Changes between Version 6 and Version 7 of EfficientStrings

Timestamp:

Aug 29, 2012 2:20:49 PM (12 years ago)

Author:

benjamin@webkit.org

Comment:

--

EfficientStrings

@@ -66 +66 @@
 
 Note: If you need to append a literal char, {{{ builder.append('c'); }}} is more efficient than {{{ builder.appendLiteral("c"); }}} 
+
+
+=== Memory ===
+
+Any of the string class uses memory on the heap to allocate a StringImpl. The only way to avoid allocating new memory is to use the methods taking a constant literal.
+
+On 64bits, the memory used for StringImpl vary between 28 bytes to (28 + length + length * 2) bytes for a string from copy that has been converted to 16 bits.
+
+For example, a 10 characters string from copy converted to 16bits + the allocators alignment would typically take:[[BR]]
+-28 + 10 = 38 -> typically allocated to 64bytes[[BR]]
+-10 * 2 = 20 -> typically allocated to 32bytes[[BR]]
+-->96bytes.[[BR]]
+Be careful when allocating strings.