Botan  2.1.0
Crypto and TLS for C++11
secqueue.cpp
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1 /*
2 * SecureQueue
3 * (C) 1999-2007 Jack Lloyd
4 * 2012 Markus Wanner
5 *
6 * Botan is released under the Simplified BSD License (see license.txt)
7 */
8 
9 #include <botan/secqueue.h>
10 #include <algorithm>
11 
12 namespace Botan {
13 
14 /**
15 * A node in a SecureQueue
16 */
17 class SecureQueueNode
18  {
19  public:
20  SecureQueueNode() : m_buffer(DEFAULT_BUFFERSIZE)
21  { m_next = nullptr; m_start = m_end = 0; }
22 
23  ~SecureQueueNode() { m_next = nullptr; m_start = m_end = 0; }
24 
25  size_t write(const uint8_t input[], size_t length)
26  {
27  size_t copied = std::min<size_t>(length, m_buffer.size() - m_end);
28  copy_mem(m_buffer.data() + m_end, input, copied);
29  m_end += copied;
30  return copied;
31  }
32 
33  size_t read(uint8_t output[], size_t length)
34  {
35  size_t copied = std::min(length, m_end - m_start);
36  copy_mem(output, m_buffer.data() + m_start, copied);
37  m_start += copied;
38  return copied;
39  }
40 
41  size_t peek(uint8_t output[], size_t length, size_t offset = 0)
42  {
43  const size_t left = m_end - m_start;
44  if(offset >= left) return 0;
45  size_t copied = std::min(length, left - offset);
46  copy_mem(output, m_buffer.data() + m_start + offset, copied);
47  return copied;
48  }
49 
50  size_t size() const { return (m_end - m_start); }
51  private:
52  friend class SecureQueue;
53  SecureQueueNode* m_next;
54  secure_vector<uint8_t> m_buffer;
55  size_t m_start, m_end;
56  };
57 
58 /*
59 * Create a SecureQueue
60 */
62  {
63  m_bytes_read = 0;
64  set_next(nullptr, 0);
65  m_head = m_tail = new SecureQueueNode;
66  }
67 
68 /*
69 * Copy a SecureQueue
70 */
73  {
74  m_bytes_read = 0;
75  set_next(nullptr, 0);
76 
77  m_head = m_tail = new SecureQueueNode;
78  SecureQueueNode* temp = input.m_head;
79  while(temp)
80  {
81  write(&temp->m_buffer[temp->m_start], temp->m_end - temp->m_start);
82  temp = temp->m_next;
83  }
84  }
85 
86 /*
87 * Destroy this SecureQueue
88 */
89 void SecureQueue::destroy()
90  {
91  SecureQueueNode* temp = m_head;
92  while(temp)
93  {
94  SecureQueueNode* holder = temp->m_next;
95  delete temp;
96  temp = holder;
97  }
98  m_head = m_tail = nullptr;
99  }
100 
101 /*
102 * Copy a SecureQueue
103 */
105  {
106  destroy();
107  m_bytes_read = input.get_bytes_read();
108  m_head = m_tail = new SecureQueueNode;
109  SecureQueueNode* temp = input.m_head;
110  while(temp)
111  {
112  write(&temp->m_buffer[temp->m_start], temp->m_end - temp->m_start);
113  temp = temp->m_next;
114  }
115  return (*this);
116  }
117 
118 /*
119 * Add some bytes to the queue
120 */
121 void SecureQueue::write(const uint8_t input[], size_t length)
122  {
123  if(!m_head)
124  m_head = m_tail = new SecureQueueNode;
125  while(length)
126  {
127  const size_t n = m_tail->write(input, length);
128  input += n;
129  length -= n;
130  if(length)
131  {
132  m_tail->m_next = new SecureQueueNode;
133  m_tail = m_tail->m_next;
134  }
135  }
136  }
137 
138 /*
139 * Read some bytes from the queue
140 */
141 size_t SecureQueue::read(uint8_t output[], size_t length)
142  {
143  size_t got = 0;
144  while(length && m_head)
145  {
146  const size_t n = m_head->read(output, length);
147  output += n;
148  got += n;
149  length -= n;
150  if(m_head->size() == 0)
151  {
152  SecureQueueNode* holder = m_head->m_next;
153  delete m_head;
154  m_head = holder;
155  }
156  }
157  m_bytes_read += got;
158  return got;
159  }
160 
161 /*
162 * Read data, but do not remove it from queue
163 */
164 size_t SecureQueue::peek(uint8_t output[], size_t length, size_t offset) const
165  {
166  SecureQueueNode* current = m_head;
167 
168  while(offset && current)
169  {
170  if(offset >= current->size())
171  {
172  offset -= current->size();
173  current = current->m_next;
174  }
175  else
176  break;
177  }
178 
179  size_t got = 0;
180  while(length && current)
181  {
182  const size_t n = current->peek(output, length, offset);
183  offset = 0;
184  output += n;
185  got += n;
186  length -= n;
187  current = current->m_next;
188  }
189  return got;
190  }
191 
192 /**
193 * Return how many bytes have been read so far.
194 */
196  {
197  return m_bytes_read;
198  }
199 
200 /*
201 * Return how many bytes the queue holds
202 */
203 size_t SecureQueue::size() const
204  {
205  SecureQueueNode* current = m_head;
206  size_t count = 0;
207 
208  while(current)
209  {
210  count += current->size();
211  current = current->m_next;
212  }
213  return count;
214  }
215 
216 /*
217 * Test if the queue has any data in it
218 */
220  {
221  return (size() == 0);
222  }
223 
224 bool SecureQueue::empty() const
225  {
226  return (size() == 0);
227  }
228 
229 }
size_t read(uint8_t[], size_t) override
Definition: secqueue.cpp:141
void set_next(Filter *f[], size_t n)
Definition: filter.h:162
SecureQueue & operator=(const SecureQueue &other)
Definition: secqueue.cpp:104
void write(const uint8_t[], size_t) override
Definition: secqueue.cpp:121
bool empty() const
Definition: secqueue.cpp:224
size_t peek(uint8_t[], size_t, size_t=0) const override
Definition: secqueue.cpp:164
size_t get_bytes_read() const override
Definition: secqueue.cpp:195
void copy_mem(T *out, const T *in, size_t n)
Definition: mem_ops.h:68
Definition: alg_id.cpp:13
size_t size() const
Definition: secqueue.cpp:203
T min(T a, T b)
Definition: ct_utils.h:180
bool end_of_data() const override
Definition: secqueue.cpp:219