 *

    if (CheckChannelErrors(statePtr, TCL_READABLE) != 0) {
	len = -1;
	goto done;
    }
    statePtr->flags = flags;

    /*
     * If we have encountered a sticky EOF, just punt without storing (sticky
     * EOF is set if we have seen the input eofChar, to prevent reading beyond
     * the eofChar). Otherwise, clear the EOF flags, and clear the BLOCKED
     * bit. We want to discover these conditions anew in each operation.
     */

    if (GotFlag(statePtr, CHANNEL_STICKY_EOF)) {
	goto done;
    }
    ResetFlag(statePtr, CHANNEL_BLOCKED | CHANNEL_EOF);

    bufPtr = AllocChannelBuffer(len);
    memcpy(InsertPoint(bufPtr), str, (size_t) len);
    bufPtr->nextAdded += len;

    if (statePtr->inQueueHead == NULL) {
	bufPtr->nextPtr = NULL;

/*
 *---------------------------------------------------------------------------
 *
 * GetInput --
 *
 *	Reads input data from a device into a channel buffer.
 *



 * Results:
 *	The return value is the Posix error code if an error occurred while
 *	reading from the file, or 0 otherwise.
 *
 * Side effects:
 *	Reads from the underlying device.
 *

    }

    /*
     * First check for more buffers in the pushback area of the topmost
     * channel in the stack and use them. They can be the result of a
     * transformation which went away without reading all the information
     * placed in the area when it was stacked.
     *
     * Two possibilities for the state: No buffers in it, or a single empty
     * buffer. In the latter case we can recycle it now.
     */

    if (chanPtr->inQueueHead != NULL) {
	if (statePtr->inQueueHead != NULL) {
	    RecycleBuffer(statePtr, statePtr->inQueueHead, 0);
	    statePtr->inQueueHead = NULL;
	}


	statePtr->inQueueHead = chanPtr->inQueueHead;
	statePtr->inQueueTail = chanPtr->inQueueTail;
	chanPtr->inQueueHead = NULL;
	chanPtr->inQueueTail = NULL;
	return 0;
    }

	toRead = SpaceLeft(bufPtr);
    } else {
	bufPtr = statePtr->saveInBufPtr;
	statePtr->saveInBufPtr = NULL;

	/*
	 * Check the actual buffersize against the requested buffersize.
	 * Buffers which are smaller than requested are squashed. This is done
	 * to honor dynamic changes of the buffersize made by the user.
	 */

	if ((bufPtr != NULL)
		&& (bufPtr->bufLength - BUFFER_PADDING < statePtr->bufSize)) {
	    ReleaseChannelBuffer(bufPtr);
	    bufPtr = NULL;
	}

	if (bufPtr == NULL) {
	    bufPtr = AllocChannelBuffer(statePtr->bufSize);
	}
	bufPtr->nextPtr = NULL;

	/*
	 * SF #427196: Use the actual size of the buffer to determine the
	 * number of bytes to read from the channel and not the size for new
	 * buffers. They can be different if the buffersize was changed
	 * between reads.
	 *
	 * Note: This affects performance negatively if the buffersize was
	 * extended but this small buffer is reused for all subsequent reads.
	 * The system never uses buffers with the requested bigger size in
	 * that case. An adjunct patch could try and delete all unused buffers
	 * it encounters and which are smaller than the formally requested
	 * buffersize.
	 */

	toRead = SpaceLeft(bufPtr);


	if (statePtr->inQueueTail == NULL) {
	    statePtr->inQueueHead = bufPtr;
	} else {
	    statePtr->inQueueTail->nextPtr = bufPtr;
	}
	statePtr->inQueueTail = bufPtr;
    }

    /*

     * If EOF is set, we should avoid calling the driver because on some
     * platforms it is impossible to read from a device after EOF.
     */

    if (GotFlag(statePtr, CHANNEL_EOF)) {
	return 0;
    }

#ifdef TCL_IO_TRACK_OS_FOR_DRIVER_WITH_BAD_BLOCKING
    /*
     * [Bug 943274]: Better emulation of non-blocking channels for channels
     * without BlockModeProc, by keeping track of true fileevents generated by
     * the OS == Data waiting and reading if and only if we are sure to have
     * data.
     */

    if (GotFlag(statePtr, CHANNEL_NONBLOCKING) &&
	    (Tcl_ChannelBlockModeProc(chanPtr->typePtr) == NULL) &&
	    !GotFlag(statePtr, CHANNEL_HAS_MORE_DATA)) {
	/*
	 * Bypass the driver, it would block, as no data is available
	 */

	nread = -1;
	result = EWOULDBLOCK;
    } else
#endif /* TCL_IO_TRACK_OS_FOR_DRIVER_WITH_BAD_BLOCKING */
    {
	PreserveChannelBuffer(bufPtr);
	nread = ChanRead(chanPtr, InsertPoint(bufPtr), toRead, &result);
    }

    if (nread > 0) {
	result = 0;
	bufPtr->nextAdded += nread;

	/*
	 * If we get a short read, signal up that we may be BLOCKED. We should
	 * avoid calling the driver because on some platforms we will block in
	 * the low level reading code even though the channel is set into
	 * nonblocking mode.
	 */

	if (nread < toRead) {
	    SetFlag(statePtr, CHANNEL_BLOCKED);
	}

#ifdef TCL_IO_TRACK_OS_FOR_DRIVER_WITH_BAD_BLOCKING
	if (nread <= toRead) {
	    /*
	     * [Bug 943274]: We have read the available data, clear flag.
	     */

	    ResetFlag(statePtr, CHANNEL_HAS_MORE_DATA);
	}
#endif /* TCL_IO_TRACK_OS_FOR_DRIVER_WITH_BAD_BLOCKING */
    } else if (nread == 0) {
	result = 0;
	SetFlag(statePtr, CHANNEL_EOF);
	statePtr->inputEncodingFlags |= TCL_ENCODING_END;
    } else if (nread < 0) {
	if ((result == EWOULDBLOCK) || (result == EAGAIN)) {
	    SetFlag(statePtr, CHANNEL_BLOCKED);

    if (BUSY_STATE(statePtr, flags) && ((flags & CHANNEL_RAW_MODE) == 0)) {
	Tcl_SetErrno(EBUSY);
	return -1;
    }

    if (direction == TCL_READABLE) {
	/*
	 * If we have not encountered a sticky EOF, clear the EOF bit (sticky
	 * EOF is set if we have seen the input eofChar, to prevent reading
	 * beyond the eofChar). Also, always clear the BLOCKED bit. We want to
	 * discover these conditions anew in each operation.
	 */

	if (!GotFlag(statePtr, CHANNEL_STICKY_EOF)) {
	    ResetFlag(statePtr, CHANNEL_EOF);
	}
	ResetFlag(statePtr, CHANNEL_BLOCKED | CHANNEL_NEED_MORE_DATA);
    }

    return 0;
}

/*

    if (sz < 1) {
	sz = 1;
    } else if (sz > MAX_CHANNEL_BUFFER_SIZE) {
	sz = MAX_CHANNEL_BUFFER_SIZE;
    }

    statePtr = ((Channel *) chan)->state;




    statePtr->bufSize = sz;
















}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_GetChannelBufferSize --
 *

    } else if (HaveOpt(7, "-buffersize")) {
	int newBufferSize;

	if (Tcl_GetInt(interp, newValue, &newBufferSize) == TCL_ERROR) {
	    return TCL_ERROR;
	}
	Tcl_SetChannelBufferSize(chan, newBufferSize);

    } else if (HaveOpt(2, "-encoding")) {
	Tcl_Encoding encoding;

	if ((newValue[0] == '\0') || (strcmp(newValue, "binary") == 0)) {
	    encoding = NULL;
	} else {
	    encoding = Tcl_GetEncoding(interp, newValue);

	statePtr->encoding = encoding;
	statePtr->inputEncodingState = NULL;
	statePtr->inputEncodingFlags = TCL_ENCODING_START;
	statePtr->outputEncodingState = NULL;
	statePtr->outputEncodingFlags = TCL_ENCODING_START;
	ResetFlag(statePtr, CHANNEL_NEED_MORE_DATA);
	UpdateInterest(chanPtr);

    } else if (HaveOpt(2, "-eofchar")) {
	if (Tcl_SplitList(interp, newValue, &argc, &argv) == TCL_ERROR) {
	    return TCL_ERROR;
	}
	if (argc == 0) {
	    statePtr->inEofChar = 0;
	    statePtr->outEofChar = 0;

    } else if (chanPtr->typePtr->setOptionProc != NULL) {
	return chanPtr->typePtr->setOptionProc(chanPtr->instanceData, interp,
		optionName, newValue);
    } else {
	return Tcl_BadChannelOption(interp, optionName, NULL);
    }

    /*
     * If bufsize changes, need to get rid of old utility buffer.
     */

    if (statePtr->saveInBufPtr != NULL) {
	RecycleBuffer(statePtr, statePtr->saveInBufPtr, 1);
	statePtr->saveInBufPtr = NULL;
    }
    if ((statePtr->inQueueHead != NULL)
	    && (statePtr->inQueueHead->nextPtr == NULL)
	    && IsBufferEmpty(statePtr->inQueueHead)) {
	RecycleBuffer(statePtr, statePtr->inQueueHead, 1);
	statePtr->inQueueHead = NULL;
	statePtr->inQueueTail = NULL;
    }

    return TCL_OK;
}

/*
 *----------------------------------------------------------------------
 *
 * CleanupChannelHandlers --

				/* State info for channel */
    ChannelHandler *chPtr;
    ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);
    NextChannelHandler nh;
    Channel *upChanPtr;
    const Tcl_ChannelType *upTypePtr;

#ifdef TCL_IO_TRACK_OS_FOR_DRIVER_WITH_BAD_BLOCKING
    /*
     * [SF Tcl Bug 943274] For a non-blocking channel without blockmodeproc we
     * keep track of actual input coming from the OS so that we can do a
     * credible imitation of non-blocking behaviour.
     */

    if ((mask & TCL_READABLE) &&
	    GotFlag(statePtr, CHANNEL_NONBLOCKING) &&
	    (Tcl_ChannelBlockModeProc(chanPtr->typePtr) == NULL) &&
	    !GotFlag(statePtr, CHANNEL_TIMER_FEV)) {
	SetFlag(statePtr, CHANNEL_HAS_MORE_DATA);
    }
#endif /* TCL_IO_TRACK_OS_FOR_DRIVER_WITH_BAD_BLOCKING */

    /*
     * In contrast to the other API functions this procedure walks towards the
     * top of a stack and not down from it.
     *
     * The channel calling this procedure is the one who generated the event,
     * and thus does not take part in handling it. IOW, its HandlerProc is not
     * called, instead we begin with the channel above it.

	/*
	 * Restart the timer in case a channel handler reenters the event loop
	 * before UpdateInterest gets called by Tcl_NotifyChannel.
	 */

	statePtr->timer = Tcl_CreateTimerHandler(SYNTHETIC_EVENT_TIME,
                ChannelTimerProc,chanPtr);

#ifdef TCL_IO_TRACK_OS_FOR_DRIVER_WITH_BAD_BLOCKING
	/*
	 * Set the TIMER flag to notify the higher levels that the driver
	 * might have no data for us. We do this only if we are in
	 * non-blocking mode and the driver has no BlockModeProc because only
	 * then we really don't know if the driver will block or not. A
	 * similar test is done in "PeekAhead".
	 */

	if (GotFlag(statePtr, CHANNEL_NONBLOCKING) &&
		(Tcl_ChannelBlockModeProc(chanPtr->typePtr) == NULL)) {
	    SetFlag(statePtr, CHANNEL_TIMER_FEV);
	}
#endif /* TCL_IO_TRACK_OS_FOR_DRIVER_WITH_BAD_BLOCKING */

	Tcl_Preserve(statePtr);
	Tcl_NotifyChannel((Tcl_Channel) chanPtr, TCL_READABLE);

#ifdef TCL_IO_TRACK_OS_FOR_DRIVER_WITH_BAD_BLOCKING
	ResetFlag(statePtr, CHANNEL_TIMER_FEV);
#endif /* TCL_IO_TRACK_OS_FOR_DRIVER_WITH_BAD_BLOCKING */

	Tcl_Release(statePtr);
    } else {
	statePtr->timer = NULL;
	UpdateInterest(chanPtr);
    }
}


}

/*
 *----------------------------------------------------------------------
 *
 * DoRead --
 *


 *	Reads a given number of bytes from a channel. No encoding conversions
 *	are applied to the bytes being read.
 *
 * Results:
 *	The number of characters read, or -1 on error. Use Tcl_GetErrno() to

 *	retrieve the error code for the error that occurred.








 *
 * Side effects:
 *	May cause input to be buffered.
 *
 *----------------------------------------------------------------------
 */

static int
DoRead(
    Channel *chanPtr,		/* The channel from which to read. */
    char *bufPtr,		/* Where to store input read. */
    int toRead,			/* Maximum number of bytes to read. */
    int allowShortReads)	/* Allow half-blocking (pipes,sockets) */
{
    ChannelState *statePtr = chanPtr->state;
				/* State info for channel */
    int copied;			/* How many characters were copied into the
				 * result string? */
    int copiedNow;		/* How many characters were copied from the
				 * current input buffer? */
    int result;			/* Of calling GetInput. */



    /*
     * If we have not encountered a sticky EOF, clear the EOF bit. Either way
     * clear the BLOCKED bit. We want to discover these anew during each

     * operation.
     */

    Tcl_Preserve(chanPtr);
    if (!GotFlag(statePtr, CHANNEL_STICKY_EOF)) {

	ResetFlag(statePtr, CHANNEL_EOF);
    }
    ResetFlag(statePtr, CHANNEL_BLOCKED | CHANNEL_NEED_MORE_DATA);

    for (copied = 0; copied < toRead; copied += copiedNow) {
	copiedNow = CopyAndTranslateBuffer(statePtr, bufPtr + copied,
		toRead - copied);
	if (copiedNow == 0) {
	    if (GotFlag(statePtr, CHANNEL_EOF)) {

		goto done;
	    }
	    if (GotFlag(statePtr, CHANNEL_BLOCKED)) {
		if (GotFlag(statePtr, CHANNEL_NONBLOCKING)) {
		    goto done;
		}
		ResetFlag(statePtr, CHANNEL_BLOCKED);
	    }
	    result = GetInput(chanPtr);

	    if (result != 0) {
		if (result != EAGAIN) {
		    copied = -1;
		}
		goto done;
	    }
	} else if (allowShortReads) {
            copied += copiedNow;

            break;
        }
    }

    ResetFlag(statePtr, CHANNEL_BLOCKED);

    /*
     * Update the notifier state so we don't block while there is still data
     * in the buffers.
     */


  done:
    UpdateInterest(chanPtr);
    Tcl_Release(chanPtr);
    return copied;
}

/*
 *----------------------------------------------------------------------
 *
 * CopyAndTranslateBuffer --
 *
 *	Copy at most one buffer of input to the result space, doing eol
 *	translations according to mode in effect currently.
 *
 * Results:
 *	Number of bytes stored in the result buffer (as opposed to the number
 *	of bytes read from the channel). May return zero if no input is
 *	available to be translated.
 *


 * Side effects:
 *	Consumes buffered input. May deallocate one buffer.
 *
 *----------------------------------------------------------------------
 */

static int
CopyAndTranslateBuffer(
    ChannelState *statePtr,	/* Channel state from which to read input. */
    char *result,		/* Where to store the copied input. */
    int space)			/* How many bytes are available in result to
				 * store the copied input? */
{
    ChannelBuffer *bufPtr;	/* The buffer from which to copy bytes. */
    int bytesInBuffer;		/* How many bytes are available to be copied
				 * in the current input buffer? */
    int copied;			/* How many characters were already copied
				 * into the destination space? */
    int i;			/* Iterates over the copied input looking for
				 * the input eofChar. */




    /*
     * If there is no input at all, return zero. The invariant is that either
     * there is no buffer in the queue, or if the first buffer is empty, it is
     * also the last buffer (and thus there is no input in the queue). Note
     * also that if the buffer is empty, we leave it in the queue.
     */

    if (statePtr->inQueueHead == NULL) {
	return 0;
    }
    bufPtr = statePtr->inQueueHead;
    bytesInBuffer = BytesLeft(bufPtr);

    copied = 0;
    switch (statePtr->inputTranslation) {
    case TCL_TRANSLATE_LF:
	if (bytesInBuffer == 0) {
	    return 0;
	}

	/*
	 * Copy the current chunk into the result buffer.
	 */

	if (bytesInBuffer < space) {
	    space = bytesInBuffer;
	}
	memcpy(result, RemovePoint(bufPtr), (size_t) space);

	bufPtr->nextRemoved += space;
	copied = space;
	break;
    case TCL_TRANSLATE_CR: {
	char *end;

	if (bytesInBuffer == 0) {
	    return 0;
	}

	/*
	 * Copy the current chunk into the result buffer, then replace all \r
	 * with \n.




	 */

	if (bytesInBuffer < space) {
	    space = bytesInBuffer;
	}
	memcpy(result, RemovePoint(bufPtr), (size_t) space);
	bufPtr->nextRemoved += space;
	copied = space;

	for (end = result + copied; result < end; result++) {
	    if (*result == '\r') {
		*result = '\n';
	    }
	}
	break;
    }
    case TCL_TRANSLATE_CRLF: {
	char *src, *end, *dst;
	int curByte;

	/*
	 * If there is a held-back "\r" at EOF, produce it now.

	 */

	if (bytesInBuffer == 0) {
	    if ((statePtr->flags & (INPUT_SAW_CR | CHANNEL_EOF)) ==
		    (INPUT_SAW_CR | CHANNEL_EOF)) {
		result[0] = '\r';
		ResetFlag(statePtr, INPUT_SAW_CR);
		return 1;
	    }
	    return 0;
	}


	/*

	 * Copy the current chunk and replace "\r\n" with "\n" (but not
	 * standalone "\r"!).
	 */

	if (bytesInBuffer < space) {
	    space = bytesInBuffer;
	}
	memcpy(result, RemovePoint(bufPtr), (size_t) space);
	bufPtr->nextRemoved += space;
	copied = space;

	end = result + copied;
	dst = result;
	for (src = result; src < end; src++) {
	    curByte = *src;
	    if (curByte == '\n') {
		ResetFlag(statePtr, INPUT_SAW_CR);
	    } else if (GotFlag(statePtr, INPUT_SAW_CR)) {
		ResetFlag(statePtr, INPUT_SAW_CR);
		*dst = '\r';
		dst++;
	    }
	    if (curByte == '\r') {
		SetFlag(statePtr, INPUT_SAW_CR);
	    } else {
		*dst = (char) curByte;
		dst++;
	    }
	}
	copied = dst - result;
	break;
    }
    case TCL_TRANSLATE_AUTO: {
	char *src, *end, *dst;
	int curByte;

	if (bytesInBuffer == 0) {
	    return 0;
	}

	/*
	 * Loop over the current buffer, converting "\r" and "\r\n" to "\n".
	 */

	if (bytesInBuffer < space) {
	    space = bytesInBuffer;
	}
	memcpy(result, RemovePoint(bufPtr), (size_t) space);
	bufPtr->nextRemoved += space;
	copied = space;

	end = result + copied;
	dst = result;
	for (src = result; src < end; src++) {
	    curByte = *src;
	    if (curByte == '\r') {
		SetFlag(statePtr, INPUT_SAW_CR);
		*dst = '\n';
		dst++;

	    } else {
		if ((curByte != '\n') || !GotFlag(statePtr, INPUT_SAW_CR)) {
		    *dst = (char) curByte;

		    dst++;
		}
		ResetFlag(statePtr, INPUT_SAW_CR);
	    }
	}
	copied = dst - result;
	break;
    }
    default:
	Tcl_Panic("unknown eol translation mode");


    }

    /*
     * If an in-stream EOF character is set for this channel, check that the
     * input we copied so far does not contain the EOF char. If it does, copy
     * only up to and excluding that character.
     */

    if (statePtr->inEofChar != 0) {
	for (i = 0; i < copied; i++) {
	    if (result[i] == (char) statePtr->inEofChar) {
		/*
		 * Set sticky EOF so that no further input is presented to the
		 * caller.
		 */

		SetFlag(statePtr, CHANNEL_EOF | CHANNEL_STICKY_EOF);
		statePtr->inputEncodingFlags |= TCL_ENCODING_END;
		copied = i;
		break;
	    }
	}
    }

    /*
     * If the current buffer is empty recycle it.
     */

    if (IsBufferEmpty(bufPtr)) {
	statePtr->inQueueHead = bufPtr->nextPtr;
	if (statePtr->inQueueHead == NULL) {
	    statePtr->inQueueTail = NULL;
	}
	RecycleBuffer(statePtr, bufPtr, 0);
    }

    /*

     * Return the number of characters copied into the result buffer. This may
     * be different from the number of bytes consumed, because of EOL
     * translations.
     */




    return copied;
}

/*
 *----------------------------------------------------------------------
 *
 * CopyBuffer --
 *

    ChannelState *statePtr;

    if (interp == NULL) {
	return TCL_ERROR;
    }
    if (objPtr->typePtr == &chanObjType) {
	/*

	 * The channel is valid until any call to DetachChannel occurs.
	 * Ensure consistency checks are done.
	 */

	statePtr = GET_CHANNELSTATE(objPtr);
	if (GotFlag(statePtr, CHANNEL_TAINTED|CHANNEL_CLOSED)) {
	    ResetFlag(statePtr, CHANNEL_TAINTED);

    ChanFlag('R', BUFFER_READY);
    ChanFlag('F', BG_FLUSH_SCHEDULED);
    ChanFlag('c', CHANNEL_CLOSED);
    ChanFlag('E', CHANNEL_EOF);
    ChanFlag('S', CHANNEL_STICKY_EOF);
    ChanFlag('B', CHANNEL_BLOCKED);
    ChanFlag('/', INPUT_SAW_CR);
    ChanFlag('*', INPUT_NEED_NL);
    ChanFlag('D', CHANNEL_DEAD);
    ChanFlag('R', CHANNEL_RAW_MODE);
#ifdef TCL_IO_TRACK_OS_FOR_DRIVER_WITH_BAD_BLOCKING
    ChanFlag('T', CHANNEL_TIMER_FEV);
    ChanFlag('H', CHANNEL_HAS_MORE_DATA);
#endif /* TCL_IO_TRACK_OS_FOR_DRIVER_WITH_BAD_BLOCKING */
    ChanFlag('x', CHANNEL_INCLOSE);

    buf[i] ='\0';

    fprintf(stderr, "%s: %s\n", str, buf);
    return 0;
}

#define CHANNEL_BLOCKED		(1<<11)	/* EWOULDBLOCK or EAGAIN occurred on
					 * this channel. This bit is cleared
					 * before every input or output
					 * operation. */
#define INPUT_SAW_CR		(1<<12)	/* Channel is in CRLF eol input
					 * translation mode and the last byte
					 * seen was a "\r". */
#define INPUT_NEED_NL		(1<<15)	/* Saw a '\r' at end of last buffer,
					 * and there should be a '\n' at
					 * beginning of next buffer. */
#define CHANNEL_DEAD		(1<<13)	/* The channel has been closed by the
					 * exit handler (on exit) but not
					 * deallocated. When any IO operation
					 * sees this flag on a channel, it
					 * does not call driver level
					 * functions to avoid referring to
					 * deallocated data. */
#define CHANNEL_NEED_MORE_DATA	(1<<14)	/* The last input operation failed
					 * because there was not enough data
					 * to complete the operation. This
					 * flag is set when gets fails to get
					 * a complete line or when read fails
					 * to get a complete character. When
					 * set, file events will not be
					 * delivered for buffered data until
					 * the state of the channel
					 * changes. */
#define CHANNEL_RAW_MODE	(1<<16)	/* When set, notes that the Raw API is
					 * being used. */
#ifdef TCL_IO_TRACK_OS_FOR_DRIVER_WITH_BAD_BLOCKING
#define CHANNEL_TIMER_FEV	(1<<17)	/* When set the event we are notified
					 * by is a fileevent generated by a
					 * timer. We don't know if the driver
					 * has more data and should not try to
					 * read from it. If the system needs
					 * more than is in the buffers out
					 * read routines will simulate a short
					 * read (0 characters read) */
#define CHANNEL_HAS_MORE_DATA   (1<<18) /* Set by NotifyChannel for a channel
					 * if and only if the channel is
					 * configured non-blocking, the driver
					 * for said channel has no
					 * blockmodeproc, and data has arrived
					 * for reading at the OS level). A
					 * GetInput will pass reading from the
					 * driver if the channel is
					 * non-blocking, without blockmode
					 * proc and the flag has not been set.
					 * A read will be performed if the
					 * flag is set. This will reset the
					 * flag as well. */
#endif /* TCL_IO_TRACK_OS_FOR_DRIVER_WITH_BAD_BLOCKING */

#define CHANNEL_INCLOSE		(1<<19)	/* Channel is currently being closed.
					 * Its structures are still live and
					 * usable, but it may not be closed
					 * again from within the close
					 * handler. */
#define CHANNEL_TAINTED		(1<<20)	/* Channel stack structure has changed.

			    int *typePtr);
MODULE_SCOPE int	TclGetOpenModeEx(Tcl_Interp *interp,
			    const char *modeString, int *seekFlagPtr,
			    int *binaryPtr);
MODULE_SCOPE Tcl_Obj *	TclGetProcessGlobalValue(ProcessGlobalValue *pgvPtr);
MODULE_SCOPE Tcl_Obj *	TclGetSourceFromFrame(CmdFrame *cfPtr, int objc,
			    Tcl_Obj *const objv[]);


MODULE_SCOPE int	TclGlob(Tcl_Interp *interp, char *pattern,
			    Tcl_Obj *unquotedPrefix, int globFlags,
			    Tcl_GlobTypeData *types);
MODULE_SCOPE int	TclIncrObj(Tcl_Interp *interp, Tcl_Obj *valuePtr,
			    Tcl_Obj *incrPtr);
MODULE_SCOPE Tcl_Obj *	TclIncrObjVar2(Tcl_Interp *interp, Tcl_Obj *part1Ptr,
			    Tcl_Obj *part2Ptr, Tcl_Obj *incrPtr, int flags);

    if (length <= limit) {
	toCopy = length;
    } else {
	if (ellipsis == NULL) {
	    ellipsis = "...";
	}

	toCopy = Tcl_UtfPrev(bytes+limit+1-strlen(ellipsis), bytes) - bytes;
    }

    /*
     * If objPtr has a valid Unicode rep, then append the Unicode conversion
     * of "bytes" to the objPtr's Unicode rep, otherwise append "bytes" to
     * objPtr's string rep.
     */

	/*
	 * Protect against case where unicode points into the existing
	 * stringPtr->unicode array. Force it to follow any relocations due to
	 * the reallocs below.
	 */

	if (unicode >= stringPtr->unicode
		&& unicode <= stringPtr->unicode + stringPtr->maxChars) {
	    offset = unicode - stringPtr->unicode;
	}

	GrowUnicodeBuffer(objPtr, numChars);
	stringPtr = GET_STRING(objPtr);

    }

    /*
     * Copy the new string onto the end of the old string, then add the
     * trailing null.
     */


    memmove(stringPtr->unicode + stringPtr->numChars, unicode,
	    appendNumChars * sizeof(Tcl_UniChar));

    stringPtr->unicode[numChars] = 0;
    stringPtr->numChars = numChars;
    stringPtr->allocated = 0;

    TclInvalidateStringRep(objPtr);
}


	/*
	 * Protect against case where unicode points into the existing
	 * stringPtr->unicode array. Force it to follow any relocations due to
	 * the reallocs below.
	 */

	if (bytes >= objPtr->bytes
		&& bytes <= objPtr->bytes + objPtr->length) {
	    offset = bytes - objPtr->bytes;
	}

	/*
	 * TODO: consider passing flag=1: no overalloc on first append. This
	 * would make test stringObj-8.1 fail.

    /*
     * Invalidate the unicode data.
     */

    stringPtr->numChars = -1;
    stringPtr->hasUnicode = 0;


    memmove(objPtr->bytes + oldLength, bytes, numBytes);

    objPtr->bytes[newLength] = 0;
    objPtr->length = newLength;
}

/*
 *----------------------------------------------------------------------
 *

    va_end(argList);
    return objPtr;
}

/*
 *---------------------------------------------------------------------------
 *
































 * TclStringObjReverse --
 *
 *	Implements the [string reverse] operation.
 *
 * Results:
 *	An unshared Tcl value which is the [string reverse] of the argument
 *	supplied. When sharing rules permit, the returned value might be the

	
    if (needed > stringPtr->maxChars) {
	GrowUnicodeBuffer(objPtr, needed);
	stringPtr = GET_STRING(objPtr);
    }

    stringPtr->hasUnicode = 1;

    stringPtr->numChars = needed;



    for (dst=stringPtr->unicode + numOrigChars; numAppendChars-- > 0; dst++) {
	bytes += TclUtfToUniChar(bytes, dst);
    }
    *dst = 0;
}

/*

    set f [open $path(test1) r]
    fconfigure $f -translation crlf -eofchar \x1a
    set l [string length [set in [read $f]]]
    set e [eof $f]
    close $f
    list $s $l $e [scan [string index $in end] %c]
} -result {9 8 1 13}
test io-35.18b {Tcl_Eof, eof char, cr write, crlf read} -constraints knownBug -body {
    file delete $path(test1)
    set f [open $path(test1) w]
    fconfigure $f -translation cr -eofchar \x1a
    puts $f {}
    close $f
    set s [file size $path(test1)]
    set f [open $path(test1) r]

    set f [open $path(test1) r]
    fconfigure $f -translation crlf -eofchar \x1a
    set l [string length [set in [read $f]]]
    set e [eof $f]
    close $f
    list $c $l $e [scan [string index $in end] %c]
} -result {17 8 1 13}
















# Test Tcl_InputBlocked

test io-36.1 {Tcl_InputBlocked on nonblocking pipe} {stdio openpipe} {
    set f1 [open "|[list [interpreter]]" r+]
    puts $f1 {puts hello_from_pipe}
    flush $f1

    fcopy $in $out
    close $in
    close $out

    file size $path(kyrillic.txt)
} 3














































































































































test io-53.1 {CopyData} {fcopy} {
    file delete $path(test1)
    set f1 [open $thisScript]
    set f2 [open $path(test1) w]
    fconfigure $f1 -translation lf -blocking 0
    fconfigure $f2 -translation cr -blocking 0

    set done
} -cleanup {
    close $outChan
    close $inChan
    removeFile out
    removeFile in
} -result {40 bytes copied}




















test io-54.1 {Recursive channel events} {socket fileevent} {
    # This test checks to see if file events are delivered during recursive
    # event loops when there is buffered data on the channel.

    proc accept {s a p} {
	variable as

    LOG MAIN_WAITING
    vwait forever
    LOG MAIN_DONE

    set res
} -cleanup {

    rename LOG {}
    rename POST {}
    rename HANDLER {}
    unset beat drive data forever res tid ch
} -match glob \
    -result {{initialize rc* read} {watch rc* read} {read rc* 4096} {watch rc* {}} {watch rc* read} {read rc* 4096} {watch rc* {}} {finalize rc*}}

# --- === *** ###########################
# method cgetall

test iocmd.tf-25.1 {chan configure, cgetall, standard options} -match glob -body {