From e0ef743090038ee02d656cee11debd2246624ba0 Mon Sep 17 00:00:00 2001
From: redpony <redpony@ec762483-ff6d-05da-a07a-a48fb63a330f>
Date: Mon, 18 Oct 2010 23:24:01 +0000
Subject: kenneth's LM preliminary integration

git-svn-id: https://ws10smt.googlecode.com/svn/trunk@681 ec762483-ff6d-05da-a07a-a48fb63a330f
---
 klm/lm/sri.hh | 102 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 102 insertions(+)
 create mode 100644 klm/lm/sri.hh

(limited to 'klm/lm/sri.hh')

diff --git a/klm/lm/sri.hh b/klm/lm/sri.hh
new file mode 100644
index 00000000..b57e9b73
--- /dev/null
+++ b/klm/lm/sri.hh
@@ -0,0 +1,102 @@
+#ifndef LM_SRI__
+#define LM_SRI__
+
+#include "lm/facade.hh"
+#include "util/murmur_hash.hh"
+
+#include <cmath>
+#include <exception>
+#include <memory>
+
+class Ngram;
+class Vocab;
+
+/* The ngram length reported uses some random API I found and may be wrong.
+ *
+ * See ngram, which should return equivalent results.
+ */
+
+namespace lm {
+namespace sri {
+
+static const unsigned int kMaxOrder = 6;
+
+/* This should match VocabIndex found in SRI's Vocab.h
+ * The reason I define this here independently is that SRI's headers
+ * pollute and increase compile time.
+ * It's difficult to extract this from their header and anyway would
+ * break packaging.
+ * If these differ there will be a compiler error in ActuallyCall.
+ */
+typedef unsigned int SRIVocabIndex;
+
+class State {
+  public:
+    // You shouldn't need to touch these, but they're public so State will be a POD.
+    // If valid_length_ < kMaxOrder - 1 then history_[valid_length_] == Vocab_None.
+    SRIVocabIndex history_[kMaxOrder - 1];
+    unsigned char valid_length_;
+};
+
+inline bool operator==(const State &left, const State &right) {
+  if (left.valid_length_ != right.valid_length_) {
+    return false;
+  }
+  for (const SRIVocabIndex *l = left.history_, *r = right.history_;
+      l != left.history_ + left.valid_length_;
+      ++l, ++r) {
+    if (*l != *r) return false;
+  }
+  return true;
+}
+
+inline size_t hash_value(const State &state) {
+  return util::MurmurHashNative(&state.history_, sizeof(SRIVocabIndex) * state.valid_length_);
+}
+
+class Vocabulary : public base::Vocabulary {
+  public:
+    Vocabulary();
+
+    ~Vocabulary();
+
+    WordIndex Index(const StringPiece &str) const {
+      std::string temp(str.data(), str.length());
+      return Index(temp.c_str());
+    }
+    WordIndex Index(const std::string &str) const {
+      return Index(str.c_str());
+    }
+    WordIndex Index(const char *str) const;
+
+    const char *Word(WordIndex index) const;
+
+  private:
+    friend class Model;
+    void FinishedLoading();
+
+    // The parent class isn't copyable so auto_ptr is the same as scoped_ptr
+    // but without the boost dependence.  
+    mutable std::auto_ptr<Vocab> sri_;
+};
+
+class Model : public base::ModelFacade<Model, State, Vocabulary> {
+  public:
+    Model(const char *file_name, unsigned int ngram_length);
+
+    ~Model();
+
+    FullScoreReturn FullScore(const State &in_state, const WordIndex new_word, State &out_state) const;
+
+  private:
+    Vocabulary vocab_;
+
+    mutable std::auto_ptr<Ngram> sri_;
+
+    WordIndex not_found_;
+};
+
+} // namespace sri
+} // namespace lm
+
+#endif // LM_SRI__
-- 
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