1 files changed, 128 insertions, 0 deletions
diff --git a/caliper/src/main/java/com/google/caliper/util/InterleavedReader.java b/caliper/src/main/java/com/google/caliper/util/InterleavedReader.java
new file mode 100644
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+++ b/caliper/src/main/java/com/google/caliper/util/InterleavedReader.java
@@ -0,0 +1,128 @@
+/*
+ * Copyright (C) 2010 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.caliper.util;
+
+import com.google.gson.JsonParser;
+
+import java.io.BufferedReader;
+import java.io.Closeable;
+import java.io.IOException;
+import java.io.Reader;
+
+/**
+ * Reads a stream containing inline JSON objects. Each JSON object is prefixed
+ * by a marker string and suffixed by a newline character.
+ */
+public final class InterleavedReader implements Closeable {
+
+  /**
+   * The length of the scratch buffer to search for markers in. Also acts as an
+   * upper bound on the length of returned strings. Not used as an I/O buffer.
+   */
+  private static final int BUFFER_LENGTH = 80;
+
+  private final String marker;
+  private final BufferedReader reader;
+  private final JsonParser jsonParser = new JsonParser();
+
+  public static final String DEFAULT_MARKER = "//ZxJ/";
+
+  public InterleavedReader(Reader reader) {
+    this(DEFAULT_MARKER, reader);
+  }
+
+  public InterleavedReader(String marker, Reader reader) {
+    if (marker.length() > BUFFER_LENGTH) {
+      throw new IllegalArgumentException("marker.length() > BUFFER_LENGTH");
+    }
+    this.marker = marker;
+    this.reader = reader instanceof BufferedReader
+        ? (BufferedReader) reader
+        : new BufferedReader(reader);
+  }
+
+  /**
+   * Returns the next value in the stream: either a String, a JsonElement, or
+   * null to indicate the end of the stream. Callers should use instanceof to
+   * inspect the return type.
+   */
+  public Object read() throws IOException {
+    char[] buffer = new char[BUFFER_LENGTH];
+    reader.mark(BUFFER_LENGTH);
+    int count = 0;
+    int textEnd;
+
+    while (true) {
+      int r = reader.read(buffer, count, buffer.length - count);
+
+      if (r == -1) {
+        // the input is exhausted; return the remaining characters
+        textEnd = count;
+        break;
+      }
+
+      count += r;
+      int possibleMarker = findPossibleMarker(buffer, count);
+
+      if (possibleMarker != 0) {
+        // return the characters that precede the marker
+        textEnd = possibleMarker;
+        break;
+      }
+
+      if (count < marker.length()) {
+        // the buffer contains only the prefix of a marker so we must read more
+        continue;
+      }
+
+      // we've read a marker so return the value that follows
+      reader.reset();
+      String json = reader.readLine().substring(marker.length());
+      return jsonParser.parse(json);
+    }
+
+    if (count == 0) {
+      return null;
+    }
+
+    // return characters
+    reader.reset();
+    count = reader.read(buffer, 0, textEnd);
+    return new String(buffer, 0, count);
+  }
+
+  @Override public void close() throws IOException {
+    reader.close();
+  }
+
+  /**
+   * Returns the index of marker in {@code chars}, stopping at {@code limit}.
+   * Should the chars end with a prefix of marker, the offset of that prefix
+   * is returned.
+   */
+  int findPossibleMarker(char[] chars, int limit) {
+    search:
+    for (int i = 0; true; i++) {
+      for (int m = 0; m < marker.length() && i + m < limit; m++) {
+        if (chars[i + m] != marker.charAt(m)) {
+          continue search;
+        }
+      }
+      return i;
+    }
+  }
+}