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161874da2a
Each URL was manually verified to ensure it did not serve up incorrect content. Change-Id: I4dc846227af95a73ee9a3074d0c379ff0fa955df Reviewed-on: https://go-review.googlesource.com/115798 Reviewed-by: Ian Lance Taylor <iant@golang.org> Run-TryBot: Ian Lance Taylor <iant@golang.org>
93 lines
2 KiB
Go
93 lines
2 KiB
Go
// Copyright 2015 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package ssa
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import "cmd/internal/src"
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// from https://research.swtch.com/sparse
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// in turn, from Briggs and Torczon
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type sparseEntry struct {
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key ID
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val int32
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aux src.XPos
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}
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type sparseMap struct {
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dense []sparseEntry
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sparse []int32
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}
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// newSparseMap returns a sparseMap that can map
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// integers between 0 and n-1 to int32s.
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func newSparseMap(n int) *sparseMap {
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return &sparseMap{dense: nil, sparse: make([]int32, n)}
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}
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func (s *sparseMap) cap() int {
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return len(s.sparse)
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}
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func (s *sparseMap) size() int {
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return len(s.dense)
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}
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func (s *sparseMap) contains(k ID) bool {
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i := s.sparse[k]
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return i < int32(len(s.dense)) && s.dense[i].key == k
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}
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// get returns the value for key k, or -1 if k does
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// not appear in the map.
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func (s *sparseMap) get(k ID) int32 {
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i := s.sparse[k]
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if i < int32(len(s.dense)) && s.dense[i].key == k {
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return s.dense[i].val
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}
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return -1
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}
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func (s *sparseMap) set(k ID, v int32, a src.XPos) {
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i := s.sparse[k]
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if i < int32(len(s.dense)) && s.dense[i].key == k {
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s.dense[i].val = v
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s.dense[i].aux = a
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return
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}
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s.dense = append(s.dense, sparseEntry{k, v, a})
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s.sparse[k] = int32(len(s.dense)) - 1
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}
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// setBit sets the v'th bit of k's value, where 0 <= v < 32
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func (s *sparseMap) setBit(k ID, v uint) {
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if v >= 32 {
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panic("bit index too large.")
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}
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i := s.sparse[k]
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if i < int32(len(s.dense)) && s.dense[i].key == k {
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s.dense[i].val |= 1 << v
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return
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}
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s.dense = append(s.dense, sparseEntry{k, 1 << v, src.NoXPos})
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s.sparse[k] = int32(len(s.dense)) - 1
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}
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func (s *sparseMap) remove(k ID) {
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i := s.sparse[k]
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if i < int32(len(s.dense)) && s.dense[i].key == k {
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y := s.dense[len(s.dense)-1]
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s.dense[i] = y
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s.sparse[y.key] = i
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s.dense = s.dense[:len(s.dense)-1]
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}
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}
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func (s *sparseMap) clear() {
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s.dense = s.dense[:0]
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}
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func (s *sparseMap) contents() []sparseEntry {
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return s.dense
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}
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