fix(stdlib): Remove intermediate resizes in Buffer.autogrow (#1125)

stdlib/buffer.gr

@@ -49,11 +49,24 @@ let getSize = ptr => WasmI32.load(ptr, _SIZE_OFFSET)
 
 /* Doubles the size of buffer's underlying byte sequence, if the given size is larger than the size of a buffer's underlying byte sequence */
 let autogrow = (len, buf) => {
- while (buf.len + len > Bytes.length(buf.data)) {
- let mut n = Bytes.length(buf.data)
- if (n == 0) n = 4
- // Make sure bytes of 0 length grow too
- buf.data = Bytes.resize(0, n, buf.data)
+ let requiredMinimumSize = buf.len + len
+ let currentSize = Bytes.length(buf.data)
+
+ if (requiredMinimumSize > currentSize) {
+ let mut newSize = if (currentSize > 0) {
+ currentSize
+ } else {
+ // Make sure bytes of 0 length grow too
+ 4
+ }
+
+ while (newSize < requiredMinimumSize) {
+ newSize *= 2
+ }
+
+ let growBy = newSize - currentSize
+
+ buf.data = Bytes.resize(0, growBy, buf.data)
  }
 }