1 files changed, 41 insertions, 2 deletions

diff --git a/java/org/brotli/dec/Dictionary.java b/java/org/brotli/dec/Dictionary.java
index a6867b7..043572f 100644
--- a/java/org/brotli/dec/Dictionary.java
+++ b/java/org/brotli/dec/Dictionary.java
@@ -18,7 +18,12 @@ import java.nio.ByteBuffer;
  * once in each classworld). To avoid this, it is enough to call {@link #getData()} proactively.
  */
 public final class Dictionary {
-  private static volatile ByteBuffer data;
+  static final int MIN_DICTIONARY_WORD_LENGTH = 4;
+  static final int MAX_DICTIONARY_WORD_LENGTH = 31;
+
+  private static ByteBuffer data;
+  static final int[] offsets = new int[32];
+  static final int[] sizeBits = new int[32];
 
   private static class DataLoader {
     static final boolean OK;
@@ -34,10 +39,44 @@ public final class Dictionary {
     }
   }
 
-  public static void setData(ByteBuffer data) {
+  public static void setData(ByteBuffer data, int[] sizeBits) {
     if (!data.isDirect() || !data.isReadOnly()) {
       throw new BrotliRuntimeException("data must be a direct read-only byte buffer");
     }
+    // TODO: is that so?
+    if (sizeBits.length > MAX_DICTIONARY_WORD_LENGTH) {
+      throw new BrotliRuntimeException(
+          "sizeBits length must be at most " + MAX_DICTIONARY_WORD_LENGTH);
+    }
+    for (int i = 0; i < MIN_DICTIONARY_WORD_LENGTH; ++i) {
+      if (sizeBits[i] != 0) {
+        throw new BrotliRuntimeException("first " + MIN_DICTIONARY_WORD_LENGTH + " must be 0");
+      }
+    }
+    int[] dictionaryOffsets = Dictionary.offsets;
+    int[] dictionarySizeBits = Dictionary.sizeBits;
+    System.arraycopy(sizeBits, 0, dictionarySizeBits, 0, sizeBits.length);
+    int pos = 0;
+    int limit = data.capacity();
+    for (int i = 0; i < sizeBits.length; ++i) {
+      dictionaryOffsets[i] = pos;
+      int bits = dictionarySizeBits[i];
+      if (bits != 0) {
+        if (bits >= 31) {
+          throw new BrotliRuntimeException("sizeBits values must be less than 31");
+        }
+        pos += i << bits;
+        if (pos <= 0 || pos > limit) {
+          throw new BrotliRuntimeException("sizeBits is inconsistent: overflow");
+        }
+      }
+    }
+    for (int i = sizeBits.length; i < 32; ++i) {
+      dictionaryOffsets[i] = pos;
+    }
+    if (pos != limit) {
+      throw new BrotliRuntimeException("sizeBits is inconsistent: underflow");
+    }
     Dictionary.data = data;
   }