compose: drop the 65535 node limit (#343)

In commit 1638409, the number of
compose nodes was limited to 65535 to enable "future optimizations",
which apparently means slightly reduced memory usage due to fitting in
a uint16_t. At this time, it was mentioned that the author was not
aware of "any compose files which come close".

However, I'm one of the users that actually do require a larger number
of nodes for their compose file. Thus, use a uint32_t again and raise
the limit significantly.

src/compose/parser.c

@@ -332,8 +332,8 @@ add_production(struct xkb_compose_table *table, struct scanner *s,
                const struct production *production)
 {
     unsigned lhs_pos = 0;
-    uint16_t curr = darray_size(table->nodes) == 1 ? 0 : 1;
-    uint16_t *pptr = NULL;
+    uint32_t curr = darray_size(table->nodes) == 1 ? 0 : 1;
+    uint32_t *pptr = NULL;
     struct compose_node *node = NULL;
 
     /* Warn before potentially going over the limit, discard silently after. */

src/compose/state.c

@@ -41,8 +41,8 @@ struct xkb_compose_state {
      * This is also sufficient for inferring the current status; see
      * xkb_compose_state_get_status().
      */
-    uint16_t prev_context;
-    uint16_t context;
+    uint32_t prev_context;
+    uint32_t context;
 };
 
 XKB_EXPORT struct xkb_compose_state *
@@ -91,7 +91,7 @@ xkb_compose_state_get_compose_table(struct xkb_compose_state *state)
 XKB_EXPORT enum xkb_compose_feed_result
 xkb_compose_state_feed(struct xkb_compose_state *state, xkb_keysym_t keysym)
 {
-    uint16_t context;
+    uint32_t context;
     const struct compose_node *node;
 
     /*

src/compose/table.h

@@ -75,16 +75,17 @@
  * \0 is so offset 0 points to an empty string).
  */
 
-/* Fits in uint16_t, also a good idea to have some limit. */
-#define MAX_COMPOSE_NODES 65535
+/* 7 nodes for every potential Unicode character and then some should be
+ * enough for all purposes. */
+#define MAX_COMPOSE_NODES (1 << 23)
 
 struct compose_node {
     xkb_keysym_t keysym;
 
     /* Offset into xkb_compose_table::nodes or 0. */
-    uint16_t lokid;
+    uint32_t lokid;
     /* Offset into xkb_compose_table::nodes or 0. */
-    uint16_t hikid;
+    uint32_t hikid;
 
     union {
         struct {
@@ -95,7 +96,7 @@ struct compose_node {
             uint32_t _pad:31;
             bool is_leaf:1;
             /* Offset into xkb_compose_table::nodes or 0. */
-            uint16_t eqkid;
+            uint32_t eqkid;
         } internal;
         struct {
             /* Offset into xkb_compose_table::utf8. */