Constify struct filter access and introduce filter_get().

This modifies all users of the filter API to not access the filter
array directly. Instead all callers now obtain a const pointer to
the filter structure through the new filter_get() accessor function.

However, the filter array can not be made constant yet because the
->init methods modify the filter structure. This requires some casts
in filter_common.c unfortunately.

diff --git a/audiod.c b/audiod.c
index e5f9c6be513103334f8a9203e6fbb5079fece853..798142f39a348ec6f0ac74e689332d18a1318444 100644 (file)
--- a/audiod.c
+++ b/audiod.c
@@ -525,11 +525,11 @@ static void close_filters(struct slot_info *s)
                return;
        for (i = a->num_filters - 1; i >= 0; i--) {
                struct filter_node *fn = s->fns + i;
-               struct filter *f;
+               const struct filter *f;
 
                if (!fn)
                        continue;
-               f = filters + fn->filter_num;
+               f = filter_get(fn->filter_num);
                if (f->close)
                        f->close(fn);
                btr_remove_node(&fn->btrn);
@@ -588,7 +588,7 @@ static void open_filters(struct slot_info *s)
        parent = s->receiver_node->btrn;
        for (i = 0; i < nf; i++) {
                char buf[20];
-               struct filter *f = filters + a->filter_nums[i];
+               const struct filter *f = filter_get(a->filter_nums[i]);
                fn = s->fns + i;
                fn->filter_num = a->filter_nums[i];
                fn->conf = a->filter_conf[i];
@@ -858,7 +858,7 @@ static int add_filter(int format, char *cmdline)
        a->filter_conf[nf] = cfg;
        a->num_filters++;
        PARA_INFO_LOG("%s filter %d: %s\n", audio_formats[format], nf,
-               filters[filter_num].name);
+               filter_get(filter_num)->name);
        return filter_num;
 }
 
@@ -993,20 +993,20 @@ static int init_default_filters(void)
                }
                /* add "dec" to audio format name */
                tmp = make_message("%sdec", audio_formats[i]);
-               for (j = 0; filters[j].name; j++)
-                       if (!strcmp(tmp, filters[j].name))
+               for (j = 0; filter_get(j); j++)
+                       if (!strcmp(tmp, filter_get(j)->name))
                                break;
                free(tmp);
                ret = -E_UNSUPPORTED_FILTER;
-               if (!filters[j].name)
+               if (!filter_get(j))
                        goto out;
-               tmp = para_strdup(filters[j].name);
+               tmp = para_strdup(filter_get(j)->name);
                ret = add_filter(i, tmp);
                free(tmp);
                if (ret < 0)
                        goto out;
                PARA_INFO_LOG("%s -> default filter: %s\n", audio_formats[i],
-                       filters[j].name);
+                       filter_get(j)->name);
        }
 out:
        return ret;

diff --git a/filter.c b/filter.c
index f9ba17ad117ebe0da4a53a80a57dd5b21d49c5f8..1ba12689b45d7b41d3e2a8b1a8c06464114211a6 100644 (file)
--- a/filter.c
+++ b/filter.c
@@ -106,7 +106,7 @@ int main(int argc, char *argv[])
 {
        static struct sched s;
        int i, ret;
-       struct filter *f;
+       const struct filter *f;
        struct btr_node *parent;
        struct filter_node **fns;
 
@@ -133,7 +133,7 @@ int main(int argc, char *argv[])
                        goto out_cleanup;
                }
                fn->filter_num = ret;
-               f = filters + fn->filter_num;
+               f = filter_get(fn->filter_num);
                PARA_DEBUG_LOG("filter #%d: %s\n", i, f->name);
                fn->btrn = btr_new_node(&(struct btr_node_description)
                        EMBRACE(.name = f->name, .parent = parent,
@@ -159,7 +159,7 @@ out_cleanup:
        for (i--; i >= 0; i--) {
                struct filter_node *fn = fns[i];
 
-               f = filters + fn->filter_num;
+               f = filter_get(fn->filter_num);
                if (f->close)
                        f->close(fn);
                btr_remove_node(&fn->btrn);

diff --git a/filter.h b/filter.h
index ab312f5d8d27ecc5eea55b8b127087bc9e8ac73c..31eedcc044d5c1a022b8a6bb6bdd37be1c0eb116 100644 (file)
--- a/filter.h
+++ b/filter.h
@@ -141,4 +141,4 @@ static inline void write_int16_host_endian(char *buf, int val)
 DECLARE_FILTER_INITS
 
 /** The filter array, one structure for each supported filter. */
-extern struct filter filters[NUM_SUPPORTED_FILTERS];
+const struct filter *filter_get(int filter_num);

diff --git a/filter_common.c b/filter_common.c
index 53cde746001b6a42eb8e482addcd6231ad5560d5..099d056ef1514e2f606adf30d779308b58bead95 100644 (file)
--- a/filter_common.c
+++ b/filter_common.c
@@ -23,7 +23,14 @@
 #define FOR_EACH_SUPPORTED_FILTER(j)  for (j = 0; j < NUM_SUPPORTED_FILTERS; j++)
 
 /** The array of supported filters. */
-struct filter filters[NUM_SUPPORTED_FILTERS] = {FILTER_ARRAY};
+static struct filter filters[NUM_SUPPORTED_FILTERS] = {FILTER_ARRAY};
+
+const struct filter *filter_get(int filter_num)
+{
+       assert(filter_num >= 0);
+       assert(filter_num < NUM_SUPPORTED_FILTERS);
+       return filters + filter_num;
+}
 
 /**
  * Call the init function of each supported filter.
@@ -34,7 +41,7 @@ void filter_init(void)
        int i;
 
        FOR_EACH_SUPPORTED_FILTER(i)
-               filters[i].init(filters + i);
+               filter_get(i)->init((struct filter *)filter_get(i));
 }
 
 /*
@@ -43,7 +50,7 @@ void filter_init(void)
  */
 static int parse_filter_args(int filter_num, char *options, void **conf)
 {
-       struct filter *f = &filters[filter_num];
+       const struct filter *f = filter_get(filter_num);
        int ret, argc;
        char **argv;
 
@@ -83,7 +90,7 @@ int check_filter_arg(char *fa, void **conf)
        *conf = NULL;
 //     PARA_DEBUG_LOG("arg: %s\n", fa);
        FOR_EACH_SUPPORTED_FILTER(j) {
-               const char *name = filters[j].name;
+               const char *name = filter_get(j)->name;
                size_t len = strlen(name);
                char c;
                if (strlen(fa) < len)
@@ -93,7 +100,7 @@ int check_filter_arg(char *fa, void **conf)
                c = fa[len];
                if (c && c != ' ')
                        continue;
-               if (c && !filters[j].parse_config)
+               if (c && !filter_get(j)->parse_config)
                        return -E_BAD_FILTER_OPTIONS;
                return parse_filter_args(j, c? fa + len + 1 :
                        fa + strlen(fa), conf);
@@ -116,12 +123,12 @@ void print_filter_helps(unsigned flags)
                        printf_or_die("\n                  ");
                        num = 0;
                }
-               num += printf_or_die("%s%s", i? " " : "", filters[i].name);
+               num += printf_or_die("%s%s", i? " " : "", filter_get(i)->name);
        }
        printf_or_die("\n");
 
        FOR_EACH_SUPPORTED_FILTER(i) {
-               struct filter *f = filters + i;
+               struct filter *f = (struct filter *)filter_get(i);
 
                if (!f->help.short_help)
                        continue;

diff --git a/play.c b/play.c
index 23d184da551273595b127c45ffc041aba81f9565..6e6b91f93865dd3623592098c339a181be2dbb6d 100644 (file)
--- a/play.c
+++ b/play.c
@@ -263,7 +263,7 @@ static int get_playback_error(struct play_task *pt)
 static int eof_cleanup(struct play_task *pt)
 {
        struct writer *w = writers + DEFAULT_WRITER;
-       struct filter *decoder = filters + pt->fn.filter_num;
+       const struct filter *decoder = filter_get(pt->fn.filter_num);
        int ret;
 
        ret = get_playback_error(pt);
@@ -368,7 +368,7 @@ static int load_file(struct play_task *pt)
        const char *af;
        char *tmp, buf[20];
        int ret;
-       struct filter *decoder;
+       const struct filter *decoder;
 
        btr_remove_node(&pt->rn.btrn);
        if (!pt->rn.receiver || pt->next_file != pt->current_file) {
@@ -393,7 +393,7 @@ static int load_file(struct play_task *pt)
        if (ret < 0)
                goto fail;
        pt->fn.filter_num = ret;
-       decoder = filters + ret;
+       decoder = filter_get(ret);
        pt->fn.btrn = btr_new_node(&(struct btr_node_description)
                EMBRACE(.name = decoder->name, .parent = pt->rn.btrn,
                        .handler = decoder->execute, .context = &pt->fn));