Commit b8b0f87

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Speed up line/column in OffsetPosition

Building the index again and again for every OffsetPosition instance makes very little sense. So this makes it build it only once for a given source. I'm not sure if this is the best way to implement it and I'm afraid that a global synchronized map may be a performance bottleneck once the number of processors goes into the hundreds, but I know very little Scala/Java to do this properly. :-( Fixes http://stackoverflow.com/questions/14707127/accessing-position-information-in-a-scala-combinatorparser-kills-performance

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src/main/scala/scala/util/parsing/input
- OffsetPosition.scala

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`‎src/main/scala/scala/util/parsing/input/OffsetPosition.scala‎`

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Original file line number	Diff line number	Diff line change
`@@ -23,6 +23,16 @@ case class OffsetPosition(source: java.lang.CharSequence, offset: Int) extends P`
`23`	`23`
`24`	`24`	`/** An index that contains all line starts, including first line, and eof. */`
`25`	`25`	`private lazy val index: Array[Int] = {`
	`26`	`+ Option(OffsetPosition.indexCache.get(source)) match {`
	`27`	`+ case Some(index) => index`
	`28`	`+ case None =>`
	`29`	`+ val index = genIndex`
	`30`	`+ OffsetPosition.indexCache.put(source, index)`
	`31`	`+ index`
	`32`	`+ }`
	`33`	`+ }`
	`34`	`+`
	`35`	`+ private def genIndex: Array[Int] = {`
`26`	`36`	`val lineStarts = new ArrayBuffer[Int]`
`27`	`37`	`lineStarts += 0`
`28`	`38`	`for (i <- 0 until source.length)`
`@@ -71,3 +81,12 @@ case class OffsetPosition(source: java.lang.CharSequence, offset: Int) extends P`
`71`	`81`	`this.line == that.line && this.column < that.column`
`72`	`82`	`}`
`73`	`83`	`}`
	`84`	`+`
	`85`	`+/** An object holding the index cache.`
	`86`	`+ *`
	`87`	`+ * @author Tomáš Janoušek`
	`88`	`+ */`
	`89`	`+object OffsetPosition {`
	`90`	`+ private lazy val indexCache = java.util.Collections.synchronizedMap(`
	`91`	`+ new java.util.WeakHashMap[java.lang.CharSequence, Array[Int]])`
	`92`	`+}`

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Commit b8b0f87

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`‎src/main/scala/scala/util/parsing/input/OffsetPosition.scala‎`

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