Botan  2.18.2
Crypto and TLS for C++11
hex.cpp
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1 /*
2 * Hex Encoding and Decoding
3 * (C) 2010,2020 Jack Lloyd
4 *
5 * Botan is released under the Simplified BSD License (see license.txt)
6 */
7 
8 #include <botan/hex.h>
9 #include <botan/mem_ops.h>
10 #include <botan/exceptn.h>
11 #include <botan/internal/ct_utils.h>
12 
13 namespace Botan {
14 
15 namespace {
16 
17 char hex_encode_nibble(uint8_t n, bool uppercase)
18  {
19  BOTAN_DEBUG_ASSERT(n <= 15);
20 
21  const auto in_09 = CT::Mask<uint8_t>::is_lt(n, 10);
22 
23  const char c_09 = n + '0';
24  const char c_af = n + (uppercase ? 'A' : 'a') - 10;
25 
26  return in_09.select(c_09, c_af);
27  }
28 
29 }
30 
31 void hex_encode(char output[],
32  const uint8_t input[],
33  size_t input_length,
34  bool uppercase)
35  {
36  for(size_t i = 0; i != input_length; ++i)
37  {
38  const uint8_t n0 = (input[i] >> 4) & 0xF;
39  const uint8_t n1 = (input[i] ) & 0xF;
40 
41  output[2*i ] = hex_encode_nibble(n0, uppercase);
42  output[2*i+1] = hex_encode_nibble(n1, uppercase);
43  }
44  }
45 
46 std::string hex_encode(const uint8_t input[],
47  size_t input_length,
48  bool uppercase)
49  {
50  std::string output(2 * input_length, 0);
51 
52  if(input_length)
53  hex_encode(&output.front(), input, input_length, uppercase);
54 
55  return output;
56  }
57 
58 namespace {
59 
60 uint8_t hex_char_to_bin(char input)
61  {
62  const uint8_t c = static_cast<uint8_t>(input);
63 
64  const auto is_alpha_upper = CT::Mask<uint8_t>::is_within_range(c, uint8_t('A'), uint8_t('F'));
65  const auto is_alpha_lower = CT::Mask<uint8_t>::is_within_range(c, uint8_t('a'), uint8_t('f'));
66  const auto is_decimal = CT::Mask<uint8_t>::is_within_range(c, uint8_t('0'), uint8_t('9'));
67 
68  const auto is_whitespace = CT::Mask<uint8_t>::is_any_of(c, {
69  uint8_t(' '), uint8_t('\t'), uint8_t('\n'), uint8_t('\r')
70  });
71 
72  const uint8_t c_upper = c - uint8_t('A') + 10;
73  const uint8_t c_lower = c - uint8_t('a') + 10;
74  const uint8_t c_decim = c - uint8_t('0');
75 
76  uint8_t ret = 0xFF; // default value
77 
78  ret = is_alpha_upper.select(c_upper, ret);
79  ret = is_alpha_lower.select(c_lower, ret);
80  ret = is_decimal.select(c_decim, ret);
81  ret = is_whitespace.select(0x80, ret);
82 
83  return ret;
84  }
85 
86 }
87 
88 
89 size_t hex_decode(uint8_t output[],
90  const char input[],
91  size_t input_length,
92  size_t& input_consumed,
93  bool ignore_ws)
94  {
95  uint8_t* out_ptr = output;
96  bool top_nibble = true;
97 
98  clear_mem(output, input_length / 2);
99 
100  for(size_t i = 0; i != input_length; ++i)
101  {
102  const uint8_t bin = hex_char_to_bin(input[i]);
103 
104  if(bin >= 0x10)
105  {
106  if(bin == 0x80 && ignore_ws)
107  continue;
108 
109  std::string bad_char(1, input[i]);
110  if(bad_char == "\t")
111  bad_char = "\\t";
112  else if(bad_char == "\n")
113  bad_char = "\\n";
114 
115  throw Invalid_Argument(
116  std::string("hex_decode: invalid hex character '") +
117  bad_char + "'");
118  }
119 
120  if(top_nibble)
121  *out_ptr |= bin << 4;
122  else
123  *out_ptr |= bin;
124 
125  top_nibble = !top_nibble;
126  if(top_nibble)
127  ++out_ptr;
128  }
129 
130  input_consumed = input_length;
131  size_t written = (out_ptr - output);
132 
133  /*
134  * We only got half of a uint8_t at the end; zap the half-written
135  * output and mark it as unread
136  */
137  if(!top_nibble)
138  {
139  *out_ptr = 0;
140  input_consumed -= 1;
141  }
142 
143  return written;
144  }
145 
146 size_t hex_decode(uint8_t output[],
147  const char input[],
148  size_t input_length,
149  bool ignore_ws)
150  {
151  size_t consumed = 0;
152  size_t written = hex_decode(output, input, input_length,
153  consumed, ignore_ws);
154 
155  if(consumed != input_length)
156  throw Invalid_Argument("hex_decode: input did not have full bytes");
157 
158  return written;
159  }
160 
161 size_t hex_decode(uint8_t output[],
162  const std::string& input,
163  bool ignore_ws)
164  {
165  return hex_decode(output, input.data(), input.length(), ignore_ws);
166  }
167 
169  size_t input_length,
170  bool ignore_ws)
171  {
172  secure_vector<uint8_t> bin(1 + input_length / 2);
173 
174  size_t written = hex_decode(bin.data(),
175  input,
176  input_length,
177  ignore_ws);
178 
179  bin.resize(written);
180  return bin;
181  }
182 
183 secure_vector<uint8_t> hex_decode_locked(const std::string& input,
184  bool ignore_ws)
185  {
186  return hex_decode_locked(input.data(), input.size(), ignore_ws);
187  }
188 
189 std::vector<uint8_t> hex_decode(const char input[],
190  size_t input_length,
191  bool ignore_ws)
192  {
193  std::vector<uint8_t> bin(1 + input_length / 2);
194 
195  size_t written = hex_decode(bin.data(),
196  input,
197  input_length,
198  ignore_ws);
199 
200  bin.resize(written);
201  return bin;
202  }
203 
204 std::vector<uint8_t> hex_decode(const std::string& input,
205  bool ignore_ws)
206  {
207  return hex_decode(input.data(), input.size(), ignore_ws);
208  }
209 
210 }
void hex_encode(char output[], const uint8_t input[], size_t input_length, bool uppercase)
Definition: hex.cpp:31
secure_vector< uint8_t > hex_decode_locked(const char input[], size_t input_length, bool ignore_ws)
Definition: hex.cpp:168
void clear_mem(T *ptr, size_t n)
Definition: mem_ops.h:115
static Mask< T > is_within_range(T v, T l, T u)
Definition: ct_utils.h:186
#define BOTAN_DEBUG_ASSERT(expr)
Definition: assert.h:123
Definition: alg_id.cpp:13
size_t hex_decode(uint8_t output[], const char input[], size_t input_length, size_t &input_consumed, bool ignore_ws)
Definition: hex.cpp:89
static Mask< T > is_any_of(T v, std::initializer_list< T > accepted)
Definition: ct_utils.h:196
std::vector< T, secure_allocator< T > > secure_vector
Definition: secmem.h:65
static Mask< T > is_lt(T x, T y)
Definition: ct_utils.h:157