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authorMartin Odersky <odersky@gmail.com>2015-04-29 10:36:16 +0200
committerMartin Odersky <odersky@gmail.com>2015-05-02 19:23:08 +0200
commit60ab9f8f525d319aa5b6d5052018c6781da036eb (patch)
treefbc5096a1f7193a4970226a7ad6f03fbf7670a4b /src/dotty/tools/dotc/core/classfile/ByteCodecs.scala
parentac46a0e4489bba4f76863cc1491bf2b8441ed1cb (diff)
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Pickling modularization reorg
The pickling package got rather large and confusing with three separate tasks that each had their own conventions: read JVM classfiles, read Scala2 pickle info, read Tasty. The classes for each task are now in separate packages.
Diffstat (limited to 'src/dotty/tools/dotc/core/classfile/ByteCodecs.scala')
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diff --git a/src/dotty/tools/dotc/core/classfile/ByteCodecs.scala b/src/dotty/tools/dotc/core/classfile/ByteCodecs.scala
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+++ b/src/dotty/tools/dotc/core/classfile/ByteCodecs.scala
@@ -0,0 +1,221 @@
+/* __ *\
+** ________ ___ / / ___ Scala API **
+** / __/ __// _ | / / / _ | (c) 2007-2011, LAMP/EPFL **
+** __\ \/ /__/ __ |/ /__/ __ | http://scala-lang.org/ **
+** /____/\___/_/ |_/____/_/ | | **
+** |/ **
+\* */
+package dotty.tools.dotc.core.classfile
+
+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)
+ 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)
+ 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 = reflect.generic.ByteCodecs.encode(Array(1,2,3))
+ * enc: Array[Byte] = Array(2, 5, 13, 1)
+ *
+ * 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)
+ }
+}
+
+
+
+
+
+
+
+