GitList
Browse code

qvalue related functions and types.

Jan Janak authored on 25/04/2004 15:29:31
Showing 1 changed files
qvalue.h
History View file @ 620d8899f8
1 1 
new file mode 100644
... ... 
@@ -0,0 +1,132 @@
0 
+/*
1 
+ * $Id$
2 
+ *
3 
+ * Handling of the q value
4 
+ *
5 
+ * Copyright (C) 2004 FhG FOKUS
6 
+ *
7 
+ * This file is part of ser, a free SIP server.
8 
+ *
9 
+ * ser is free software; you can redistribute it and/or modify
10 
+ * it under the terms of the GNU General Public License as published by
11 
+ * the Free Software Foundation; either version 2 of the License, or
12 
+ * (at your option) any later version
13 
+ *
14 
+ * For a license to use the ser software under conditions
15 
+ * other than those described here, or to purchase support for this
16 
+ * software, please contact iptel.org by e-mail at the following addresses:
17 
+ *    info@iptel.org
18 
+ *
19 
+ * ser is distributed in the hope that it will be useful,
20 
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
21 
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
22 
+ * GNU General Public License for more details.
23 
+ *
24 
+ * You should have received a copy of the GNU General Public License
25 
+ * along with this program; if not, write to the Free Software
26 
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
27 
+ *
28 
+ * History
29 
+ * ------
30 
+ * 2004-04-25 created (janakj)
31 
+ */
32 
+
33 
+#ifndef _QVALUE_H
34 
+#define _QVALUE_H 1
35 
+
36 
+#include <string.h>
37 
+
38 
+/*
39 
+ * The q value expresses the priority of a URI within a set of URIs
40 
+ * (Contact header field in the same SIP message or dset array in
41 
+ * ser. The higher is the q value of a URI the higher is the priority
42 
+ * of the URI.
43 
+ *
44 
+ * The q value is usually expressed as a floating point number with
45 
+ * limited number of decimal digits, for example 0.346. RFC3261 allows
46 
+ * 0-3 decimal digits.
47 
+ *
48 
+ * To speed things up we represent the q value as integer number, it
49 
+ * is then easier to handle/print the value. To convert float into
50 
+ * integer we multiply the q value by 1000, i.e.
51 
+ * (float)0.567 == (int)567. In the opposite direction, values
52 
+ * higher or equal to 1000 are converted to 1.0 and values below or
53 
+ * equal to 0 are converted to 0.
54 
+ *
55 
+ * Value Q_UNSPECIFIED (which is in fact -1) has a special meaning, it
56 
+ * means that the q value is not known and the parameter should not be
57 
+ * printed when printing Contacts, implementations will then use
58 
+ * implementation specific pre-defined values.
59 
+ */
60 
+
61 
+typedef int qvalue_t;
62 
+
63 
+/*
64 
+ * Use this if the value of q is not specified
65 
+ */
66 
+#define Q_UNSPECIFIED ((qvalue_t)-1)
67 
+
68 
+
69 
+#define MAX_Q ((qvalue_t)1000)
70 
+#define MIN_Q ((qvalue_t)0)
71 
+
72 
+#define MAX_Q_STR "1"
73 
+#define MAX_Q_STR_LEN (sizeof(MAX_Q_STR) - 1)
74 
+
75 
+#define MIN_Q_STR "0"
76 
+#define MIN_Q_STR_LEN (sizeof(MIN_Q_STR) - 1)
77 
+
78 
+#define Q_PREFIX "0."
79 
+#define Q_PREFIX_LEN (sizeof(Q_PREFIX) - 1)
80 
+
81 
+
82 
+/*
83 
+ * Calculate the length of printed q
84 
+ */
85 
+static inline size_t len_q(qvalue_t q)
86 
+{
87 
+	if (q == Q_UNSPECIFIED) {
88 
+		return 0;
89 
+	} else if (q >= MAX_Q) {
90 
+		return MAX_Q_STR_LEN;
91 
+	} else if (q <= MIN_Q) {
92 
+		return MIN_Q_STR_LEN;
93 
+	} else if (q % 100 == 0) {
94 
+		return Q_PREFIX_LEN + 1;
95 
+	} else if (q % 10 == 0) {
96 
+		return Q_PREFIX_LEN + 2;
97 
+	} else {
98 
+		return Q_PREFIX_LEN + 3;
99 
+	}
100 
+}
101 
+
102 
+
103 
+/*
104 
+ * Print the q parameter
105 
+ */
106 
+static inline size_t print_q(char* p, qvalue_t q)
107 
+{
108 
+	if (q == Q_UNSPECIFIED) {
109 
+		return 0;
110 
+	} else if (q >= MAX_Q) {
111 
+		memcpy(p, MAX_Q_STR, MAX_Q_STR_LEN);
112 
+		return MAX_Q_STR_LEN;
113 
+	} else if (q <= MIN_Q) {
114 
+		memcpy(p, MIN_Q_STR, MIN_Q_STR_LEN);
115 
+		return MIN_Q_STR_LEN;
116 
+	}
117 
+
118 
+	memcpy(p, Q_PREFIX, Q_PREFIX_LEN);
119 
+	p += Q_PREFIX_LEN;
120 
+
121 
+	*p++ = q / 100 + '0';
122 
+	q %= 100;
123 
+	if (!q) return Q_PREFIX_LEN + 1;
124 
+	*p++ = q / 10 + '0';
125 
+	q %= 10;
126 
+	if (!q) return Q_PREFIX_LEN + 2;
127 
+	*p = q + '0';
128 
+	return Q_PREFIX_LEN + 3;
129 
+}
130 
+
131 
+#endif /* _QVALUE_H */