1 files changed, 167 insertions, 0 deletions
diff --git a/vendor/github.com/ulikunitz/xz/lzma/header.go b/vendor/github.com/ulikunitz/xz/lzma/header.go
new file mode 100644
index 000000000..bc708969f
--- /dev/null
+++ b/vendor/github.com/ulikunitz/xz/lzma/header.go
@@ -0,0 +1,167 @@
+// 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
+
+import (
+	"errors"
+	"fmt"
+)
+
+// uint32LE reads an uint32 integer from a byte slice
+func uint32LE(b []byte) uint32 {
+	x := uint32(b[3]) << 24
+	x |= uint32(b[2]) << 16
+	x |= uint32(b[1]) << 8
+	x |= uint32(b[0])
+	return x
+}
+
+// uint64LE converts the uint64 value stored as little endian to an uint64
+// value.
+func uint64LE(b []byte) uint64 {
+	x := uint64(b[7]) << 56
+	x |= uint64(b[6]) << 48
+	x |= uint64(b[5]) << 40
+	x |= uint64(b[4]) << 32
+	x |= uint64(b[3]) << 24
+	x |= uint64(b[2]) << 16
+	x |= uint64(b[1]) << 8
+	x |= uint64(b[0])
+	return x
+}
+
+// putUint32LE puts an uint32 integer into a byte slice that must have at least
+// a length of 4 bytes.
+func putUint32LE(b []byte, x uint32) {
+	b[0] = byte(x)
+	b[1] = byte(x >> 8)
+	b[2] = byte(x >> 16)
+	b[3] = byte(x >> 24)
+}
+
+// putUint64LE puts the uint64 value into the byte slice as little endian
+// value. The byte slice b must have at least place for 8 bytes.
+func putUint64LE(b []byte, x uint64) {
+	b[0] = byte(x)
+	b[1] = byte(x >> 8)
+	b[2] = byte(x >> 16)
+	b[3] = byte(x >> 24)
+	b[4] = byte(x >> 32)
+	b[5] = byte(x >> 40)
+	b[6] = byte(x >> 48)
+	b[7] = byte(x >> 56)
+}
+
+// noHeaderSize defines the value of the length field in the LZMA header.
+const noHeaderSize uint64 = 1<<64 - 1
+
+// HeaderLen provides the length of the LZMA file header.
+const HeaderLen = 13
+
+// header represents the header of an LZMA file.
+type header struct {
+	properties Properties
+	dictCap    int
+	// uncompressed size; negative value if no size is given
+	size int64
+}
+
+// marshalBinary marshals the header.
+func (h *header) marshalBinary() (data []byte, err error) {
+	if err = h.properties.verify(); err != nil {
+		return nil, err
+	}
+	if !(0 <= h.dictCap && int64(h.dictCap) <= MaxDictCap) {
+		return nil, fmt.Errorf("lzma: DictCap %d out of range",
+			h.dictCap)
+	}
+
+	data = make([]byte, 13)
+
+	// property byte
+	data[0] = h.properties.Code()
+
+	// dictionary capacity
+	putUint32LE(data[1:5], uint32(h.dictCap))
+
+	// uncompressed size
+	var s uint64
+	if h.size > 0 {
+		s = uint64(h.size)
+	} else {
+		s = noHeaderSize
+	}
+	putUint64LE(data[5:], s)
+
+	return data, nil
+}
+
+// unmarshalBinary unmarshals the header.
+func (h *header) unmarshalBinary(data []byte) error {
+	if len(data) != HeaderLen {
+		return errors.New("lzma.unmarshalBinary: data has wrong length")
+	}
+
+	// properties
+	var err error
+	if h.properties, err = PropertiesForCode(data[0]); err != nil {
+		return err
+	}
+
+	// dictionary capacity
+	h.dictCap = int(uint32LE(data[1:]))
+	if h.dictCap < 0 {
+		return errors.New(
+			"LZMA header: dictionary capacity exceeds maximum " +
+				"integer")
+	}
+
+	// uncompressed size
+	s := uint64LE(data[5:])
+	if s == noHeaderSize {
+		h.size = -1
+	} else {
+		h.size = int64(s)
+		if h.size < 0 {
+			return errors.New(
+				"LZMA header: uncompressed size " +
+					"out of int64 range")
+		}
+	}
+
+	return nil
+}
+
+// validDictCap checks whether the dictionary capacity is correct. This
+// is used to weed out wrong file headers.
+func validDictCap(dictcap int) bool {
+	if int64(dictcap) == MaxDictCap {
+		return true
+	}
+	for n := uint(10); n < 32; n++ {
+		if dictcap == 1<<n {
+			return true
+		}
+		if dictcap == 1<<n+1<<(n-1) {
+			return true
+		}
+	}
+	return false
+}
+
+// ValidHeader checks for a valid LZMA file header. It allows only
+// dictionary sizes of 2^n or 2^n+2^(n-1) with n >= 10 or 2^32-1. If
+// there is an explicit size it must not exceed 256 GiB. The length of
+// the data argument must be HeaderLen.
+func ValidHeader(data []byte) bool {
+	var h header
+	if err := h.unmarshalBinary(data); err != nil {
+		return false
+	}
+	if !validDictCap(h.dictCap) {
+		return false
+	}
+	return h.size < 0 || h.size <= 1<<38
+}