tree 75d1870f7d330ea6d488becfbddeecea1215c2f1
parent 5df3663f607a52ab3a11dad085c88e7668273cdd
author bnc <bnc@google.com> 1601591339 -0700
committer Copybara-Service <copybara-worker@google.com> 1601591373 -0700

Pre-allocate storage in http2::HuffmanEncode().

Also, do not call http2::HuffmanEncode() in
QpackInstructionEncoder::DoStartString() if it does not result in size savings.

Note that performance gets worse for short strings, presumably because
std::string::reserve() for small values is a no-op due to small string
optimization.  However, I plan to modify http2::HuffmanEncode() not to clear the
output string and modify QpackInstructionEncoder to avoid copying, which should
result in a performance improvement overall.

Also I'll add a slightly faster implementation in the next CL, so this is really
only to change the API to make tests simpler.

PiperOrigin-RevId: 334909897
Change-Id: Idd7414c0dcaa56fc62d0822ec06250d480d2972c