bump(golang.org/x/tools/container/intsets): 2382e3994d48b1d22acc2c86bcad0a2aff028e32

Godeps/Godeps.json

@@ -2739,6 +2739,10 @@
 			"ImportPath": "golang.org/x/time/rate",
 			"Rev": "f51c12702a4d776e4c1fa9b0fabab841babae631"
 		},
+		{
+			"ImportPath": "golang.org/x/tools/container/intsets",
+			"Rev": "2382e3994d48b1d22acc2c86bcad0a2aff028e32"
+		},
 		{
 			"ImportPath": "google.golang.org/api/cloudmonitoring/v2beta2",
 			"Rev": "e3824ed33c72bf7e81da0286772c34b987520914"

Godeps/LICENSES

@@ -83172,6 +83172,41 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 ================================================================================
 
 
+================================================================================
+= vendor/golang.org/x/tools/container/intsets licensed under: =
+
+Copyright (c) 2009 The Go Authors. All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are
+met:
+
+   * Redistributions of source code must retain the above copyright
+notice, this list of conditions and the following disclaimer.
+   * Redistributions in binary form must reproduce the above
+copyright notice, this list of conditions and the following disclaimer
+in the documentation and/or other materials provided with the
+distribution.
+   * Neither the name of Google Inc. nor the names of its
+contributors may be used to endorse or promote products derived from
+this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+= vendor/golang.org/x/tools/LICENSE 5d4950ecb7b26d2c5e4e7b4e0dd74707  -
+================================================================================
+
+
 ================================================================================
 = vendor/google.golang.org/api/cloudmonitoring/v2beta2 licensed under: =
 

vendor/BUILD

@@ -346,6 +346,7 @@ filegroup(
         "//vendor/golang.org/x/text/unicode/norm:all-srcs",
         "//vendor/golang.org/x/text/width:all-srcs",
         "//vendor/golang.org/x/time/rate:all-srcs",
+        "//vendor/golang.org/x/tools/container/intsets:all-srcs",
         "//vendor/google.golang.org/api/cloudmonitoring/v2beta2:all-srcs",
         "//vendor/google.golang.org/api/compute/v0.alpha:all-srcs",
         "//vendor/google.golang.org/api/compute/v0.beta:all-srcs",

vendor/golang.org/x/tools/AUTHORS

@@ -0,0 +1,3 @@
+# This source code refers to The Go Authors for copyright purposes.
+# The master list of authors is in the main Go distribution,
+# visible at http://tip.golang.org/AUTHORS.

vendor/golang.org/x/tools/CONTRIBUTORS

@@ -0,0 +1,3 @@
+# This source code was written by the Go contributors.
+# The master list of contributors is in the main Go distribution,
+# visible at http://tip.golang.org/CONTRIBUTORS.

vendor/golang.org/x/tools/LICENSE

@@ -0,0 +1,27 @@
+Copyright (c) 2009 The Go Authors. All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are
+met:
+
+   * Redistributions of source code must retain the above copyright
+notice, this list of conditions and the following disclaimer.
+   * Redistributions in binary form must reproduce the above
+copyright notice, this list of conditions and the following disclaimer
+in the documentation and/or other materials provided with the
+distribution.
+   * Neither the name of Google Inc. nor the names of its
+contributors may be used to endorse or promote products derived from
+this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

vendor/golang.org/x/tools/PATENTS

@@ -0,0 +1,22 @@
+Additional IP Rights Grant (Patents)
+
+"This implementation" means the copyrightable works distributed by
+Google as part of the Go project.
+
+Google hereby grants to You a perpetual, worldwide, non-exclusive,
+no-charge, royalty-free, irrevocable (except as stated in this section)
+patent license to make, have made, use, offer to sell, sell, import,
+transfer and otherwise run, modify and propagate the contents of this
+implementation of Go, where such license applies only to those patent
+claims, both currently owned or controlled by Google and acquired in
+the future, licensable by Google that are necessarily infringed by this
+implementation of Go.  This grant does not include claims that would be
+infringed only as a consequence of further modification of this
+implementation.  If you or your agent or exclusive licensee institute or
+order or agree to the institution of patent litigation against any
+entity (including a cross-claim or counterclaim in a lawsuit) alleging
+that this implementation of Go or any code incorporated within this
+implementation of Go constitutes direct or contributory patent
+infringement, or inducement of patent infringement, then any patent
+rights granted to you under this License for this implementation of Go
+shall terminate as of the date such litigation is filed.

vendor/golang.org/x/tools/container/intsets/BUILD

@@ -0,0 +1,32 @@
+package(default_visibility = ["//visibility:public"])
+
+licenses(["notice"])
+
+load(
+    "@io_bazel_rules_go//go:def.bzl",
+    "go_library",
+)
+
+go_library(
+    name = "go_default_library",
+    srcs = [
+        "popcnt_amd64.go",
+        "popcnt_amd64.s",
+        "sparse.go",
+        "util.go",
+    ],
+    tags = ["automanaged"],
+)
+
+filegroup(
+    name = "package-srcs",
+    srcs = glob(["**"]),
+    tags = ["automanaged"],
+    visibility = ["//visibility:private"],
+)
+
+filegroup(
+    name = "all-srcs",
+    srcs = [":package-srcs"],
+    tags = ["automanaged"],
+)

vendor/golang.org/x/tools/container/intsets/popcnt_amd64.go

@@ -0,0 +1,20 @@
+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build amd64,!appengine,!gccgo
+
+package intsets
+
+func popcnt(x word) int
+func havePOPCNT() bool
+
+var hasPOPCNT = havePOPCNT()
+
+// popcount returns the population count (number of set bits) of x.
+func popcount(x word) int {
+	if hasPOPCNT {
+		return popcnt(x)
+	}
+	return popcountTable(x) // faster than Hacker's Delight
+}

vendor/golang.org/x/tools/container/intsets/popcnt_amd64.s

@@ -0,0 +1,30 @@
+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build amd64,!appengine,!gccgo
+
+#include "textflag.h"
+
+// func havePOPCNT() bool
+TEXT ·havePOPCNT(SB),4,$0
+	MOVQ	$1, AX
+	CPUID
+	SHRQ	$23, CX
+	ANDQ	$1, CX
+	MOVB	CX, ret+0(FP)
+	RET
+
+// func popcnt(word) int
+TEXT ·popcnt(SB),NOSPLIT,$0-8
+	XORQ	AX, AX
+	MOVQ	x+0(FP), SI
+	// POPCNT (SI), AX is not recognized by Go assembler,
+	// so we assemble it ourselves.
+	BYTE	$0xf3
+	BYTE	$0x48
+	BYTE	$0x0f
+	BYTE	$0xb8
+	BYTE	$0xc6
+	MOVQ	AX, ret+8(FP)
+	RET

vendor/golang.org/x/tools/container/intsets/popcnt_gccgo.go

@@ -0,0 +1,9 @@
+// Copyright 2015 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build gccgo
+
+package intsets
+
+func popcount(x word) int

vendor/golang.org/x/tools/container/intsets/popcnt_gccgo_c.c

@@ -0,0 +1,19 @@
+// Copyright 2015 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build gccgo
+
+#include <errno.h>
+#include <stdint.h>
+#include <unistd.h>
+
+#define _STRINGIFY2_(x) #x
+#define _STRINGIFY_(x) _STRINGIFY2_(x)
+#define GOSYM_PREFIX _STRINGIFY_(__USER_LABEL_PREFIX__)
+
+extern intptr_t popcount(uintptr_t x) __asm__(GOSYM_PREFIX GOPKGPATH ".popcount");
+
+intptr_t popcount(uintptr_t x) {
+	return __builtin_popcountl((unsigned long)(x));
+}

vendor/golang.org/x/tools/container/intsets/popcnt_generic.go

@@ -0,0 +1,33 @@
+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build !amd64 appengine
+// +build !gccgo
+
+package intsets
+
+import "runtime"
+
+// We compared three algorithms---Hacker's Delight, table lookup,
+// and AMD64's SSE4.1 hardware POPCNT---on a 2.67GHz Xeon X5550.
+//
+// % GOARCH=amd64 go test -run=NONE -bench=Popcount
+// POPCNT               5.12 ns/op
+// Table                8.53 ns/op
+// HackersDelight       9.96 ns/op
+//
+// % GOARCH=386 go test -run=NONE -bench=Popcount
+// Table               10.4  ns/op
+// HackersDelight       5.23 ns/op
+//
+// (AMD64's ABM1 hardware supports ntz and nlz too,
+// but they aren't critical.)
+
+// popcount returns the population count (number of set bits) of x.
+func popcount(x word) int {
+	if runtime.GOARCH == "386" {
+		return popcountHD(uint32(x))
+	}
+	return popcountTable(x)
+}

vendor/golang.org/x/tools/container/intsets/sparse.go

@@ -0,0 +1,967 @@
+// Copyright 2014 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package intsets provides Sparse, a compact and fast representation
+// for sparse sets of int values.
+//
+// The time complexity of the operations Len, Insert, Remove and Has
+// is in O(n) but in practice those methods are faster and more
+// space-efficient than equivalent operations on sets based on the Go
+// map type.  The IsEmpty, Min, Max, Clear and TakeMin operations
+// require constant time.
+//
+package intsets
+
+// TODO(adonovan):
+// - Add InsertAll(...int), RemoveAll(...int)
+// - Add 'bool changed' results for {Intersection,Difference}With too.
+//
+// TODO(adonovan): implement Dense, a dense bit vector with a similar API.
+// The space usage would be proportional to Max(), not Len(), and the
+// implementation would be based upon big.Int.
+//
+// TODO(adonovan): experiment with making the root block indirect (nil
+// iff IsEmpty).  This would reduce the memory usage when empty and
+// might simplify the aliasing invariants.
+//
+// TODO(adonovan): opt: make UnionWith and Difference faster.
+// These are the hot-spots for go/pointer.
+
+import (
+	"bytes"
+	"fmt"
+)
+
+// A Sparse is a set of int values.
+// Sparse operations (even queries) are not concurrency-safe.
+//
+// The zero value for Sparse is a valid empty set.
+//
+// Sparse sets must be copied using the Copy method, not by assigning
+// a Sparse value.
+//
+type Sparse struct {
+	// An uninitialized Sparse represents an empty set.
+	// An empty set may also be represented by
+	//  root.next == root.prev == &root.
+	// In a non-empty set, root.next points to the first block and
+	// root.prev to the last.
+	// root.offset and root.bits are unused.
+	root block
+}
+
+type word uintptr
+
+const (
+	_m            = ^word(0)
+	bitsPerWord   = 8 << (_m>>8&1 + _m>>16&1 + _m>>32&1)
+	bitsPerBlock  = 256 // optimal value for go/pointer solver performance
+	wordsPerBlock = bitsPerBlock / bitsPerWord
+)
+
+// Limit values of implementation-specific int type.
+const (
+	MaxInt = int(^uint(0) >> 1)
+	MinInt = -MaxInt - 1
+)
+
+// -- block ------------------------------------------------------------
+
+// A set is represented as a circular doubly-linked list of blocks,
+// each containing an offset and a bit array of fixed size
+// bitsPerBlock; the blocks are ordered by increasing offset.
+//
+// The set contains an element x iff the block whose offset is x - (x
+// mod bitsPerBlock) has the bit (x mod bitsPerBlock) set, where mod
+// is the Euclidean remainder.
+//
+// A block may only be empty transiently.
+//
+type block struct {
+	offset     int                 // offset mod bitsPerBlock == 0
+	bits       [wordsPerBlock]word // contains at least one set bit
+	next, prev *block              // doubly-linked list of blocks
+}
+
+// wordMask returns the word index (in block.bits)
+// and single-bit mask for the block's ith bit.
+func wordMask(i uint) (w uint, mask word) {
+	w = i / bitsPerWord
+	mask = 1 << (i % bitsPerWord)
+	return
+}
+
+// insert sets the block b's ith bit and
+// returns true if it was not already set.
+//
+func (b *block) insert(i uint) bool {
+	w, mask := wordMask(i)
+	if b.bits[w]&mask == 0 {
+		b.bits[w] |= mask
+		return true
+	}
+	return false
+}
+
+// remove clears the block's ith bit and
+// returns true if the bit was previously set.
+// NB: may leave the block empty.
+//
+func (b *block) remove(i uint) bool {
+	w, mask := wordMask(i)
+	if b.bits[w]&mask != 0 {
+		b.bits[w] &^= mask
+		return true
+	}
+	return false
+}
+
+// has reports whether the block's ith bit is set.
+func (b *block) has(i uint) bool {
+	w, mask := wordMask(i)
+	return b.bits[w]&mask != 0
+}
+
+// empty reports whether b.len()==0, but more efficiently.
+func (b *block) empty() bool {
+	for _, w := range b.bits {
+		if w != 0 {
+			return false
+		}
+	}
+	return true
+}
+
+// len returns the number of set bits in block b.
+func (b *block) len() int {
+	var l int
+	for _, w := range b.bits {
+		l += popcount(w)
+	}
+	return l
+}
+
+// max returns the maximum element of the block.
+// The block must not be empty.
+//
+func (b *block) max() int {
+	bi := b.offset + bitsPerBlock
+	// Decrement bi by number of high zeros in last.bits.
+	for i := len(b.bits) - 1; i >= 0; i-- {
+		if w := b.bits[i]; w != 0 {
+			return bi - nlz(w) - 1
+		}
+		bi -= bitsPerWord
+	}
+	panic("BUG: empty block")
+}
+
+// min returns the minimum element of the block,
+// and also removes it if take is set.
+// The block must not be initially empty.
+// NB: may leave the block empty.
+//
+func (b *block) min(take bool) int {
+	for i, w := range b.bits {
+		if w != 0 {
+			tz := ntz(w)
+			if take {
+				b.bits[i] = w &^ (1 << uint(tz))
+			}
+			return b.offset + int(i*bitsPerWord) + tz
+		}
+	}
+	panic("BUG: empty block")
+}
+
+// forEach calls f for each element of block b.
+// f must not mutate b's enclosing Sparse.
+func (b *block) forEach(f func(int)) {
+	for i, w := range b.bits {
+		offset := b.offset + i*bitsPerWord
+		for bi := 0; w != 0 && bi < bitsPerWord; bi++ {
+			if w&1 != 0 {
+				f(offset)
+			}
+			offset++
+			w >>= 1
+		}
+	}
+}
+
+// offsetAndBitIndex returns the offset of the block that would
+// contain x and the bit index of x within that block.
+//
+func offsetAndBitIndex(x int) (int, uint) {
+	mod := x % bitsPerBlock
+	if mod < 0 {
+		// Euclidean (non-negative) remainder
+		mod += bitsPerBlock
+	}
+	return x - mod, uint(mod)
+}
+
+// -- Sparse --------------------------------------------------------------
+
+// start returns the root's next block, which is the root block
+// (if s.IsEmpty()) or the first true block otherwise.
+// start has the side effect of ensuring that s is properly
+// initialized.
+//
+func (s *Sparse) start() *block {
+	root := &s.root
+	if root.next == nil {
+		root.next = root
+		root.prev = root
+	} else if root.next.prev != root {
+		// Copying a Sparse x leads to pernicious corruption: the
+		// new Sparse y shares the old linked list, but iteration
+		// on y will never encounter &y.root so it goes into a
+		// loop.  Fail fast before this occurs.
+		panic("A Sparse has been copied without (*Sparse).Copy()")
+	}
+
+	return root.next
+}
+
+// IsEmpty reports whether the set s is empty.
+func (s *Sparse) IsEmpty() bool {
+	return s.start() == &s.root
+}
+
+// Len returns the number of elements in the set s.
+func (s *Sparse) Len() int {
+	var l int
+	for b := s.start(); b != &s.root; b = b.next {
+		l += b.len()
+	}
+	return l
+}
+
+// Max returns the maximum element of the set s, or MinInt if s is empty.
+func (s *Sparse) Max() int {
+	if s.IsEmpty() {
+		return MinInt
+	}
+	return s.root.prev.max()
+}
+
+// Min returns the minimum element of the set s, or MaxInt if s is empty.
+func (s *Sparse) Min() int {
+	if s.IsEmpty() {
+		return MaxInt
+	}
+	return s.root.next.min(false)
+}
+
+// block returns the block that would contain offset,
+// or nil if s contains no such block.
+//
+func (s *Sparse) block(offset int) *block {
+	b := s.start()
+	for b != &s.root && b.offset <= offset {
+		if b.offset == offset {
+			return b
+		}
+		b = b.next
+	}
+	return nil
+}
+
+// Insert adds x to the set s, and reports whether the set grew.
+func (s *Sparse) Insert(x int) bool {
+	offset, i := offsetAndBitIndex(x)
+	b := s.start()
+	for b != &s.root && b.offset <= offset {
+		if b.offset == offset {
+			return b.insert(i)
+		}
+		b = b.next
+	}
+
+	// Insert new block before b.
+	new := &block{offset: offset}
+	new.next = b
+	new.prev = b.prev
+	new.prev.next = new
+	new.next.prev = new
+	return new.insert(i)
+}
+
+func (s *Sparse) removeBlock(b *block) {
+	b.prev.next = b.next
+	b.next.prev = b.prev
+}
+
+// Remove removes x from the set s, and reports whether the set shrank.
+func (s *Sparse) Remove(x int) bool {
+	offset, i := offsetAndBitIndex(x)
+	if b := s.block(offset); b != nil {
+		if !b.remove(i) {
+			return false
+		}
+		if b.empty() {
+			s.removeBlock(b)
+		}
+		return true
+	}
+	return false
+}
+
+// Clear removes all elements from the set s.
+func (s *Sparse) Clear() {
+	s.root.next = &s.root
+	s.root.prev = &s.root
+}
+
+// If set s is non-empty, TakeMin sets *p to the minimum element of
+// the set s, removes that element from the set and returns true.
+// Otherwise, it returns false and *p is undefined.
+//
+// This method may be used for iteration over a worklist like so:
+//
+// 	var x int
+// 	for worklist.TakeMin(&x) { use(x) }
+//
+func (s *Sparse) TakeMin(p *int) bool {
+	head := s.start()
+	if head == &s.root {
+		return false
+	}
+	*p = head.min(true)
+	if head.empty() {
+		s.removeBlock(head)
+	}
+	return true
+}
+
+// Has reports whether x is an element of the set s.
+func (s *Sparse) Has(x int) bool {
+	offset, i := offsetAndBitIndex(x)
+	if b := s.block(offset); b != nil {
+		return b.has(i)
+	}
+	return false
+}
+
+// forEach applies function f to each element of the set s in order.
+//
+// f must not mutate s.  Consequently, forEach is not safe to expose
+// to clients.  In any case, using "range s.AppendTo()" allows more
+// natural control flow with continue/break/return.
+//
+func (s *Sparse) forEach(f func(int)) {
+	for b := s.start(); b != &s.root; b = b.next {
+		b.forEach(f)
+	}
+}
+
+// Copy sets s to the value of x.
+func (s *Sparse) Copy(x *Sparse) {
+	if s == x {
+		return
+	}
+
+	xb := x.start()
+	sb := s.start()
+	for xb != &x.root {
+		if sb == &s.root {
+			sb = s.insertBlockBefore(sb)
+		}
+		sb.offset = xb.offset
+		sb.bits = xb.bits
+		xb = xb.next
+		sb = sb.next
+	}
+	s.discardTail(sb)
+}
+
+// insertBlockBefore returns a new block, inserting it before next.
+func (s *Sparse) insertBlockBefore(next *block) *block {
+	b := new(block)
+	b.next = next
+	b.prev = next.prev
+	b.prev.next = b
+	next.prev = b
+	return b
+}
+
+// discardTail removes block b and all its successors from s.
+func (s *Sparse) discardTail(b *block) {
+	if b != &s.root {
+		b.prev.next = &s.root
+		s.root.prev = b.prev
+	}
+}
+
+// IntersectionWith sets s to the intersection s ∩ x.
+func (s *Sparse) IntersectionWith(x *Sparse) {
+	if s == x {
+		return
+	}
+
+	xb := x.start()
+	sb := s.start()
+	for xb != &x.root && sb != &s.root {
+		switch {
+		case xb.offset < sb.offset:
+			xb = xb.next
+
+		case xb.offset > sb.offset:
+			sb = sb.next
+			s.removeBlock(sb.prev)
+
+		default:
+			var sum word
+			for i := range sb.bits {
+				r := xb.bits[i] & sb.bits[i]
+				sb.bits[i] = r
+				sum |= r
+			}
+			if sum != 0 {
+				sb = sb.next
+			} else {
+				// sb will be overwritten or removed
+			}
+
+			xb = xb.next
+		}
+	}
+
+	s.discardTail(sb)
+}
+
+// Intersection sets s to the intersection x ∩ y.
+func (s *Sparse) Intersection(x, y *Sparse) {
+	switch {
+	case s == x:
+		s.IntersectionWith(y)
+		return
+	case s == y:
+		s.IntersectionWith(x)
+		return
+	case x == y:
+		s.Copy(x)
+		return
+	}
+
+	xb := x.start()
+	yb := y.start()
+	sb := s.start()
+	for xb != &x.root && yb != &y.root {
+		switch {
+		case xb.offset < yb.offset:
+			xb = xb.next
+			continue
+		case xb.offset > yb.offset:
+			yb = yb.next
+			continue
+		}
+
+		if sb == &s.root {
+			sb = s.insertBlockBefore(sb)
+		}
+		sb.offset = xb.offset
+
+		var sum word
+		for i := range sb.bits {
+			r := xb.bits[i] & yb.bits[i]
+			sb.bits[i] = r
+			sum |= r
+		}
+		if sum != 0 {
+			sb = sb.next
+		} else {
+			// sb will be overwritten or removed
+		}
+
+		xb = xb.next
+		yb = yb.next
+	}
+
+	s.discardTail(sb)
+}
+
+// Intersects reports whether s ∩ x ≠ ∅.
+func (s *Sparse) Intersects(x *Sparse) bool {
+	sb := s.start()
+	xb := x.start()
+	for sb != &s.root && xb != &x.root {
+		switch {
+		case xb.offset < sb.offset:
+			xb = xb.next
+		case xb.offset > sb.offset:
+			sb = sb.next
+		default:
+			for i := range sb.bits {
+				if sb.bits[i]&xb.bits[i] != 0 {
+					return true
+				}
+			}
+			sb = sb.next
+			xb = xb.next
+		}
+	}
+	return false
+}
+
+// UnionWith sets s to the union s ∪ x, and reports whether s grew.
+func (s *Sparse) UnionWith(x *Sparse) bool {
+	if s == x {
+		return false
+	}
+
+	var changed bool
+	xb := x.start()
+	sb := s.start()
+	for xb != &x.root {
+		if sb != &s.root && sb.offset == xb.offset {
+			for i := range xb.bits {
+				if sb.bits[i] != xb.bits[i] {
+					sb.bits[i] |= xb.bits[i]
+					changed = true
+				}
+			}
+			xb = xb.next
+		} else if sb == &s.root || sb.offset > xb.offset {
+			sb = s.insertBlockBefore(sb)
+			sb.offset = xb.offset
+			sb.bits = xb.bits
+			changed = true
+
+			xb = xb.next
+		}
+		sb = sb.next
+	}
+	return changed
+}
+
+// Union sets s to the union x ∪ y.
+func (s *Sparse) Union(x, y *Sparse) {
+	switch {
+	case x == y:
+		s.Copy(x)
+		return
+	case s == x:
+		s.UnionWith(y)
+		return
+	case s == y:
+		s.UnionWith(x)
+		return
+	}
+
+	xb := x.start()
+	yb := y.start()
+	sb := s.start()
+	for xb != &x.root || yb != &y.root {
+		if sb == &s.root {
+			sb = s.insertBlockBefore(sb)
+		}
+		switch {
+		case yb == &y.root || (xb != &x.root && xb.offset < yb.offset):
+			sb.offset = xb.offset
+			sb.bits = xb.bits
+			xb = xb.next
+
+		case xb == &x.root || (yb != &y.root && yb.offset < xb.offset):
+			sb.offset = yb.offset
+			sb.bits = yb.bits
+			yb = yb.next
+
+		default:
+			sb.offset = xb.offset
+			for i := range xb.bits {
+				sb.bits[i] = xb.bits[i] | yb.bits[i]
+			}
+			xb = xb.next
+			yb = yb.next
+		}
+		sb = sb.next
+	}
+
+	s.discardTail(sb)
+}
+
+// DifferenceWith sets s to the difference s ∖ x.
+func (s *Sparse) DifferenceWith(x *Sparse) {
+	if s == x {
+		s.Clear()
+		return
+	}
+
+	xb := x.start()
+	sb := s.start()
+	for xb != &x.root && sb != &s.root {
+		switch {
+		case xb.offset > sb.offset:
+			sb = sb.next
+
+		case xb.offset < sb.offset:
+			xb = xb.next
+
+		default:
+			var sum word
+			for i := range sb.bits {
+				r := sb.bits[i] & ^xb.bits[i]
+				sb.bits[i] = r
+				sum |= r
+			}
+			sb = sb.next
+			xb = xb.next
+
+			if sum == 0 {
+				s.removeBlock(sb.prev)
+			}
+		}
+	}
+}
+
+// Difference sets s to the difference x ∖ y.
+func (s *Sparse) Difference(x, y *Sparse) {
+	switch {
+	case x == y:
+		s.Clear()
+		return
+	case s == x:
+		s.DifferenceWith(y)
+		return
+	case s == y:
+		var y2 Sparse
+		y2.Copy(y)
+		s.Difference(x, &y2)
+		return
+	}
+
+	xb := x.start()
+	yb := y.start()
+	sb := s.start()
+	for xb != &x.root && yb != &y.root {
+		if xb.offset > yb.offset {
+			// y has block, x has none
+			yb = yb.next
+			continue
+		}
+
+		if sb == &s.root {
+			sb = s.insertBlockBefore(sb)
+		}
+		sb.offset = xb.offset
+
+		switch {
+		case xb.offset < yb.offset:
+			// x has block, y has none
+			sb.bits = xb.bits
+
+			sb = sb.next
+
+		default:
+			// x and y have corresponding blocks
+			var sum word
+			for i := range sb.bits {
+				r := xb.bits[i] & ^yb.bits[i]
+				sb.bits[i] = r
+				sum |= r
+			}
+			if sum != 0 {
+				sb = sb.next
+			} else {
+				// sb will be overwritten or removed
+			}
+
+			yb = yb.next
+		}
+		xb = xb.next
+	}
+
+	for xb != &x.root {
+		if sb == &s.root {
+			sb = s.insertBlockBefore(sb)
+		}
+		sb.offset = xb.offset
+		sb.bits = xb.bits
+		sb = sb.next
+
+		xb = xb.next
+	}
+
+	s.discardTail(sb)
+}
+
+// SymmetricDifferenceWith sets s to the symmetric difference s ∆ x.
+func (s *Sparse) SymmetricDifferenceWith(x *Sparse) {
+	if s == x {
+		s.Clear()
+		return
+	}
+
+	sb := s.start()
+	xb := x.start()
+	for xb != &x.root && sb != &s.root {
+		switch {
+		case sb.offset < xb.offset:
+			sb = sb.next
+		case xb.offset < sb.offset:
+			nb := s.insertBlockBefore(sb)
+			nb.offset = xb.offset
+			nb.bits = xb.bits
+			xb = xb.next
+		default:
+			var sum word
+			for i := range sb.bits {
+				r := sb.bits[i] ^ xb.bits[i]
+				sb.bits[i] = r
+				sum |= r
+			}
+			sb = sb.next
+			xb = xb.next
+			if sum == 0 {
+				s.removeBlock(sb.prev)
+			}
+		}
+	}
+
+	for xb != &x.root { // append the tail of x to s
+		sb = s.insertBlockBefore(sb)
+		sb.offset = xb.offset
+		sb.bits = xb.bits
+		sb = sb.next
+		xb = xb.next
+	}
+}
+
+// SymmetricDifference sets s to the symmetric difference x ∆ y.
+func (s *Sparse) SymmetricDifference(x, y *Sparse) {
+	switch {
+	case x == y:
+		s.Clear()
+		return
+	case s == x:
+		s.SymmetricDifferenceWith(y)
+		return
+	case s == y:
+		s.SymmetricDifferenceWith(x)
+		return
+	}
+
+	sb := s.start()
+	xb := x.start()
+	yb := y.start()
+	for xb != &x.root && yb != &y.root {
+		if sb == &s.root {
+			sb = s.insertBlockBefore(sb)
+		}
+		switch {
+		case yb.offset < xb.offset:
+			sb.offset = yb.offset
+			sb.bits = yb.bits
+			sb = sb.next
+			yb = yb.next
+		case xb.offset < yb.offset:
+			sb.offset = xb.offset
+			sb.bits = xb.bits
+			sb = sb.next
+			xb = xb.next
+		default:
+			var sum word
+			for i := range sb.bits {
+				r := xb.bits[i] ^ yb.bits[i]
+				sb.bits[i] = r
+				sum |= r
+			}
+			if sum != 0 {
+				sb.offset = xb.offset
+				sb = sb.next
+			}
+			xb = xb.next
+			yb = yb.next
+		}
+	}
+
+	for xb != &x.root { // append the tail of x to s
+		if sb == &s.root {
+			sb = s.insertBlockBefore(sb)
+		}
+		sb.offset = xb.offset
+		sb.bits = xb.bits
+		sb = sb.next
+		xb = xb.next
+	}
+
+	for yb != &y.root { // append the tail of y to s
+		if sb == &s.root {
+			sb = s.insertBlockBefore(sb)
+		}
+		sb.offset = yb.offset
+		sb.bits = yb.bits
+		sb = sb.next
+		yb = yb.next
+	}
+
+	s.discardTail(sb)
+}
+
+// SubsetOf reports whether s ∖ x = ∅.
+func (s *Sparse) SubsetOf(x *Sparse) bool {
+	if s == x {
+		return true
+	}
+
+	sb := s.start()
+	xb := x.start()
+	for sb != &s.root {
+		switch {
+		case xb == &x.root || xb.offset > sb.offset:
+			return false
+		case xb.offset < sb.offset:
+			xb = xb.next
+		default:
+			for i := range sb.bits {
+				if sb.bits[i]&^xb.bits[i] != 0 {
+					return false
+				}
+			}
+			sb = sb.next
+			xb = xb.next
+		}
+	}
+	return true
+}
+
+// Equals reports whether the sets s and t have the same elements.
+func (s *Sparse) Equals(t *Sparse) bool {
+	if s == t {
+		return true
+	}
+	sb := s.start()
+	tb := t.start()
+	for {
+		switch {
+		case sb == &s.root && tb == &t.root:
+			return true
+		case sb == &s.root || tb == &t.root:
+			return false
+		case sb.offset != tb.offset:
+			return false
+		case sb.bits != tb.bits:
+			return false
+		}
+
+		sb = sb.next
+		tb = tb.next
+	}
+}
+
+// String returns a human-readable description of the set s.
+func (s *Sparse) String() string {
+	var buf bytes.Buffer
+	buf.WriteByte('{')
+	s.forEach(func(x int) {
+		if buf.Len() > 1 {
+			buf.WriteByte(' ')
+		}
+		fmt.Fprintf(&buf, "%d", x)
+	})
+	buf.WriteByte('}')
+	return buf.String()
+}
+
+// BitString returns the set as a string of 1s and 0s denoting the sum
+// of the i'th powers of 2, for each i in s.  A radix point, always
+// preceded by a digit, appears if the sum is non-integral.
+//
+// Examples:
+//              {}.BitString() =      "0"
+//           {4,5}.BitString() = "110000"
+//            {-3}.BitString() =      "0.001"
+//      {-3,0,4,5}.BitString() = "110001.001"
+//
+func (s *Sparse) BitString() string {
+	if s.IsEmpty() {
+		return "0"
+	}
+
+	min, max := s.Min(), s.Max()
+	var nbytes int
+	if max > 0 {
+		nbytes = max
+	}
+	nbytes++ // zero bit
+	radix := nbytes
+	if min < 0 {
+		nbytes += len(".") - min
+	}
+
+	b := make([]byte, nbytes)
+	for i := range b {
+		b[i] = '0'
+	}
+	if radix < nbytes {
+		b[radix] = '.'
+	}
+	s.forEach(func(x int) {
+		if x >= 0 {
+			x += len(".")
+		}
+		b[radix-x] = '1'
+	})
+	return string(b)
+}
+
+// GoString returns a string showing the internal representation of
+// the set s.
+//
+func (s *Sparse) GoString() string {
+	var buf bytes.Buffer
+	for b := s.start(); b != &s.root; b = b.next {
+		fmt.Fprintf(&buf, "block %p {offset=%d next=%p prev=%p",
+			b, b.offset, b.next, b.prev)
+		for _, w := range b.bits {
+			fmt.Fprintf(&buf, " 0%016x", w)
+		}
+		fmt.Fprintf(&buf, "}\n")
+	}
+	return buf.String()
+}
+
+// AppendTo returns the result of appending the elements of s to slice
+// in order.
+func (s *Sparse) AppendTo(slice []int) []int {
+	s.forEach(func(x int) {
+		slice = append(slice, x)
+	})
+	return slice
+}
+
+// -- Testing/debugging ------------------------------------------------
+
+// check returns an error if the representation invariants of s are violated.
+func (s *Sparse) check() error {
+	if !s.root.empty() {
+		return fmt.Errorf("non-empty root block")
+	}
+	if s.root.offset != 0 {
+		return fmt.Errorf("root block has non-zero offset %d", s.root.offset)
+	}
+	for b := s.start(); b != &s.root; b = b.next {
+		if b.offset%bitsPerBlock != 0 {
+			return fmt.Errorf("bad offset modulo: %d", b.offset)
+		}
+		if b.empty() {
+			return fmt.Errorf("empty block")
+		}
+		if b.prev.next != b {
+			return fmt.Errorf("bad prev.next link")
+		}
+		if b.next.prev != b {
+			return fmt.Errorf("bad next.prev link")
+		}
+		if b.prev != &s.root {
+			if b.offset <= b.prev.offset {
+				return fmt.Errorf("bad offset order: b.offset=%d, prev.offset=%d",
+					b.offset, b.prev.offset)
+			}
+		}
+	}
+	return nil
+}

vendor/golang.org/x/tools/container/intsets/util.go

@@ -0,0 +1,84 @@
+// Copyright 2013 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package intsets
+
+// From Hacker's Delight, fig 5.2.
+func popcountHD(x uint32) int {
+	x -= (x >> 1) & 0x55555555
+	x = (x & 0x33333333) + ((x >> 2) & 0x33333333)
+	x = (x + (x >> 4)) & 0x0f0f0f0f
+	x = x + (x >> 8)
+	x = x + (x >> 16)
+	return int(x & 0x0000003f)
+}
+
+var a [1 << 8]byte
+
+func init() {
+	for i := range a {
+		var n byte
+		for x := i; x != 0; x >>= 1 {
+			if x&1 != 0 {
+				n++
+			}
+		}
+		a[i] = n
+	}
+}
+
+func popcountTable(x word) int {
+	return int(a[byte(x>>(0*8))] +
+		a[byte(x>>(1*8))] +
+		a[byte(x>>(2*8))] +
+		a[byte(x>>(3*8))] +
+		a[byte(x>>(4*8))] +
+		a[byte(x>>(5*8))] +
+		a[byte(x>>(6*8))] +
+		a[byte(x>>(7*8))])
+}
+
+// nlz returns the number of leading zeros of x.
+// From Hacker's Delight, fig 5.11.
+func nlz(x word) int {
+	x |= (x >> 1)
+	x |= (x >> 2)
+	x |= (x >> 4)
+	x |= (x >> 8)
+	x |= (x >> 16)
+	x |= (x >> 32)
+	return popcount(^x)
+}
+
+// ntz returns the number of trailing zeros of x.
+// From Hacker's Delight, fig 5.13.
+func ntz(x word) int {
+	if x == 0 {
+		return bitsPerWord
+	}
+	n := 1
+	if bitsPerWord == 64 {
+		if (x & 0xffffffff) == 0 {
+			n = n + 32
+			x = x >> 32
+		}
+	}
+	if (x & 0x0000ffff) == 0 {
+		n = n + 16
+		x = x >> 16
+	}
+	if (x & 0x000000ff) == 0 {
+		n = n + 8
+		x = x >> 8
+	}
+	if (x & 0x0000000f) == 0 {
+		n = n + 4
+		x = x >> 4
+	}
+	if (x & 0x00000003) == 0 {
+		n = n + 2
+		x = x >> 2
+	}
+	return n - int(x&1)
+}