X-Git-Url: https://git.sesse.net/?p=fjl;a=blobdiff_plain;f=zigzag.h;h=5d9df28ec457e9a048587d14ae81321d714a5b98;hp=3fc137710581211a137edc7d84633bee0c653b1e;hb=12195f1ed80bebbfecfa7505ec965177228ea916;hpb=8326dff1cbad02c5d660696648e15a0f575c9afd

diff --git a/zigzag.h b/zigzag.h
index 3fc1377..5d9df28 100644
--- a/zigzag.h
+++ b/zigzag.h
@@ -4,10 +4,10 @@
 #include "idct.h"
 
 // Table for transforming from zig-zag order to natural order.
-// We use the same trick as libjpeg here; there are 16 extra entries
+// We use the same trick as libjpeg here; there are 64 extra entries
 // after the end of the table, since the run-length decoder could
 // potentially cause entries indices >= 64 to be decoded.
-static const unsigned unzigzag[DCTSIZE2 + 16] = {
+static const unsigned unzigzag[DCTSIZE2 * 2] = {
 	// Regular entries.
 	 0,  1,  8, 16,  9,  2,  3, 10,
 	17, 24, 32, 25, 18, 11,  4,  5,
@@ -18,7 +18,14 @@ static const unsigned unzigzag[DCTSIZE2 + 16] = {
 	58, 59, 52, 45, 38, 31, 39, 46,
 	53, 60, 61, 54, 47, 55, 62, 63,
 
-	// Extra padding entries; should never be referenced in well-formed data.
+	// Extra padding entries.
+	// May get referenced by malformed data or during end-of-block processing.
+	63, 63, 63, 63, 63, 63, 63, 63,
+	63, 63, 63, 63, 63, 63, 63, 63,
+	63, 63, 63, 63, 63, 63, 63, 63,
+	63, 63, 63, 63, 63, 63, 63, 63,
+	63, 63, 63, 63, 63, 63, 63, 63,
+	63, 63, 63, 63, 63, 63, 63, 63,
 	63, 63, 63, 63, 63, 63, 63, 63,
 	63, 63, 63, 63, 63, 63, 63, 63,
 };