1 files changed, 132 insertions, 0 deletions
diff --git a/vendor/github.com/ulikunitz/xz/lzma/literalcodec.go b/vendor/github.com/ulikunitz/xz/lzma/literalcodec.go
new file mode 100644
index 000000000..c949d6ebd
--- /dev/null
+++ b/vendor/github.com/ulikunitz/xz/lzma/literalcodec.go
@@ -0,0 +1,132 @@
+// Copyright 2014-2017 Ulrich Kunitz. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package lzma
+
+// literalCodec supports the encoding of literal. It provides 768 probability
+// values per literal state. The upper 512 probabilities are used with the
+// context of a match bit.
+type literalCodec struct {
+	probs []prob
+}
+
+// deepcopy initializes literal codec c as a deep copy of the source.
+func (c *literalCodec) deepcopy(src *literalCodec) {
+	if c == src {
+		return
+	}
+	c.probs = make([]prob, len(src.probs))
+	copy(c.probs, src.probs)
+}
+
+// init initializes the literal codec.
+func (c *literalCodec) init(lc, lp int) {
+	switch {
+	case !(minLC <= lc && lc <= maxLC):
+		panic("lc out of range")
+	case !(minLP <= lp && lp <= maxLP):
+		panic("lp out of range")
+	}
+	c.probs = make([]prob, 0x300<<uint(lc+lp))
+	for i := range c.probs {
+		c.probs[i] = probInit
+	}
+}
+
+// Encode encodes the byte s using a range encoder as well as the current LZMA
+// encoder state, a match byte and the literal state.
+func (c *literalCodec) Encode(e *rangeEncoder, s byte,
+	state uint32, match byte, litState uint32,
+) (err error) {
+	k := litState * 0x300
+	probs := c.probs[k : k+0x300]
+	symbol := uint32(1)
+	r := uint32(s)
+	if state >= 7 {
+		m := uint32(match)
+		for {
+			matchBit := (m >> 7) & 1
+			m <<= 1
+			bit := (r >> 7) & 1
+			r <<= 1
+			i := ((1 + matchBit) << 8) | symbol
+			if err = probs[i].Encode(e, bit); err != nil {
+				return
+			}
+			symbol = (symbol << 1) | bit
+			if matchBit != bit {
+				break
+			}
+			if symbol >= 0x100 {
+				break
+			}
+		}
+	}
+	for symbol < 0x100 {
+		bit := (r >> 7) & 1
+		r <<= 1
+		if err = probs[symbol].Encode(e, bit); err != nil {
+			return
+		}
+		symbol = (symbol << 1) | bit
+	}
+	return nil
+}
+
+// Decode decodes a literal byte using the range decoder as well as the LZMA
+// state, a match byte, and the literal state.
+func (c *literalCodec) Decode(d *rangeDecoder,
+	state uint32, match byte, litState uint32,
+) (s byte, err error) {
+	k := litState * 0x300
+	probs := c.probs[k : k+0x300]
+	symbol := uint32(1)
+	if state >= 7 {
+		m := uint32(match)
+		for {
+			matchBit := (m >> 7) & 1
+			m <<= 1
+			i := ((1 + matchBit) << 8) | symbol
+			bit, err := d.DecodeBit(&probs[i])
+			if err != nil {
+				return 0, err
+			}
+			symbol = (symbol << 1) | bit
+			if matchBit != bit {
+				break
+			}
+			if symbol >= 0x100 {
+				break
+			}
+		}
+	}
+	for symbol < 0x100 {
+		bit, err := d.DecodeBit(&probs[symbol])
+		if err != nil {
+			return 0, err
+		}
+		symbol = (symbol << 1) | bit
+	}
+	s = byte(symbol - 0x100)
+	return s, nil
+}
+
+// minLC and maxLC define the range for LC values.
+const (
+	minLC = 0
+	maxLC = 8
+)
+
+// minLC and maxLC define the range for LP values.
+const (
+	minLP = 0
+	maxLP = 4
+)
+
+// minState and maxState define a range for the state values stored in
+// the State values.
+const (
+	minState = 0
+	maxState = 11
+)