Allocation on rustbiteshttps://www.rustbites.com/tags/allocation/Recent content in Allocation on rustbitesHugoenWed, 10 Jun 2026 20:23:05 +0200194. Reuse One Buffer with .clear() — Allocate Once, Loop Many Timeshttps://www.rustbites.com/posts/bite-194/Wed, 10 Jun 2026 17:00:00 +0100https://www.rustbites.com/posts/bite-194/<p><code>with_capacity</code> (bite 193) buys a buffer once instead of growing it repeatedly. But if you allocate a <em>fresh</em> <code>String</code> or <code>Vec</code> inside a loop, you throw that buffer away every iteration. <code>.clear()</code> resets the length to zero while keeping the capacity — so one allocation serves the whole loop.</p>193. Vec::with_capacity — Size Up Front, Skip the Realloc Churnhttps://www.rustbites.com/posts/bite-193/Wed, 10 Jun 2026 09:00:00 +0100https://www.rustbites.com/posts/bite-193/<p>A <code>Vec</code> you <code>push</code> into one element at a time doesn&rsquo;t grow one element at a time — it doubles, copying every existing item to a fresh allocation each time it outgrows its buffer. If you already know how many items are coming, <code>Vec::with_capacity</code> buys the whole buffer once.</p>