1 files changed, 63 insertions, 21 deletions

diff --git a/generic/tclEncoding.c b/generic/tclEncoding.c
index 95c59c0..179ca17 100644
--- a/generic/tclEncoding.c
+++ b/generic/tclEncoding.c
@@ -1206,7 +1206,10 @@ Tcl_ExternalToUtf(
 				 * output buffer. */
 {
     const Encoding *encodingPtr;
-    int result, srcRead, dstWrote, dstChars;
+    int result, srcRead, dstWrote, dstChars = 0;
+    int noTerminate = flags & TCL_ENCODING_NO_TERMINATE;
+    int charLimited = (flags & TCL_ENCODING_CHAR_LIMIT) && dstCharsPtr;
+    int maxChars = INT_MAX;
     Tcl_EncodingState state;
 
     if (encoding == NULL) {
@@ -1231,19 +1234,40 @@ Tcl_ExternalToUtf(
     }
     if (dstCharsPtr == NULL) {
 	dstCharsPtr = &dstChars;
+	flags &= ~TCL_ENCODING_CHAR_LIMIT;
+    } else if (charLimited) {
+	maxChars = *dstCharsPtr;
     }
 
-    /*
-     * If there are any null characters in the middle of the buffer, they will
-     * converted to the UTF-8 null character (\xC080). To get the actual \0 at
-     * the end of the destination buffer, we need to append it manually.
-     */
+    if (!noTerminate) {
+	/*
+	 * If there are any null characters in the middle of the buffer,
+	 * they will converted to the UTF-8 null character (\xC080). To get
+	 * the actual \0 at the end of the destination buffer, we need to
+	 * append it manually.  First make room for it...
+	 */
 
-    dstLen--;
-    result = encodingPtr->toUtfProc(encodingPtr->clientData, src, srcLen,
-	    flags, statePtr, dst, dstLen, srcReadPtr, dstWrotePtr,
-	    dstCharsPtr);
-    dst[*dstWrotePtr] = '\0';
+	dstLen--;
+    }
+    do {
+	int savedFlags = flags;
+	Tcl_EncodingState savedState = *statePtr;
+
+	result = encodingPtr->toUtfProc(encodingPtr->clientData, src, srcLen,
+		flags, statePtr, dst, dstLen, srcReadPtr, dstWrotePtr,
+		dstCharsPtr);
+	if (*dstCharsPtr <= maxChars) {
+	    break;
+	}
+	dstLen = Tcl_UtfAtIndex(dst, maxChars) - 1 - dst + TCL_UTF_MAX;
+	flags = savedFlags;
+	*statePtr = savedState;
+    } while (1);
+    if (!noTerminate) {
+	/* ...and then append it */
+
+	dst[*dstWrotePtr] = '\0';
+    }
 
     return result;
 }
@@ -2107,6 +2131,9 @@ BinaryProc(
     if (dstLen < 0) {
 	dstLen = 0;
     }
+    if ((flags & TCL_ENCODING_CHAR_LIMIT) && srcLen > *dstCharsPtr) {
+	srcLen = *dstCharsPtr;
+    }
     if (srcLen > dstLen) {
 	srcLen = dstLen;
 	result = TCL_CONVERT_NOSPACE;
@@ -2267,7 +2294,7 @@ UtfToUtfProc(
 {
     const char *srcStart, *srcEnd, *srcClose;
     const char *dstStart, *dstEnd;
-    int result, numChars;
+    int result, numChars, charLimit = INT_MAX;
     Tcl_UniChar ch;
 
     result = TCL_OK;
@@ -2278,11 +2305,14 @@ UtfToUtfProc(
     if ((flags & TCL_ENCODING_END) == 0) {
 	srcClose -= TCL_UTF_MAX;
     }
+    if (flags & TCL_ENCODING_CHAR_LIMIT) {
+	charLimit = *dstCharsPtr;
+    }
 
     dstStart = dst;
     dstEnd = dst + dstLen - TCL_UTF_MAX;
 
-    for (numChars = 0; src < srcEnd; numChars++) {
+    for (numChars = 0; src < srcEnd && numChars <= charLimit; numChars++) {
 	if ((src > srcClose) && (!Tcl_UtfCharComplete(src, srcEnd - src))) {
 	    /*
 	     * If there is more string to follow, this will ensure that the
@@ -2378,9 +2408,12 @@ UnicodeToUtfProc(
 {
     const char *srcStart, *srcEnd;
     const char *dstEnd, *dstStart;
-    int result, numChars;
+    int result, numChars, charLimit = INT_MAX;
     Tcl_UniChar ch;
 
+    if (flags & TCL_ENCODING_CHAR_LIMIT) {
+	charLimit = *dstCharsPtr;
+    }
     result = TCL_OK;
     if ((srcLen % sizeof(Tcl_UniChar)) != 0) {
 	result = TCL_CONVERT_MULTIBYTE;
@@ -2394,7 +2427,7 @@ UnicodeToUtfProc(
     dstStart = dst;
     dstEnd = dst + dstLen - TCL_UTF_MAX;
 
-    for (numChars = 0; src < srcEnd; numChars++) {
+    for (numChars = 0; src < srcEnd && numChars <= charLimit; numChars++) {
 	if (dst > dstEnd) {
 	    result = TCL_CONVERT_NOSPACE;
 	    break;
@@ -2562,12 +2595,15 @@ TableToUtfProc(
 {
     const char *srcStart, *srcEnd;
     const char *dstEnd, *dstStart, *prefixBytes;
-    int result, byte, numChars;
+    int result, byte, numChars, charLimit = INT_MAX;
     Tcl_UniChar ch;
     const unsigned short *const *toUnicode;
     const unsigned short *pageZero;
     TableEncodingData *dataPtr = clientData;
 
+    if (flags & TCL_ENCODING_CHAR_LIMIT) {
+	charLimit = *dstCharsPtr;
+    }
     srcStart = src;
     srcEnd = src + srcLen;
 
@@ -2579,7 +2615,7 @@ TableToUtfProc(
     pageZero = toUnicode[0];
 
     result = TCL_OK;
-    for (numChars = 0; src < srcEnd; numChars++) {
+    for (numChars = 0; src < srcEnd && numChars <= charLimit; numChars++) {
 	if (dst > dstEnd) {
 	    result = TCL_CONVERT_NOSPACE;
 	    break;
@@ -2793,8 +2829,11 @@ Iso88591ToUtfProc(
 {
     const char *srcStart, *srcEnd;
     const char *dstEnd, *dstStart;
-    int result, numChars;
+    int result, numChars, charLimit = INT_MAX;
 
+    if (flags & TCL_ENCODING_CHAR_LIMIT) {
+	charLimit = *dstCharsPtr;
+    }
     srcStart = src;
     srcEnd = src + srcLen;
 
@@ -2802,7 +2841,7 @@ Iso88591ToUtfProc(
     dstEnd = dst + dstLen - TCL_UTF_MAX;
 
     result = TCL_OK;
-    for (numChars = 0; src < srcEnd; numChars++) {
+    for (numChars = 0; src < srcEnd && numChars <= charLimit; numChars++) {
 	Tcl_UniChar ch;
 
 	if (dst > dstEnd) {
@@ -3018,9 +3057,12 @@ EscapeToUtfProc(
     const char *prefixBytes, *tablePrefixBytes, *srcStart, *srcEnd;
     const unsigned short *const *tableToUnicode;
     const Encoding *encodingPtr;
-    int state, result, numChars;
+    int state, result, numChars, charLimit = INT_MAX;
     const char *dstStart, *dstEnd;
 
+    if (flags & TCL_ENCODING_CHAR_LIMIT) {
+	charLimit = *dstCharsPtr;
+    }
     result = TCL_OK;
     tablePrefixBytes = NULL;	/* lint. */
     tableToUnicode = NULL;	/* lint. */
@@ -3038,7 +3080,7 @@ EscapeToUtfProc(
 	state = 0;
     }
 
-    for (numChars = 0; src < srcEnd; ) {
+    for (numChars = 0; src < srcEnd && numChars <= charLimit; ) {
 	int byte, hi, lo, ch;
 
 	if (dst > dstEnd) {