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Optimize Write16/32/Double a bit.

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Change-Id: I3d09a9d1b0b33da401312b3389234f7680da6f97
This commit is contained in:
Peter Johnson
2015-07-04 10:48:47 -07:00
parent 1634773529
commit c1c0c8d418
2 changed files with 18 additions and 15 deletions
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19
src/WireEncoder.cpp
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@@ -31,15 +31,16 @@ WireEncoder::~WireEncoder() { std::free(m_start); }
void WireEncoder::WriteDouble(double val) {
Reserve(8);
// The highest performance way to do this, albeit non-portable.
std::uint64_t v = *reinterpret_cast<uint64_t*>(&val);
*m_cur++ = (char)((v >> 56) & 0xff);
*m_cur++ = (char)((v >> 48) & 0xff);
*m_cur++ = (char)((v >> 40) & 0xff);
*m_cur++ = (char)((v >> 32) & 0xff);
*m_cur++ = (char)((v >> 24) & 0xff);
*m_cur++ = (char)((v >> 16) & 0xff);
*m_cur++ = (char)((v >> 8) & 0xff);
*m_cur++ = (char)(v & 0xff);
std::uint64_t v = reinterpret_cast<uint64_t&>(val);
m_cur[7] = (char)(v & 0xff); v >>= 8;
m_cur[6] = (char)(v & 0xff); v >>= 8;
m_cur[5] = (char)(v & 0xff); v >>= 8;
m_cur[4] = (char)(v & 0xff); v >>= 8;
m_cur[3] = (char)(v & 0xff); v >>= 8;
m_cur[2] = (char)(v & 0xff); v >>= 8;
m_cur[1] = (char)(v & 0xff); v >>= 8;
m_cur[0] = (char)(v & 0xff);
m_cur += 8;
}
void WireEncoder::ReserveSlow(std::size_t len) {