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1/*
2 This file is part of TALER
3 (C) 2014 Christian Grothoff (and other contributing authors)
4
5 TALER is free software; you can redistribute it and/or modify it under the
6 terms of the GNU General Public License as published by the Free Software
7 Foundation; either version 3, or (at your option) any later version.
8
9 TALER is distributed in the hope that it will be useful, but WITHOUT ANY
10 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
11 A PARTICULAR PURPOSE. See the GNU General Public License for more details.
12
13 You should have received a copy of the GNU General Public License along with
14 TALER; see the file COPYING. If not, If not, see <http://www.gnu.org/licenses/>
15*/
16
17/**
18 * @file include/taler_util.h
19 * @brief Interface for common utility functions
20 * @author Sree Harsha Totakura <sreeharsha@totakura.in>
21 */
22
23#ifndef UTIL_H_
24#define UTIL_H_
25
26#include <gnunet/gnunet_util_lib.h>
27#include <gcrypt.h>
28
29/* Define logging functions */
30#define LOG_DEBUG(...) \
31 GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, __VA_ARGS__)
32
33#define LOG_WARNING(...) \
34 GNUNET_log (GNUNET_ERROR_TYPE_WARNING, __VA_ARGS__)
35
36#define LOG_ERROR(...) \
37 GNUNET_log (GNUNET_ERROR_TYPE_ERROR, __VA_ARGS__)
38
39
40/**
41 * Tests a given as assertion and if failed prints it as a warning with the
42 * given reason
43 *
44 * @param EXP the expression to test as assertion
45 * @param reason string to print as warning
46 */
47#define TALER_assert_as(EXP, reason) \
48 do { \
49 if (EXP) break; \
50 LOG_ERROR("%s at %s:%d\n", reason, __FILE__, __LINE__); \
51 abort(); \
52 } while(0)
53
54
55
56/**
57 * Log an error message at log-level 'level' that indicates
58 * a failure of the command 'cmd' with the message given
59 * by gcry_strerror(rc).
60 */
61#define LOG_GCRY_ERROR(cmd, rc) do { LOG_ERROR("`%s' failed at %s:%d with error: %s\n", cmd, __FILE__, __LINE__, gcry_strerror(rc)); } while(0)
62
63
64#define TALER_gcry_ok(cmd) \
65 do {int rc; rc = cmd; if (!rc) break; LOG_ERROR("A Gcrypt call failed at %s:%d with error: %s\n", __FILE__, __LINE__, gcry_strerror(rc)); abort(); } while (0)
66
67
68#define TALER_CURRENCY_LEN 4
69
70
71GNUNET_NETWORK_STRUCT_BEGIN
72
73struct TALER_AmountNBO
74{
75 uint32_t value;
76 uint32_t fraction;
77 char currency[TALER_CURRENCY_LEN];
78};
79
80GNUNET_NETWORK_STRUCT_END
81
82struct TALER_HashContext
83{
84 gcry_md_hd_t hd;
85};
86
87
88
89/**
90 * Representation of monetary value in a given currency.
91 */
92struct TALER_Amount
93{
94 /**
95 * Value (numerator of fraction)
96 */
97 uint32_t value;
98 /**
99 * Fraction (denominator of fraction)
100 */
101 uint32_t fraction;
102 /**
103 * Currency string, left adjusted and padded with zeros.
104 */
105 char currency[4];
106};
107
108
109/**
110 * Initialize Gcrypt library.
111 */
112void
113TALER_gcrypt_init();
114
115
116/**
117 * Generate a ECC private key.
118 *
119 * @return the s-expression representing the generated ECC private key; NULL
120 * upon error
121 */
122gcry_sexp_t
123TALER_genkey ();
124
125
126/**
127 * Parse denomination description, in the format "T : V : F".
128 *
129 * @param str denomination description
130 * @param denom denomination to write the result to
131 * @return GNUNET_OK if the string is a valid denomination specification,
132 * GNUNET_SYSERR if it is invalid.
133 */
134int
135TALER_string_to_amount (const char *str, struct TALER_Amount *denom);
136
137
138/**
139 * FIXME
140 */
141struct TALER_AmountNBO
142TALER_amount_hton (struct TALER_Amount d);
143
144
145/**
146 * FIXME
147 */
148struct TALER_Amount
149TALER_amount_ntoh (struct TALER_AmountNBO dn);
150
151/**
152 * Compare the value/fraction of two amounts. Does not compare the currency,
153 * i.e. comparing amounts with the same value and fraction but different
154 * currency would return 0.
155 *
156 * @param a1 first amount
157 * @param a2 second amount
158 * @return result of the comparison
159 */
160int
161TALER_amount_cmp (struct TALER_Amount a1, struct TALER_Amount a2);
162
163
164/**
165 * Perform saturating subtraction of amounts.
166 *
167 * @param a1 amount to subtract from
168 * @param a2 amount to subtract
169 * @return (a1-a2) or 0 if a2>=a1
170 */
171struct TALER_Amount
172TALER_amount_subtract (struct TALER_Amount a1, struct TALER_Amount a2);
173
174
175/**
176 * Perform saturating addition of amounts
177 *
178 * @param a1 first amount to add
179 * @param a2 second amount to add
180 * @return sum of a1 and a2
181 */
182struct TALER_Amount
183TALER_amount_add (struct TALER_Amount a1, struct TALER_Amount a2);
184
185
186/**
187 * Normalize the given amount.
188 *
189 * @param amout amount to normalize
190 * @return normalized amount
191 */
192struct TALER_Amount
193TALER_amount_normalize (struct TALER_Amount amount);
194
195
196/**
197 * Convert amount to string.
198 *
199 * @param amount amount to convert to string
200 * @return freshly allocated string representation
201 */
202char *
203TALER_amount_to_string (struct TALER_Amount amount);
204
205
206/**
207 * Return the base32crockford encoding of the given buffer.
208 *
209 * The returned string will be freshly allocated, and must be free'd
210 * with GNUNET_free.
211 *
212 * @param buffer with data
213 * @param size size of the buffer
214 * @return freshly allocated, null-terminated string
215 */
216char *
217TALER_data_to_string_alloc (const void *buf, size_t size);
218
219
220/**
221 * Get encoded binary data from a configuration.
222 *
223 * @return GNUNET_OK on success
224 * GNUNET_NO is the value does not exist
225 * GNUNET_SYSERR on encoding error
226 */
227int
228TALER_configuration_get_data (const struct GNUNET_CONFIGURATION_Handle *cfg,
229 const char *section, const char *option,
230 void *buf, size_t buf_size);
231
232
233
234
235int
236TALER_refresh_decrypt (const void *input, size_t input_size, const struct GNUNET_HashCode *secret, void *result);
237
238int
239TALER_refresh_encrypt (const void *input, size_t input_size, const struct GNUNET_HashCode *secret, void *result);
240
241
242
243void
244TALER_hash_context_start (struct TALER_HashContext *hc);
245
246
247void
248TALER_hash_context_read (struct TALER_HashContext *hc, void *buf, size_t size);
249
250
251void
252TALER_hash_context_finish (struct TALER_HashContext *hc,
253 struct GNUNET_HashCode *r_hash);
254
255#endif