From ca8dc7ada663e44aafe470944dd17256dbde151c Mon Sep 17 00:00:00 2001
From: Martin Odersky <odersky@gmail.com>
Date: Wed, 17 Apr 2013 09:48:22 +0200
Subject: Scanners added.

Moving Positions, Chars to new packages.
Added Source positions.
Added untyped trees module.
Factored out behavior between typed and untyped trees.
---
 src/dotty/tools/dotc/util/SourceFile.scala | 109 +++++++++++++++++++++++++++++
 1 file changed, 109 insertions(+)
 create mode 100644 src/dotty/tools/dotc/util/SourceFile.scala

(limited to 'src/dotty/tools/dotc/util/SourceFile.scala')

diff --git a/src/dotty/tools/dotc/util/SourceFile.scala b/src/dotty/tools/dotc/util/SourceFile.scala
new file mode 100644
index 000000000..a7a677560
--- /dev/null
+++ b/src/dotty/tools/dotc/util/SourceFile.scala
@@ -0,0 +1,109 @@
+package dotty.tools
+package dotc
+package util
+
+import scala.collection.mutable.ArrayBuffer
+import dotty.tools.io._
+import annotation.tailrec
+import java.util.regex.Pattern
+import java.io.IOException
+import Chars._
+import ScriptSourceFile._
+import Positions._
+
+object ScriptSourceFile {
+  private val headerPattern = Pattern.compile("""^(::)?!#.*(\r|\n|\r\n)""", Pattern.MULTILINE)
+  private val headerStarts  = List("#!", "::#!")
+
+  def apply(file: AbstractFile, content: Array[Char]) = {
+    /** Length of the script header from the given content, if there is one.
+     *  The header begins with "#!" or "::#!" and ends with a line starting
+     *  with "!#" or "::!#".
+     */
+    val headerLength =
+      if (headerStarts exists (content startsWith _)) {
+        val matcher = headerPattern matcher content.mkString
+        if (matcher.find) matcher.end
+        else throw new IOException("script file does not close its header with !# or ::!#")
+      } else 0
+    new SourceFile(file, content drop headerLength) {
+      override val underlying = new SourceFile(file, content)
+    }
+  }
+}
+
+case class SourceFile(file: AbstractFile, content: Array[Char]) {
+
+  def this(_file: AbstractFile)                 = this(_file, _file.toCharArray)
+  def this(sourceName: String, cs: Seq[Char])   = this(new VirtualFile(sourceName), cs.toArray)
+  def this(file: AbstractFile, cs: Seq[Char])   = this(file, cs.toArray)
+
+  override def equals(that : Any) = that match {
+    case that : SourceFile => file.path == that.file.path && start == that.start
+    case _ => false
+  }
+  override def hashCode = file.path.## + start.##
+
+  val length = content.length
+
+  /** true for all source files except `NoSource` */
+  def exists: Boolean = true
+
+  /** The underlying source file */
+  def underlying: SourceFile = this
+
+  /** The start of this file in the underlying source file */
+  def start = 0
+
+  def atPos(pos: Position): SourcePosition =
+    SourcePosition(underlying, pos)
+
+  def isSelfContained = underlying eq this
+
+  /** Map a position to a position in the underlying source file.
+   *  For regular source files, simply return the argument.
+   */
+  def positionInUltimateSource(position: SourcePosition): SourcePosition =
+    SourcePosition(underlying, position.pos shift start)
+
+  def isLineBreak(idx: Int) =
+    if (idx >= length) false else {
+      val ch = content(idx)
+      // don't identify the CR in CR LF as a line break, since LF will do.
+      if (ch == CR) (idx + 1 == length) || (content(idx + 1) != LF)
+      else isLineBreakChar(ch)
+    }
+
+  def calculateLineIndices(cs: Array[Char]) = {
+    val buf = new ArrayBuffer[Int]
+    buf += 0
+    for (i <- 0 until cs.length) if (isLineBreak(i)) buf += i + 1
+    buf += cs.length // sentinel, so that findLine below works smoother
+    buf.toArray
+  }
+  private lazy val lineIndices: Array[Int] = calculateLineIndices(content)
+
+  /** Map line to offset of first character in line */
+  def lineToOffset(index : Int): Int = lineIndices(index)
+
+  /** A cache to speed up offsetToLine searches to similar lines */
+  private var lastLine = 0
+
+  /** Convert offset to line in this source file
+   *  Lines are numbered from 0
+   */
+  def offsetToLine(offset: Int): Int = {
+    val lines = lineIndices
+    def findLine(lo: Int, hi: Int, mid: Int): Int =
+      if (offset < lines(mid)) findLine(lo, mid - 1, (lo + mid - 1) / 2)
+      else if (offset >= lines(mid + 1)) findLine(mid + 1, hi, (mid + 1 + hi) / 2)
+      else mid
+    lastLine = findLine(0, lines.length, lastLine)
+    lastLine
+  }
+}
+
+object NoSource extends SourceFile("<no source>", Nil) {
+  override def exists = false
+}
+
-- 
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