diff options
| -rw-r--r-- | ChangeLog | 10 | ||||
| -rw-r--r-- | generic/tclIO.c | 35 |
2 files changed, 34 insertions, 11 deletions
@@ -1,3 +1,13 @@ +2001-07-17 Andreas Kupries <andreas_kupries@users.sourceforge.net> + + * generic/tclIO.c (GetInput): Fixed [SF #427196]. Memory was + overwritten because a buffer was used after a change of the + requested buffersize together with that requested buffersize and + not its actual size, which was smaller. Note that the continous + reuse of the smaller buffer negatively impacts performance. The + system never allocates a buffer with the newly requested bigger + buffersize. + 2001-07-16 Jeff Hobbs <jeffh@ActiveState.com> * win/tclWinPipe.c (PipeClose2Proc): constrained the mutex lock to diff --git a/generic/tclIO.c b/generic/tclIO.c index 5eb2b31..815e1a4 100644 --- a/generic/tclIO.c +++ b/generic/tclIO.c @@ -10,7 +10,7 @@ * See the file "license.terms" for information on usage and redistribution * of this file, and for a DISCLAIMER OF ALL WARRANTIES. * - * RCS: @(#) $Id: tclIO.c,v 1.20.2.6 2001/04/03 22:54:37 hobbs Exp $ + * RCS: @(#) $Id: tclIO.c,v 1.20.2.7 2001/07/17 20:43:52 hobbs Exp $ */ #include "tclInt.h" @@ -4707,24 +4707,37 @@ GetInput(chanPtr) bufPtr = statePtr->inQueueTail; if ((bufPtr != NULL) && (bufPtr->nextAdded < bufPtr->bufLength)) { - toRead = bufPtr->bufLength - bufPtr->nextAdded; + toRead = bufPtr->bufLength - bufPtr->nextAdded; } else { bufPtr = statePtr->saveInBufPtr; statePtr->saveInBufPtr = NULL; if (bufPtr == NULL) { bufPtr = AllocChannelBuffer(statePtr->bufSize); } - bufPtr->nextPtr = (ChannelBuffer *) NULL; + bufPtr->nextPtr = (ChannelBuffer *) 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 = statePtr->bufSize; - if (statePtr->inQueueTail == NULL) { - statePtr->inQueueHead = bufPtr; - } else { - statePtr->inQueueTail->nextPtr = bufPtr; - } - statePtr->inQueueTail = bufPtr; + toRead = bufPtr->bufLength - bufPtr->nextAdded; + 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. |