DecodeMacRoman() is missing an upper bounds check before indexing into Mac2Unicode array

[ddkilzer]

DecodeMacRoman() is missing an upper bounds check before indexing into the Mac2Unicode array:

/* Function to convert from MacRoman to Unicode */
uint TY_(DecodeMacRoman)(uint c)
{
    if (127 < c)
        c = Mac2Unicode[c - 128];
    return c;
}

It should do this instead, like DecodeIbm850() does:

    if (127 < c && c < 256)
        c = Mac2Unicode[c - 128];
    return c;

[geoffmcl]

@ddkilzer I like your upper bounds check...

Does this patch work for you?

diff --git a/src/streamio.c b/src/streamio.c
index d23f056..ed3f396 100644
--- a/src/streamio.c
+++ b/src/streamio.c
@@ -724,7 +724,7 @@ static const uint Mac2Unicode[128] =
 /* Function to convert from MacRoman to Unicode */
 uint TY_(DecodeMacRoman)(uint c)
 {
-    if (127 < c)
+    if (127 < c && c < 256) // is. #891
         c = Mac2Unicode[c - 128];
     return c;
 }

If ok, will try to merge it soon... thanks...

[geoffmcl]

Oops, I mean with Tidy comments ;=))

+    if (127 < c && c < 256) /* is. #891 */

That's better...

[ddkilzer]

+    if (127 < c && c < 256) /* is. #891 */

Looks good to me. Thanks!

[geoffmcl]

20201130: @ddkilzer eventually done... thanks...