eina: add functions to alloc strings from a printf fmt

src/lib/eina/eina_str.c

@@ -652,3 +652,44 @@ eina_str_toupper(char **str)
    for (p = *str; (*p); p++)
       *p = toupper((unsigned char)(*p));
 }
+
+EAPI size_t
+eina_str_vprintf_length(const char *format, va_list args)
+{
+    char c;
+    size_t len;
+
+    len = vsnprintf(&c, 1, format, args) + 1;
+    return len;
+}
+
+EAPI char *
+eina_str_vprintf_dup(const char *format, va_list args)
+{
+    size_t length;
+    char *ret;
+    va_list copy;
+
+    /* be sure to use a copy or the printf implementation will
+     * step into the args
+     */
+    va_copy(copy, args);
+    length = eina_str_vprintf_length(format, copy);
+    va_end(copy);
+
+    ret = calloc(length, sizeof(char));
+    vsprintf(ret, format, args);
+    return ret;
+}
+
+EAPI char *
+eina_str_printf_dup(const char *format, ...)
+{
+    char *ret;
+    va_list args;
+
+    va_start(args, format);
+    ret = eina_str_vprintf_dup(format, args);
+    va_end(args);
+    return ret;
+}

src/lib/eina/eina_str.h

@@ -345,6 +345,39 @@ static inline size_t eina_str_join(char *dst, size_t size, char sep, const char
 
 static inline size_t eina_strlen_bounded(const char *str, size_t maxlen) EINA_PURE EINA_WARN_UNUSED_RESULT EINA_ARG_NONNULL(1);
 
+/**
+ * @brief Gets the length needed for a string based on a printf format and args
+ * 
+ * @param format The printf format
+ * @param args The printf args
+ * @return The length needed for such format and args
+ * @since 1.7.9
+ */
+EAPI size_t eina_str_vprintf_length(const char *format, va_list args);
+
+/**
+ * @brief Gets a newly allocated string that represents the printf format and args
+ *
+ * @param format The printf format
+ * @param args The printf args
+ * @return A newly allocated string
+ *
+ * @see eina_str_dup_printf
+ * @since 1.7.9
+ */
+EAPI char * eina_str_vprintf_dup(const char *format, va_list args);
+
+/**
+ * @brief Gets a newly allocated string that represents the printf format and args
+ *
+ * @param format The printf format
+ * @return A newly allocated string
+ *
+ * @see eina_str_dup_vprintf
+ * @since 1.7.9
+ */
+EAPI char * eina_str_printf_dup(const char *format, ...);
+
 #include "eina_inline_str.x"
 
 /**