rtp_engine: Skip useless self-assignment in ast_rtp_engine_unload_format.

When running valgrind on Asterisk, it complained about:

    ==32423== Source and destination overlap in memcpy(0x85a920, 0x85a920, 304)
    ==32423==    at 0x4C2F71C: memcpy@@GLIBC_2.14 (in /usr/lib/valgrind/...)
    ==32423==    by 0x55BA91: ast_rtp_engine_unload_format (rtp_engine.c:2292)
    ==32423==    by 0x4EEFB7: ast_format_attr_unreg_interface (format.c:1437)

The code in question is a struct assignment, which may be performed by
memcpy as a compiler optimization. It is changed to only copy the struct
contents if source and destination are different.

ASTERISK-25219 #close

Change-Id: I6d3546c326b03378ca8e9b8cefd41c16e0088b9a

diff --git a/main/rtp_engine.c b/main/rtp_engine.c
index 13d003d4fb005cfc351cec0a1140220c9f66c732..60b3f55edd618e75abbb03a85c0baa9838303e04 100644 (file)
--- a/main/rtp_engine.c
+++ b/main/rtp_engine.c
@@ -2289,7 +2289,9 @@ int ast_rtp_engine_unload_format(const struct ast_format *format)
                if (ast_format_cmp(&ast_rtp_mime_types[x].payload_type.format, format) == AST_FORMAT_CMP_EQUAL) {
                        continue;
                }
-               ast_rtp_mime_types[y] = ast_rtp_mime_types[x];
+               if (x != y) {
+                       ast_rtp_mime_types[y] = ast_rtp_mime_types[x];
+               }
                y++;
        }
        mime_types_len = y;