Implement external strings.

runtime/vm/object.h

 // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef VM_OBJECT_H_
 #define VM_OBJECT_H_
 
 #include "vm/assert.h"
 #include "vm/dart.h"
 #include "vm/globals.h"
@@ skipping 2347 matching lines @@
   intptr_t Length() const { return Smi::Value(raw_ptr()->length_); }
   static intptr_t length_offset() { return OFFSET_OF(RawString, length_); }
 
   virtual intptr_t Hash() const;
   static intptr_t hash_offset() { return OFFSET_OF(RawString, hash_); }
   static intptr_t Hash(const String& str, intptr_t begin_index, intptr_t len);
   static intptr_t Hash(const uint8_t* characters, intptr_t len);
   static intptr_t Hash(const uint16_t* characters, intptr_t len);
   static intptr_t Hash(const uint32_t* characters, intptr_t len);
 
+  bool HasOneByteChar() const {
+    return IsOneByteString() || IsExternalOneByteString();
+  }
+
+  bool HasTwoByteChar() const {
+    return IsTwoByteString() || IsExternalTwoByteString();
+  }
+
+  bool HasFourByteChar() const {
+    return IsFourByteString() || IsExternalFourByteString();
+  }

[turnidge, 2011/10/25 18:07:20]

Passing thought... Would it make sense to add a virtual to the base string that
lets you just get the character size directly?  Something like
'GetCharacterSize()' that returns 1, 2, or 4?

It would let you use "int size = max(s1.GetCharacterSize(),
s2.GetCharacterSize())" inside of Concat...

Feel free to file this comment for later...

[cshapiro, 2011/10/25 20:42:47]

Sounds like a good idea.  This will show up in my next patch set.

+
   virtual int32_t CharAt(intptr_t index) const;
 
   bool Equals(const String& str, intptr_t begin_index, intptr_t len) const;
   bool Equals(const char* str) const;
   bool Equals(const uint8_t* characters, intptr_t len) const;
   bool Equals(const uint16_t* characters, intptr_t len) const;
   bool Equals(const uint32_t* characters, intptr_t len) const;
 
   virtual bool Equals(const Instance& other) const;
 
@@ skipping 117 matching lines @@
   static RawOneByteString* New(const OneByteString& str,
                                Heap::Space space);
 
   static RawOneByteString* Concat(const String& str1,
                                   const String& str2,
                                   Heap::Space space);
   static RawOneByteString* ConcatAll(const Array& strings,
                                      intptr_t len,
                                      Heap::Space space);
 
-  static RawString* SubString(const OneByteString& str,
-                              intptr_t begin_index,
-                              intptr_t length,
-                              Heap::Space space);
-
   static RawOneByteString* Transform(int32_t (*mapping)(int32_t ch),
                                      const String& str,
                                      Heap::Space space);
 
  private:
   uint8_t* CharAddr(intptr_t index) const {
     // TODO(iposva): Determine if we should throw an exception here.
     ASSERT((index >= 0) && (index < Length()));
     return &raw_ptr()->data_[index];
   }
@@ skipping 30 matching lines @@
   static RawTwoByteString* New(const TwoByteString& str,
                                Heap::Space space);
 
   static RawTwoByteString* Concat(const String& str1,
                                   const String& str2,
                                   Heap::Space space);
   static RawTwoByteString* ConcatAll(const Array& strings,
                                      intptr_t len,
                                      Heap::Space space);
 
-  static RawString* SubString(const TwoByteString& str,
-                              intptr_t begin_index,
-                              intptr_t length,
-                              Heap::Space space);
-
   static RawTwoByteString* Transform(int32_t (*mapping)(int32_t ch),
                                      const String& str,
                                      Heap::Space space);
 
  private:
   uint16_t* CharAddr(intptr_t index) const {
     ASSERT((index >= 0) && (index < Length()));
     return &raw_ptr()->data_[index];
   }
 
@@ skipping 26 matching lines @@
   static RawFourByteString* New(const FourByteString& str,
                                 Heap::Space space);
 
   static RawFourByteString* Concat(const String& str1,
                                    const String& str2,
                                    Heap::Space space);
   static RawFourByteString* ConcatAll(const Array& strings,
                                       intptr_t len,
                                       Heap::Space space);
 
-  static RawString* SubString(const FourByteString& str,
-                              intptr_t begin_index,
-                              intptr_t length,
-                              Heap::Space space);
-
   static RawFourByteString* Transform(int32_t (*mapping)(int32_t ch),
                                       const String& str,
                                       Heap::Space space);
 
  private:
   uint32_t* CharAddr(intptr_t index) const {
     ASSERT((index >= 0) && (index < Length()));
     return &raw_ptr()->data_[index];
   }
 
   HEAP_OBJECT_IMPLEMENTATION(FourByteString, String);
   friend class Class;
   friend class String;
 };
 
 
+class ExternalOneByteString : public String {
+ public:
+  typedef void (*Finalizer)(uint8_t* characters);
+
+  virtual int32_t CharAt(intptr_t index) const {
+    return *CharAddr(index);
+  }
+
+  static intptr_t InstanceSize() {
+    return RoundedAllocationSize(sizeof(RawExternalOneByteString));
+  }
+
+  static RawExternalOneByteString* New(const uint8_t* characters,
+                                       intptr_t len,
+                                       Finalizer finalizer,
+                                       Heap::Space space = Heap::kNew);
+
+ private:
+  uint8_t* CharAddr(intptr_t index) const {
+    // TODO(iposva): Determine if we should throw an exception here.
+    ASSERT((index >= 0) && (index < Length()));
+    return &raw_ptr()->data_[index];
+  }
+
+  void SetData(const uint8_t* characters) {
+    raw_ptr()->data_ = const_cast<uint8_t*>(characters);
+  }
+
+  HEAP_OBJECT_IMPLEMENTATION(ExternalOneByteString, String);
+  friend class Class;
+  friend class String;
+};
+
+
+class ExternalTwoByteString : public String {
+ public:
+  typedef void (*Finalizer)(uint16_t* characters);
+
+  virtual int32_t CharAt(intptr_t index) const {
+    return *CharAddr(index);
+  }
+
+  static intptr_t InstanceSize() {
+    return RoundedAllocationSize(sizeof(RawExternalTwoByteString));
+  }
+
+  static RawExternalTwoByteString* New(const uint16_t* characters,
+                                       intptr_t len,
+                                       Finalizer finalizer,
+                                       Heap::Space space = Heap::kNew);
+
+ private:
+  uint16_t* CharAddr(intptr_t index) const {
+    // TODO(iposva): Determine if we should throw an exception here.
+    ASSERT((index >= 0) && (index < Length()));
+    return &raw_ptr()->data_[index];
+  }
+
+  void SetData(const uint16_t* characters) {
+    raw_ptr()->data_ = const_cast<uint16_t*>(characters);
+  }
+
+  HEAP_OBJECT_IMPLEMENTATION(ExternalTwoByteString, String);
+  friend class Class;
+  friend class String;
+};
+
+
+class ExternalFourByteString : public String {
+ public:
+  typedef void (*Finalizer)(uint32_t* characters);
+
+  virtual int32_t CharAt(intptr_t index) const {
+    return *CharAddr(index);
+  }
+
+  static intptr_t InstanceSize() {
+    return RoundedAllocationSize(sizeof(RawExternalFourByteString));
+  }
+
+  static RawExternalFourByteString* New(const uint32_t* characters,
+                                        intptr_t len,
+                                        Finalizer finalizer,
+                                        Heap::Space space = Heap::kNew);
+
+ private:
+  uint32_t* CharAddr(intptr_t index) const {
+    // TODO(iposva): Determine if we should throw an exception here.
+    ASSERT((index >= 0) && (index < Length()));
+    return &raw_ptr()->data_[index];
+  }
+
+  void SetData(const uint32_t* characters) {
+    raw_ptr()->data_ = const_cast<uint32_t*>(characters);
+  }
+
+  HEAP_OBJECT_IMPLEMENTATION(ExternalFourByteString, String);
+  friend class Class;
+  friend class String;
+};
+
+
 class Bool : public Instance {
  public:
   bool value() const {
     return raw_ptr()->value_;
   }
 
   static intptr_t InstanceSize() {
     return RoundedAllocationSize(sizeof(RawBool));
   }
 
@@ skipping 318 matching lines @@
 }
 
 
 void Context::SetAt(intptr_t index, const Instance& value) const {
   StorePointer(InstanceAddr(index), value.raw());
 }
 
 }  // namespace dart
 
 #endif  // VM_OBJECT_H_