-
Notifications
You must be signed in to change notification settings - Fork 0
/
psbytes.go
263 lines (253 loc) · 5.53 KB
/
psbytes.go
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
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
// Copyright (c) 2022, Joshua J Baker. All rights reserved.
// Use of this source code is governed by an MIT-style
// license that can be found in the LICENSE file.
package progsort
import (
"math"
"runtime"
"sync"
"sync/atomic"
"time"
)
// SortBytes data given the provided less function.
//
// The spare param is a slice that the caller can provide for helping with the
// merge sort algorithm. When this is provided it must the same length as the
// data slice, also the caller is responsible for checking the return value to
// determine if the data slice or the spare slice has the final sorted data.
// Setting spare to nil will have the sort operation manage the memory of the
// spare slice under-the-hood by allocating the needed memory, which also
// ensures that the data slice will always end up with the final sorted data.
//
// The prog function can be optionally provided if the caller want to monitor
// the continual progress of the sort operation, which is a percentage between
// the range [0.0,1.0]. Set prog to nil if progress monitoring is not needed.
// Returning false from the prog function will cancel the sorting early.
func SortBytes(
data []byte,
spare []byte,
elsize int,
less func(a, b []byte) bool,
prog func(prec float64) bool,
) (swapped bool) {
if len(data)%elsize != 0 {
panic("len(data)%elsize != 0")
}
var spared bool
if spare == nil {
spare = make([]byte, len(data))
}
if len(data) != len(spare) {
panic("len(active) != len(spare)")
}
nprocs := runtime.NumCPU()
var vprog int32
var vcancel int32
var vdone int32
var wg sync.WaitGroup
if prog != nil {
wg.Add(1)
go func() {
defer wg.Done()
var lperc float64
for {
done := atomic.LoadInt32(&vdone) == 1
perc := float64(atomic.LoadInt32(&vprog)) / math.MaxInt32
if perc > lperc {
if !prog(perc) {
atomic.StoreInt32(&vcancel, 1)
break
}
}
if done {
break
}
time.Sleep(time.Second / 5)
}
}()
}
swapped = mergeSortBytes(data, spare,
len(data)/elsize, elsize, nprocs,
less, &vprog, &vcancel)
if swapped && spared {
copy(data, spare)
swapped = false
}
atomic.StoreInt32(&vprog, math.MaxInt32)
atomic.StoreInt32(&vdone, 1)
wg.Wait()
return swapped
}
func mergeSortBytes(
active []byte,
spare []byte,
nitems int,
elsize int,
nprocs int,
less func(a, b []byte) bool,
prog *int32,
cancel *int32,
) (swapped bool) {
start, end := 0, nitems
nmlevels := calcMergeLevels(end - start)
nsteps := int64(nmlevels * (end - start))
var smu sync.Mutex
var steps int64
var datas [2][]byte
datas[0] = active
datas[1] = spare
var wg sync.WaitGroup
mergeC := make(chan mergeGroup, nprocs*16)
defer func() {
close(mergeC)
wg.Wait()
}()
for g := 0; g < nprocs; g++ {
go func() {
var scounter int64
for m := range mergeC {
for i := 0; i < m.count; i++ {
var ok bool
scounter, ok = mergeSortUnitBytes(
m.i1, m.i1+m.z1, m.i2, m.i2+m.z2,
active, spare, nitems, elsize, less, prog, cancel,
&smu, &steps, nsteps,
scounter,
)
if !ok {
break
}
m.i1 += m.z1 + m.z2
m.i2 = m.i1 + m.z1
}
if scounter > pchunk {
if !addSteps(scounter, prog, cancel, &smu, &steps, nsteps) {
break
}
scounter = 0
}
wg.Add(-m.count)
}
}()
}
var gm mergeGroup
csize := 1
mlevel := 0
for ; mlevel < nmlevels; mlevel++ {
active = datas[mlevel&1]
spare = datas[(mlevel+1)&1]
for i := start; i < end; {
i1 := i
i2 := i + csize
size1 := csize
size2 := csize
if i2 > end {
size1 = end - i1
i2 = end
size2 = 0
} else if i2+size2 > end {
size2 = end - i2
}
m := mergeGroup{i1: i1, z1: size1, i2: i2, z2: size2}
if mlevel > 7 || size1 != csize || size2 != csize {
wg.Add(1)
m.count = 1
mergeC <- m
} else {
if gm.count == 0 {
gm = m
}
gm.count++
if gm.count == 256>>mlevel {
wg.Add(gm.count)
mergeC <- gm
gm.count = 0
}
}
if atomic.LoadInt32(cancel) != 0 {
break
}
i += size1 + size2
}
if gm.count > 0 {
wg.Add(gm.count)
mergeC <- gm
gm.count = 0
}
wg.Wait()
if atomic.LoadInt32(cancel) != 0 {
break
}
csize *= 2
}
swapped = mlevel&1 == 1
return swapped
}
func mergeSortUnitBytes(
start1, end1 int,
start2, end2 int,
active, spare []byte,
nitems int,
elsize int,
less func(a, b []byte) bool,
prog *int32,
cancel *int32,
smu *sync.Mutex,
steps *int64,
nsteps int64,
scounter int64,
) (int64, bool) {
i := start1
var a, b []byte
var aset, bset bool
for start1 < end1 && start2 < end2 {
if !aset {
a = active[start1*elsize:][:elsize]
}
if !bset {
b = active[start2*elsize:][:elsize]
}
if less(b, a) {
copy(spare[i*elsize:][:elsize], active[start2*elsize:][:elsize])
start2++
bset = false
} else {
copy(spare[i*elsize:][:elsize], active[start1*elsize:][:elsize])
start1++
aset = false
}
i++
scounter++
if scounter > pchunk {
if !addSteps(scounter, prog, cancel, smu, steps, nsteps) {
return 0, false
}
scounter = 0
}
}
for start1 < end1 {
copy(spare[i*elsize:][:elsize], active[start1*elsize:][:elsize])
start1++
i++
scounter++
if scounter > pchunk {
if !addSteps(scounter, prog, cancel, smu, steps, nsteps) {
return 0, false
}
scounter = 0
}
}
for start2 < end2 {
copy(spare[i*elsize:][:elsize], active[start2*elsize:][:elsize])
start2++
i++
scounter++
if scounter > pchunk {
if !addSteps(scounter, prog, cancel, smu, steps, nsteps) {
return 0, false
}
scounter = 0
}
}
return scounter, true
}