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
|
/* __ *\
** ________ ___ / / ___ Scala API **
** / __/ __// _ | / / / _ | (c) 2007-2013, LAMP/EPFL **
** __\ \/ /__/ __ |/ /__/ __ | http://scala-lang.org/ **
** /____/\___/_/ |_/____/_/ | | **
** |/ **
\* */
package scala
package reflect.internal.pickling
object ByteCodecs {
def avoidZero(src: Array[Byte]): Array[Byte] = {
var i = 0
val srclen = src.length
var count = 0
while (i < srclen) {
if (src(i) == 0x7f) count += 1
i += 1
}
val dst = new Array[Byte](srclen + count)
i = 0
var j = 0
while (i < srclen) {
val in = src(i)
if (in == 0x7f) {
dst(j) = (0xc0).toByte
dst(j + 1) = (0x80).toByte
j += 2
} else {
dst(j) = (in + 1).toByte
j += 1
}
i += 1
}
dst
}
def regenerateZero(src: Array[Byte]): Int = {
var i = 0
val srclen = src.length
var j = 0
while (i < srclen) {
val in: Int = src(i) & 0xff
if (in == 0xc0 && (src(i + 1) & 0xff) == 0x80) {
src(j) = 0x7f
i += 2
} else if (in == 0) {
src(j) = 0x7f
i += 1
} else {
src(j) = (in - 1).toByte
i += 1
}
j += 1
}
j
}
def encode8to7(src: Array[Byte]): Array[Byte] = {
val srclen = src.length
val dstlen = (srclen * 8 + 6) / 7
val dst = new Array[Byte](dstlen)
var i = 0
var j = 0
while (i + 6 < srclen) {
var in: Int = src(i) & 0xff
dst(j) = (in & 0x7f).toByte
var out: Int = in >>> 7
in = src(i + 1) & 0xff
dst(j + 1) = (out | (in << 1) & 0x7f).toByte
out = in >>> 6
in = src(i + 2) & 0xff
dst(j + 2) = (out | (in << 2) & 0x7f).toByte
out = in >>> 5
in = src(i + 3) & 0xff
dst(j + 3) = (out | (in << 3) & 0x7f).toByte
out = in >>> 4
in = src(i + 4) & 0xff
dst(j + 4) = (out | (in << 4) & 0x7f).toByte
out = in >>> 3
in = src(i + 5) & 0xff
dst(j + 5) = (out | (in << 5) & 0x7f).toByte
out = in >>> 2
in = src(i + 6) & 0xff
dst(j + 6) = (out | (in << 6) & 0x7f).toByte
out = in >>> 1
dst(j + 7) = out.toByte
i += 7
j += 8
}
if (i < srclen) {
var in: Int = src(i) & 0xff
dst(j) = (in & 0x7f).toByte; j += 1
var out: Int = in >>> 7
if (i + 1 < srclen) {
in = src(i + 1) & 0xff
dst(j) = (out | (in << 1) & 0x7f).toByte; j += 1
out = in >>> 6
if (i + 2 < srclen) {
in = src(i + 2) & 0xff
dst(j) = (out | (in << 2) & 0x7f).toByte; j += 1
out = in >>> 5
if (i + 3 < srclen) {
in = src(i + 3) & 0xff
dst(j) = (out | (in << 3) & 0x7f).toByte; j += 1
out = in >>> 4
if (i + 4 < srclen) {
in = src(i + 4) & 0xff
dst(j) = (out | (in << 4) & 0x7f).toByte; j += 1
out = in >>> 3
if (i + 5 < srclen) {
in = src(i + 5) & 0xff
dst(j) = (out | (in << 5) & 0x7f).toByte; j += 1
out = in >>> 2
}
}
}
}
}
if (j < dstlen) dst(j) = out.toByte
}
dst
}
def decode7to8(src: Array[Byte], srclen: Int): Int = {
var i = 0
var j = 0
val dstlen = (srclen * 7 + 7) / 8
while (i + 7 < srclen) {
var out: Int = src(i).toInt
var in: Byte = src(i + 1)
src(j) = (out | (in & 0x01) << 7).toByte
out = in >>> 1
in = src(i + 2)
src(j + 1) = (out | (in & 0x03) << 6).toByte
out = in >>> 2
in = src(i + 3)
src(j + 2) = (out | (in & 0x07) << 5).toByte
out = in >>> 3
in = src(i + 4)
src(j + 3) = (out | (in & 0x0f) << 4).toByte
out = in >>> 4
in = src(i + 5)
src(j + 4) = (out | (in & 0x1f) << 3).toByte
out = in >>> 5
in = src(i + 6)
src(j + 5) = (out | (in & 0x3f) << 2).toByte
out = in >>> 6
in = src(i + 7)
src(j + 6) = (out | in << 1).toByte
i += 8
j += 7
}
if (i < srclen) {
var out: Int = src(i).toInt
if (i + 1 < srclen) {
var in: Byte = src(i + 1)
src(j) = (out | (in & 0x01) << 7).toByte; j += 1
out = in >>> 1
if (i + 2 < srclen) {
in = src(i + 2)
src(j) = (out | (in & 0x03) << 6).toByte; j += 1
out = in >>> 2
if (i + 3 < srclen) {
in = src(i + 3)
src(j) = (out | (in & 0x07) << 5).toByte; j += 1
out = in >>> 3
if (i + 4 < srclen) {
in = src(i + 4)
src(j) = (out | (in & 0x0f) << 4).toByte; j += 1
out = in >>> 4
if (i + 5 < srclen) {
in = src(i + 5)
src(j) = (out | (in & 0x1f) << 3).toByte; j += 1
out = in >>> 5
if (i + 6 < srclen) {
in = src(i + 6)
src(j) = (out | (in & 0x3f) << 2).toByte; j += 1
out = in >>> 6
}
}
}
}
}
}
if (j < dstlen) src(j) = out.toByte
}
dstlen
}
def encode(xs: Array[Byte]): Array[Byte] = avoidZero(encode8to7(xs))
/**
* Destructively decodes array xs and returns the length of the decoded array.
*
* Sometimes returns (length+1) of the decoded array. Example:
*
* scala> val enc = scala.reflect.generic.ByteCodecs.encode(Array(1,2,3))
* enc: Array[Byte] = Array(2, 5, 13, 1)
*
* scala> scala.reflect.generic.ByteCodecs.decode(enc)
* res43: Int = 4
*
* scala> enc
* res44: Array[Byte] = Array(1, 2, 3, 0)
*
* However, this does not always happen.
*/
def decode(xs: Array[Byte]): Int = {
val len = regenerateZero(xs)
decode7to8(xs, len)
}
}
|