devtools/decodemsg: decode encoded_short_ids.

$ devtools/decodemsg 010806226e46111a0b59caaf126043eb5bbf28c34f3a5e332a1fc7b2b73cf188910f000000000000ffff0100160178da6360486760606400824c285d00a60111710144
$ devtools/decodemsg 010506226e46111a0b59caaf126043eb5bbf28c34f3a5e332a1fc7b2b73cf188910f00110000006700000100000000690000010000

Before:
    WIRE_REPLY_CHANNEL_RANGE:
    chain_hash=0f9188f13cb7b2c71f2a335e3a4fc328bf5beb436012afca590b1a11466e2206
    first_blocknum=0
    number_of_blocks=65535
    complete=1
    encoded_short_ids=[0178da6360486760606400824c285d00a60111710144]
    WIRE_QUERY_SHORT_CHANNEL_IDS:
    chain_hash=0f9188f13cb7b2c71f2a335e3a4fc328bf5beb436012afca590b1a11466e2206
    encoded_short_ids=[0000006700000100000000690000010000]

After:

    WIRE_REPLY_CHANNEL_RANGE:
    chain_hash=0f9188f13cb7b2c71f2a335e3a4fc328bf5beb436012afca590b1a11466e2206
    first_blocknum=0
    number_of_blocks=65535
    complete=1
    encoded_short_ids=[ (ZLIB) 103:1:0 105:1:0 112:1:0 ]
    WIRE_QUERY_SHORT_CHANNEL_IDS:
    chain_hash=0f9188f13cb7b2c71f2a335e3a4fc328bf5beb436012afca590b1a11466e2206
    encoded_short_ids=[ (UNCOMPRESSED) 103:1:0 105:1:0 ]

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

devtools/Makefile

@@ -8,6 +8,7 @@ DEVTOOLS_COMMON_OBJS :=				\
 	common/bech32.o				\
 	common/bech32_util.o			\
 	common/bolt11.o				\
+	common/decode_short_channel_ids.o	\
 	common/hash_u5.o			\
 	common/type_to_string.o			\
 	common/utils.o				\

devtools/decodemsg.c

@@ -1,4 +1,5 @@
 #include <ccan/err/err.h>
+#include <common/decode_short_channel_ids.h>
 #include <common/utils.h>
 #include <devtools/gen_print_wire.h>
 #include <stdio.h>

devtools/print_wire.c

@@ -1,5 +1,6 @@
 #include <ccan/mem/mem.h>
 #include <ccan/utf8/utf8.h>
+#include <common/decode_short_channel_ids.h>
 #include <common/type_to_string.h>
 #include <devtools/print_wire.h>
 #include <errno.h>
@@ -100,6 +101,46 @@ static void printwire_addresses(const u8 **cursor, size_t *plen, size_t len)
 	printf(" ]\n");
 }
 
+static void printwire_encoded_short_ids(const u8 **cursor, size_t *plen, size_t len)
+{
+	struct short_channel_id *scids;
+	u8 *arr = tal_arr(tmpctx, u8, len);
+
+	fromwire_u8_array(cursor, plen, arr, len);
+	if (!*cursor)
+		return;
+
+	printf("[");
+	scids = decode_short_ids(tmpctx, arr);
+	if (scids) {
+		switch (arr[0]) {
+		case SHORTIDS_UNCOMPRESSED:
+			printf(" (UNCOMPRESSED)");
+			break;
+		case SHORTIDS_ZLIB:
+			printf(" (ZLIB)");
+			break;
+		default:
+			abort();
+		}
+		for (size_t i = 0; i < tal_count(scids); i++)
+			printf(" %s",
+			       short_channel_id_to_str(tmpctx, &scids[i]));
+	} else {
+		/* If it was unknown, that's different from corrupt */
+		if (len == 0
+		    || arr[0] == SHORTIDS_UNCOMPRESSED
+		    || arr[0] == SHORTIDS_ZLIB) {
+			printf(" **CORRUPT**");
+			return;
+		} else {
+			printf(" UNKNOWN:");
+			print_hexstring(cursor, plen, len);
+		}
+	}
+	printf(" ]\n");
+}
+
 void printwire_u8_array(const char *fieldname, const u8 **cursor, size_t *plen, size_t len)
 {
 	if (streq(fieldname, "node_announcement.alias")) {
@@ -110,6 +151,10 @@ void printwire_u8_array(const char *fieldname, const u8 **cursor, size_t *plen,
 		printwire_addresses(cursor, plen, len);
 		return;
 	}
+	if (strends(fieldname, ".encoded_short_ids")) {
+		printwire_encoded_short_ids(cursor, plen, len);
+		return;
+	}
 
 	printf("[");
 	if (!print_hexstring(cursor, plen, len))