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1 /*
2  * libjingle
3  * Copyright 2004-2010, Google Inc.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions are met:
7  *
8  *  1. Redistributions of source code must retain the above copyright notice,
9  *     this list of conditions and the following disclaimer.
10  *  2. Redistributions in binary form must reproduce the above copyright notice,
11  *     this list of conditions and the following disclaimer in the documentation
12  *     and/or other materials provided with the distribution.
13  *  3. The name of the author may not be used to endorse or promote products
14  *     derived from this software without specific prior written permission.
15  *
16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
17  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
18  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
19  * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
20  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
21  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
22  * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
23  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
24  * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
25  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26  */
27 
28 #ifndef TALK_BASE_BUFFER_H_
29 #define TALK_BASE_BUFFER_H_
30 
31 #include <cstring>
32 
33 #include "talk/base/scoped_ptr.h"
34 
35 namespace talk_base {
36 
37 // Basic buffer class, can be grown and shrunk dynamically.
38 // Unlike std::string/vector, does not initialize data when expanding capacity.
39 class Buffer {
40  public:
Buffer()41   Buffer() {
42     Construct(NULL, 0, 0);
43   }
Buffer(const void * data,size_t length)44   Buffer(const void* data, size_t length) {
45     Construct(data, length, length);
46   }
Buffer(const void * data,size_t length,size_t capacity)47   Buffer(const void* data, size_t length, size_t capacity) {
48     Construct(data, length, capacity);
49   }
Buffer(const Buffer & buf)50   Buffer(const Buffer& buf) {
51     Construct(buf.data(), buf.length(), buf.length());
52   }
53 
data()54   const char* data() const { return data_.get(); }
data()55   char* data() { return data_.get(); }
56   // TODO: should this be size(), like STL?
length()57   size_t length() const { return length_; }
capacity()58   size_t capacity() const { return capacity_; }
59 
60   Buffer& operator=(const Buffer& buf) {
61     if (&buf != this) {
62       Construct(buf.data(), buf.length(), buf.length());
63     }
64     return *this;
65   }
66   bool operator==(const Buffer& buf) const {
67     return (length_ == buf.length() &&
68             memcmp(data_.get(), buf.data(), length_) == 0);
69   }
70   bool operator!=(const Buffer& buf) const {
71     return !operator==(buf);
72   }
73 
SetData(const void * data,size_t length)74   void SetData(const void* data, size_t length) {
75     ASSERT(data != NULL || length == 0);
76     SetLength(length);
77     memcpy(data_.get(), data, length);
78   }
AppendData(const void * data,size_t length)79   void AppendData(const void* data, size_t length) {
80     ASSERT(data != NULL || length == 0);
81     size_t old_length = length_;
82     SetLength(length_ + length);
83     memcpy(data_.get() + old_length, data, length);
84   }
SetLength(size_t length)85   void SetLength(size_t length) {
86     SetCapacity(length);
87     length_ = length;
88   }
SetCapacity(size_t capacity)89   void SetCapacity(size_t capacity) {
90     if (capacity > capacity_) {
91       talk_base::scoped_array<char> data(new char[capacity]);
92       memcpy(data.get(), data_.get(), length_);
93       data_.swap(data);
94       capacity_ = capacity;
95     }
96   }
97 
TransferTo(Buffer * buf)98   void TransferTo(Buffer* buf) {
99     ASSERT(buf != NULL);
100     buf->data_.reset(data_.release());
101     buf->length_ = length_;
102     buf->capacity_ = capacity_;
103     Construct(NULL, 0, 0);
104   }
105 
106  protected:
Construct(const void * data,size_t length,size_t capacity)107   void Construct(const void* data, size_t length, size_t capacity) {
108     data_.reset(new char[capacity_ = capacity]);
109     SetData(data, length);
110   }
111 
112   scoped_array<char> data_;
113   size_t length_;
114   size_t capacity_;
115 };
116 
117 }  // namespace talk_base
118 
119 #endif  // TALK_BASE_BUFFER_H_
120