bitcoin/chainparams: add an utility to retrieve chainparams for all networks

bitcoin/chainparams.c

@@ -1,6 +1,7 @@
 #include "chainparams.h"
 #include <ccan/array_size/array_size.h>
 #include <ccan/str/str.h>
+#include <common/utils.h>
 #include <string.h>
 
 /* Version codes for BIP32 extended keys in libwally-core.
@@ -220,6 +221,14 @@ const struct chainparams *chainparams_for_network(const char *network_name)
 	return NULL;
 }
 
+const struct chainparams **chainparams_for_networks(const tal_t *ctx)
+{
+	const struct chainparams **params = tal_arr(ctx, const struct chainparams*, 0);
+	for (size_t i = 0; i < ARRAY_SIZE(networks); i++)
+		tal_arr_expand(&params, &networks[i]);
+	return params;
+}
+
 const struct chainparams *chainparams_by_chainhash(const struct bitcoin_blkid *chain_hash)
 {
 	for (size_t i = 0; i < ARRAY_SIZE(networks); i++) {

bitcoin/chainparams.h

@@ -46,6 +46,12 @@ struct chainparams {
  */
 const struct chainparams *chainparams_for_network(const char *network_name);
 
+/**
+ * chainparams_for_networks - Get blockchain parameters for all known networks,
+ *                            as a tal array.
+ */
+const struct chainparams **chainparams_for_networks(const tal_t *ctx);
+
 /**
  * chainparams_by_bip173 - Helper to get a network by its bip173 name
  *