Tcl Source Code

    int inAllocated, outAllocated;
				/* Sizes of working buffers. */
    GzipHeader inHeader;	/* Header read from input stream, when
				 * decompressing a gzip stream. */
    GzipHeader outHeader;	/* Header to write to an output stream, when
				 * compressing a gzip stream. */
    Tcl_TimerToken timer;	/* Timer used for keeping events fresh. */
    Tcl_DString decompressed;	/* Buffer for decompression results. */
} ZlibChannelData;

/*
 * Value bits for the flags field. Definitions are:
 *	ASYNC -		Whether this is an asynchronous channel.
 *	IN_HEADER -	Whether the inHeader field has been registered with
 *			the input compressor.

/*
 * Size of buffers allocated by default. Should be enough...
 */

#define DEFAULT_BUFFER_SIZE	4096

/*
 * Time to wait before delivering a timer event.
 */

#define TRANSFORM_TIMEOUT	0

/*
 * Prototypes for private procedures defined later in this file:
 */

static Tcl_CmdDeleteProc	ZlibStreamCmdDelete;
static Tcl_DriverBlockModeProc	ZlibTransformBlockMode;
static Tcl_DriverCloseProc	ZlibTransformClose;
static Tcl_DriverGetHandleProc	ZlibTransformGetHandle;
static Tcl_DriverGetOptionProc	ZlibTransformGetOption;
static Tcl_DriverHandlerProc	ZlibTransformEventHandler;
static Tcl_DriverInputProc	ZlibTransformInput;
static Tcl_DriverOutputProc	ZlibTransformOutput;
static Tcl_DriverSetOptionProc	ZlibTransformSetOption;
static Tcl_DriverWatchProc	ZlibTransformWatch;
static Tcl_ObjCmdProc		ZlibCmd;
static Tcl_ObjCmdProc		ZlibStreamCmd;

static void		ConvertError(Tcl_Interp *interp, int code);
static void		ExtractHeader(gz_header *headerPtr, Tcl_Obj *dictObj);
static int		GenerateHeader(Tcl_Interp *interp, Tcl_Obj *dictObj,
			    GzipHeader *headerPtr, int *extraSizePtr);
static inline int	ResultCopy(ZlibChannelData *cd, char *buf,
			    int toRead);
static int		ResultGenerate(ZlibChannelData *cd, int n, int flush,
			    int *errorCodePtr);
static Tcl_Channel	ZlibStackChannelTransform(Tcl_Interp *interp,
			    int mode, int format, int level,
			    Tcl_Channel channel, Tcl_Obj *gzipHeaderDictPtr);
static void		ZlibStreamCleanup(ZlibStreamHandle *zshPtr);
static inline void	ZlibTransformEventTimerKill(ZlibChannelData *cd);
static void		ZlibTransformTimerRun(ClientData clientData);


/*
 * Type of zlib-based compressing and decompressing channels.
 */

static const Tcl_ChannelType zlibChannelType = {
    "zlib",
    TCL_CHANNEL_VERSION_3,
    ZlibTransformClose,
    ZlibTransformInput,
    ZlibTransformOutput,
    NULL,			/* seekProc */
    ZlibTransformSetOption,
    ZlibTransformGetOption,
    ZlibTransformWatch,
    ZlibTransformGetHandle,
    NULL,			/* close2Proc */
    ZlibTransformBlockMode,
    NULL,			/* flushProc */
    ZlibTransformEventHandler,
    NULL,			/* wideSeekProc */
    NULL,
    NULL
};

/*
 *----------------------------------------------------------------------

    return TCL_OK;
}

/*
 *----------------------------------------------------------------------
 *	Set of functions to support channel stacking.
 *----------------------------------------------------------------------
 *
 * ZlibTransformClose --
 *
 *	How to shut down a stacked compressing/decompressing transform.
 *
 *----------------------------------------------------------------------
 */

static int
ZlibTransformClose(
    ClientData instanceData,
    Tcl_Interp *interp)
{
    ZlibChannelData *cd = instanceData;
    int e, result = TCL_OK;

    /*
     * Delete the support timer.
     */

    ZlibTransformEventTimerKill(cd);

    /*
     * Flush any data waiting to be compressed.
     */

    if (cd->mode == TCL_ZLIB_STREAM_DEFLATE) {
	cd->outStream.avail_in = 0;

	e = inflateEnd(&cd->inStream);
    }

    /*
     * Release all memory.
     */

    Tcl_DStringFree(&cd->decompressed);

    if (cd->inBuffer) {
	ckfree(cd->inBuffer);
	cd->inBuffer = NULL;
    }
    if (cd->outBuffer) {
	ckfree(cd->outBuffer);
	cd->outBuffer = NULL;
    }
    ckfree(cd);
    return result;
}

/*
 *----------------------------------------------------------------------
 *
 * ZlibTransformInput --
 *
 *	Reader filter that does decompression.
 *
 *----------------------------------------------------------------------
 */

static int
ZlibTransformInput(
    ClientData instanceData,
    char *buf,
    int toRead,
    int *errorCodePtr)

    gotBytes = 0;
    while (toRead > 0) {
	/*
	 * Loop until the request is satisfied (or no data available from
	 * below, possibly EOF).
	 */

	copied = ResultCopy(cd, buf, toRead);
	toRead -= copied;
	buf += copied;
	gotBytes += copied;

	if (toRead == 0) {
	    return gotBytes;
	}

	/*
	 * The buffer is exhausted, but the caller wants even more. We now
	 * have to go to the underlying channel, get more bytes and then
	 * transform them for delivery. We may not get what we want (full EOF
	 * or temporarily out of data).
	 *
	 * Length (cd->decompressed) == 0, toRead > 0 here.
	 *
	 * The zlib transform allows us to read at most one character from the
	 * underlying channel to properly identify Z_STREAM_END without
	 * reading over the border.
	 */

	readBytes = Tcl_ReadRaw(cd->parent, cd->inBuffer, 1);

	/*
	 * Three cases here:
	 *  1.	Got some data from the underlying channel (readBytes > 0) so
	 *	it should be fed through the decompression engine.
	 *  2.	Got an error (readBytes < 0) which we should report up except
	 *	for the case where we can convert it to a short read.
	 *  3.	Got an end-of-data from EOF or blocking (readBytes == 0). If
	 *	it is EOF, try flushing the data out of the decompressor.
	 */

	if (readBytes < 0) {
	    /*
	     * Report errors to caller. The state of the seek system is
	     * unchanged!
	     */

	    if ((Tcl_GetErrno() == EAGAIN) && (gotBytes > 0)) {
		/*
		 * EAGAIN is a special situation. If we had some data before
		 * we report that instead of the request to re-try.
		 */

		return gotBytes;
	    }

	    *errorCodePtr = Tcl_GetErrno();


	    return -1;
	} else if (readBytes == 0) {
	    /*
	     * Check wether we hit on EOF in 'parent' or not. If not,
	     * differentiate between blocking and non-blocking modes. In
	     * non-blocking mode we ran temporarily out of data. Signal this
	     * to the caller via EWOULDBLOCK and error return (-1). In the
	     * other cases we simply return what we got and let the caller
	     * wait for more. On the other hand, if we got an EOF we have to
	     * convert and flush all waiting partial data.
	     */

	    if (!Tcl_Eof(cd->parent)) {
		/*
		 * The state of the seek system is unchanged!
		 */

		if ((gotBytes == 0) && (cd->flags & ASYNC)) {
		    *errorCodePtr = EWOULDBLOCK;
		    return -1;
		}
		return gotBytes;
	    }

	    /*
	     * (Semi-)Eof in parent.
	     *
	     * Now this is a bit different. The partial data waiting is
	     * converted and returned.
	     */

	    if (ResultGenerate(cd, 0, Z_SYNC_FLUSH, errorCodePtr) != TCL_OK) {
		return -1;
	    }

	    if (Tcl_DStringLength(&cd->decompressed) == 0) {
		/*
		 * The drain delivered nothing. Time to deliver what we've
		 * got.
		 */

		return gotBytes;
	    }

	    /*
	     * Reset eof, force caller to drain result buffer.
	     */

	    ((Channel *) cd->parent)->state->flags &= ~CHANNEL_EOF;


	} else /* readBytes > 0 */ {

	    /*
	     * Transform the read chunk, which was not empty. Anything we get
	     * back is a transformation result to be put into our buffers, and
	     * the next iteration will put it into the result.
	     */

	    if (ResultGenerate(cd, readBytes, Z_NO_FLUSH,
		    errorCodePtr) != TCL_OK) {
		return -1;
	    }

	}

    }
    return gotBytes;
}




/*
 *----------------------------------------------------------------------
 *
 * ZlibTransformOutput --
 *
 *	Writer filter that does compression.
 *
 *----------------------------------------------------------------------
 */

static int
ZlibTransformOutput(
    ClientData instanceData,
    const char *buf,
    int toWrite,
    int *errorCodePtr)

		Tcl_NewStringObj(cd->outStream.msg, -1));
	*errorCodePtr = EINVAL;
	return -1;
    }

    return toWrite - cd->outStream.avail_in;
}

/*
 *----------------------------------------------------------------------
 *
 * ZlibTransformSetOption --
 *
 *	Writing side of [fconfigure] on our channel.
 *
 *----------------------------------------------------------------------
 */

static int
ZlibTransformSetOption(			/* not used */
    ClientData instanceData,
    Tcl_Interp *interp,
    const char *optionName,
    const char *value)

		ConvertError(interp, e);
		return TCL_ERROR;
	    } else if (cd->outStream.avail_out == 0) {
		break;
	    }

	    if (Tcl_WriteRaw(cd->parent, cd->outBuffer,
		    cd->outStream.next_out - (Bytef *) cd->outBuffer) < 0) {
		Tcl_AppendResult(interp, "problem flushing channel: ",
			Tcl_PosixError(interp), NULL);
		return TCL_ERROR;
	    }
	}
	return TCL_OK;
    }

    if (setOptionProc == NULL) {
	return Tcl_BadChannelOption(interp, optionName, chanOptions);
    }

    /*
     * Pass all unknown options down, to deeper transforms and/or the base
     * channel.
     */

    return setOptionProc(Tcl_GetChannelInstanceData(cd->parent), interp,
	    optionName, value);
}

/*
 *----------------------------------------------------------------------
 *
 * ZlibTransformGetOption --
 *
 *	Reading side of [fconfigure] on our channel.
 *
 *----------------------------------------------------------------------
 */

static int
ZlibTransformGetOption(
    ClientData instanceData,
    Tcl_Interp *interp,
    const char *optionName,
    Tcl_DString *dsPtr)

		interp, optionName, dsPtr);
    }
    if (optionName == NULL) {
	return TCL_OK;
    }
    return Tcl_BadChannelOption(interp, optionName, chanOptions);
}

/*
 *----------------------------------------------------------------------
 *
 * ZlibTransformWatch, ZlibTransformEventHandler --
 *
 *	If we have data pending, trigger a readable event after a short time
 *	(in order to allow a real event to catch up).
 *
 *----------------------------------------------------------------------
 */

static void
ZlibTransformWatch(
    ClientData instanceData,
    int mask)
{
    ZlibChannelData *cd = instanceData;
    Tcl_DriverWatchProc *watchProc;

    /*
     * This code is based on the code in tclIORTrans.c
     */

    watchProc = Tcl_ChannelWatchProc(Tcl_GetChannelType(cd->parent));
    watchProc(Tcl_GetChannelInstanceData(cd->parent), mask);

    if (!(mask & TCL_READABLE) || Tcl_DStringLength(&cd->decompressed) == 0) {








	ZlibTransformEventTimerKill(cd);





    } else if (cd->timer == NULL) {


	cd->timer = Tcl_CreateTimerHandler(TRANSFORM_TIMEOUT,

		ZlibTransformTimerRun, cd);




    }




}



static int
ZlibTransformEventHandler(
    ClientData instanceData,
    int interestMask)
{
    ZlibChannelData *cd = instanceData;

    ZlibTransformEventTimerKill(cd);
    return interestMask;
}

static inline void










ZlibTransformEventTimerKill(
    ZlibChannelData *cd)
{
    if (cd->timer != NULL) {
	Tcl_DeleteTimerHandler(cd->timer);
	cd->timer = NULL;
    }
}

static void
ZlibTransformTimerRun(
    ClientData clientData)
{
    ZlibChannelData *cd = clientData;

    cd->timer = NULL;
    Tcl_NotifyChannel(cd->chan, TCL_READABLE);
}

/*
 *----------------------------------------------------------------------
 *
 * ZlibTransformGetHandle --
 *
 *	Anything that needs the OS handle is told to get it from what we are
 *	stacked on top of.
 *
 *----------------------------------------------------------------------
 */

static int
ZlibTransformGetHandle(
    ClientData instanceData,
    int direction,
    ClientData *handlePtr)
{
    ZlibChannelData *cd = instanceData;

    return Tcl_GetChannelHandle(cd->parent, direction, handlePtr);
}

/*
 *----------------------------------------------------------------------
 *
 * ZlibTransformBlockMode --
 *
 *	We need to keep track of the blocking mode; it changes our behavior.
 *
 *----------------------------------------------------------------------
 */

static int
ZlibTransformBlockMode(
    ClientData instanceData,
    int mode)
{
    ZlibChannelData *cd = instanceData;

    if (mode == TCL_MODE_NONBLOCKING) {
	cd->flags |= ASYNC;
    } else {
	cd->flags &= ~ASYNC;
    }
    return TCL_OK;
}

/*
 *----------------------------------------------------------------------
 *
 * ZlibStackChannelTransform --
 *
 *	Stacks either compression or decompression onto a channel.

	    e = deflateSetHeader(&cd->outStream, &cd->outHeader.header);
	    if (e != Z_OK) {
		goto error;
	    }
	}
    }

    Tcl_DStringInit(&cd->decompressed);

    chan = Tcl_StackChannel(interp, &zlibChannelType, cd,
	    Tcl_GetChannelMode(channel), channel);
    if (chan == NULL) {
	goto error;
    }
    cd->chan = chan;

 *
 * Result:
 *	The number of actually copied bytes, possibly less than 'toRead'.
 *
 *----------------------------------------------------------------------
 */

static inline int
ResultCopy(
    ZlibChannelData *cd,	/* The location of the buffer to read from. */
    char *buf,			/* The buffer to copy into */
    int toRead)			/* Number of requested bytes */
{
    int have = Tcl_DStringLength(&cd->decompressed);

    if (have == 0) {
	/*
	 * Nothing to copy in the case of an empty buffer.
	 */

	return 0;

    } else if (have > toRead) {
	/*
	 * The internal buffer contains more than requested. Copy the
	 * requested subset to the caller, shift the remaining bytes down, and
	 * truncate.
	 */

	char *src = Tcl_DStringValue(&cd->decompressed);

	memcpy(buf, src, toRead);
	memmove(src, src + toRead, have - toRead);

	Tcl_DStringSetLength(&cd->decompressed, have - toRead);
	return toRead;
    } else /* have <= toRead */ {
	/*
	 * There is just or not enough in the buffer to fully satisfy the
	 * caller, so take everything as best effort.
	 */

	memcpy(buf, Tcl_DStringValue(&cd->decompressed), have);
	Tcl_DStringSetLength(&cd->decompressed, 0);
	return have;
    }
}

/*
 *----------------------------------------------------------------------
 *
 * ResultGenerate --
 *
 *	Extract uncompressed bytes from the compression engine and store them
 *	in our working buffer.
 *
 * Result:
 *	TCL_OK/TCL_ERROR (with *errorCodePtr updated with reason).
 *
 * Side effects:
 *	See above.
 *
 *----------------------------------------------------------------------
 */

	/*
	 * avail_out is now the left over space in the output.  Therefore
	 * "MAXBUF - avail_out" is the amount of bytes generated.
	 */

	written = MAXBUF - cd->inStream.avail_out;
	if (written) {
	    Tcl_DStringAppend(&cd->decompressed, (char *) buf, written);
	}

	/*
	 * The cases where we're definitely done.
	 */

	if (((flush == Z_SYNC_FLUSH) && (e == Z_BUF_ERROR))
		|| (e == Z_STREAM_END)
		|| (e == Z_OK && cd->inStream.avail_out == 0)) {
	    return TCL_OK;
	}

	/*
	 * Z_BUF_ERROR can be ignored as per http://www.zlib.net/zlib_how.html
	 *
	 * Just indicates that the zlib couldn't consume input/produce output,
	 * and is fixed by supplying more input.
	 *
	 * Otherwise, we've got errors and need to report to higher-up.
	 */

	if ((e != Z_OK) && (e != Z_BUF_ERROR)) {
	    Tcl_Obj *errObj = Tcl_NewListObj(0, NULL);

	    Tcl_ListObjAppendElement(NULL, errObj,
		    Tcl_NewStringObj(cd->inStream.msg, -1));
	    Tcl_SetChannelError(cd->parent, errObj);
	    *errorCodePtr = EINVAL;
	    return TCL_ERROR;
	}

	/*
	 * Check if the inflate stopped early.
	 */

	if (cd->inStream.avail_in <= 0 && flush != Z_SYNC_FLUSH) {
	    return TCL_OK;
	}
    }
}

/*
 *----------------------------------------------------------------------
 *	Finally, the TclZlibInit function. Used to install the zlib API.