mx_util: Add mx_strconcat()

mx_util.c

@@ -856,6 +856,47 @@ int mx_strscan_ll(char **str, long long int *to)
     return res;
 }
 
+char *_mx_strconcat_do(char *first, ...)
+{
+    va_list ap;
+    char *join = NULL;
+    char *str;
+    char *ptr;
+    size_t len;
+
+    if (!first) {
+        join = strdup("");
+        return join;
+    }
+
+    len = strlen(first);
+
+    va_start(ap, first);
+        do {
+            str = va_arg(ap, char *);
+            if (!str)
+                break;
+            len += strlen(str);
+        } while(1);
+    va_end(ap);
+
+    join = malloc(len+1);
+    if (!join)
+        return NULL;
+
+    ptr = stpcpy(join, first);
+    va_start(ap, first);
+        do {
+            str = va_arg(ap, char *);
+            if (!str)
+                break;
+            ptr = stpcpy(ptr, str);
+        } while(1);
+    va_end(ap);
+
+    return join;
+}
+
 int mx_sleep(unsigned int seconds)
 {
     if (seconds)

mx_util.h

@@ -136,6 +136,9 @@ int mx_read_first_line_from_file(char *fname, char **line);
 int mx_strscan_ull(char **str, unsigned long long int *to);
 int mx_strscan_ll(char **str, long long int *to);
 
+char *_mx_strconcat_do(char *first, ...);
+#define mx_strconcat(s, ...) _mx_strconcat_do((s), ##__VA_ARGS__, NULL)
+
 int mx_sleep(unsigned int seconds);
 int mx_sleep_nofail(unsigned int seconds);
 

test_mx_util.c

@@ -384,6 +384,27 @@ static void test_mx_strvec() {
     mx_strvec_free(strvec);
 }
 
+static void test_mx_strcat() {
+    char *str;
+    char *str2;
+
+    assert(str = mx_strconcat(NULL));
+    assert(mx_streq(str, ""));
+    mx_free_null(str);
+
+    assert(str = mx_strconcat("abc", "123"));
+    assert(mx_streq(str, "abc123"));
+
+    assert(str2 = mx_strconcat(str, "def", str, "456"));
+    assert(mx_streq(str2, "abc123defabc123456"));
+    mx_free_null(str2);
+
+    assert(str2 = mx_strconcat(str));
+    assert(mx_streq(str, str2));
+    mx_free_null(str);
+    mx_free_null(str2);
+}
+
 static void test_mx_cpuset(void)
 {
     cpu_set_t cpuset;
@@ -421,6 +442,7 @@ int main(int argc, char *argv[])
     test_mx_read_first_line_from_file();
     test_mx_strscan();
     test_mx_strvec();
+    test_mx_strcat();
     test_mx_cpuset();
     return 0;
 }