From ce67a1556085862e27d654bf5e6ee45ae885abfe Mon Sep 17 00:00:00 2001 From: Martin Odersky Date: Fri, 12 Mar 2010 18:39:40 +0000 Subject: Added an object to mangle byte arrays into Java... Added an object to mangle byte arrays into Java classfile's version of UTF8. --- src/library/scala/reflect/generic/ByteCodecs.scala | 269 +++++++++++++++++++++ 1 file changed, 269 insertions(+) create mode 100644 src/library/scala/reflect/generic/ByteCodecs.scala (limited to 'src') diff --git a/src/library/scala/reflect/generic/ByteCodecs.scala b/src/library/scala/reflect/generic/ByteCodecs.scala new file mode 100644 index 0000000000..a172e425ef --- /dev/null +++ b/src/library/scala/reflect/generic/ByteCodecs.scala @@ -0,0 +1,269 @@ +/* __ *\ +** ________ ___ / / ___ Scala API ** +** / __/ __// _ | / / / _ | (c) 2007-2010, LAMP/EPFL ** +** __\ \/ /__/ __ |/ /__/ __ | http://scala-lang.org/ ** +** /____/\___/_/ |_/____/_/ | | ** +** |/ ** +\* */ +package scala.reflect.generic + +object ByteCodecs { + + def bump(src: Array[Byte], len: Int, delta: Int) { + var i = 0 + while (i < len) { + val in: Int = src(i) & 0xff + src(i) = (in + delta).toByte + i += 1 + } + } + + def encodeZeroes(src: Array[Byte]): Array[Byte] = { + var i = 0 + val srclen = src.length + var count = 0 + while (i < srclen) { + if (src(i) == 0) 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 == 0) { + dst(j) = (0xc0).toByte + dst(j + 1) = (0x80).toByte + j += 2 + } else { + dst(j) = in + j += 1 + } + i += 1 + } + dst + } + + def decodeZeroes(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) = 0 + i += 2 + } else { + src(j) = in.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, dstlen: Int) { + var i = 0 + var j = 0 + 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 + } + } + + def encode(xs: Array[Byte]): Array[Byte] = { + val ys = xs.clone() + bump(ys, ys.length, 1) + encodeZeroes(encode8to7(ys)) + } + + /** Destructively decode array xs */ + def decode(xs: Array[Byte], dstlen: Int) { + val len = decodeZeroes(xs) + decode7to8(xs, len, dstlen) + bump(xs, dstlen, -1) + } + +// test & debug, preliminary ---------------------------------- + + def testBump(xs: Array[Byte]) { + val xs0 = xs.clone() + bump(xs, xs.length, 1) + bump(xs, xs.length, -1) + assert(xs.deep == xs0.deep, xs0.deep) + } + + def testZeroes(xs: Array[Byte]) { + val ys = encodeZeroes(xs) + val len = decodeZeroes(ys) + assert(len == xs.length && ys.take(len).deep == xs.deep, + "testZeroes("+xs.deep+") failed; len = "+len+", result = "+ys.take(len).deep) + } + + def test8to7(xs: Array[Byte]) { + val ys = encode8to7(xs) + decode7to8(ys, ys.length, xs.length) + assert(ys.take(xs.length).deep == xs.deep, + "test8to7("+xs.deep+") failed, result = "+ys.take(xs.length).deep) + } + + def testAll(xs: Array[Byte]) { + val ys = encode(xs) + decode(ys, xs.length) + assert(ys.take(xs.length).deep == xs.deep, + "testAll("+xs.deep+") failed, result = "+ys.take(xs.length).deep) + } + + def test(inputs: Array[Byte]*) { + for (input <- inputs) { + testBump(input) + test8to7(input) + testAll(input) + } + } + + def main(args: Array[String]) { + test( + Array(1, 2, 3), + Array(1, 2, 3, 4, 5, 6, 7), + Array(1, -2, 0, -3, -5, -6, -7), + Array(1, 3, -1, -128, 0, 0, -128, 1, 2, 3)) + val rand = new scala.util.Random() + for (i <- 1 until 50000) { + if (i % 100 == 0) println("tested "+i) + var xs = new Array[Byte](i) + rand.nextBytes(xs) + test(xs) + } + println("tested OK") + } +} + + + + + + + + -- cgit v1.2.3