From 5bd544a6cb88b10d477dd24b956bc7ceddeb706b Mon Sep 17 00:00:00 2001
From: Joseph Hunkeler <jhunkeler@gmail.com>
Date: Thu, 5 Mar 2026 16:11:30 -0500
Subject: Add strlist_appendf function (future use)

---
 src/lib/core/include/strlist.h |  1 +
 src/lib/core/strlist.c         | 22 ++++++++++++++++++++++
 tests/test_strlist.c           | 15 +++++++++++++++
 3 files changed, 38 insertions(+)

diff --git a/src/lib/core/include/strlist.h b/src/lib/core/include/strlist.h
index 18c60eb..1aaae3e 100644
--- a/src/lib/core/include/strlist.h
+++ b/src/lib/core/include/strlist.h
@@ -46,6 +46,7 @@ void strlist_append_strlist(struct StrList *pStrList1, struct StrList *pStrList2
 void strlist_append(struct StrList **pStrList, char *str);
 void strlist_append_array(struct StrList *pStrList, char **arr);
 void strlist_append_tokenize(struct StrList *pStrList, char *str, char *delim);
+int strlist_appendf(struct StrList **pStrList, const char *fmt, ...);
 struct StrList *strlist_copy(struct StrList *pStrList);
 int strlist_cmp(struct StrList *a, struct StrList *b);
 void strlist_free(struct StrList **pStrList);
diff --git a/src/lib/core/strlist.c b/src/lib/core/strlist.c
index b742d37..3479c44 100644
--- a/src/lib/core/strlist.c
+++ b/src/lib/core/strlist.c
@@ -229,6 +229,28 @@ void strlist_append_strlist(struct StrList *pStrList1, struct StrList *pStrList2
     guard_free(tmp);
  }
 
+/**
+ * Append a formatted string
+ * Behavior is identical to asprintf-family of functions
+ * @param pStrList `StrList`
+ * @param fmt printf format string
+ * @param ... format arguments
+ * @return same as vasnprintf
+ */
+int strlist_appendf(struct StrList **pStrList, const char *fmt, ...) {
+    char *s = NULL;
+    va_list ap;
+    va_start(ap, fmt);
+    const int len = vasprintf(&s, fmt, ap);
+    va_end(ap);
+
+    if (pStrList && *pStrList && len >= 0) {
+        strlist_append(pStrList, s);
+    }
+    guard_free(s);
+    return len;
+}
+
 /**
  * Produce a new copy of a `StrList`
  * @param pStrList  `StrList`
diff --git a/tests/test_strlist.c b/tests/test_strlist.c
index 47722c0..38343f4 100644
--- a/tests/test_strlist.c
+++ b/tests/test_strlist.c
@@ -200,6 +200,20 @@ void test_strlist_append_tokenize() {
     guard_strlist_free(&list);
 }
 
+void test_strlist_appendf() {
+    const char *fmt = "%c %s %d";
+    struct StrList *list;
+    list = strlist_init();
+    const int len = strlist_appendf(NULL, fmt, 'a', "abc", strlen(fmt));
+    STASIS_ASSERT(strlist_appendf(&list, fmt, 'a', "abc", strlen(fmt)) == len, "length of formatted string should be 7");
+    const char *item = strlist_item(list, 0);
+    STASIS_ASSERT(item != NULL, "valid pointer expected, item should not be NULL");
+    STASIS_ASSERT(strncmp(item, "a", 1) == 0, "first character should be 'a'");
+    STASIS_ASSERT(strncmp(item + 2, "abc", 3) == 0, "string should be 'abc'");
+    STASIS_ASSERT(strncmp(item + 6, "8", 1) == 0, "length of the raw format should be 8");
+    guard_strlist_free(&list);
+}
+
 void test_strlist_copy() {
     struct StrList *list = strlist_init();
     struct StrList *list_copy;
@@ -628,6 +642,7 @@ void test_strlist_item_as_long_double() {
 int main(int argc, char *argv[]) {
     STASIS_TEST_BEGIN_MAIN();
     STASIS_TEST_FUNC *tests[] = {
+        test_strlist_appendf,
         test_strlist_init,
         test_strlist_free,
         test_strlist_append,
-- 
cgit