1 /*
2 * SysDB - src/include/core/data.h
3 * Copyright (C) 2012-2014 Sebastian 'tokkee' Harl <sh@tokkee.org>
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
16 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
17 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
18 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR
19 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
20 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
21 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
22 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
23 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
24 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
25 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26 */
28 #ifndef SDB_CORE_DATA_H
29 #define SDB_CORE_DATA_H 1
31 #include "core/time.h"
33 #include <inttypes.h>
34 #include <stddef.h>
36 #ifdef __cplusplus
37 extern "C" {
38 #endif
40 enum {
41 SDB_TYPE_INTEGER = 1,
42 SDB_TYPE_DECIMAL,
43 SDB_TYPE_STRING,
44 SDB_TYPE_DATETIME,
45 SDB_TYPE_BINARY,
46 };
48 #define SDB_TYPE_TO_STRING(t) \
49 (((t) == SDB_TYPE_INTEGER) \
50 ? "INTEGER" \
51 : ((t) == SDB_TYPE_DECIMAL) \
52 ? "DECIMAL" \
53 : ((t) == SDB_TYPE_STRING) \
54 ? "STRING" \
55 : ((t) == SDB_TYPE_DATETIME) \
56 ? "DATETIME" \
57 : ((t) == SDB_TYPE_BINARY) \
58 ? "BINARY" \
59 : "UNKNOWN")
61 /*
62 * sdb_data_t:
63 * A datum retrieved from an arbitrary data source.
64 */
65 typedef struct {
66 int type;
67 union {
68 int64_t integer; /* SDB_TYPE_INTEGER */
69 double decimal; /* SDB_TYPE_DECIMAL */
70 char *string; /* SDB_TYPE_STRING */
71 sdb_time_t datetime; /* SDB_TYPE_DATETIME */
72 struct {
73 size_t length;
74 unsigned char *datum;
75 } binary; /* SDB_TYPE_BINARY */
76 } data;
77 } sdb_data_t;
78 #define SDB_DATA_INIT { 0, { .integer = 0 } }
80 /*
81 * sdb_data_copy:
82 * Copy the datum stored in 'src' to the memory location pointed to by 'dst'.
83 * Any dynamic data (strings, binary data) is copied to newly allocated
84 * memory. Use, for example, sdb_data_free_datum() to free any dynamic memory
85 * stored in a datum. On error, 'dst' is unchanged. Else, any dynamic memory
86 * in 'dst' will be freed.
87 *
88 * Returns:
89 * - 0 on success
90 * - a negative value else
91 */
92 int
93 sdb_data_copy(sdb_data_t *dst, const sdb_data_t *src);
95 /*
96 * sdb_data_free_datum:
97 * Free any dynamic memory referenced by the specified datum. Does not free
98 * the memory allocated by the sdb_data_t object itself. This function must
99 * not be used if any static or stack memory is referenced from the data
100 * object.
101 */
102 void
103 sdb_data_free_datum(sdb_data_t *datum);
105 /*
106 * sdb_data_cmp:
107 * Compare two data points. A NULL datum is considered less than any non-NULL
108 * datum. On data-type mismatch, the function always returns a non-zero value.
109 *
110 * Returns:
111 * - a value less than zero if d1 compares less than d2
112 * - zero if d1 compares equal to d2
113 * - a value greater than zero if d1 compares greater than d2
114 */
115 int
116 sdb_data_cmp(const sdb_data_t *d1, const sdb_data_t *d2);
118 /*
119 * sdb_data_isnull:
120 * Determine whether a datum is NULL. A datum is considered to be NULL if
121 * either datum is NULL or if the string or binary datum is NULL.
122 */
123 _Bool
124 sdb_data_isnull(const sdb_data_t *datum);
126 /*
127 * Operators supported by sdb_data_eval_expr.
128 */
129 enum {
130 SDB_DATA_ADD = 1, /* addition */
131 SDB_DATA_SUB, /* substraction */
132 SDB_DATA_MUL, /* multiplication */
133 SDB_DATA_DIV, /* division */
134 SDB_DATA_MOD, /* modulo */
135 SDB_DATA_CONCAT, /* string / binary data concatenation */
136 };
138 #define SDB_DATA_OP_TO_STRING(op) \
139 (((op) == SDB_DATA_ADD) \
140 ? "+" \
141 : ((op) == SDB_DATA_SUB) \
142 ? "-" \
143 : ((op) == SDB_DATA_MUL) \
144 ? "*" \
145 : ((op) == SDB_DATA_DIV) \
146 ? "/" \
147 : ((op) == SDB_DATA_MOD) \
148 ? "%" \
149 : ((op) == SDB_DATA_CONCAT) \
150 ? "||" : "UNKNOWN")
152 /*
153 * sdb_data_expr_eval:
154 * Evaluate a simple arithmetic expression on two data points. String and
155 * binary data only support concatenation and all other data types only
156 * support the other operators. The result may be allocated dynamically and
157 * has to be freed by the caller (using sdb_data_free_datum).
158 *
159 * The data-types of d1 and d2 have to be the same, except for the following
160 * cases:
161 * - <integer> or <decimal> <mul> <datetime>
162 * - <datetime> <mul> or <div> or <mod> <integer> or <decimal>
163 *
164 * Returns:
165 * - 0 on success
166 * - a negative value else
167 */
168 int
169 sdb_data_expr_eval(int op, const sdb_data_t *d1, const sdb_data_t *d2,
170 sdb_data_t *res);
172 /*
173 * sdb_data_strlen:
174 * Returns a (worst-case) estimate for the number of bytes required to format
175 * the datum as a string. Does not take the terminating null byte into
176 * account.
177 */
178 size_t
179 sdb_data_strlen(const sdb_data_t *datum);
181 enum {
182 SDB_UNQUOTED = 0,
183 SDB_SINGLE_QUOTED,
184 SDB_DOUBLE_QUOTED,
185 };
187 /*
188 * sdb_data_format:
189 * Output the specified datum to the specified string using a default format.
190 * The value of 'quoted' determines whether and how non-integer and
191 * non-decimal values are quoted. If the buffer size is less than the return
192 * value of sdb_data_strlen, the datum may be truncated. The buffer will
193 * always be nul-terminated after calling this function.
194 *
195 * Returns:
196 * - the number of characters written to the buffer (excluding the terminated
197 * null byte) or the number of characters which would have been written in
198 * case the output was truncated
199 * - a negative value else
200 */
201 int
202 sdb_data_format(const sdb_data_t *datum, char *buf, size_t buflen, int quoted);
204 /*
205 * sdb_data_parse:
206 * Parse the specified string into a datum using the specified type. The
207 * string value is expected to be a raw value of the specified type. Integer
208 * and decimal numbers may be signed or unsigned octal (base 8, if the first
209 * character of the string is "0"), sedecimal (base 16, if the string includes
210 * the "0x" prefix), or decimal. Decimal numbers may also be "infinity" or
211 * "NaN" or may use a decimal exponent. Date-time values are expected to be
212 * specified as (floating point) number of seconds since the epoch. For string
213 * and binary data, the input string is passed to the datum. The function does
214 * not allocate new memory for that purpose. Use sdb_data_copy() if you want
215 * to do that.
216 *
217 * Returns:
218 * - 0 on success
219 * - a negative value else
220 */
221 int
222 sdb_data_parse(char *str, int type, sdb_data_t *data);
224 #ifdef __cplusplus
225 } /* extern "C" */
226 #endif
228 #endif /* ! SDB_CORE_DATA_H */
230 /* vim: set tw=78 sw=4 ts=4 noexpandtab : */