diff options
Diffstat (limited to 'chromium/net/quic/quic_data_reader.cc')
-rw-r--r-- | chromium/net/quic/quic_data_reader.cc | 34 |
1 files changed, 34 insertions, 0 deletions
diff --git a/chromium/net/quic/quic_data_reader.cc b/chromium/net/quic/quic_data_reader.cc index 3bb7fc3f8ab..b9a6acf32f5 100644 --- a/chromium/net/quic/quic_data_reader.cc +++ b/chromium/net/quic/quic_data_reader.cc @@ -4,6 +4,9 @@ #include "net/quic/quic_data_reader.h" +#include "net/base/int128.h" +#include "net/quic/quic_protocol.h" + using base::StringPiece; namespace net { @@ -59,6 +62,37 @@ bool QuicDataReader::ReadUInt128(uint128* result) { return true; } +bool QuicDataReader::ReadUFloat16(uint64* result) { + uint16 value; + if (!ReadUInt16(&value)) { + return false; + } + + *result = value; + if (*result < (1 << kUFloat16MantissaEffectiveBits)) { + // Fast path: either the value is denormalized (no hidden bit), or + // normalized (hidden bit set, exponent offset by one) with exponent zero. + // Zero exponent offset by one sets the bit exactly where the hidden bit is. + // So in both cases the value encodes itself. + return true; + } + + uint16 exponent = value >> kUFloat16MantissaBits; // No sign extend on uint! + // After the fast pass, the exponent is at least one (offset by one). + // Un-offset the exponent. + --exponent; + DCHECK_GE(exponent, 1); + DCHECK_LE(exponent, kUFloat16MaxExponent); + // Here we need to clear the exponent and set the hidden bit. We have already + // decremented the exponent, so when we subtract it, it leaves behind the + // hidden bit. + *result -= exponent << kUFloat16MantissaBits; + *result <<= exponent; + DCHECK_GE(value, 1 << kUFloat16MantissaEffectiveBits); + DCHECK_LE(value, kUFloat16MaxValue); + return true; +} + bool QuicDataReader::ReadStringPiece16(StringPiece* result) { // Read resultant length. uint16 result_len; |