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09ca2cbf JR |
1 | /* |
2 | The software in this package is distributed under the GNU General | |
3 | Public License version 2 (with a special exception described below). | |
4 | ||
5 | A copy of GNU General Public License (GPL) is included in this distribution, | |
6 | in the file COPYING.GPL. | |
7 | ||
8 | As a special exception, if other files instantiate templates or use macros | |
9 | or inline functions from this file, or you compile this file and link it | |
10 | with other works to produce a work based on this file, this file | |
11 | does not by itself cause the resulting work to be covered | |
12 | by the GNU General Public License. | |
13 | ||
14 | However the source code for this file must still be made available | |
15 | in accordance with section (3) of the GNU General Public License. | |
16 | ||
17 | This exception does not invalidate any other reasons why a work based | |
18 | on this file might be covered by the GNU General Public License. | |
19 | */ | |
20 | /** @file | |
21 | * @brief restricts html messages to an allowed group of tags. | |
22 | * | |
23 | * @copyright © Copyright 2017 Intra2net AG | |
24 | * | |
25 | */ | |
26 | ||
27 | #include <string> | |
a93685ca JR |
28 | #include <sstream> |
29 | #include <iomanip> | |
09ca2cbf JR |
30 | |
31 | #include <stringfunc.hxx> | |
32 | #include <restricted_html.hpp> | |
33 | ||
34 | using namespace std; | |
35 | ||
36 | ||
37 | namespace I2n | |
38 | { | |
39 | ||
40 | ||
41 | ||
a93685ca JR |
42 | /** |
43 | * @brief Replace all "+" characters found in s to spaces (" "). | |
44 | * | |
45 | * @param s string that will be modified. | |
46 | */ | |
47 | static void unescape_space(string &s) | |
48 | { | |
49 | string::size_type pos; | |
50 | while ((pos=s.find('+')) != string::npos) | |
51 | s[pos]=' '; | |
52 | } | |
53 | ||
54 | /** | |
55 | * @brief Converts a hexadecimal sequence to its respective character. | |
56 | * | |
57 | * @param s string of size 2. Example: "77" | |
58 | * @return respective character represented by the hex sequence. | |
59 | */ | |
60 | static char x2c(const string& s) | |
61 | { | |
62 | char digit; | |
63 | digit=(s[0]>='A' ? ((s[0] & 0xdf)-'A')+10 : (s[0]-'0')); | |
64 | digit*=16; | |
65 | digit+=(s[1]>='A' ? ((s[1] & 0xdf)-'A')+10 : (s[1]-'0')); | |
66 | return digit; | |
67 | } | |
68 | ||
69 | /** | |
70 | * @brief Scan a string to find escaped hex chars in the format "%HH" and replace | |
71 | * for their respective character. | |
72 | * Example: "www%2E" becomes "www." | |
73 | * | |
74 | * @param s String that will be modified. | |
75 | */ | |
76 | static void unescape_hex(string& s) | |
77 | { | |
78 | static char hex_escape='%'; | |
79 | string::size_type escape_pos; | |
80 | string hex_seq; | |
81 | string rest=s; | |
82 | for (s=""; ((escape_pos=rest.find(hex_escape)) != string::npos);) | |
83 | { | |
84 | if (escape_pos+2<static_cast<unsigned int>(rest.length()) | |
85 | && ::isalnum(rest[escape_pos+1]) && ::isalnum(rest[escape_pos+2])) | |
86 | { | |
87 | hex_seq=rest.substr(escape_pos+1,2); | |
88 | s=s+rest.substr(0,escape_pos)+x2c(hex_seq); | |
89 | rest=rest.erase(0,escape_pos+3); | |
90 | } | |
91 | else | |
92 | { | |
93 | s=s+rest.substr(0,escape_pos+1); | |
94 | rest=rest.erase(0,escape_pos+1); | |
95 | } | |
96 | } | |
97 | s+=rest; | |
98 | } | |
99 | ||
100 | /** | |
101 | * @brief Decode url that contains percent-encoding. Replace space " " with "+". | |
102 | * Example: "%77%77%77%2E" becomes "www." | |
103 | * | |
104 | * @param s url string. | |
105 | * @return the decoded string. | |
106 | */ | |
107 | string decode_url(string s) | |
108 | { | |
109 | unescape_space (s); | |
110 | unescape_hex (s); | |
111 | return (s); | |
112 | } | |
113 | ||
114 | /** | |
115 | * @brief Verify if the parameter character requires encoding, If it is non | |
116 | * alphanumeric or valid ascii signs. | |
117 | * | |
118 | * @param c character to be verified. | |
119 | * @return true if the character should be encoded. | |
120 | */ | |
121 | bool needs_encoding (const char &c) | |
122 | { | |
123 | // some valid ascii signs | |
124 | if (c == '_' || c == '-') | |
125 | return false; | |
126 | ||
127 | // is digit? | |
128 | if (c > 47 && c < 58) | |
129 | return false; | |
130 | ||
131 | // is uppercase letter? | |
132 | if (c > 64 && c < 91) | |
133 | return false; | |
134 | ||
135 | // is lowercase letter? | |
136 | if (c > 96 && c < 123) | |
137 | return false; | |
138 | ||
139 | return true; | |
140 | } | |
141 | ||
142 | /** | |
143 | * @brief Encode url with percent-encoding. Any non-alphanumeric character is | |
144 | * converted to its hex value with the percent character (%) as prefix, except "_" | |
145 | * and "-". Replace space " " with "+". | |
146 | * | |
147 | * @param s url string. | |
148 | * @return the encoded url string. | |
149 | */ | |
150 | string encode_url(string s) | |
151 | { | |
152 | // convert non-alphanumeric characters to hex, convert space to + | |
153 | ostringstream out; | |
154 | for (string::iterator pos2=s.begin(); pos2 != s.end(); pos2++) | |
155 | { | |
156 | if (*pos2 == ' ') | |
157 | out << '+'; | |
158 | else if (needs_encoding (*pos2)) | |
159 | out << '%' << std::uppercase << setw(2) << setfill('0') << \ | |
160 | std::hex << (int)(unsigned char)*pos2; | |
161 | else | |
162 | out << (*pos2); | |
163 | } | |
164 | ||
165 | return out.str(); | |
166 | } | |
09ca2cbf | 167 | } // eo namespace I2n |