net/tools/balsa/simple_buffer.h

   1 // Copyright 2013 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef NET_TOOLS_BALSA_SIMPLE_BUFFER_H__
   6 #define NET_TOOLS_BALSA_SIMPLE_BUFFER_H__
   7
   8 #include <string>
   9
  10 #include "base/compiler_specific.h"
  11 #include "net/tools/balsa/buffer_interface.h"
  12
  13 namespace net {
  14
  15 class SimpleBuffer : public BufferInterface {
  16  public:
  17   SimpleBuffer();
  18   explicit SimpleBuffer(int size);
  19   virtual ~SimpleBuffer();
  20
  21   std::string str() const;
  22
  23   typedef char * iterator;
  24   typedef const char * const_iterator;
  25
  26   iterator begin() { return storage_ + read_idx_; }
  27   const_iterator begin() const { return storage_ + read_idx_; }
  28
  29   iterator end() { return storage_ + write_idx_; }
  30   const_iterator end() const { return storage_ + write_idx_; }
  31
  32   // The following functions all override pure virtual functions
  33   // in BufferInterface. See buffer_interface.h for a description
  34   // of what they do.
  35   virtual int ReadableBytes() const OVERRIDE;
  36   virtual int BufferSize() const OVERRIDE;
  37   virtual int BytesFree() const OVERRIDE;
  38
  39   virtual bool Empty() const OVERRIDE;
  40   virtual bool Full() const OVERRIDE;
  41
  42   virtual int Write(const char* bytes, int size) OVERRIDE;
  43
  44   virtual void GetWritablePtr(char **ptr, int* size) const OVERRIDE;
  45
  46   virtual void GetReadablePtr(char **ptr, int* size) const OVERRIDE;
  47
  48   virtual int Read(char* bytes, int size) OVERRIDE;
  49
  50   virtual void Clear() OVERRIDE;
  51
  52   // This can be an expensive operation: costing a new/delete, and copying of
  53   // all existing data. Even if the existing buffer does not need to be
  54   // resized, unread data may still need to be non-destructively copied to
  55   // consolidate fragmented free space.
  56   virtual bool Reserve(int size) OVERRIDE;
  57
  58   virtual void AdvanceReadablePtr(int amount_to_advance) OVERRIDE;
  59
  60   virtual void AdvanceWritablePtr(int amount_to_advance) OVERRIDE;
  61
  62   void Swap(SimpleBuffer* other) {
  63     char* tmp = storage_;
  64     storage_ = other->storage_;
  65     other->storage_ = tmp;
  66
  67     int tmp_int = write_idx_;
  68     write_idx_ = other->write_idx_;
  69     other->write_idx_ = tmp_int;
  70
  71     tmp_int = read_idx_;
  72     read_idx_ = other->read_idx_;
  73     other->read_idx_ = tmp_int;
  74
  75     tmp_int = storage_size_;
  76     storage_size_ = other->storage_size_;
  77     other->storage_size_ = tmp_int;
  78   }
  79
  80  protected:
  81   char* storage_;
  82   int write_idx_;
  83   int read_idx_;
  84   int storage_size_;
  85
  86  private:
  87   //DISALLOW_COPY_AND_ASSIGN(SimpleBuffer);
  88 };
  89
  90 }  // namespace net
  91
  92 #endif  // NET_TOOLS_BALSA_SIMPLE_BUFFER_H__