Pass newly added tests :fingers-crossed:

1 files changed, 33 insertions, 17 deletions

diff --git a/src/main/java/dev/morling/onebrc/CalculateAverage_palmr.java b/src/main/java/dev/morling/onebrc/CalculateAverage_palmr.java
index c687031..5dcfcde 100644
--- a/src/main/java/dev/morling/onebrc/CalculateAverage_palmr.java
+++ b/src/main/java/dev/morling/onebrc/CalculateAverage_palmr.java
@@ -27,16 +27,15 @@ import java.util.stream.StreamSupport;
 public class CalculateAverage_palmr {
     private static final String FILE = "./measurements.txt";
     private static final int CHUNK_SIZE = 1024 * 1024 * 10; // Trial and error showed ~10MB to be a good size on our machine
-    private static final int STATION_NAME_BUFFER_SIZE = 50;
+    private static final int STATION_NAME_BUFFER_SIZE = 128;
     private static final int THREAD_COUNT = Math.min(8, Runtime.getRuntime().availableProcessors());
     private static final char SEPARATOR_CHAR = ';';
-    private static final char NEWLINE_CHAR = '\n';
+    private static final char END_OF_RECORD = '\n';
     private static final char MINUS_CHAR = '-';
     private static final char DECIMAL_POINT_CHAR = '.';
 
     public static void main(String[] args) throws IOException {
 
-        @SuppressWarnings("resource") // It's faster to leak the file than be well-behaved
         final var file = new RandomAccessFile(FILE, "r");
         final var channel = file.getChannel();
 
@@ -50,22 +49,33 @@ public class CalculateAverage_palmr {
     private record ThreadChunk(long startPoint, long endPoint, long size) {
         public static Spliterator<CalculateAverage_palmr.ThreadChunk> chunk(final RandomAccessFile file, final int chunkCount) throws IOException {
             final var fileSize = file.length();
-            final var idealChunkSize = fileSize / THREAD_COUNT;
+            final var idealChunkSize = Math.max(CHUNK_SIZE, fileSize / THREAD_COUNT);
             final var chunks = new CalculateAverage_palmr.ThreadChunk[chunkCount];
 
+            var validChunks = 0;
             var startPoint = 0L;
             for (int i = 0; i < chunkCount; i++) {
                 var endPoint = Math.min(startPoint + idealChunkSize, fileSize);
-                file.seek(endPoint);
-                while (endPoint < fileSize && file.readByte() != NEWLINE_CHAR) {
-                    endPoint++;
+                if (startPoint + idealChunkSize < fileSize)
+                {
+                    file.seek(endPoint);
+                    while (endPoint++ < fileSize && file.readByte() != END_OF_RECORD) {
+                        Thread.onSpinWait();
+                    }
                 }
+
                 final var actualSize = endPoint - startPoint;
-                chunks[i] = new CalculateAverage_palmr.ThreadChunk(startPoint, endPoint, actualSize);
-                startPoint += actualSize;
+                if (actualSize > 1) {
+                    chunks[i] = new CalculateAverage_palmr.ThreadChunk(startPoint, endPoint, actualSize);
+                    startPoint += actualSize;
+                    validChunks++;
+                }
+                else {
+                    break;
+                }
             }
 
-            return Spliterators.spliterator(chunks,
+            return Spliterators.spliterator(chunks, 0, validChunks,
                     Spliterator.ORDERED |
                             Spliterator.DISTINCT |
                             Spliterator.SORTED |
@@ -101,7 +111,8 @@ public class CalculateAverage_palmr {
 
                 if (currentChar == SEPARATOR_CHAR) {
                     state.parsingValue = true;
-                } else if (currentChar == NEWLINE_CHAR) {
+                }
+                else if (currentChar == END_OF_RECORD) {
                     if (state.stationPointerEnd != 0) {
                         final var value = state.measurementValue * state.exponent;
 
@@ -114,20 +125,24 @@ public class CalculateAverage_palmr {
 
                     // reset
                     state.reset();
-                } else {
+                }
+                else {
                     if (!state.parsingValue) {
                         state.stationBuffer[state.stationPointerEnd++] = currentChar;
                         state.signedHashCode = 31 * state.signedHashCode + (currentChar & 0xff);
-                    } else {
+                    }
+                    else {
                         if (currentChar == MINUS_CHAR) {
                             state.exponent = -0.1;
-                        } else if (currentChar != DECIMAL_POINT_CHAR) {
+                        }
+                        else if (currentChar != DECIMAL_POINT_CHAR) {
                             state.measurementValue = state.measurementValue * 10 + (currentChar - '0');
                         }
                     }
                 }
             }
-        } catch (IOException e) {
+        }
+        catch (IOException e) {
             throw new RuntimeException(e);
         }
     }
@@ -188,7 +203,7 @@ public class CalculateAverage_palmr {
      * IT also uses Linear probing for collision resolution, which given the minimal collision count should hold up well.
      */
     private static class ByteArrayKeyedMap {
-        private final int BUCKET_COUNT = 0xFFF; // 413 unique stations in the data set, & 0xFFF ~= 399 (only 14 collisions (given our hashcode implementation))
+        private final int BUCKET_COUNT = 0xFFFF;
         private final MeasurementAggregator[] buckets = new MeasurementAggregator[BUCKET_COUNT + 1];
         private final List<MeasurementAggregator> compactUnorderedBuckets = new ArrayList<>(413);
 
@@ -203,7 +218,8 @@ public class CalculateAverage_palmr {
                     }
                     index++;
                     index &= BUCKET_COUNT;
-                } else {
+                }
+                else {
                     final var copiedKey = Arrays.copyOf(key, keyLength);
                     MeasurementAggregator measurementAggregator = new MeasurementAggregator(copiedKey, keyHashCode);
                     buckets[index] = measurementAggregator;