1 files changed, 46 insertions, 5 deletions

diff --git a/brotli/enc/hash.h b/brotli/enc/hash.h
index cb38e8f..d6a415b 100644
--- a/brotli/enc/hash.h
+++ b/brotli/enc/hash.h
@@ -24,7 +24,9 @@
 #include <sys/types.h>
 #include <algorithm>
 #include <cstdlib>
+#include <string>
 
+#include "./transform.h"
 #include "./fast_log.h"
 #include "./find_match_length.h"
 #include "./port.h"
@@ -150,7 +152,10 @@ class HashLongestMatch {
                         size_t * __restrict best_len_out,
                         size_t * __restrict best_len_code_out,
                         size_t * __restrict best_distance_out,
-                        double * __restrict best_score_out) {
+                        double * __restrict best_score_out,
+                        bool * __restrict in_dictionary) {
+    *in_dictionary = true;
+    *best_len_code_out = 0;
     const size_t cur_ix_masked = cur_ix & ring_buffer_mask;
     const double start_cost4 = literal_cost == NULL ? 20 :
         literal_cost[cur_ix_masked] +
@@ -166,9 +171,9 @@ class HashLongestMatch {
         literal_cost[(cur_ix + 1) & ring_buffer_mask] + 1.2;
     bool match_found = false;
     // Don't accept a short copy from far away.
-    double best_score = 8.25;
+    double best_score = 8.11;
     if (insert_length_ < 4) {
-      double cost_diff[4] = { 0.20, 0.09, 0.05, 0.03 };
+      double cost_diff[4] = { 0.10, 0.04, 0.02, 0.01 };
       best_score += cost_diff[insert_length_];
     }
     size_t best_len = *best_len_out;
@@ -235,6 +240,7 @@ class HashLongestMatch {
           *best_distance_out = best_ix;
           *best_score_out = best_score;
           match_found = true;
+          *in_dictionary = backward > max_backward;
         }
       }
     }
@@ -257,7 +263,7 @@ class HashLongestMatch {
         continue;
       }
       int len = 2;
-      const double score = start_cost2 - 1.70 * Log2Floor(backward);
+      const double score = start_cost2 - 2.3 * Log2Floor(backward);
 
       if (best_score < score) {
         best_score = score;
@@ -272,7 +278,41 @@ class HashLongestMatch {
     for (int i = num_[key] - 1; i >= down; --i) {
       int prev_ix = bucket[i & kBlockMask];
       if (prev_ix < 0) {
-        continue;
+        prev_ix *= -1;
+        prev_ix -= 1;
+        int copy_len_code = prev_ix >> 20;
+        int word_id = prev_ix & 0xfffff;
+        std::string word = GetTransformedDictionaryWord(copy_len_code, word_id);
+        int len = word.size();
+        const size_t backward = max_backward + word_id + 1;
+        bool word_matched = (len >= 3 && len <= max_length);
+        for (int k = 0; k < len && word_matched; ++k) {
+          if ((uint8_t)(word[k]) != data[cur_ix_masked + k]) {
+            word_matched = false;
+          }
+        }
+        if (word_matched) {
+          const double score = BackwardReferenceScore(average_cost_,
+                                                      start_cost4,
+                                                      start_cost3,
+                                                      start_cost2,
+                                                      len, backward,
+                                                      last_distance1_,
+                                                      last_distance2_,
+                                                      last_distance3_,
+                                                      last_distance4_);
+          if (best_score < score) {
+            best_score = score;
+            best_len = len;
+            best_ix = backward;
+            *best_len_out = best_len;
+            *best_len_code_out = copy_len_code;
+            *best_distance_out = best_ix;
+            *best_score_out = best_score;
+            match_found = true;
+            *in_dictionary = true;
+          }
+        }
       } else {
         const size_t backward = cur_ix - prev_ix;
         if (PREDICT_FALSE(backward > max_backward)) {
@@ -309,6 +349,7 @@ class HashLongestMatch {
             *best_distance_out = best_ix;
             *best_score_out = best_score;
             match_found = true;
+            *in_dictionary = false;
           }
         }
       }