1 /*=============================================================================
2 Copyright (c) 2002-2003 Joel de Guzman
3 http://spirit.sourceforge.net/
4
5 Use, modification and distribution is subject to the Boost Software
6 License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
7 http://www.boost.org/LICENSE_1_0.txt)
8 =============================================================================*/
9 #include <boost/spirit/include/classic_core.hpp>
10 #include <boost/spirit/include/classic_push_back_actor.hpp>
11 #include <boost/spirit/include/classic_if.hpp>
12 #include <boost/spirit/include/classic_for.hpp>
13 #include <boost/spirit/include/phoenix1.hpp>
14 #include <iostream>
15 #include <string>
16 #include <vector>
17 #include <algorithm>
18
19 ///////////////////////////////////////////////////////////////////////////////
20 //
21 // Please check it out ipv4.cpp sample first!
22 // << See ipv4.cpp sample for details >>
23 //
24 // This is a variation of the ipv4.cpp sample. The original ipv4.cpp code
25 // compiles to 36k on MSVC7.1. Not bad! Yet, we want to shave a little bit
26 // more. Is it possible? Yes! This time, we'll use subrules and just store
27 // the rules in a plain old struct. We are parsing at the char level anyway,
28 // so we know what type of rule we'll need: a plain rule<>. The result: we
29 // shaved off another 20k. Now the code compiles to 16k on MSVC7.1.
30 //
31 // Could we have done better? Yes, but only if only we had typeof! << See
32 // the techniques section of the User's guide >> ... Someday... :-)
33 //
34 ///////////////////////////////////////////////////////////////////////////////
35 using namespace std;
36 using namespace BOOST_SPIRIT_CLASSIC_NS;
37 using namespace phoenix;
38
39 struct ipv4_prefix_data
40 {
41 char prefix_len, n0, n1, n2, n3;
42
ipv4_prefix_dataipv4_prefix_data43 ipv4_prefix_data()
44 : prefix_len(0),n0(0),n1(0),n2(0),n3(0) {}
45 };
46
47 struct ipv4_data
48 {
49 char packet_len, header_len;
50 std::string header;
51 std::vector<ipv4_prefix_data> prefixes;
52
ipv4_dataipv4_data53 ipv4_data()
54 : packet_len(0),header_len(0){}
55
56 };
57
58 struct ipv4
59 {
ipv4ipv460 ipv4(ipv4_data& data)
61 : data(data)
62 {
63 start =
64 (
65 packet =
66 '\xff'
67 >> anychar_p[var(data.packet_len) = arg1]
68 >> payload
69 ,
70
71 payload =
72 anychar_p[var(data.header_len) = arg1]
73 >> for_p(var(i) = 0, var(i) < var(data.header_len), ++var(i))
74 [
75 anychar_p[var(data.header) += arg1]
76 ]
77 >> *ipv4_prefix
78 ,
79
80 ipv4_prefix =
81 anychar_p
82 [
83 var(temp.prefix_len) = arg1,
84 var(temp.n0) = 0,
85 var(temp.n1) = 0,
86 var(temp.n2) = 0,
87 var(temp.n3) = 0
88 ]
89
90 >> if_p(var(temp.prefix_len) > 0x00)
91 [
92 anychar_p[var(temp.n0) = arg1]
93 >> if_p(var(temp.prefix_len) > 0x08)
94 [
95 anychar_p[var(temp.n1) = arg1]
96 >> if_p(var(temp.prefix_len) > 0x10)
97 [
98 anychar_p[var(temp.n2) = arg1]
99 >> if_p(var(temp.prefix_len) > 0x18)
100 [
101 anychar_p[var(temp.n3) = arg1]
102 ]
103 ]
104 ]
105 ]
106 [
107 push_back_a(data.prefixes, temp)
108 ]
109 );
110 }
111
112 int i;
113 ipv4_prefix_data temp;
114
115 rule<> start;
116 subrule<0> packet;
117 subrule<1> payload;
118 subrule<2> ipv4_prefix;
119 ipv4_data& data;
120 };
121
122 ////////////////////////////////////////////////////////////////////////////
123 //
124 // Main program
125 //
126 ////////////////////////////////////////////////////////////////////////////
127 int
as_byte(char n)128 as_byte(char n)
129 {
130 if (n < 0)
131 return n + 256;
132 return n;
133 }
134
135 void
print_prefix(ipv4_prefix_data const & prefix)136 print_prefix(ipv4_prefix_data const& prefix)
137 {
138 cout << "prefix length = " << as_byte(prefix.prefix_len) << endl;
139 cout << "n0 = " << as_byte(prefix.n0) << endl;
140 cout << "n1 = " << as_byte(prefix.n1) << endl;
141 cout << "n2 = " << as_byte(prefix.n2) << endl;
142 cout << "n3 = " << as_byte(prefix.n3) << endl;
143 }
144
145 void
parse_ipv4(char const * str,unsigned len)146 parse_ipv4(char const* str, unsigned len)
147 {
148 ipv4_data data;
149 ipv4 g(data);
150 parse_info<> info = parse(str, str+len, g.start);
151
152 if (info.full)
153 {
154 cout << "-------------------------\n";
155 cout << "Parsing succeeded\n";
156
157 cout << "packet length = " << as_byte(data.packet_len) << endl;
158 cout << "header length = " << as_byte(data.header_len) << endl;
159 cout << "header = " << data.header << endl;
160
161 for_each(data.prefixes.begin(), data.prefixes.end(), print_prefix);
162 cout << "-------------------------\n";
163 }
164 else
165 {
166 cout << "Parsing failed\n";
167 cout << "stopped at:";
168 for (char const* s = info.stop; s != str+len; ++s)
169 cout << static_cast<int>(*s) << endl;
170 }
171 }
172
173 // Test inputs:
174
175 // The string in the header is "empty", the prefix list is empty.
176 char const i1[8] =
177 {
178 0xff,0x08,0x05,
179 'e','m','p','t','y'
180 };
181
182 // The string in the header is "default route", the prefix list
183 // has just one element, 0.0.0.0/0.
184 char const i2[17] =
185 {
186 0xff,0x11,0x0d,
187 'd','e','f','a','u','l','t',' ',
188 'r','o','u','t','e',
189 0x00
190 };
191
192 // The string in the header is "private address space", the prefix list
193 // has the elements 10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16.
194 char const i3[32] =
195 {
196 0xff,0x20,0x15,
197 'p','r','i','v','a','t','e',' ',
198 'a','d','d','r','e','s','s',' ',
199 's','p','a','c','e',
200 0x08,0x0a,
201 0x0c,0xac,0x10,
202 0x10,0xc0,0xa8
203 };
204
205 int
main()206 main()
207 {
208 parse_ipv4(i1, sizeof(i1));
209 parse_ipv4(i2, sizeof(i2));
210 parse_ipv4(i3, sizeof(i3));
211 return 0;
212 }
213
214