From c47b0765a8605b9afcc6205a6d2396ccbe3d5e05 Mon Sep 17 00:00:00 2001
From: cbdev <cb@cbcdn.com>
Date: Sun, 4 Jun 2017 22:49:27 +0200
Subject: Implement channel mapping

---
 backend.c     | 42 ++++++++++++++++++++++++++++++++++++++++++
 backend.h     |  1 +
 config.c      | 59 +++++++++++++++++++++++++++++++++++++++++++++++++++++------
 midimonster.c | 43 +++++++++++++++++++++++++++++++++++++++++++
 midimonster.h | 41 +++++++++++++++++++++++++++++++++++++++++
 monster.cfg   |  4 ++--
 6 files changed, 182 insertions(+), 8 deletions(-)

diff --git a/backend.c b/backend.c
index 1d728d1..65ee748 100644
--- a/backend.c
+++ b/backend.c
@@ -6,6 +6,35 @@ static size_t nbackends = 0;
 static backend* backends = NULL;
 static size_t ninstances = 0;
 static instance** instances = NULL;
+static size_t nchannels = 0;
+static channel** channels = NULL;
+
+channel* mm_channel(instance* i, uint64_t ident){
+	size_t u;
+	for(u = 0; u < nchannels; u++){
+		if(channels[u]->instance == 0 && channels[u]->ident == ident){
+			return channels[u];
+		}
+	}
+
+	channel** new_chan = realloc(channels, (nchannels + 1) * sizeof(channel*));
+	if(!new_chan){
+		fprintf(stderr, "Failed to allocate memory\n");
+		nchannels = 0;
+		return NULL;
+	}
+
+	channels = new_chan;
+	channels[nchannels] = calloc(1, sizeof(channel));
+	if(!channels[nchannels]){
+		fprintf(stderr, "Failed to allocate memory\n");
+		return NULL;
+	}
+
+	channels[nchannels]->instance = i;
+	channels[nchannels]->ident = ident;
+	return channels[nchannels++];
+}
 
 instance* mm_instance(){
 	instance** new_inst = realloc(instances, (ninstances + 1) * sizeof(instance*));
@@ -65,6 +94,19 @@ void instances_free(){
 	ninstances = 0;
 }
 
+void channels_free(){
+	size_t u;
+	for(u = 0; u < nchannels; u++){
+		if(channels[u]->impl){
+			channels[u]->instance->backend->channel_free(channels[u]);
+		}
+		free(channels[u]);
+		channels[u] = NULL;
+	}
+	free(channels);
+	nchannels = 0;
+}
+
 backend* backend_match(char* name){
 	size_t u;
 	for(u = 0; u < nbackends; u++){
diff --git a/backend.h b/backend.h
index 65ca97e..e1ad4ab 100644
--- a/backend.h
+++ b/backend.h
@@ -3,3 +3,4 @@ instance* instance_match(char* name);
 int backends_start();
 int backends_stop();
 void instances_free();
+void channels_free();
diff --git a/config.c b/config.c
index f425fe4..d3605e2 100644
--- a/config.c
+++ b/config.c
@@ -4,15 +4,15 @@
 #include "config.h"
 #include "backend.h"
 
-enum {
+static enum {
 	none,
 	backend_cfg,
 	instance_cfg,
 	map
 } parser_state = none;
 
-backend* current_backend = NULL;
-instance* current_instance = NULL;
+static backend* current_backend = NULL;
+static instance* current_instance = NULL;
 
 static char* config_trim_line(char* in){
 	ssize_t u;
@@ -28,6 +28,48 @@ static char* config_trim_line(char* in){
 	return in;
 }
 
+static int config_map(char* to, char* from){
+	char* chanspec_to = to, *chanspec_from = from;
+	instance* instance_to = NULL, *instance_from = NULL;
+	channel* channel_from = NULL, *channel_to = NULL;
+
+	//separate channel spec from instance
+	for(; *chanspec_to && *chanspec_to != '.'; chanspec_to++){
+	}
+
+	for(; *chanspec_from && *chanspec_from != '.'; chanspec_from++){
+	}
+
+	if(!*chanspec_to || !*chanspec_from){
+		fprintf(stderr, "Mapping does not contain a proper instance specification\n");
+		return 1;
+	}
+
+	//terminate
+	*chanspec_to = *chanspec_from = 0;
+	chanspec_to++;
+	chanspec_from++;
+
+	//find matching instances
+	instance_to = instance_match(to);
+	instance_from = instance_match(from);
+
+	if(!instance_to || !instance_from){
+		fprintf(stderr, "No such instance %s\n", instance_from ? to : from);
+		return 1;
+	}
+
+	channel_from = instance_from->backend->channel(instance_from, chanspec_from);
+	channel_to = instance_to->backend->channel(instance_to, chanspec_to);
+
+	if(!channel_from || !channel_to){
+		fprintf(stderr, "Failed to parse channel specifications\n");
+		return 1;
+	}
+
+	return mm_map_channel(channel_from, channel_to);
+}
+
 int config_read(char* cfg_file){
 	int rv = 1;
 	size_t line_alloc = 0;
@@ -114,17 +156,22 @@ int config_read(char* cfg_file){
 
 			*separator = 0;
 			separator++;
+			line = config_trim_line(line);
+			separator = config_trim_line(separator);
 
-			if(parser_state == backend_cfg && current_backend->conf(config_trim_line(line), config_trim_line(separator))){
+			if(parser_state == backend_cfg && current_backend->conf(line, separator)){
 				fprintf(stderr, "Failed to configure backend %s\n", current_backend->name);
 				goto bail;
 			}
-			else if(parser_state == instance_cfg && current_backend->conf_instance(current_instance, config_trim_line(line), config_trim_line(separator))){
+			else if(parser_state == instance_cfg && current_backend->conf_instance(current_instance, line, separator)){
 				fprintf(stderr, "Failed to configure instance %s\n", current_instance->name);
 				goto bail;
 			}
 			else if(parser_state == map){
-				//TODO map two channels
+				if(config_map(line, separator)){
+					fprintf(stderr, "Failed to map channel\n");
+					goto bail;
+				}
 			}
 		}
 	}
diff --git a/midimonster.c b/midimonster.c
index e59b7f9..aeaf04d 100644
--- a/midimonster.c
+++ b/midimonster.c
@@ -8,6 +8,48 @@ int artnet_init();
 int midi_init();
 int osc_init();
 
+static size_t mappings = 0;
+static channel_mapping* map = NULL;
+
+int mm_map_channel(channel* from, channel* to){
+	size_t u, m;
+	//find existing source mapping
+	for(u = 0; u < mappings; u++){
+		if(map[u].from == from){
+			break;
+		}
+	}
+
+	//create new entry
+	if(u == mappings){
+		map = realloc(map, (mappings + 1) * sizeof(channel_mapping));
+		if(!map){
+			fprintf(stderr, "Failed to allocate memory\n");
+			return 1;
+		}
+		memset(map + mappings, 0, sizeof(channel_mapping));
+		mappings++;
+	}
+
+	//check whether the target is already mapped
+	for(m = 0; m < map[u].destinations; m++){
+		if(map[u].to[m] == to){
+			return 0;
+		}
+	}
+
+	map[u].to = realloc(map[u].to, (map[u].destinations + 1) * sizeof(channel*));
+	if(!map[u].to){
+		fprintf(stderr, "Failed to allocate memory\n");
+		map[u].destinations = 0;
+		return 1;
+	}
+
+	map[u].to[map[u].destinations] = to;
+	map[u].destinations++;
+	return 0;
+}
+
 int usage(char* fn){
 	fprintf(stderr, "MIDIMonster v0.1\n");
 	fprintf(stderr, "Usage:\n");
@@ -49,6 +91,7 @@ int main(int argc, char** argv){
 bail:
 	//free all data
 	backends_stop();
+	channels_free();
 	instances_free();
 
 	return rv;
diff --git a/midimonster.h b/midimonster.h
index 9026222..b2af7a3 100644
--- a/midimonster.h
+++ b/midimonster.h
@@ -13,6 +13,7 @@ struct _backend_instance;
 typedef int (*mmbackend_handle_event)(size_t channels, struct _backend_channel* c, struct _channel_value* v);
 typedef struct _backend_instance* (*mmbackend_create_instance)();
 typedef struct _backend_channel* (*mmbackend_parse_channel)(struct _backend_instance* instance, char* spec);
+typedef void (*mmbackend_free_channel)(struct _backend_channel* c);
 typedef int (*mmbackend_configure)(char* option, char* value);
 typedef int (*mmbackend_configure_instance)(struct _backend_instance* instance, char* option, char* value);
 typedef int (*mmbackend_process_fd)(size_t fds, int* fd, void** impl);
@@ -36,6 +37,7 @@ typedef struct /*_mm_backend*/ {
 	mmbackend_process_fd process;
 	mmbackend_start start;
 	mmbackend_shutdown shutdown;
+	mmbackend_free_channel channel_free;
 } backend;
 
 typedef struct _backend_instance {
@@ -58,9 +60,48 @@ typedef struct /*_mm_managed_fd*/ {
 	void* impl;
 } managed_fd;
 
+typedef struct /*_mm_channel_mapping*/ {
+	channel* from;
+	size_t destinations;
+	channel** to;
+} channel_mapping;
+
+/*
+ * Register a new backend.
+ */
 int mm_backend_register(backend b);
+
+/*
+ * Provides a pointer to a newly (zero-)allocated instance.
+ * All instance pointers need to be allocated via this API
+ * in order to be assignable from the configuration parser.
+ * This API should be called from the mmbackend_create_instance
+ * call of your backend.
+ *
+ * Instances returned from this call are freed by midimonster.
+ * The contents of the impl members should be freed in the
+ * mmbackend_shutdown procedure of the backend, eg. by querying
+ * all instances for the backend.
+ */
 instance* mm_instance();
+/*
+ * Provides a pointer to a channel structure, pre-filled with
+ * the provided instance reference and identifier.
+ * Will return previous allocations if the provided fields
+ * match.
+ * This API is just a convenience function. The array
+ * of channels is only used for mapping internally,
+ * creating and managing your own channel store is
+ * possible.
+ * For each channel with a non-NULL impl field, the backend
+ * will receive a call to its channel_free function.
+ */
+channel* mm_channel(instance* i, uint64_t ident);
 int mm_manage_fd(int fd, char* backend, int manage, void* impl);
 int mm_channel_event(channel* c, channel_value v);
+/*
+ * Query all active instances for a given backend.
+ */
 int mm_backend_instances(char* backend, size_t* n, instance*** i);
+int mm_map_channel(channel* from, channel* to);
 #endif
diff --git a/monster.cfg b/monster.cfg
index 4bb7bd2..b638e56 100644
--- a/monster.cfg
+++ b/monster.cfg
@@ -28,5 +28,5 @@ output = true
 net = 0
 
 [map]
-artnet.231 = lc1.cc5
-artent.231 = osc.f/channel5/ toggle=127
+net1.231 = lc1.cc5
+;net1.231 = osc.f/channel5/ toggle=127
-- 
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