1 //===-- UniqueCStringMap.h --------------------------------------*- C++ -*-===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 
10 #ifndef liblldb_UniqueCStringMap_h_
11 #define liblldb_UniqueCStringMap_h_
12 #if defined(__cplusplus)
13 
14 #include <assert.h>
15 #include <algorithm>
16 #include <vector>
17 
18 #include "lldb/Core/RegularExpression.h"
19 
20 namespace lldb_private {
21 
22 
23 
24 //----------------------------------------------------------------------
25 // Templatized uniqued string map.
26 //
27 // This map is useful for mapping unique C string names to values of
28 // type T. Each "const char *" name added must be unique for a given
29 // C string value. ConstString::GetCString() can provide such strings.
30 // Any other string table that has guaranteed unique values can also
31 // be used.
32 //----------------------------------------------------------------------
33 template <typename T>
34 class UniqueCStringMap
35 {
36 public:
37     struct Entry
38     {
EntryEntry39         Entry () :
40             cstring(NULL),
41             value()
42         {
43         }
44 
EntryEntry45         Entry (const char *cstr) :
46             cstring(cstr),
47             value()
48         {
49         }
50 
EntryEntry51         Entry (const char *cstr, const T&v) :
52             cstring(cstr),
53             value(v)
54         {
55         }
56 
57         bool
58         operator < (const Entry& rhs) const
59         {
60             return cstring < rhs.cstring;
61         }
62 
63         const char* cstring;
64         T value;
65     };
66 
67     //------------------------------------------------------------------
68     // Call this function multiple times to add a bunch of entries to
69     // this map, then later call UniqueCStringMap<T>::Sort() before doing
70     // any searches by name.
71     //------------------------------------------------------------------
72     void
Append(const char * unique_cstr,const T & value)73     Append (const char *unique_cstr, const T& value)
74     {
75         m_map.push_back (typename UniqueCStringMap<T>::Entry(unique_cstr, value));
76     }
77 
78     void
Append(const Entry & e)79     Append (const Entry &e)
80     {
81         m_map.push_back (e);
82     }
83 
84     void
Clear()85     Clear ()
86     {
87         m_map.clear();
88     }
89 
90     //------------------------------------------------------------------
91     // Call this function to always keep the map sorted when putting
92     // entries into the map.
93     //------------------------------------------------------------------
94     void
Insert(const char * unique_cstr,const T & value)95     Insert (const char *unique_cstr, const T& value)
96     {
97         typename UniqueCStringMap<T>::Entry e(unique_cstr, value);
98         m_map.insert (std::upper_bound (m_map.begin(), m_map.end(), e), e);
99     }
100 
101     void
Insert(const Entry & e)102     Insert (const Entry &e)
103     {
104         m_map.insert (std::upper_bound (m_map.begin(), m_map.end(), e), e);
105     }
106 
107     //------------------------------------------------------------------
108     // Get an entries by index in a variety of forms.
109     //
110     // The caller is responsible for ensuring that the collection does
111     // not change during while using the returned values.
112     //------------------------------------------------------------------
113     bool
GetValueAtIndex(uint32_t idx,T & value)114     GetValueAtIndex (uint32_t idx, T &value) const
115     {
116         if (idx < m_map.size())
117         {
118             value = m_map[idx].value;
119             return true;
120         }
121         return false;
122     }
123 
124     const char *
GetCStringAtIndexUnchecked(uint32_t idx)125     GetCStringAtIndexUnchecked (uint32_t idx) const
126     {
127         return m_map[idx].cstring;
128     }
129 
130     // Use this function if you have simple types in your map that you
131     // can easily copy when accessing values by index.
132     T
GetValueAtIndexUnchecked(uint32_t idx)133     GetValueAtIndexUnchecked (uint32_t idx) const
134     {
135         return m_map[idx].value;
136     }
137 
138     // Use this function if you have complex types in your map that you
139     // don't want to copy when accessing values by index.
140     const T &
GetValueRefAtIndexUnchecked(uint32_t idx)141     GetValueRefAtIndexUnchecked (uint32_t idx) const
142     {
143         return m_map[idx].value;
144     }
145 
146     const char *
GetCStringAtIndex(uint32_t idx)147     GetCStringAtIndex (uint32_t idx) const
148     {
149         if (idx < m_map.size())
150             return m_map[idx].cstring;
151         return NULL;
152     }
153 
154     //------------------------------------------------------------------
155     // Find the value for the unique string in the map.
156     //
157     // Return the value for \a unique_cstr if one is found, return
158     // \a fail_value otherwise. This method works well for simple type
159     // T values and only if there is a sensible failure value that can
160     // be returned and that won't match any existing values.
161     //------------------------------------------------------------------
162     T
Find(const char * unique_cstr,T fail_value)163     Find (const char *unique_cstr, T fail_value) const
164     {
165         Entry search_entry (unique_cstr);
166         const_iterator end = m_map.end();
167         const_iterator pos = std::lower_bound (m_map.begin(), end, search_entry);
168         if (pos != end)
169         {
170             if (pos->cstring == unique_cstr)
171                 return pos->value;
172         }
173         return fail_value;
174     }
175     //------------------------------------------------------------------
176     // Get a pointer to the first entry that matches "name". NULL will
177     // be returned if there is no entry that matches "name".
178     //
179     // The caller is responsible for ensuring that the collection does
180     // not change during while using the returned pointer.
181     //------------------------------------------------------------------
182     const Entry *
FindFirstValueForName(const char * unique_cstr)183     FindFirstValueForName (const char *unique_cstr) const
184     {
185         Entry search_entry (unique_cstr);
186         const_iterator end = m_map.end();
187         const_iterator pos = std::lower_bound (m_map.begin(), end, search_entry);
188         if (pos != end)
189         {
190             const char *pos_cstr = pos->cstring;
191             if (pos_cstr == unique_cstr)
192                 return &(*pos);
193         }
194         return NULL;
195     }
196 
197     //------------------------------------------------------------------
198     // Get a pointer to the next entry that matches "name" from a
199     // previously returned Entry pointer. NULL will be returned if there
200     // is no subsequent entry that matches "name".
201     //
202     // The caller is responsible for ensuring that the collection does
203     // not change during while using the returned pointer.
204     //------------------------------------------------------------------
205     const Entry *
FindNextValueForName(const Entry * entry_ptr)206     FindNextValueForName (const Entry *entry_ptr) const
207     {
208         if (!m_map.empty())
209         {
210             const Entry *first_entry = &m_map[0];
211             const Entry *after_last_entry = first_entry + m_map.size();
212             const Entry *next_entry = entry_ptr + 1;
213             if (first_entry <= next_entry && next_entry < after_last_entry)
214             {
215                 if (next_entry->cstring == entry_ptr->cstring)
216                     return next_entry;
217             }
218         }
219         return NULL;
220     }
221 
222     size_t
GetValues(const char * unique_cstr,std::vector<T> & values)223     GetValues (const char *unique_cstr, std::vector<T> &values) const
224     {
225         const size_t start_size = values.size();
226 
227         Entry search_entry (unique_cstr);
228         const_iterator pos, end = m_map.end();
229         for (pos = std::lower_bound (m_map.begin(), end, search_entry); pos != end; ++pos)
230         {
231             if (pos->cstring == unique_cstr)
232                 values.push_back (pos->value);
233             else
234                 break;
235         }
236 
237         return values.size() - start_size;
238     }
239 
240     size_t
GetValues(const RegularExpression & regex,std::vector<T> & values)241     GetValues (const RegularExpression& regex, std::vector<T> &values) const
242     {
243         const size_t start_size = values.size();
244 
245         const_iterator pos, end = m_map.end();
246         for (pos = m_map.begin(); pos != end; ++pos)
247         {
248             if (regex.Execute(pos->cstring))
249                 values.push_back (pos->value);
250         }
251 
252         return values.size() - start_size;
253     }
254 
255     //------------------------------------------------------------------
256     // Get the total number of entries in this map.
257     //------------------------------------------------------------------
258     size_t
GetSize()259     GetSize () const
260     {
261         return m_map.size();
262     }
263 
264 
265     //------------------------------------------------------------------
266     // Returns true if this map is empty.
267     //------------------------------------------------------------------
268     bool
IsEmpty()269     IsEmpty() const
270     {
271         return m_map.empty();
272     }
273 
274     //------------------------------------------------------------------
275     // Reserve memory for at least "n" entries in the map. This is
276     // useful to call when you know you will be adding a lot of entries
277     // using UniqueCStringMap::Append() (which should be followed by a
278     // call to UniqueCStringMap::Sort()) or to UniqueCStringMap::Insert().
279     //------------------------------------------------------------------
280     void
Reserve(size_t n)281     Reserve (size_t n)
282     {
283         m_map.reserve (n);
284     }
285 
286     //------------------------------------------------------------------
287     // Sort the unsorted contents in this map. A typical code flow would
288     // be:
289     // size_t approximate_num_entries = ....
290     // UniqueCStringMap<uint32_t> my_map;
291     // my_map.Reserve (approximate_num_entries);
292     // for (...)
293     // {
294     //      my_map.Append (UniqueCStringMap::Entry(GetName(...), GetValue(...)));
295     // }
296     // my_map.Sort();
297     //------------------------------------------------------------------
298     void
Sort()299     Sort ()
300     {
301         std::sort (m_map.begin(), m_map.end());
302     }
303 
304     //------------------------------------------------------------------
305     // Since we are using a vector to contain our items it will always
306     // double its memory consumption as things are added to the vector,
307     // so if you intend to keep a UniqueCStringMap around and have
308     // a lot of entries in the map, you will want to call this function
309     // to create a new vector and copy _only_ the exact size needed as
310     // part of the finalization of the string map.
311     //------------------------------------------------------------------
312     void
SizeToFit()313     SizeToFit ()
314     {
315         if (m_map.size() < m_map.capacity())
316         {
317             collection temp (m_map.begin(), m_map.end());
318             m_map.swap(temp);
319         }
320     }
321 
322     size_t
Erase(const char * unique_cstr)323     Erase (const char *unique_cstr)
324     {
325         size_t num_removed = 0;
326         Entry search_entry (unique_cstr);
327         iterator end = m_map.end();
328         iterator begin = m_map.begin();
329         iterator lower_pos = std::lower_bound (begin, end, search_entry);
330         if (lower_pos != end)
331         {
332             if (lower_pos->cstring == unique_cstr)
333             {
334                 iterator upper_pos = std::upper_bound (lower_pos, end, search_entry);
335                 if (lower_pos == upper_pos)
336                 {
337                     m_map.erase (lower_pos);
338                     num_removed = 1;
339                 }
340                 else
341                 {
342                     num_removed = std::distance (lower_pos, upper_pos);
343                     m_map.erase (lower_pos, upper_pos);
344                 }
345             }
346         }
347         return num_removed;
348     }
349 protected:
350     typedef std::vector<Entry> collection;
351     typedef typename collection::iterator iterator;
352     typedef typename collection::const_iterator const_iterator;
353     collection m_map;
354 };
355 
356 
357 
358 } // namespace lldb_private
359 
360 #endif  // #if defined(__cplusplus)
361 #endif  // liblldb_UniqueCStringMap_h_
362