Fix use of XMaxTransChars in stead of TCL_UTF_MAX in some places. This should prevent possible buffer overflow when TCL_UTF_MAX=6

Micro-optimizations in tkEntry and ttkEntry

8 files changed, 18 insertions, 16 deletions

diff --git a/generic/tkEntry.c b/generic/tkEntry.c
index 5681e47..a66cf18 100644
--- a/generic/tkEntry.c
+++ b/generic/tkEntry.c
@@ -1927,7 +1927,7 @@ EntryComputeGeometry(
 
     if (entryPtr->showChar != NULL) {
 	Tcl_UniChar ch;
-	char buf[TCL_UTF_MAX];
+	char buf[4];
 	int size;
 
 	/*
@@ -1945,7 +1945,8 @@ EntryComputeGeometry(
 	entryPtr->displayString = p;
 
 	for (i = entryPtr->numChars; --i >= 0; ) {
-	    p += Tcl_UniCharToUtf(ch, p);
+	    memcpy(p, buf, size);
+	    p += size;
 	}
 	*p = '\0';
     }
diff --git a/generic/tkSelect.c b/generic/tkSelect.c
index ab9018a..74b3964 100644
--- a/generic/tkSelect.c
+++ b/generic/tkSelect.c
@@ -26,7 +26,7 @@ typedef struct {
     int charOffset;		/* The offset of the next char to retrieve. */
     int byteOffset;		/* The expected byte offset of the next
 				 * chunk. */
-    char buffer[TCL_UTF_MAX];	/* A buffer to hold part of a UTF character
+    char buffer[4];		/* A buffer to hold part of a UTF character
 				 * that is split across chunks. */
     char command[1];		/* Command to invoke. Actual space is
 				 * allocated as large as necessary. This must
diff --git a/generic/ttk/ttkEntry.c b/generic/ttk/ttkEntry.c
index f395649..d80e1fd 100644
--- a/generic/ttk/ttkEntry.c
+++ b/generic/ttk/ttkEntry.c
@@ -283,14 +283,15 @@ static char *EntryDisplayString(const char *showChar, int numChars)
     char *displayString, *p;
     int size;
     Tcl_UniChar ch;
-    char buf[TCL_UTF_MAX];
+    char buf[4];
 
     Tcl_UtfToUniChar(showChar, &ch);
     size = Tcl_UniCharToUtf(ch, buf);
     p = displayString = ckalloc(numChars * size + 1);
 
     while (numChars--) {
-	p += Tcl_UniCharToUtf(ch, p);
+	memcpy(p, buf, size);
+	p += size;
     }
     *p = '\0';
 
diff --git a/unix/tkUnixFont.c b/unix/tkUnixFont.c
index 1f4a1d4..a6826b5 100644
--- a/unix/tkUnixFont.c
+++ b/unix/tkUnixFont.c
@@ -513,7 +513,7 @@ Ucs2beToUtfProc(
     srcEnd = src + srcLen;
 
     dstStart = dst;
-    dstEnd = dst + dstLen - TCL_UTF_MAX;
+    dstEnd = dst + dstLen - 4;
 
     for (numChars = 0; src < srcEnd; numChars++) {
 	if (dst > dstEnd) {
@@ -588,7 +588,7 @@ UtfToUcs2beProc(
     srcEnd = src + srcLen;
     srcClose = srcEnd;
     if (!(flags & TCL_ENCODING_END)) {
-	srcClose -= TCL_UTF_MAX;
+	srcClose -= 4;
     }
 
     dstStart = dst;
@@ -2202,7 +2202,7 @@ FontMapLoadPage(
     int row)			/* Index of the page to be loaded into the
 				 * cache. */
 {
-    char buf[16], src[TCL_UTF_MAX];
+    char buf[16], src[4];
     int minHi, maxHi, minLo, maxLo, scale, checkLo;
     int i, end, bitOffset, isTwoByteFont, n;
     Tcl_Encoding encoding;
@@ -2406,7 +2406,7 @@ CanUseFallback(
     unsigned bestScore[2];
     char **nameList;
     char **nameListOrig;
-    char src[TCL_UTF_MAX];
+    char src[4];
     FontAttributes want, got;
     Display *display;
     SubFont subFont;
diff --git a/unix/tkUnixSelect.c b/unix/tkUnixSelect.c
index 4bb462e..53275d1 100644
--- a/unix/tkUnixSelect.c
+++ b/unix/tkUnixSelect.c
@@ -21,7 +21,7 @@ typedef struct ConvertInfo {
 				 * offset of the next chunk of data to
 				 * transfer. */
     Tcl_EncodingState state;	/* The encoding state needed across chunks. */
-    char buffer[TCL_UTF_MAX];	/* A buffer to hold part of a UTF character
+    char buffer[4];		/* A buffer to hold part of a UTF character
 				 * that is split across chunks.*/
 } ConvertInfo;
 
@@ -439,7 +439,7 @@ TkSelPropProc(
 		 * Preserve any left-over bytes.
 		 */
 
-		if (srcLen > TCL_UTF_MAX) {
+		if (srcLen > 4) {
 		    Tcl_Panic("selection conversion left too many bytes unconverted");
 		}
 		memcpy(incrPtr->converts[i].buffer, src, (size_t) srcLen+1);
diff --git a/win/tkWinFont.c b/win/tkWinFont.c
index 7b5e4c9..10ea1b9 100644
--- a/win/tkWinFont.c
+++ b/win/tkWinFont.c
@@ -2188,7 +2188,7 @@ FontMapLoadPage(
 {
     FontFamily *familyPtr;
     Tcl_Encoding encoding;
-    char src[TCL_UTF_MAX], buf[16];
+    char src[XMaxTransChars], buf[16];
     USHORT *startCount, *endCount;
     int i, j, bitOffset, end, segCount;
 
diff --git a/win/tkWinKey.c b/win/tkWinKey.c
index ed546f7..5591133 100644
--- a/win/tkWinKey.c
+++ b/win/tkWinKey.c
@@ -102,7 +102,7 @@ TkpGetString(
 	 */
 
 	int unichar;
-	char buf[TCL_UTF_MAX];
+	char buf[XMaxTransChars];
 	int len;
 
 	unichar = keyEv->trans_chars[1] & 0xff;
@@ -129,7 +129,7 @@ TkpGetString(
 
 	if (((keysym != NoSymbol) && (keysym > 0) && (keysym < 256))
 		|| (keysym == XK_Return) || (keysym == XK_Tab)) {
-	    char buf[TCL_UTF_MAX];
+	    char buf[XMaxTransChars];
 	    int len;
 
 	    len = Tcl_UniCharToUtf((Tcl_UniChar) (keysym & 255), buf);
diff --git a/win/tkWinX.c b/win/tkWinX.c
index 7e25826..21c607c 100644
--- a/win/tkWinX.c
+++ b/win/tkWinX.c
@@ -1215,13 +1215,13 @@ GenerateXEvent(
 	    break;
 
 	case WM_UNICHAR: {
-	    char buffer[TCL_UTF_MAX+1];
+	    char buffer[XMaxTransChars];
 	    int i;
 	    event.type = KeyPress;
 	    event.xany.send_event = -3;
 	    event.xkey.keycode = wParam;
 	    event.xkey.nbytes = Tcl_UniCharToUtf((int)wParam, buffer);
-	    for (i=0; i<event.xkey.nbytes && i<TCL_UTF_MAX; ++i) {
+	    for (i=0; i<event.xkey.nbytes && i<XMaxTransChars; ++i) {
 		event.xkey.trans_chars[i] = buffer[i];
 	    }
 	    Tk_QueueWindowEvent(&event, TCL_QUEUE_TAIL);