From 4d86abb0012923158b5f271cea0884c5af233336 Mon Sep 17 00:00:00 2001
From: yanyiwu <wuyanyi09@foxmail.com>
Date: Thu, 23 Jul 2015 21:10:56 +0800
Subject: [PATCH] =?UTF-8?q?=E6=96=B0=E5=A2=9EfindByLimit=E5=87=BD=E6=95=B0?=
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---
 src/DictTrie.hpp        |  7 +++++++
 src/Trie.hpp            | 40 +++++++++++++++++++++++++++---------
 test/unittest/TTrie.cpp | 45 +++++++++++++++++++++++++++++++++++++++++
 3 files changed, 82 insertions(+), 10 deletions(-)

diff --git a/src/DictTrie.hpp b/src/DictTrie.hpp
index f5347b5..9a5a5ad 100644
--- a/src/DictTrie.hpp
+++ b/src/DictTrie.hpp
@@ -71,6 +71,13 @@ class DictTrie {
     vector<Dag>& res) const {
     trie_->find(begin, end, res);
   }
+  void findByLimit(Unicode::const_iterator begin, 
+        Unicode::const_iterator end, 
+        vector<struct Dag>&res, 
+        size_t min_word_len, 
+        size_t max_word_len) const {
+    trie_->findByLimit(begin, end, res, min_word_len, max_word_len);
+  }
   bool isUserDictSingleChineseWord(const Rune& word) const {
     return isIn(userDictSingleChineseWord_, word);
   }
diff --git a/src/Trie.hpp b/src/Trie.hpp
index c42c383..7768dfc 100644
--- a/src/Trie.hpp
+++ b/src/Trie.hpp
@@ -8,6 +8,9 @@
 namespace CppJieba {
 using namespace std;
 
+const size_t MIN_WORD_LENGTH = 1;
+const size_t MAX_WORD_LENGTH = 512;
+
 struct DictUnit {
   Unicode word;
   double weight;
@@ -35,7 +38,8 @@ typedef Rune TrieKey;
 
 class TrieNode {
  public :
-  TrieNode(): next(NULL), ptValue(NULL) {}
+  TrieNode(): next(NULL), ptValue(NULL) {
+  }
  public:
   typedef unordered_map<TrieKey, TrieNode*> NextMap;
   NextMap *next;
@@ -82,22 +86,32 @@ class Trie {
     return ptNode->ptValue;
   }
 
-  void find(Unicode::const_iterator begin,
-    Unicode::const_iterator end,
-    vector<struct Dag>& res) const {
+  void findByLimit(Unicode::const_iterator begin, 
+        Unicode::const_iterator end, 
+        vector<struct Dag>&res, 
+        size_t min_word_len, 
+        size_t max_word_len) const {
     res.resize(end - begin);
 
+    // min_word_len start from 1;
+    if (min_word_len < 1) {
+      min_word_len = 1;
+    }
+
     const TrieNode *ptNode = NULL;
     TrieNode::NextMap::const_iterator citer;
     for (size_t i = 0; i < size_t(end - begin); i++) {
-      Rune ch = *(begin + i);
-      ptNode = _base + ch;
-      res[i].rune = ch;
+      Rune rune = *(begin + i);
+      ptNode = _base + rune;
+      res[i].rune = rune;
       assert(res[i].nexts.empty());
 
-      res[i].nexts.push_back(pair<size_t, const DictUnit*>(i, ptNode->ptValue));
+      if (min_word_len <= 1) {
+        res[i].nexts.push_back(pair<size_t, const DictUnit*>(i, ptNode->ptValue));
+      }
 
-      for (size_t j = i + 1; j < size_t(end - begin); j++) {
+      // min_word_len start from 1;
+      for (size_t j = i + 1; j < size_t(end - begin) && (j - i + 1) <= max_word_len ; j++) {
         if (ptNode->next == NULL) {
           break;
         }
@@ -106,12 +120,18 @@ class Trie {
           break;
         }
         ptNode = citer->second;
-        if (NULL != ptNode->ptValue) {
+        if (NULL != ptNode->ptValue && (j - i + 1) >= min_word_len) {
           res[i].nexts.push_back(pair<size_t, const DictUnit*>(j, ptNode->ptValue));
         }
       }
     }
   }
+
+  void find(Unicode::const_iterator begin,
+    Unicode::const_iterator end,
+    vector<struct Dag>& res) const {
+    findByLimit(begin, end, res, MIN_WORD_LENGTH, MAX_WORD_LENGTH);
+  }
   void insertNode(const Unicode& key, const DictUnit* ptValue) {
     if (key.begin() == key.end()) {
       return;
diff --git a/test/unittest/TTrie.cpp b/test/unittest/TTrie.cpp
index d40d8e6..8f030da 100644
--- a/test/unittest/TTrie.cpp
+++ b/test/unittest/TTrie.cpp
@@ -6,6 +6,20 @@ using namespace CppJieba;
 
 static const char* const DICT_FILE = "../test/testdata/extra_dict/jieba.dict.small.utf8";
 
+TEST(TrieTest, Empty) {
+  vector<Unicode> keys;
+  vector<const DictUnit*> values;
+  Trie trie(keys, values);
+}
+
+TEST(TrieTest, Construct) {
+  vector<Unicode> keys;
+  vector<const DictUnit*> values;
+  keys.push_back(TransCode::decode("你"));
+  values.push_back((const DictUnit*)(NULL));
+  Trie trie(keys, values);
+}
+
 TEST(DictTrieTest, NewAndDelete) {
   DictTrie * trie;
   trie = new DictTrie(DICT_FILE);
@@ -14,6 +28,7 @@ TEST(DictTrieTest, NewAndDelete) {
   delete trie;
 }
 
+
 TEST(DictTrieTest, Test1) {
   string s1, s2;
   DictTrie trie;
@@ -106,4 +121,34 @@ TEST(DictTrieTest, Dag) {
       ASSERT_EQ(res[i].nexts.size(), nexts_sizes[i]);
     }
   }
+
+  //findByLimit [2, 3]
+  {
+    string word = "长江大桥";
+    Unicode unicode;
+    ASSERT_TRUE(TransCode::decode(word, unicode));
+    vector<struct Dag> res;
+    trie.findByLimit(unicode.begin(), unicode.end(), res, 2, 3);
+
+    size_t nexts_sizes[] = {1, 0, 1, 0};
+    ASSERT_EQ(res.size(), sizeof(nexts_sizes)/sizeof(nexts_sizes[0]));
+    for (size_t i = 0; i < res.size(); i++) {
+      ASSERT_EQ(res[i].nexts.size(), nexts_sizes[i]);
+    }
+  }
+
+  //findByLimit [0, 4]
+  {
+    string word = "长江大桥";
+    Unicode unicode;
+    ASSERT_TRUE(TransCode::decode(word, unicode));
+    vector<struct Dag> res;
+    trie.findByLimit(unicode.begin(), unicode.end(), res, 0, 4);
+
+    size_t nexts_sizes[] = {3, 1, 2, 1};
+    ASSERT_EQ(res.size(), sizeof(nexts_sizes)/sizeof(nexts_sizes[0]));
+    for (size_t i = 0; i < res.size(); i++) {
+      ASSERT_EQ(res[i].nexts.size(), nexts_sizes[i]);
+    }
+  }
 }