From 2345d1123fa48420bcbb68fa17b975adcc68b450 Mon Sep 17 00:00:00 2001
From: Don McCaughey <don@donm.cc>
Date: Thu, 8 Feb 2024 11:10:50 -0800
Subject: [PATCH] Extract common `from_ip_and_port_str()` function.

Remove duplication between `sa_from_ipv4_and_port_str()` and
`sa_from_ipv6_and_port_str()`.

Add `copy_str()` function to encapsulate string copying details.
---
 TODO.md |  5 +++++
 sa.c    | 67 ++++++++++++++++++++++++++++++++-------------------------
 2 files changed, 43 insertions(+), 29 deletions(-)
 create mode 100644 TODO.md

diff --git a/TODO.md b/TODO.md
new file mode 100644
index 0000000..9bf05d2
--- /dev/null
+++ b/TODO.md
@@ -0,0 +1,5 @@
+# To Do
+
+- consistently use str "len" (nul not included) and "size" (nul included)
+- add aliases for INET_ADDRSTRLEN and INET6_ADDRSTRLEN which include nul
+- consistent convention for string containing a port vs string without a port
diff --git a/sa.c b/sa.c
index 34ea8a6..653d8fc 100644
--- a/sa.c
+++ b/sa.c
@@ -10,29 +10,38 @@
 
 
 static bool
-split_ip_and_port_str(
+copy_str(char *destination, size_t destination_size, char const *source_begin, char const *source_end)
+{
+    size_t source_len = source_end - source_begin;
+    if (source_len >= destination_size) return false;
+
+    strncpy(destination, source_begin, source_len);
+    destination[source_len] = '\0';
+    return true;
+}
+
+
+typedef bool from_ip_str_and_port_fn(union sa *, char const *, in_port_t);
+
+
+static bool
+from_ip_and_port_str(
+        union sa *address,
         char const *ip_and_port_str,
-        char *ip_str,
-        size_t ip_str_size,
-        in_port_t *port
+        size_t ip_str_max_len,
+        from_ip_str_and_port_fn from_ip_str_and_port
 ) {
-    if (!ip_and_port_str) return false;
-    if (ip_str_size != INET_ADDRSTRLEN && ip_str_size != INET6_ADDRSTRLEN) {
-        return false;
-    }
-    if (!ip_str) return false;
-    if (!port) return false;
+    // TODO: check arguments
 
-    char const *colon;
-    if (!sa_find_port_in_str(ip_and_port_str, port, &colon)) return false;
+    char const *ip_str_end;
+    in_port_t port;
+    if (!sa_find_port_in_str(ip_and_port_str, &port, &ip_str_end)) return false;
 
-    size_t ip_len = colon - ip_and_port_str;
-    if (ip_len >= ip_str_size) return false;
+    char ip_str[ip_str_max_len];
+    if (!copy_str(ip_str, sizeof ip_str, ip_and_port_str, ip_str_end)) return false;
 
-    strncpy(ip_str, ip_and_port_str, ip_len);
-    ip_str[ip_len] = '\0';
+    return from_ip_str_and_port(address, ip_str, port);
 
-    return true;
 }
 
 
@@ -142,24 +151,24 @@ sa_from_path(union sa *address, char const *path)
 bool
 sa_from_ipv4_and_port_str(union sa *address, char const *ipv4_and_port_str)
 {
-    char ip[INET_ADDRSTRLEN];
-    in_port_t port;
-    if (!split_ip_and_port_str(ipv4_and_port_str, ip, INET_ADDRSTRLEN, &port)) {
-        return false;
-    }
-    return sa_from_ipv4_str_and_port(address, ip, port);
+    return from_ip_and_port_str(
+            address,
+            ipv4_and_port_str,
+            INET_ADDRSTRLEN,
+            sa_from_ipv4_str_and_port
+    );
 }
 
 
 bool
 sa_from_ipv6_and_port_str(union sa *address, char const *ipv6_and_port_str)
 {
-    char ip[INET6_ADDRSTRLEN];
-    in_port_t port;
-    if (!split_ip_and_port_str(ipv6_and_port_str, ip, INET6_ADDRSTRLEN, &port)) {
-        return false;
-    }
-    return sa_from_ipv6_str_and_port(address, ip, port);
+    return from_ip_and_port_str(
+            address,
+            ipv6_and_port_str,
+            INET6_ADDRSTRLEN,
+            sa_from_ipv6_str_and_port
+    );
 }
 
 
-- 
2.45.2