[SPARK-6811] Copy SparkR lib in make-distribution.sh

This change also remove native libraries from SparkR to make sure our distribution works across platforms

Tested by building on Mac, running on Amazon Linux (CentOS), Windows VM and vice-versa (built on Linux run on Mac)

I will also test this with YARN soon and update this PR.

Author: Shivaram Venkataraman <shivaram@cs.berkeley.edu>

Closes #6373 from shivaram/sparkr-binary and squashes the following commits:

ae41b5c [Shivaram Venkataraman] Remove native libraries from SparkR Also include the built SparkR package in make-distribution.sh

R/pkg/NAMESPACE

 # Imports from base R
 importFrom(methods, setGeneric, setMethod, setOldClass)
-useDynLib(SparkR, stringHashCode)
+
+# Disable native libraries till we figure out how to package it
+# See SPARKR-7839
+#useDynLib(SparkR, stringHashCode)
 
 # S3 methods exported
 export("sparkR.init")

R/pkg/R/utils.R

@@ -122,13 +122,49 @@ hashCode <- function(key) {
     intBits <- packBits(rawToBits(rawVec), "integer")
     as.integer(bitwXor(intBits[2], intBits[1]))
   } else if (class(key) == "character") {
-    .Call("stringHashCode", key)
+    # TODO: SPARK-7839 means we might not have the native library available
+    if (is.loaded("stringHashCode")) {
+      .Call("stringHashCode", key)
+    } else {
+      n <- nchar(key)
+      if (n == 0) {
+        0L
+      } else {
+        asciiVals <- sapply(charToRaw(key), function(x) { strtoi(x, 16L) })
+        hashC <- 0
+        for (k in 1:length(asciiVals)) {
+          hashC <- mult31AndAdd(hashC, asciiVals[k])
+        }
+        as.integer(hashC)
+      }
+    }
   } else {
     warning(paste("Could not hash object, returning 0", sep = ""))
     as.integer(0)
   }
 }
 
+# Helper function used to wrap a 'numeric' value to integer bounds.
+# Useful for implementing C-like integer arithmetic
+wrapInt <- function(value) {
+  if (value > .Machine$integer.max) {
+    value <- value - 2 * .Machine$integer.max - 2
+  } else if (value < -1 * .Machine$integer.max) {
+    value <- 2 * .Machine$integer.max + value + 2
+  }
+  value
+}
+
+# Multiply `val` by 31 and add `addVal` to the result. Ensures that
+# integer-overflows are handled at every step.
+mult31AndAdd <- function(val, addVal) {
+  vec <- c(bitwShiftL(val, c(4,3,2,1,0)), addVal)
+  Reduce(function(a, b) {
+          wrapInt(as.numeric(a) + as.numeric(b))
+         },
+         vec)
+}
+
 # Create a new RDD with serializedMode == "byte".
 # Return itself if already in "byte" format.
 serializeToBytes <- function(rdd) {

make-distribution.sh

@@ -229,6 +229,8 @@ cp "$SPARK_HOME"/conf/*.template "$DISTDIR"/conf
 cp "$SPARK_HOME/README.md" "$DISTDIR"
 cp -r "$SPARK_HOME/bin" "$DISTDIR"
 cp -r "$SPARK_HOME/python" "$DISTDIR"
+mkdir -p "$DISTDIR"/R/lib
+cp -r "$SPARK_HOME/R/lib/SparkR" "$DISTDIR"/R/lib
 cp -r "$SPARK_HOME/sbin" "$DISTDIR"
 cp -r "$SPARK_HOME/ec2" "$DISTDIR"