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      1 //===--- StmtIterator.h - Iterators for Statements --------------*- 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 // This file defines the StmtIterator and ConstStmtIterator classes.
     11 //
     12 //===----------------------------------------------------------------------===//
     13 
     14 #ifndef LLVM_CLANG_AST_STMT_ITR_H
     15 #define LLVM_CLANG_AST_STMT_ITR_H
     16 
     17 #include "llvm/Support/DataTypes.h"
     18 #include <cassert>
     19 #include <cstddef>
     20 #include <iterator>
     21 #include <utility>
     22 
     23 namespace clang {
     24 
     25 class Stmt;
     26 class Decl;
     27 class VariableArrayType;
     28 
     29 class StmtIteratorBase {
     30 protected:
     31   enum { DeclMode = 0x1, SizeOfTypeVAMode = 0x2, DeclGroupMode = 0x3,
     32          Flags = 0x3 };
     33 
     34   Stmt **stmt;
     35   union { Decl *decl; Decl **DGI; };
     36   uintptr_t RawVAPtr;
     37   Decl **DGE;
     38 
     39   bool inDecl() const {
     40     return (RawVAPtr & Flags) == DeclMode;
     41   }
     42 
     43   bool inDeclGroup() const {
     44     return (RawVAPtr & Flags) == DeclGroupMode;
     45   }
     46 
     47   bool inSizeOfTypeVA() const {
     48     return (RawVAPtr & Flags) == SizeOfTypeVAMode;
     49   }
     50 
     51   bool inStmt() const {
     52     return (RawVAPtr & Flags) == 0;
     53   }
     54 
     55   const VariableArrayType *getVAPtr() const {
     56     return reinterpret_cast<const VariableArrayType*>(RawVAPtr & ~Flags);
     57   }
     58 
     59   void setVAPtr(const VariableArrayType *P) {
     60     assert (inDecl() || inDeclGroup() || inSizeOfTypeVA());
     61     RawVAPtr = reinterpret_cast<uintptr_t>(P) | (RawVAPtr & Flags);
     62   }
     63 
     64   void NextDecl(bool ImmediateAdvance = true);
     65   bool HandleDecl(Decl* D);
     66   void NextVA();
     67 
     68   Stmt*& GetDeclExpr() const;
     69 
     70   StmtIteratorBase(Stmt **s) : stmt(s), decl(0), RawVAPtr(0) {}
     71   StmtIteratorBase(Decl *d, Stmt **s);
     72   StmtIteratorBase(const VariableArrayType *t);
     73   StmtIteratorBase(Decl **dgi, Decl **dge);
     74   StmtIteratorBase() : stmt(0), decl(0), RawVAPtr(0) {}
     75 };
     76 
     77 
     78 template <typename DERIVED, typename REFERENCE>
     79 class StmtIteratorImpl : public StmtIteratorBase,
     80                          public std::iterator<std::forward_iterator_tag,
     81                                               REFERENCE, ptrdiff_t,
     82                                               REFERENCE, REFERENCE> {
     83 protected:
     84   StmtIteratorImpl(const StmtIteratorBase& RHS) : StmtIteratorBase(RHS) {}
     85 public:
     86   StmtIteratorImpl() {}
     87   StmtIteratorImpl(Stmt **s) : StmtIteratorBase(s) {}
     88   StmtIteratorImpl(Decl **dgi, Decl **dge) : StmtIteratorBase(dgi, dge) {}
     89   StmtIteratorImpl(Decl *d, Stmt **s) : StmtIteratorBase(d, s) {}
     90   StmtIteratorImpl(const VariableArrayType *t) : StmtIteratorBase(t) {}
     91 
     92   DERIVED& operator++() {
     93     if (inStmt())
     94       ++stmt;
     95     else if (getVAPtr())
     96       NextVA();
     97     else
     98       NextDecl();
     99 
    100     return static_cast<DERIVED&>(*this);
    101   }
    102 
    103   DERIVED operator++(int) {
    104     DERIVED tmp = static_cast<DERIVED&>(*this);
    105     operator++();
    106     return tmp;
    107   }
    108 
    109   bool operator==(const DERIVED& RHS) const {
    110     return stmt == RHS.stmt && decl == RHS.decl && RawVAPtr == RHS.RawVAPtr;
    111   }
    112 
    113   bool operator!=(const DERIVED& RHS) const {
    114     return stmt != RHS.stmt || decl != RHS.decl || RawVAPtr != RHS.RawVAPtr;
    115   }
    116 
    117   REFERENCE operator*() const {
    118     return (REFERENCE) (inStmt() ? *stmt : GetDeclExpr());
    119   }
    120 
    121   REFERENCE operator->() const { return operator*(); }
    122 };
    123 
    124 struct StmtIterator : public StmtIteratorImpl<StmtIterator,Stmt*&> {
    125   explicit StmtIterator() : StmtIteratorImpl<StmtIterator,Stmt*&>() {}
    126 
    127   StmtIterator(Stmt** S) : StmtIteratorImpl<StmtIterator,Stmt*&>(S) {}
    128 
    129   StmtIterator(Decl** dgi, Decl** dge)
    130    : StmtIteratorImpl<StmtIterator,Stmt*&>(dgi, dge) {}
    131 
    132   StmtIterator(const VariableArrayType *t)
    133     : StmtIteratorImpl<StmtIterator,Stmt*&>(t) {}
    134 
    135   StmtIterator(Decl* D, Stmt **s = 0)
    136     : StmtIteratorImpl<StmtIterator,Stmt*&>(D, s) {}
    137 };
    138 
    139 struct ConstStmtIterator : public StmtIteratorImpl<ConstStmtIterator,
    140                                                    const Stmt*> {
    141   explicit ConstStmtIterator() :
    142     StmtIteratorImpl<ConstStmtIterator,const Stmt*>() {}
    143 
    144   ConstStmtIterator(const StmtIterator& RHS) :
    145     StmtIteratorImpl<ConstStmtIterator,const Stmt*>(RHS) {}
    146 };
    147 
    148 /// A range of statement iterators.
    149 ///
    150 /// This class provides some extra functionality beyond std::pair
    151 /// in order to allow the following idiom:
    152 ///   for (StmtRange range = stmt->children(); range; ++range)
    153 struct StmtRange : std::pair<StmtIterator,StmtIterator> {
    154   StmtRange() {}
    155   StmtRange(const StmtIterator &begin, const StmtIterator &end)
    156     : std::pair<StmtIterator,StmtIterator>(begin, end) {}
    157 
    158   bool empty() const { return first == second; }
    159   operator bool() const { return !empty(); }
    160 
    161   Stmt *operator->() const { return first.operator->(); }
    162   Stmt *&operator*() const { return first.operator*(); }
    163 
    164   StmtRange &operator++() {
    165     assert(!empty() && "incrementing on empty range");
    166     ++first;
    167     return *this;
    168   }
    169 
    170   StmtRange operator++(int) {
    171     assert(!empty() && "incrementing on empty range");
    172     StmtRange copy = *this;
    173     ++first;
    174     return copy;
    175   }
    176 
    177   friend const StmtIterator &begin(const StmtRange &range) {
    178     return range.first;
    179   }
    180   friend const StmtIterator &end(const StmtRange &range) {
    181     return range.second;
    182   }
    183 };
    184 
    185 /// A range of const statement iterators.
    186 ///
    187 /// This class provides some extra functionality beyond std::pair
    188 /// in order to allow the following idiom:
    189 ///   for (ConstStmtRange range = stmt->children(); range; ++range)
    190 struct ConstStmtRange : std::pair<ConstStmtIterator,ConstStmtIterator> {
    191   ConstStmtRange() {}
    192   ConstStmtRange(const ConstStmtIterator &begin,
    193                  const ConstStmtIterator &end)
    194     : std::pair<ConstStmtIterator,ConstStmtIterator>(begin, end) {}
    195   ConstStmtRange(const StmtRange &range)
    196     : std::pair<ConstStmtIterator,ConstStmtIterator>(range.first, range.second)
    197   {}
    198   ConstStmtRange(const StmtIterator &begin, const StmtIterator &end)
    199     : std::pair<ConstStmtIterator,ConstStmtIterator>(begin, end) {}
    200 
    201   bool empty() const { return first == second; }
    202   operator bool() const { return !empty(); }
    203 
    204   const Stmt *operator->() const { return first.operator->(); }
    205   const Stmt *operator*() const { return first.operator*(); }
    206 
    207   ConstStmtRange &operator++() {
    208     assert(!empty() && "incrementing on empty range");
    209     ++first;
    210     return *this;
    211   }
    212 
    213   ConstStmtRange operator++(int) {
    214     assert(!empty() && "incrementing on empty range");
    215     ConstStmtRange copy = *this;
    216     ++first;
    217     return copy;
    218   }
    219 
    220   friend const ConstStmtIterator &begin(const ConstStmtRange &range) {
    221     return range.first;
    222   }
    223   friend const ConstStmtIterator &end(const ConstStmtRange &range) {
    224     return range.second;
    225   }
    226 };
    227 
    228 } // end namespace clang
    229 
    230 #endif
    231