1 files changed, 42 insertions, 20 deletions

diff --git a/klm/lm/model.hh b/klm/lm/model.hh
index 21595321..c278acd6 100644
--- a/klm/lm/model.hh
+++ b/klm/lm/model.hh
@@ -12,6 +12,8 @@
 #include "lm/vocab.hh"
 #include "lm/weights.hh"
 
+#include "util/murmur_hash.hh"
+
 #include <algorithm>
 #include <vector>
 
@@ -27,42 +29,41 @@ namespace ngram {
 class State {
   public:
     bool operator==(const State &other) const {
-      if (valid_length_ != other.valid_length_) return false;
-      const WordIndex *end = history_ + valid_length_;
-      for (const WordIndex *first = history_, *second = other.history_;
-          first != end; ++first, ++second) {
-        if (*first != *second) return false;
-      }
-      // If the histories are equal, so are the backoffs.  
-      return true;
+      if (length != other.length) return false;
+      return !memcmp(words, other.words, length * sizeof(WordIndex));
     }
 
     // Three way comparison function.  
     int Compare(const State &other) const {
-      if (valid_length_ == other.valid_length_) {
-        return memcmp(history_, other.history_, valid_length_ * sizeof(WordIndex));
-      }
-      return (valid_length_ < other.valid_length_) ? -1 : 1;
+      if (length != other.length) return length < other.length ? -1 : 1;
+      return memcmp(words, other.words, length * sizeof(WordIndex));
+    }
+
+    bool operator<(const State &other) const {
+      if (length != other.length) return length < other.length;
+      return memcmp(words, other.words, length * sizeof(WordIndex)) < 0;
     }
 
     // Call this before using raw memcmp.  
     void ZeroRemaining() {
-      for (unsigned char i = valid_length_; i < kMaxOrder - 1; ++i) {
-        history_[i] = 0;
-        backoff_[i] = 0.0;
+      for (unsigned char i = length; i < kMaxOrder - 1; ++i) {
+        words[i] = 0;
+        backoff[i] = 0.0;
       }
     }
 
-    unsigned char ValidLength() const { return valid_length_; }
+    unsigned char Length() const { return length; }
 
     // You shouldn't need to touch anything below this line, but the members are public so FullState will qualify as a POD.  
     // This order minimizes total size of the struct if WordIndex is 64 bit, float is 32 bit, and alignment of 64 bit integers is 64 bit.  
-    WordIndex history_[kMaxOrder - 1];
-    float backoff_[kMaxOrder - 1];
-    unsigned char valid_length_;
+    WordIndex words[kMaxOrder - 1];
+    float backoff[kMaxOrder - 1];
+    unsigned char length;
 };
 
-size_t hash_value(const State &state);
+inline size_t hash_value(const State &state) {
+  return util::MurmurHashNative(state.words, sizeof(WordIndex) * state.length);
+}
 
 namespace detail {
 
@@ -75,6 +76,8 @@ template <class Search, class VocabularyT> class GenericModel : public base::Mod
     // This is the model type returned by RecognizeBinary.
     static const ModelType kModelType;
 
+    static const unsigned int kVersion = Search::kVersion;
+
     /* Get the size of memory that will be mapped given ngram counts.  This
      * does not include small non-mapped control structures, such as this class
      * itself.  
@@ -114,6 +117,25 @@ template <class Search, class VocabularyT> class GenericModel : public base::Mod
      */
     void GetState(const WordIndex *context_rbegin, const WordIndex *context_rend, State &out_state) const;
 
+    /* More efficient version of FullScore where a partial n-gram has already
+     * been scored.  
+     * NOTE: THE RETURNED .prob IS RELATIVE, NOT ABSOLUTE.  So for example, if
+     * the n-gram does not end up extending further left, then 0 is returned.
+     */
+    FullScoreReturn ExtendLeft(
+        // Additional context in reverse order.  This will update add_rend to 
+        const WordIndex *add_rbegin, const WordIndex *add_rend,
+        // Backoff weights to use.  
+        const float *backoff_in,
+        // extend_left returned by a previous query.
+        uint64_t extend_pointer,
+        // Length of n-gram that the pointer corresponds to.  
+        unsigned char extend_length,
+        // Where to write additional backoffs for [extend_length + 1, min(Order() - 1, return.ngram_length)]
+        float *backoff_out,
+        // Amount of additional content that should be considered by the next call.
+        unsigned char &next_use) const;
+
   private:
     friend void LoadLM<>(const char *file, const Config &config, GenericModel<Search, VocabularyT> &to);