audio: allow more than 20 channel map entries

This could trigger an assertion when using ao_alsa or ao_coreaudio. The
code was simply assuming the number of channel maps was bounded
statically (which was true at first in both AOs).

Fix by using dynamic memory allocation. It needs to be explicitly
enabled by the AOs by setting a temp context, because otherwise the
memory couldn't be freed. (Or at least this seems to be the most elegant
solution.)

Fixes #1306.

1 files changed, 12 insertions, 5 deletions

diff --git a/audio/chmap_sel.c b/audio/chmap_sel.c
index 160f1ce5fa..8e591aea44 100644
--- a/audio/chmap_sel.c
+++ b/audio/chmap_sel.c
@@ -81,14 +81,21 @@ void mp_chmap_sel_add_alsa_def(struct mp_chmap_sel *s)
     }
 }
 
-#define ARRAY_LEN(x) (sizeof(x) / sizeof((x)[0]))
-
 // Add a channel map that should be allowed.
 void mp_chmap_sel_add_map(struct mp_chmap_sel *s, const struct mp_chmap *map)
 {
-    assert(s->num_chmaps < ARRAY_LEN(s->chmaps));
-    if (mp_chmap_is_valid(map))
-        s->chmaps[s->num_chmaps++] = *map;
+    if (!mp_chmap_is_valid(map))
+        return;
+    if (!s->chmaps)
+        s->chmaps = s->chmaps_storage;
+    if (s->num_chmaps == MP_ARRAY_SIZE(s->chmaps)) {
+        if (!s->tmp)
+            return;
+        s->chmaps = talloc_memdup(s->tmp, s->chmaps, sizeof(s->chmaps_storage));
+    }
+    if (s->chmaps != s->chmaps_storage)
+        MP_TARRAY_GROW(s->tmp, s->chmaps, s->num_chmaps);
+    s->chmaps[s->num_chmaps++] = *map;
 }
 
 // Allow all waveext formats in default order.