enhance bitfield copy
[babeltrace.git] / types / bitfield.c
CommitLineData
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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 <stdint.h>
23
24/*
25 * Shortcut to integer copy if we copy bit-aligned data with 0 start_offset.
26 * This skips the bitfield overhead when dealing with enumerations (which use
27 * the bitfield copy functions).
28 */
29extern
30size_t integer_copy(unsigned char *dest, const struct format *fdest,
31 const unsigned char *src, const struct format *fsrc,
32 const struct type_class *type_class);
33
34size_t bitfield_copy(unsigned char *dest, const struct format *fdest,
35 const unsigned char *src, const struct format *fsrc,
36 const struct type_class *type_class)
37{
38 struct type_class_bitfield *bitfield_class =
39 container_of(type_class, struct type_class_bitfield, p);
40 struct type_class_integer *int_class = &bitfield_class->p;
41
42 if (!(int_class->p.alignment % CHAR_BIT)
43 && !(int_class->len % CHAR_BIT)
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44 && !(bitfield_class->start_offset % CHAR_BIT)) {
45 size_t offset = bitfield_class->start_offset / CHAR_BIT;
46 dest += offset;
47 src += offset;
698f0fe4 48 return integer_copy(dest, fdest, src, fsrc, type_class);
3c1bd98a 49 }
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50
51 if (!int_class->signedness) {
52 uint64_t v;
53
54 v = fsrc->bitfield_unsigned_read(src,
55 bitfield_class->start_offset,
56 int_class->len,
57 int_class->byte_order);
58 return fdest->bitfield_unsigned_write(dest,
59 bitfield_class->start_offset,
60 int_class->len, int_class->byte_order,
61 v);
62 } else {
63 int64_t v;
64
65 v = fsrc->bitfield_signed_read(src,
66 bitfield_class->start_offset,
67 int_class->len,
68 int_class->byte_order);
69 return fdest->bitfield_signed_write(dest,
70 bitfield_class->start_offset,
71 int_class->len, int_class->byte_order,
72 v);
73 }
74}
75
76int bitfield_type_new(const char *name, size_t start_offset,
77 size_t len, int byte_order, int signedness)
78{
79 struct type_class_bitfield bitfield_class;
80 struct type_class_integer *int_class;
81 int ret;
82
83 /*
84 * Freed when type is unregistered.
85 */
86 bitfield_class = g_new(struct type_class_bitfield, 1);
87 int_class = &bitfield_class->p;
88 int_class->p.name = g_quark_from_string(name);
89 int_class->len = len;
90 int_class->byte_order = byte_order;
91 int_class->signedness = signedness;
92 bitfield_class->start_offset = start_offset;
93 ret = ctf_register_type(&int_class->p);
94 if (ret)
95 g_free(bitfield_class);
96 return ret;
97}
98
99/* TODO: bitfield_type_free */
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