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Diffstat (limited to 'src/compiler/scala/reflect/common/pickling/ByteCodecs.scala')
| -rw-r--r-- | src/compiler/scala/reflect/common/pickling/ByteCodecs.scala | 224 |
1 files changed, 224 insertions, 0 deletions
diff --git a/src/compiler/scala/reflect/common/pickling/ByteCodecs.scala b/src/compiler/scala/reflect/common/pickling/ByteCodecs.scala new file mode 100644 index 0000000000..57d5eb63e8 --- /dev/null +++ b/src/compiler/scala/reflect/common/pickling/ByteCodecs.scala @@ -0,0 +1,224 @@ +/* __ *\ +** ________ ___ / / ___ Scala API ** +** / __/ __// _ | / / / _ | (c) 2007-2011, LAMP/EPFL ** +** __\ \/ /__/ __ |/ /__/ __ | http://scala-lang.org/ ** +** /____/\___/_/ |_/____/_/ | | ** +** |/ ** +\* */ +package scala.reflect.common.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 { + 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 + } + + @deprecated("use 2-argument version instead", "2.8.0") + def decode7to8(src: Array[Byte], srclen: Int, dstlen: Int) { decode7to8(src, srclen) } + + 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)) + + @deprecated("use 1-argument version instead", "2.8.0") + def decode(xs: Array[Byte], dstlen: Int) { decode(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) + } +} + + + + + + + + |