Implemented some missing functionality in function C_readtablehead.

com.oracle.truffle.r.nodes.builtin/src/com/oracle/truffle/r/nodes/builtin/base/foreign/ReadTableHead.java

@@ -12,9 +12,12 @@
 package com.oracle.truffle.r.nodes.builtin.base.foreign;
 
 import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
 
 import com.oracle.truffle.api.CompilerDirectives.TruffleBoundary;
 import com.oracle.truffle.api.dsl.Specialization;
+import com.oracle.truffle.r.nodes.builtin.CastBuilder.Predef;
 import com.oracle.truffle.r.nodes.builtin.RExternalBuiltinNode;
 import com.oracle.truffle.r.runtime.RError;
 import com.oracle.truffle.r.runtime.RError.Message;
@@ -28,17 +31,51 @@ public abstract class ReadTableHead extends RExternalBuiltinNode.Arg7 {
         Casts casts = new Casts(ReadTableHead.class);
         casts.arg(0).defaultError(Message.INVALID_CONNECTION).mustNotBeNull().asIntegerVector().findFirst();
         casts.arg(1).mustNotBeNull().asIntegerVector().findFirst();
+        casts.arg(2).mustNotBeMissing().mustBe(Predef.stringValue()).asStringVector().findFirst();
+        casts.arg(3).mustNotBeMissing().mustBe(Predef.logicalValue()).asLogicalVector().findFirst().map(Predef.toBoolean());
+        casts.arg(4).mustNotBeMissing().mustBe(Predef.stringValue()).asStringVector().findFirst();
+        casts.arg(5).mustNotBeMissing().mustBe(Predef.stringValue()).asStringVector().findFirst();
+        casts.arg(6).mustNotBeMissing().mustBe(Predef.logicalValue()).asLogicalVector().findFirst().map(Predef.toBoolean());
     }
 
     @Specialization
     @TruffleBoundary
-    public RAbstractStringVector read(int con, int nlines, @SuppressWarnings("unused") Object commentChar, @SuppressWarnings("unused") Object blankLinesSkip,
-                    @SuppressWarnings("unused") Object quote, @SuppressWarnings("unused") Object sep, @SuppressWarnings("unused") Object skipNull) {
+    public RAbstractStringVector read(int con, int nlines, String commentChar, boolean blankLinesSkip,
+                    String quote, String sep, boolean skipNull) {
         // TODO This is quite incomplete and just uses readLines, which works for some inputs
         try (RConnection openConn = RConnection.fromIndex(con).forceOpen("r")) {
-            return RDataFactory.createStringVector(openConn.readLines(nlines, true, false), RDataFactory.COMPLETE_VECTOR);
+            List<String> lines = new ArrayList<>(nlines);
+            int totalLines = 0;
+            while (totalLines < nlines) {
+                String[] readLines = openConn.readLines(nlines - totalLines, true, skipNull);
+                if (readLines.length == 0) {
+                    break;
+                }
+
+                for (int i = 0; i < readLines.length; i++) {
+                    postprocessLine(lines, readLines[i], commentChar, blankLinesSkip, quote, sep);
+                }
+                totalLines += lines.size();
+            }
+
+            return RDataFactory.createStringVector(lines.toArray(new String[0]), RDataFactory.COMPLETE_VECTOR);
         } catch (IOException ex) {
             throw error(RError.Message.ERROR_READING_CONNECTION, ex.getMessage());
         }
     }
+
+    private static void postprocessLine(List<String> lines, String string, String commentChar, boolean blankLinesSkip, @SuppressWarnings("unused") String quote,
+                    @SuppressWarnings("unused") String sep) {
+        // TODO quote, sep
+        if (blankLinesSkip && string.isEmpty()) {
+            return;
+        }
+
+        if (commentChar != null && !commentChar.isEmpty() && string.startsWith(commentChar)) {
+            return;
+        }
+
+        // no reason why not to add
+        lines.add(string);
+    }
 }