03d3bbcbafd31aca219ea988289b3f6e6f84517c
[babeltrace.git] / types / bitfield.c
1 /*
2 * BabelTrace - Bitfield Type Converter
3 *
4 * Copyright (c) 2010 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
5 *
6 * This library is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2.1 of the License, or (at your option) any later version.
10 *
11 * This library is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Lesser General Public License for more details.
15 *
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with this library; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19 */
20
21 #include <babeltrace/compiler.h>
22 #include <babeltrace/types.h>
23 #include <stdint.h>
24
25 /*
26 * Shortcut to integer copy if we copy bit-aligned data with 0 start_offset.
27 * This skips the bitfield overhead when dealing with enumerations (which use
28 * the bitfield copy functions).
29 */
30 extern
31 size_t integer_copy(unsigned char *dest, const struct format *fdest,
32 const unsigned char *src, const struct format *fsrc,
33 const struct type_class *type_class);
34
35 size_t bitfield_copy(unsigned char *dest, const struct format *fdest,
36 const unsigned char *src, const struct format *fsrc,
37 const struct type_class *type_class)
38 {
39 struct type_class_bitfield *bitfield_class =
40 container_of(type_class, struct type_class_bitfield, p);
41 struct type_class_integer *int_class = &bitfield_class->p;
42
43 if (!(int_class->p.alignment % CHAR_BIT)
44 && !(int_class->len % CHAR_BIT)
45 && !(bitfield_class->start_offset % CHAR_BIT)) {
46 size_t offset = bitfield_class->start_offset / CHAR_BIT;
47 dest += offset;
48 src += offset;
49 return integer_copy(dest, fdest, src, fsrc, type_class);
50 }
51
52 if (!int_class->signedness) {
53 uint64_t v;
54
55 v = fsrc->bitfield_unsigned_read(src,
56 bitfield_class->start_offset,
57 int_class->len,
58 int_class->byte_order);
59 return fdest->bitfield_unsigned_write(dest,
60 bitfield_class->start_offset,
61 int_class->len, int_class->byte_order,
62 v);
63 } else {
64 int64_t v;
65
66 v = fsrc->bitfield_signed_read(src,
67 bitfield_class->start_offset,
68 int_class->len,
69 int_class->byte_order);
70 return fdest->bitfield_signed_write(dest,
71 bitfield_class->start_offset,
72 int_class->len, int_class->byte_order,
73 v);
74 }
75 }
76
77 struct type_class_bitfield *bitfield_type_new(const char *name,
78 size_t start_offset,
79 size_t len, int byte_order,
80 int signedness,
81 size_t alignment)
82 {
83 struct type_class_bitfield *bitfield_class;
84 struct type_class_integer *int_class;
85 int ret;
86
87 bitfield_class = g_new(struct type_class_bitfield, 1);
88 int_class = &bitfield_class->p;
89 int_class->p.name = g_quark_from_string(name);
90 int_class->p.alignment = alignment;
91 int_class->len = len;
92 int_class->byte_order = byte_order;
93 int_class->signedness = signedness;
94 bitfield_class->start_offset = start_offset;
95 if (int_class->p.name) {
96 ret = ctf_register_type(&int_class->p);
97 if (ret) {
98 g_free(bitfield_class);
99 return NULL;
100 }
101 }
102 return bitfield_class;
103 }
104
105 void bitfield_type_free(struct type_class_bitfield *bitfield_class)
106 {
107 g_free(bitfield_class);
108 }
This page took 0.044074 seconds and 3 git commands to generate.