Messages in this thread | | | From | Jann Horn <> | Date | Thu, 12 Nov 2020 01:06:32 +0100 | Subject | Re: [PATCH 2/3] lib: zlib_inflate: improves decompression performance |
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On Wed, Nov 11, 2020 at 5:06 PM Zhaoxiu Zeng <zengzhaoxiu@163.com> wrote: > 在 2020/11/11 11:46, Jann Horn 写道: > > On Mon, Nov 9, 2020 at 8:27 PM <zengzhaoxiu@163.com> wrote: > >> This patch does: > >> 1. Cleanup code and reduce branches > >> 2. Use copy_from_back to copy the matched bytes from the back output buffer > > > > What exactly is copy_from_back()? Is it like memmove()? If yes, have > > you tried using memmove() instead of the code added in patch 1/3? > > > > If use memcpy(or memmove), the code will be like this: > while (dist < len) { > memcpy(out, out - dist, dist); > out += dist; > len -= dist; > } > memcpy(out, out - dist, len);
Ah, thanks. So basically it means: "repeatedly copy a pattern of length `dist` from `out-dist` to `out` until `len` bytes have been written"
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