[VOL-4291] Rw-core updates for gRPC migration
Change-Id: I8d5a554409115b29318089671ca4e1ab3fa98810
diff --git a/vendor/github.com/klauspost/compress/fse/fse.go b/vendor/github.com/klauspost/compress/fse/fse.go
new file mode 100644
index 0000000..535cbad
--- /dev/null
+++ b/vendor/github.com/klauspost/compress/fse/fse.go
@@ -0,0 +1,144 @@
+// Copyright 2018 Klaus Post. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+// Based on work Copyright (c) 2013, Yann Collet, released under BSD License.
+
+// Package fse provides Finite State Entropy encoding and decoding.
+//
+// Finite State Entropy encoding provides a fast near-optimal symbol encoding/decoding
+// for byte blocks as implemented in zstd.
+//
+// See https://github.com/klauspost/compress/tree/master/fse for more information.
+package fse
+
+import (
+ "errors"
+ "fmt"
+ "math/bits"
+)
+
+const (
+ /*!MEMORY_USAGE :
+ * Memory usage formula : N->2^N Bytes (examples : 10 -> 1KB; 12 -> 4KB ; 16 -> 64KB; 20 -> 1MB; etc.)
+ * Increasing memory usage improves compression ratio
+ * Reduced memory usage can improve speed, due to cache effect
+ * Recommended max value is 14, for 16KB, which nicely fits into Intel x86 L1 cache */
+ maxMemoryUsage = 14
+ defaultMemoryUsage = 13
+
+ maxTableLog = maxMemoryUsage - 2
+ maxTablesize = 1 << maxTableLog
+ defaultTablelog = defaultMemoryUsage - 2
+ minTablelog = 5
+ maxSymbolValue = 255
+)
+
+var (
+ // ErrIncompressible is returned when input is judged to be too hard to compress.
+ ErrIncompressible = errors.New("input is not compressible")
+
+ // ErrUseRLE is returned from the compressor when the input is a single byte value repeated.
+ ErrUseRLE = errors.New("input is single value repeated")
+)
+
+// Scratch provides temporary storage for compression and decompression.
+type Scratch struct {
+ // Private
+ count [maxSymbolValue + 1]uint32
+ norm [maxSymbolValue + 1]int16
+ br byteReader
+ bits bitReader
+ bw bitWriter
+ ct cTable // Compression tables.
+ decTable []decSymbol // Decompression table.
+ maxCount int // count of the most probable symbol
+
+ // Per block parameters.
+ // These can be used to override compression parameters of the block.
+ // Do not touch, unless you know what you are doing.
+
+ // Out is output buffer.
+ // If the scratch is re-used before the caller is done processing the output,
+ // set this field to nil.
+ // Otherwise the output buffer will be re-used for next Compression/Decompression step
+ // and allocation will be avoided.
+ Out []byte
+
+ // DecompressLimit limits the maximum decoded size acceptable.
+ // If > 0 decompression will stop when approximately this many bytes
+ // has been decoded.
+ // If 0, maximum size will be 2GB.
+ DecompressLimit int
+
+ symbolLen uint16 // Length of active part of the symbol table.
+ actualTableLog uint8 // Selected tablelog.
+ zeroBits bool // no bits has prob > 50%.
+ clearCount bool // clear count
+
+ // MaxSymbolValue will override the maximum symbol value of the next block.
+ MaxSymbolValue uint8
+
+ // TableLog will attempt to override the tablelog for the next block.
+ TableLog uint8
+}
+
+// Histogram allows to populate the histogram and skip that step in the compression,
+// It otherwise allows to inspect the histogram when compression is done.
+// To indicate that you have populated the histogram call HistogramFinished
+// with the value of the highest populated symbol, as well as the number of entries
+// in the most populated entry. These are accepted at face value.
+// The returned slice will always be length 256.
+func (s *Scratch) Histogram() []uint32 {
+ return s.count[:]
+}
+
+// HistogramFinished can be called to indicate that the histogram has been populated.
+// maxSymbol is the index of the highest set symbol of the next data segment.
+// maxCount is the number of entries in the most populated entry.
+// These are accepted at face value.
+func (s *Scratch) HistogramFinished(maxSymbol uint8, maxCount int) {
+ s.maxCount = maxCount
+ s.symbolLen = uint16(maxSymbol) + 1
+ s.clearCount = maxCount != 0
+}
+
+// prepare will prepare and allocate scratch tables used for both compression and decompression.
+func (s *Scratch) prepare(in []byte) (*Scratch, error) {
+ if s == nil {
+ s = &Scratch{}
+ }
+ if s.MaxSymbolValue == 0 {
+ s.MaxSymbolValue = 255
+ }
+ if s.TableLog == 0 {
+ s.TableLog = defaultTablelog
+ }
+ if s.TableLog > maxTableLog {
+ return nil, fmt.Errorf("tableLog (%d) > maxTableLog (%d)", s.TableLog, maxTableLog)
+ }
+ if cap(s.Out) == 0 {
+ s.Out = make([]byte, 0, len(in))
+ }
+ if s.clearCount && s.maxCount == 0 {
+ for i := range s.count {
+ s.count[i] = 0
+ }
+ s.clearCount = false
+ }
+ s.br.init(in)
+ if s.DecompressLimit == 0 {
+ // Max size 2GB.
+ s.DecompressLimit = (2 << 30) - 1
+ }
+
+ return s, nil
+}
+
+// tableStep returns the next table index.
+func tableStep(tableSize uint32) uint32 {
+ return (tableSize >> 1) + (tableSize >> 3) + 3
+}
+
+func highBits(val uint32) (n uint32) {
+ return uint32(bits.Len32(val) - 1)
+}