Botan: src/filters/data_src.cpp Source File

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data_src.cpp
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1 /*
2 * DataSource
3 * (C) 1999-2007 Jack Lloyd
4 * 2005 Matthew Gregan
5 *
6 * Distributed under the terms of the Botan license
7 */
8
9 #include <botan/data_src.h>
10 #include <botan/exceptn.h>
11 #include <fstream>
12 #include <algorithm>
13
14 namespace Botan {
15
16 /*
17 * Read a single byte from the DataSource
18 */
19 size_t DataSource::read_byte(byte& out)
20 {
21 return read(&out, 1);
22 }
23
24 /*
25 * Peek a single byte from the DataSource
26 */
27 size_t DataSource::peek_byte(byte& out) const
28 {
29 return peek(&out, 1, 0);
30 }
31
32 /*
33 * Discard the next N bytes of the data
34 */
35 size_t DataSource::discard_next(size_t n)
36 {
37 size_t discarded = 0;
38 byte dummy;
39 for(size_t j = 0; j != n; ++j)
40 discarded += read_byte(dummy);
41 return discarded;
42 }
43
44 /*
45 * Read from a memory buffer
46 */
47 size_t DataSource_Memory::read(byte out[], size_t length)
48 {
49 size_t got = std::min<size_t>(source.size() - offset, length);
50 copy_mem(out, &source[offset], got);
51 offset += got;
52 return got;
53 }
54
55 /*
56 * Peek into a memory buffer
57 */
58 size_t DataSource_Memory::peek(byte out[], size_t length,
59 size_t peek_offset) const
60 {
61 const size_t bytes_left = source.size() - offset;
62 if(peek_offset >= bytes_left) return 0;
63
64 size_t got = std::min(bytes_left - peek_offset, length);
65 copy_mem(out, &source[offset + peek_offset], got);
66 return got;
67 }
68
69 /*
70 * Check if the memory buffer is empty
71 */
72 bool DataSource_Memory::end_of_data() const
73 {
74 return (offset == source.size());
75 }
76
77 /*
78 * DataSource_Memory Constructor
79 */
80 DataSource_Memory::DataSource_Memory(const byte in[], size_t length) :
81 source(in, length)
82 {
83 offset = 0;
84 }
85
86 /*
87 * DataSource_Memory Constructor
88 */
89 DataSource_Memory::DataSource_Memory(const MemoryRegion<byte>& in) :
90 source(in)
91 {
92 offset = 0;
93 }
94
95 /*
96 * DataSource_Memory Constructor
97 */
98 DataSource_Memory::DataSource_Memory(const std::string& in) :
99 source(reinterpret_cast<const byte*>(in.data()), in.length())
100 {
101 offset = 0;
102 }
103
104 bool DataSource_Memory::check_available(size_t n)
105 {
106 return (n <= (source.size() - offset));
107 }
108
109 /*
110 * Read from a stream
111 */
112 size_t DataSource_Stream::read(byte out[], size_t length)
113 {
114 source.read(reinterpret_cast<char*>(out), length);
115 if(source.bad())
116 throw Stream_IO_Error("DataSource_Stream::read: Source failure");
117
118 size_t got = source.gcount();
119 total_read += got;
120 return got;
121 }
122
123 bool DataSource_Stream::check_available(size_t n)
124 {
125 const std::streampos orig_pos = source.tellg();
126 source.seekg(0, std::ios::end);
127 const size_t avail = source.tellg() - orig_pos;
128 source.seekg(orig_pos);
129 return (avail >= n);
130 }
131
132 /*
133 * Peek into a stream
134 */
135 size_t DataSource_Stream::peek(byte out[], size_t length, size_t offset) const
136 {
137 if(end_of_data())
138 throw Invalid_State("DataSource_Stream: Cannot peek when out of data");
139
140 size_t got = 0;
141
142 if(offset)
143 {
144 SecureVector<byte> buf(offset);
145 source.read(reinterpret_cast<char*>(&buf[0]), buf.size());
146 if(source.bad())
147 throw Stream_IO_Error("DataSource_Stream::peek: Source failure");
148 got = source.gcount();
149 }
150
151 if(got == offset)
152 {
153 source.read(reinterpret_cast<char*>(out), length);
154 if(source.bad())
155 throw Stream_IO_Error("DataSource_Stream::peek: Source failure");
156 got = source.gcount();
157 }
158
159 if(source.eof())
160 source.clear();
161 source.seekg(total_read, std::ios::beg);
162
163 return got;
164 }
165
166 /*
167 * Check if the stream is empty or in error
168 */
169 bool DataSource_Stream::end_of_data() const
170 {
171 return (!source.good());
172 }
173
174 /*
175 * Return a human-readable ID for this stream
176 */
177 std::string DataSource_Stream::id() const
178 {
179 return identifier;
180 }
181
182 /*
183 * DataSource_Stream Constructor
184 */
185 DataSource_Stream::DataSource_Stream(const std::string& path,
186 bool use_binary) :
187 identifier(path),
188 source_p(new std::ifstream(
189 path.c_str(),
190 use_binary ? std::ios::binary : std::ios::in)),
191 source(*source_p),
192 total_read(0)
193 {
194 if(!source.good())
195 {
196 delete source_p;
197 throw Stream_IO_Error("DataSource: Failure opening file " + path);
198 }
199 }
200
201 /*
202 * DataSource_Stream Constructor
203 */
204 DataSource_Stream::DataSource_Stream(std::istream& in,
205 const std::string& name) :
206 identifier(name),
207 source_p(0),
208 source(in),
209 total_read(0)
210 {
211 }
212
213 /*
214 * DataSource_Stream Destructor
215 */
216 DataSource_Stream::~DataSource_Stream()
217 {
218 delete source_p;
219 }
220
221 }
Botan::DataSource_Stream::check_available
bool check_available(size_t n)
Definition: data_src.cpp:123
Botan::Stream_IO_Error
Definition: exceptn.h:165
Botan::DataSource_Memory::peek
size_t peek(byte[], size_t, size_t) const
Definition: data_src.cpp:58
Botan::DataSource_Stream::id
std::string id() const
Definition: data_src.cpp:177
Botan::DataSource::read
virtual size_t read(byte out[], size_t length)=0
Botan::DataSource::peek_byte
size_t peek_byte(byte &out) const
Definition: data_src.cpp:27
Botan::DataSource::discard_next
size_t discard_next(size_t N)
Definition: data_src.cpp:35
Botan::MemoryRegion::clear
void clear()
Definition: secmem.h:152
std
Definition: secmem.h:422
Botan::DataSource::peek
virtual size_t peek(byte out[], size_t length, size_t peek_offset) const =0
Botan::Invalid_State
Definition: exceptn.h:25
Botan::byte
unsigned char byte
Definition: types.h:22
Botan::DataSource_Stream::DataSource_Stream
DataSource_Stream(std::istream &, const std::string &id="<std::istream>")
Definition: data_src.cpp:204
Botan::DataSource_Stream::peek
size_t peek(byte[], size_t, size_t) const
Definition: data_src.cpp:135
Botan::DataSource::read_byte
size_t read_byte(byte &out)
Definition: data_src.cpp:19
Botan::MemoryRegion::size
size_t size() const
Definition: secmem.h:29
Botan::MemoryRegion< byte >
Botan::copy_mem
void copy_mem(T *out, const T *in, size_t n)
Definition: mem_ops.h:22
Botan
Definition: algo_base.h:14
Botan::DataSource_Memory::read
size_t read(byte[], size_t)
Definition: data_src.cpp:47
Botan::DataSource_Memory::check_available
bool check_available(size_t n)
Definition: data_src.cpp:104
Botan::DataSource_Stream::end_of_data
bool end_of_data() const
Definition: data_src.cpp:169
Botan::DataSource_Memory::DataSource_Memory
DataSource_Memory(const std::string &in)
Definition: data_src.cpp:98
Botan::DataSource_Memory::end_of_data
bool end_of_data() const
Definition: data_src.cpp:72
Botan::SecureVector< byte >
Botan::DataSource_Stream::read
size_t read(byte[], size_t)
Definition: data_src.cpp:112
Botan::DataSource_Stream::~DataSource_Stream
~DataSource_Stream()
Definition: data_src.cpp:216