From 8668b6a55854eda404e29a80ace4027e1ffd2e5b Mon Sep 17 00:00:00 2001
From: Kenneth Heafield <kenlm@kheafield.com>
Date: Mon, 26 Sep 2011 16:54:16 -0400
Subject: Fix trie pointer segfault

---
 klm/lm/bhiksha.hh | 2 ++
 klm/lm/trie.cc    | 6 ++----
 klm/lm/trie.hh    | 7 ++++---
 3 files changed, 8 insertions(+), 7 deletions(-)

diff --git a/klm/lm/bhiksha.hh b/klm/lm/bhiksha.hh
index ff7fe452..bc705959 100644
--- a/klm/lm/bhiksha.hh
+++ b/klm/lm/bhiksha.hh
@@ -11,6 +11,7 @@
  */
 
 #include <inttypes.h>
+#include <assert.h>
 
 #include "lm/model_type.hh"
 #include "lm/trie.hh"
@@ -78,6 +79,7 @@ class ArrayBhiksha {
         util::ReadInt57(base, bit_offset, next_inline_.bits, next_inline_.mask);
       out.end = ((end_it - offset_begin_) << next_inline_.bits) | 
         util::ReadInt57(base, bit_offset + total_bits, next_inline_.bits, next_inline_.mask);
+      //assert(out.end >= out.begin);
     }
 
     void WriteNext(void *base, uint64_t bit_offset, uint64_t index, uint64_t value) {
diff --git a/klm/lm/trie.cc b/klm/lm/trie.cc
index 4e60b184..20075bb8 100644
--- a/klm/lm/trie.cc
+++ b/klm/lm/trie.cc
@@ -91,16 +91,14 @@ template <class Quant, class Bhiksha> bool BitPackedMiddle<Quant, Bhiksha>::Find
   if (!FindBitPacked(base_, word_mask_, word_bits_, total_bits_, range.begin, range.end, max_vocab_, word, at_pointer)) {
     return false;
   }
-  uint64_t index = at_pointer;
+  pointer = at_pointer;
   at_pointer *= total_bits_;
   at_pointer += word_bits_;
 
-  pointer = at_pointer;
-
   quant_.Read(base_, at_pointer, prob, backoff);
   at_pointer += quant_.TotalBits();
 
-  bhiksha_.ReadNext(base_, at_pointer, index, total_bits_, range);
+  bhiksha_.ReadNext(base_, at_pointer, pointer, total_bits_, range);
 
   return true;
 }
diff --git a/klm/lm/trie.hh b/klm/lm/trie.hh
index a9f5e417..06cc96ac 100644
--- a/klm/lm/trie.hh
+++ b/klm/lm/trie.hh
@@ -99,10 +99,11 @@ template <class Quant, class Bhiksha> class BitPackedMiddle : public BitPacked {
     bool FindNoProb(WordIndex word, float &backoff, NodeRange &range) const;
 
     NodeRange ReadEntry(uint64_t pointer, float &prob) {
-      quant_.ReadProb(base_, pointer, prob);
+      uint64_t addr = pointer * total_bits_;
+      addr += word_bits_;
+      quant_.ReadProb(base_, addr, prob);
       NodeRange ret;
-      // pointer/total_bits_ should always round down.  
-      bhiksha_.ReadNext(base_, pointer + quant_.TotalBits(), pointer / total_bits_, total_bits_, ret);
+      bhiksha_.ReadNext(base_, addr + quant_.TotalBits(), pointer, total_bits_, ret);
       return ret;
     }
 
-- 
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