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1 /*
2  * Copyright (c) 2000-2007 Niels Provos <provos@citi.umich.edu>
3  * Copyright (c) 2007-2012 Niels Provos and Nick Mathewson
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 3. The name of the author may not be used to endorse or promote products
14  *    derived from this software without specific prior written permission.
15  *
16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
17  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
18  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
19  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
20  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
21  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
22  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
23  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
24  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
25  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26  */
27 #ifndef EVENT2_TAG_H_INCLUDED_
28 #define EVENT2_TAG_H_INCLUDED_
29 
30 /** @file event2/tag.h
31 
32   Helper functions for reading and writing tagged data onto buffers.
33 
34  */
35 
36 #include <event2/visibility.h>
37 
38 #ifdef __cplusplus
39 extern "C" {
40 #endif
41 
42 #include <event2/event-config.h>
43 #ifdef EVENT__HAVE_SYS_TYPES_H
44 #include <sys/types.h>
45 #endif
46 #ifdef EVENT__HAVE_SYS_TIME_H
47 #include <sys/time.h>
48 #endif
49 
50 /* For int types. */
51 #include <event2/util.h>
52 
53 struct evbuffer;
54 
55 /*
56  * Marshaling tagged data - We assume that all tags are inserted in their
57  * numeric order - so that unknown tags will always be higher than the
58  * known ones - and we can just ignore the end of an event buffer.
59  */
60 
61 EVENT2_EXPORT_SYMBOL
62 void evtag_init(void);
63 
64 /**
65    Unmarshals the header and returns the length of the payload
66 
67    @param evbuf the buffer from which to unmarshal data
68    @param ptag a pointer in which the tag id is being stored
69    @returns -1 on failure or the number of bytes in the remaining payload.
70 */
71 EVENT2_EXPORT_SYMBOL
72 int evtag_unmarshal_header(struct evbuffer *evbuf, ev_uint32_t *ptag);
73 
74 EVENT2_EXPORT_SYMBOL
75 void evtag_marshal(struct evbuffer *evbuf, ev_uint32_t tag, const void *data,
76     ev_uint32_t len);
77 EVENT2_EXPORT_SYMBOL
78 void evtag_marshal_buffer(struct evbuffer *evbuf, ev_uint32_t tag,
79     struct evbuffer *data);
80 
81 /**
82   Encode an integer and store it in an evbuffer.
83 
84   We encode integers by nybbles; the first nibble contains the number
85   of significant nibbles - 1;  this allows us to encode up to 64-bit
86   integers.  This function is byte-order independent.
87 
88   @param evbuf evbuffer to store the encoded number
89   @param number a 32-bit integer
90  */
91 EVENT2_EXPORT_SYMBOL
92 void evtag_encode_int(struct evbuffer *evbuf, ev_uint32_t number);
93 EVENT2_EXPORT_SYMBOL
94 void evtag_encode_int64(struct evbuffer *evbuf, ev_uint64_t number);
95 
96 EVENT2_EXPORT_SYMBOL
97 void evtag_marshal_int(struct evbuffer *evbuf, ev_uint32_t tag,
98     ev_uint32_t integer);
99 EVENT2_EXPORT_SYMBOL
100 void evtag_marshal_int64(struct evbuffer *evbuf, ev_uint32_t tag,
101     ev_uint64_t integer);
102 
103 EVENT2_EXPORT_SYMBOL
104 void evtag_marshal_string(struct evbuffer *buf, ev_uint32_t tag,
105     const char *string);
106 
107 EVENT2_EXPORT_SYMBOL
108 void evtag_marshal_timeval(struct evbuffer *evbuf, ev_uint32_t tag,
109     struct timeval *tv);
110 
111 EVENT2_EXPORT_SYMBOL
112 int evtag_unmarshal(struct evbuffer *src, ev_uint32_t *ptag,
113     struct evbuffer *dst);
114 EVENT2_EXPORT_SYMBOL
115 int evtag_peek(struct evbuffer *evbuf, ev_uint32_t *ptag);
116 EVENT2_EXPORT_SYMBOL
117 int evtag_peek_length(struct evbuffer *evbuf, ev_uint32_t *plength);
118 EVENT2_EXPORT_SYMBOL
119 int evtag_payload_length(struct evbuffer *evbuf, ev_uint32_t *plength);
120 EVENT2_EXPORT_SYMBOL
121 int evtag_consume(struct evbuffer *evbuf);
122 
123 EVENT2_EXPORT_SYMBOL
124 int evtag_unmarshal_int(struct evbuffer *evbuf, ev_uint32_t need_tag,
125     ev_uint32_t *pinteger);
126 EVENT2_EXPORT_SYMBOL
127 int evtag_unmarshal_int64(struct evbuffer *evbuf, ev_uint32_t need_tag,
128     ev_uint64_t *pinteger);
129 
130 EVENT2_EXPORT_SYMBOL
131 int evtag_unmarshal_fixed(struct evbuffer *src, ev_uint32_t need_tag,
132     void *data, size_t len);
133 
134 EVENT2_EXPORT_SYMBOL
135 int evtag_unmarshal_string(struct evbuffer *evbuf, ev_uint32_t need_tag,
136     char **pstring);
137 
138 EVENT2_EXPORT_SYMBOL
139 int evtag_unmarshal_timeval(struct evbuffer *evbuf, ev_uint32_t need_tag,
140     struct timeval *ptv);
141 
142 #ifdef __cplusplus
143 }
144 #endif
145 
146 #endif /* EVENT2_TAG_H_INCLUDED_ */
147