1 files changed, 34 insertions, 10 deletions

diff --git a/generic/tclIO.c b/generic/tclIO.c
index dcde8d1..9283bf5 100644
--- a/generic/tclIO.c
+++ b/generic/tclIO.c
@@ -3894,7 +3894,10 @@ Tcl_Write(
     if (srcLen < 0) {
 	srcLen = strlen(src);
     }
-    return WriteBytes(chanPtr, src, srcLen);
+    if (WriteBytes(chanPtr, src, srcLen) < 0) {
+	return -1;
+    }
+    return srcLen;
 }
 
 /*
@@ -6046,12 +6049,11 @@ ReadChars(
 	    /* 
 	     * We read more chars than allowed.  Reset limits to
 	     * prevent that and try again.  Don't forget the extra
-	     * padding of TCL_UTF_MAX - 1 bytes demanded by the
+	     * padding of TCL_UTF_MAX bytes demanded by the
 	     * Tcl_ExternalToUtf() call!
 	     */
 
-	    dstLimit = Tcl_UtfAtIndex(dst, charsToRead + 1) 
-		    + TCL_UTF_MAX - 1 - dst;
+	    dstLimit = Tcl_UtfAtIndex(dst, charsToRead) + TCL_UTF_MAX - dst;
 	    statePtr->flags = savedFlags;
 	    statePtr->inputEncodingFlags = savedIEFlags;
 	    statePtr->inputEncodingState = savedState;
@@ -9021,7 +9023,7 @@ MBRead(
     }
 
     code = GetInput(inStatePtr->topChanPtr);
-    if (code == 0) {
+    if (code == 0 || GotFlag(inStatePtr, CHANNEL_BLOCKED)) {
 	return TCL_OK;
     } else {
 	MBError(csPtr, TCL_READABLE, code);
@@ -9271,6 +9273,10 @@ CopyData(
 			csPtr);
 	    }
 	    if (size == 0) {
+		if (!GotFlag(inStatePtr, CHANNEL_NONBLOCKING)) {
+		    /* We allowed a short read.  Keep trying. */
+		    continue;
+		}
 		if (bufObj != NULL) {
 		    TclDecrRefCount(bufObj);
 		    bufObj = NULL;
@@ -9503,21 +9509,39 @@ DoRead(
 	}
 
 	/*
-	 * If there is not enough data in the buffers to possibly
-	 * complete the read, then go get more.
+	 * Don't read more data if we have what we need. 
 	 */
 
-	if (bufPtr == NULL || BytesLeft(bufPtr) < bytesToRead) {
+	while (!bufPtr ||			/* We got no buffer!   OR */
+		(!IsBufferFull(bufPtr) && 	/* Our buffer has room AND */
+		(BytesLeft(bufPtr) < bytesToRead) ) ) {
+						/* Not enough bytes in it 
+						 * yet to fill the dst */
+	    int code;
+
 	moreData:
-	    if (GetInput(chanPtr)) {
+	    code = GetInput(chanPtr);
+	    bufPtr = statePtr->inQueueHead;
+
+	    assert (bufPtr != NULL);
+
+	    if (GotFlag(statePtr, CHANNEL_EOF|CHANNEL_BLOCKED)) {
+		/* Further reads cannot do any more */
+		break;
+	    }
+
+	    if (code) {
 		/* Read error */
 		UpdateInterest(chanPtr);
 		TclChannelRelease((Tcl_Channel)chanPtr);
 		return -1;
 	    }
-	    bufPtr = statePtr->inQueueHead;
+
+	    assert (IsBufferFull(bufPtr));
 	}
 
+	assert (bufPtr != NULL);
+
 	bytesRead = BytesLeft(bufPtr);
 	bytesWritten = bytesToRead;