hphp/runtime/vm/fixed-string-map.h

   1 /*
   2    +----------------------------------------------------------------------+
   3    | HipHop for PHP                                                       |
   4    +----------------------------------------------------------------------+
   5    | Copyright (c) 2010-present Facebook, Inc. (http://www.facebook.com)  |
   6    +----------------------------------------------------------------------+
   7    | This source file is subject to version 3.01 of the PHP license,      |
   8    | that is bundled with this package in the file LICENSE, and is        |
   9    | available through the world-wide-web at the following url:           |
  10    | http://www.php.net/license/3_01.txt                                  |
  11    | If you did not receive a copy of the PHP license and are unable to   |
  12    | obtain it through the world-wide-web, please send a note to          |
  13    | license@php.net so we can mail you a copy immediately.               |
  14    +----------------------------------------------------------------------+
  15 */
  16
  17 #ifndef incl_HPHP_FIXED_STRING_MAP_H_
  18 #define incl_HPHP_FIXED_STRING_MAP_H_
  19
  20 #include <cstdint>
  21 #include <limits>
  22 #include <vector>
  23
  24 #include "hphp/runtime/base/string-data.h"
  25
  26 #include "hphp/util/functional.h"
  27 #include "hphp/util/hash-map-typedefs.h"
  28
  29 namespace HPHP {
  30
  31 //////////////////////////////////////////////////////////////////////
  32
  33 template<class V, bool case_sensitive, class ExtraType = int32_t>
  34 struct FixedStringMap {
  35   explicit FixedStringMap(int num) : m_table(nullptr) { init(num); }
  36   FixedStringMap() : m_mask(0), m_table(nullptr) {}
  37   ~FixedStringMap() { clear(); }
  38
  39   FixedStringMap(const FixedStringMap&) = delete;
  40   const FixedStringMap& operator=(const FixedStringMap&) = delete;
  41
  42   void clear();
  43   void init(int num, uint32_t numExtraBytes = 0);
  44   void add(const StringData* s, const V& v);
  45   V* find(const StringData* s) const;
  46
  47   void* extraData() { return m_table; }
  48   const void* extraData() const { return m_table; }
  49   ExtraType& extra() { return m_extra; }
  50   const ExtraType& extra() const { return m_extra; }
  51
  52   static constexpr ptrdiff_t tableOff() {
  53     return offsetof(FixedStringMap, m_table);
  54   }
  55   ExtraType size() const { return m_extra; }
  56
  57 private:
  58   struct Elm {
  59     LowStringPtr sd;
  60     V data;
  61   };
  62
  63   /*
  64    * The fields we need here are just m_mask and m_table.  This would leave 4
  65    * byte padding hole, though, which some users (e.g. IndexedStringMap) might
  66    * have a use for, so we expose it as a slot for our users.
  67    */
  68   uint32_t  m_mask;
  69   ExtraType m_extra;  // not ours
  70   Elm*      m_table;
  71 };
  72
  73 //////////////////////////////////////////////////////////////////////
  74
  75 template<class T, class V, bool case_sensitive, class ExtraType = int32_t>
  76 struct FixedStringMapBuilder {
  77   using EqObject = typename std::conditional<
  78     case_sensitive,
  79     string_data_same,
  80     string_data_isame
  81   >::type;
  82
  83   using Map = hphp_hash_map<const StringData*, V, string_data_hash, EqObject>;
  84   using FSMap = FixedStringMap<V, case_sensitive, ExtraType>;
  85
  86   using const_iterator = typename Map::const_iterator;
  87   using iterator = typename Map::iterator;
  88
  89   iterator find(const StringData* key) { return m_map.find(key); }
  90   iterator begin()                     { return m_map.begin(); }
  91   iterator end()                       { return m_map.end(); }
  92   V        size() const                { return m_list.size(); }
  93
  94   const_iterator find(const StringData* key) const {
  95     return m_map.find(key);
  96   }
  97   const_iterator begin() const { return m_map.begin(); }
  98   const_iterator end()   const { return m_map.end(); }
  99
 100   T& operator[](V idx);
 101   const T& operator[](V idx) const;
 102
 103   /*
 104    * Add an object to the position on the end, and allow lookup by `name'.
 105    */
 106   void add(const StringData* name, const T& t);
 107
 108   /*
 109    * Add an object that occupies an index but can't be located by name.
 110    */
 111   void addUnnamed(const T& t);
 112
 113   /*
 114    * Create a FixedStringMap from the builder.
 115    */
 116   void create(FSMap& map);
 117
 118 private:
 119   std::vector<T> m_list;
 120   Map m_map;
 121 };
 122
 123 //////////////////////////////////////////////////////////////////////
 124
 125 }
 126
 127 #include "hphp/runtime/vm/fixed-string-map-inl.h"
 128
 129 #endif