Corrections to compression stream flushing to make Tk generate PNGs correctly. Tk bug [9eb55debc5].

2 files changed, 23 insertions, 4 deletions

diff --git a/generic/tclZlib.c b/generic/tclZlib.c
index 50d9a30..691d57a 100644
--- a/generic/tclZlib.c
+++ b/generic/tclZlib.c
@@ -1194,11 +1194,12 @@ Tcl_ZlibStreamPut(
 	zshPtr->stream.next_out = (Bytef *) dataTmp;
 
 	e = deflate(&zshPtr->stream, flush);
-	while (e == Z_BUF_ERROR) {
+	while (e == Z_BUF_ERROR || (flush == Z_FINISH && e == Z_OK)) {
 	    /*
-	     * Output buffer too small to hold the data being generated; so
-	     * put a new buffer into place after saving the old generated
-	     * data to the outData list.
+	     * Output buffer too small to hold the data being generated or we
+	     * are doing the end-of-stream flush (which can spit out masses of
+	     * data). This means we need to put a new buffer into place after
+	     * saving the old generated data to the outData list.
 	     */
 
 	    obj = Tcl_NewByteArrayObj((unsigned char *) dataTmp, outSize);
diff --git a/tests/zlib.test b/tests/zlib.test
index 7a486ba..968469d 100644
--- a/tests/zlib.test
+++ b/tests/zlib.test
@@ -875,6 +875,24 @@ test zlib-11.3 {Bug 3595576 variant} -setup {
 } -cleanup {
     removeFile $file
 } -returnCodes error -result {can't set "noSuchNs::foo": parent namespace doesn't exist}
+
+test zlib-12.1 {Tk Bug 9eb55debc5} -constraints zlib -setup {
+    set stream [zlib stream compress]
+} -body {
+    for {set opts {};set y 0} {$y < 60} {incr y} {
+	for {set line {};set x 0} {$x < 100} {incr x} {
+	    append line [binary format ccc $x $y 128]
+	}
+	if {$y == 59} {
+	    set opts -finalize
+	}
+	$stream put {*}$opts $line
+    }
+    set data [$stream get]
+    list [string length $data] [string length [zlib decompress $data]]
+} -cleanup {
+    $stream close
+} -result {12026 18000}
 
 ::tcltest::cleanupTests
 return