api: add function "asprintf"

src/core/core-string.c

@@ -70,6 +70,61 @@ int string_concat_index = 0;
 char **string_concat_buffer[STRING_NUM_CONCAT_BUFFERS];
 
 
+/*
+ * Formats a message in a string allocated by the function.
+ *
+ * This function is defined for systems where the GNU function `asprintf()`
+ * is not available.
+ * The behavior is almost the same except that `*result` is set to NULL on error.
+ *
+ * Returns the number of bytes in the resulting string, negative value in case
+ * of error.
+ *
+ * Value of `*result` is allocated with the result string (NULL if error),
+ * it must be freed after use.
+ */
+
+int
+string_asprintf (char **result, const char *fmt, ...)
+{
+    va_list argptr;
+    int num_bytes;
+    size_t size;
+
+    if (!result)
+        return -1;
+
+    *result = NULL;
+
+    if (!fmt)
+        return -1;
+
+    /* determine required size */
+    va_start (argptr, fmt);
+    num_bytes = vsnprintf (NULL, 0, fmt, argptr);
+    va_end (argptr);
+
+    if (num_bytes < 0)
+        return num_bytes;
+
+    size = (size_t)num_bytes + 1;
+    *result = malloc (size);
+    if (!*result)
+        return -1;
+
+    va_start (argptr, fmt);
+    num_bytes = vsnprintf (*result, size, fmt, argptr);
+    va_end (argptr);
+
+    if (num_bytes < 0)
+    {
+        free (*result);
+        *result = NULL;
+    }
+
+    return num_bytes;
+}
+
 /*
  * Defines a "strndup" function for systems where this function does not exist
  * (FreeBSD and maybe others).

src/core/core-string.h

@@ -39,6 +39,7 @@ struct t_string_dyn
 
 struct t_hashtable;
 
+extern int string_asprintf (char **result, const char *fmt, ...);
 extern char *string_strndup (const char *string, int bytes);
 extern char *string_cut (const char *string, int length, int count_suffix,
                          int screen, const char *cut_suffix);

src/plugins/plugin.c

@@ -608,6 +608,7 @@ plugin_load (const char *filename, int init_plugin, int argc, char **argv)
         new_plugin->iconv_from_internal = &string_iconv_from_internal;
         new_plugin->gettext = &plugin_api_gettext;
         new_plugin->ngettext = &plugin_api_ngettext;
+        new_plugin->asprintf = &string_asprintf;
         new_plugin->strndup = &string_strndup;
         new_plugin->string_cut = &string_cut;
         new_plugin->string_tolower = &string_tolower;

src/plugins/weechat-plugin.h

@@ -73,7 +73,7 @@ struct t_weelist_item;
  * please change the date with current one; for a second change at same
  * date, increment the 01, otherwise please keep 01.
  */
-#define WEECHAT_PLUGIN_API_VERSION "20240307-01"
+#define WEECHAT_PLUGIN_API_VERSION "20240402-01"
 
 /* macros for defining plugin infos */
 #define WEECHAT_PLUGIN_NAME(__name)                                     \
@@ -316,6 +316,7 @@ struct t_weechat_plugin
     char *(*iconv_from_internal) (const char *charset, const char *string);
     const char *(*gettext) (const char *string);
     const char *(*ngettext) (const char *single, const char *plural, int count);
+    int (*asprintf) (char **result, const char *fmt, ...);
     char *(*strndup) (const char *string, int bytes);
     char *(*string_cut) (const char *string, int length, int count_suffix,
                          int screen, const char *cut_suffix);
@@ -1290,7 +1291,9 @@ extern int weechat_plugin_end (struct t_weechat_plugin *plugin);
 #define weechat_gettext(string) (weechat_plugin->gettext)(string)
 #define weechat_ngettext(single,plural,number)                          \
     (weechat_plugin->ngettext)(single, plural, number)
-#define weechat_strndup(__string, __bytes)                              \
+#define weechat_asprintf(__result, __fmt, __argz...)                    \
+    (weechat_plugin->asprintf)(__result, __fmt, ##__argz)
+#define weechat_strndup(__string, __bytes)              \
     (weechat_plugin->strndup)(__string, __bytes)
 #define weechat_string_cut(__string, __length, __count_suffix,          \
                            __screen, __cut_suffix)                      \