aboutsummaryrefslogtreecommitdiff
path: root/src/cmd/compile/internal/ssa/biasedsparsemap.go
blob: 0d351544540e6f8ff3c94b2192c804971fa9a881 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
// Copyright 2018 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 ssa

import (
	"cmd/internal/src"
	"math"
)

// A biasedSparseMap is a sparseMap for integers between J and K inclusive,
// where J might be somewhat larger than zero (and K-J is probably much smaller than J).
// (The motivating use case is the line numbers of statements for a single function.)
// Not all features of a SparseMap are exported, and it is also easy to treat a
// biasedSparseMap like a SparseSet.
type biasedSparseMap struct {
	s     *sparseMap
	first int
}

// newBiasedSparseMap returns a new biasedSparseMap for values between first and last, inclusive.
func newBiasedSparseMap(first, last int) *biasedSparseMap {
	if first > last {
		return &biasedSparseMap{first: math.MaxInt32, s: nil}
	}
	return &biasedSparseMap{first: first, s: newSparseMap(1 + last - first)}
}

// cap returns one more than the largest key valid for s
func (s *biasedSparseMap) cap() int {
	if s == nil || s.s == nil {
		return 0
	}
	return s.s.cap() + int(s.first)
}

// size returns the number of entries stored in s
func (s *biasedSparseMap) size() int {
	if s == nil || s.s == nil {
		return 0
	}
	return s.s.size()
}

// contains reports whether x is a key in s
func (s *biasedSparseMap) contains(x uint) bool {
	if s == nil || s.s == nil {
		return false
	}
	if int(x) < s.first {
		return false
	}
	if int(x) >= s.cap() {
		return false
	}
	return s.s.contains(ID(int(x) - s.first))
}

// get returns the value s maps for key x, or -1 if
// x is not mapped or is out of range for s.
func (s *biasedSparseMap) get(x uint) int32 {
	if s == nil || s.s == nil {
		return -1
	}
	if int(x) < s.first {
		return -1
	}
	if int(x) >= s.cap() {
		return -1
	}
	return s.s.get(ID(int(x) - s.first))
}

// getEntry returns the i'th key and value stored in s,
// where 0 <= i < s.size()
func (s *biasedSparseMap) getEntry(i int) (x uint, v int32) {
	e := s.s.contents()[i]
	x = uint(int(e.key) + s.first)
	v = e.val
	return
}

// add inserts x->0 into s, provided that x is in the range of keys stored in s.
func (s *biasedSparseMap) add(x uint) {
	if int(x) < s.first || int(x) >= s.cap() {
		return
	}
	s.s.set(ID(int(x)-s.first), 0, src.NoXPos)
}

// add inserts x->v into s, provided that x is in the range of keys stored in s.
func (s *biasedSparseMap) set(x uint, v int32) {
	if int(x) < s.first || int(x) >= s.cap() {
		return
	}
	s.s.set(ID(int(x)-s.first), v, src.NoXPos)
}

// remove removes key x from s.
func (s *biasedSparseMap) remove(x uint) {
	if int(x) < s.first || int(x) >= s.cap() {
		return
	}
	s.s.remove(ID(int(x) - s.first))
}

func (s *biasedSparseMap) clear() {
	if s.s != nil {
		s.s.clear()
	}
}