From 1c5f3b75f7e70e8608d6be442087857bd4a6b2cc Mon Sep 17 00:00:00 2001
From: Martin Odersky <odersky@gmail.com>
Date: Tue, 10 Feb 2015 12:39:15 +0100
Subject: Add TASTY readers and printers for TASTy info.

So far printing is the only reader, ie. deserializer.

Numerous bugfixes to make first tests work.
---
 .../tools/dotc/core/pickling/TastyReader.scala     | 78 ++++++++++++++++++++++
 1 file changed, 78 insertions(+)
 create mode 100644 src/dotty/tools/dotc/core/pickling/TastyReader.scala

(limited to 'src/dotty/tools/dotc/core/pickling/TastyReader.scala')

diff --git a/src/dotty/tools/dotc/core/pickling/TastyReader.scala b/src/dotty/tools/dotc/core/pickling/TastyReader.scala
new file mode 100644
index 000000000..659eb8977
--- /dev/null
+++ b/src/dotty/tools/dotc/core/pickling/TastyReader.scala
@@ -0,0 +1,78 @@
+package dotty.tools
+package dotc
+package core
+package pickling
+
+
+import TastyBuffer._
+import TastyName.NameRef
+import collection.mutable
+
+/** A byte array bufferfer that can be filled with bytes or natural numbers in TASTY format,
+ *  and that supports reading and patching addresses represented as natural numbers.
+ */
+class TastyReader(val bytes: Array[Byte], val from: Addr, val end: Addr) {
+  
+  def this(bytes: Array[Byte]) = this(bytes, Addr(0), Addr(bytes.length))
+  
+  private var bp: Int = from.index
+  
+  def currentAddr: Addr = Addr(bp)
+    
+  def atEnd: Boolean = bp == end.index
+  
+  /** Read a byte of data. */
+  def readByte(): Int = {
+    val result = bytes(bp) & 0xff
+    bp += 1
+    result
+  }
+  
+  /** Read the next `n` bytes of `data`. */
+  def readBytes(n: Int): Array[Byte] = {
+    val result = new Array[Byte](n)
+    Array.copy(bytes, bp, result, 0, n)
+    bp += n
+    result
+  }
+
+  /** Read a natural number fitting in an Int in big endian format, base 128.
+   *  All but the last digits have bit 0x80 set.
+   */
+  def readNat(): Int = readLongNat.toInt
+    
+  /** Read a natural number fitting in a Long in big endian format, base 128.
+   *  All but the last digits have bit 0x80 set.
+   */
+  def readLongNat(): Long = {
+    var b = 0L
+    var x = 0L
+    do {
+      b = bytes(bp)
+      x = (x << 7) | (b & 0x7f)
+      bp += 1
+    } while ((b & 0x80) == 0)
+    x
+  }
+  
+  /** Read `nbytes` bytes in big endian format into a Long */
+  def readRaw(nbytes: Int): Unit = {
+    def recur(x: Long, n: Int): Long = 
+      if (n == 0) x else recur((x << 8) | (readByte & 0xff), n - 1)
+    recur(0, nbytes)
+  }
+  
+  def readNameRef() = NameRef(readNat())
+  
+  def readEnd(): Addr = Addr(readNat() + bp)
+  
+  def skipTo(addr: Addr): Unit = 
+    bp = addr.index
+  
+  def until[T](end: Addr)(op: => T): List[T] = {
+    val buf = new mutable.ListBuffer[T]
+    while (bp < end.index) buf += op
+    assert(bp == end.index)
+    buf.toList
+  }
+}
-- 
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