1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
|
/* -*- mode: c; c-basic-offset: 4; indent-tabs-mode: nil -*- */
/* include/k5-buf.h - k5buf interface declarations */
/*
* Copyright 2008 Massachusetts Institute of Technology.
* All Rights Reserved.
*
* Export of this software from the United States of America may
* require a specific license from the United States Government.
* It is the responsibility of any person or organization contemplating
* export to obtain such a license before exporting.
*
* WITHIN THAT CONSTRAINT, permission to use, copy, modify, and
* distribute this software and its documentation for any purpose and
* without fee is hereby granted, provided that the above copyright
* notice appear in all copies and that both that copyright notice and
* this permission notice appear in supporting documentation, and that
* the name of M.I.T. not be used in advertising or publicity pertaining
* to distribution of the software without specific, written prior
* permission. Furthermore if you modify this software you must label
* your software as modified software and not distribute it in such a
* fashion that it might be confused with the original M.I.T. software.
* M.I.T. makes no representations about the suitability of
* this software for any purpose. It is provided "as is" without express
* or implied warranty.
*/
#ifndef K5_BUF_H
#define K5_BUF_H
#include <stdarg.h>
#include <string.h>
/*
* The k5buf module is intended to allow multi-step string construction in a
* fixed or dynamic buffer without the need to check for a failure at each step
* (and without aborting on malloc failure). If an allocation failure occurs
* or the fixed buffer runs out of room, the buffer will be set to an error
* state which can be detected with k5_buf_status. Data in a buffer is not
* automatically terminated with a zero byte; call k5_buf_cstring() to use the
* contents as a C string.
*
* k5buf structures are usually stack-allocated. Do not put k5buf structure
* pointers into public APIs. It is okay to reference the data and len fields
* of a buffer (they will be NULL/0 if the buffer is in an error state), but do
* not change them.
*/
/* Buffer type values */
enum k5buftype { K5BUF_ERROR, K5BUF_FIXED, K5BUF_DYNAMIC, K5BUF_DYNAMIC_ZAP };
struct k5buf {
enum k5buftype buftype;
void *data;
size_t space;
size_t len;
};
#define EMPTY_K5BUF { K5BUF_ERROR }
/* Initialize a k5buf using a fixed-sized, existing buffer. SPACE must be
* more than zero, or an assertion failure will result. */
void k5_buf_init_fixed(struct k5buf *buf, void *data, size_t space);
/* Initialize a k5buf using an internally allocated dynamic buffer. */
void k5_buf_init_dynamic(struct k5buf *buf);
/* Initialize a k5buf using an internally allocated dynamic buffer, zeroing
* memory when reallocating or freeing. */
void k5_buf_init_dynamic_zap(struct k5buf *buf);
/* Add a C string to BUF. */
void k5_buf_add(struct k5buf *buf, const char *data);
/* Add a counted series of bytes to BUF. */
void k5_buf_add_len(struct k5buf *buf, const void *data, size_t len);
/* Add sprintf-style formatted data to BUF. For a fixed-length buffer this
* operation will fail if there isn't room for a zero terminator. */
void k5_buf_add_fmt(struct k5buf *buf, const char *fmt, ...)
#if !defined(__cplusplus) && (__GNUC__ > 2)
__attribute__((__format__(__printf__, 2, 3)))
#endif
;
/* Add sprintf-style formatted data to BUF, with a va_list. The value of ap is
* undefined after the call. */
void k5_buf_add_vfmt(struct k5buf *buf, const char *fmt, va_list ap)
#if !defined(__cplusplus) && (__GNUC__ > 2)
__attribute__((__format__(__printf__, 2, 0)))
#endif
;
/* Without changing the length of buf, ensure that there is a zero byte after
* buf.data and return it. Return NULL on error. */
char *k5_buf_cstring(struct k5buf *buf);
/* Extend the length of buf by len and return a pointer to the reserved space,
* to be filled in by the caller. Return NULL on error. */
void *k5_buf_get_space(struct k5buf *buf, size_t len);
/* Truncate BUF. LEN must be between 0 and the existing buffer
* length, or an assertion failure will result. */
void k5_buf_truncate(struct k5buf *buf, size_t len);
/* Return ENOMEM if buf is in an error state, 0 otherwise. */
int k5_buf_status(struct k5buf *buf);
/*
* Free the storage used in the dynamic buffer BUF. The caller may choose to
* take responsibility for freeing the data pointer instead of using this
* function. If BUF is a fixed buffer, an assertion failure will result.
* Freeing a buffer in the error state, a buffer initialized with EMPTY_K5BUF,
* or a zeroed k5buf structure is a no-op.
*/
void k5_buf_free(struct k5buf *buf);
static inline void
k5_buf_add_byte(struct k5buf *buf, uint8_t val)
{
k5_buf_add_len(buf, &val, 1);
}
static inline void
k5_buf_add_uint16_be(struct k5buf *buf, uint16_t val)
{
void *p = k5_buf_get_space(buf, 2);
if (p != NULL)
store_16_be(val, p);
}
static inline void
k5_buf_add_uint16_le(struct k5buf *buf, uint16_t val)
{
void *p = k5_buf_get_space(buf, 2);
if (p != NULL)
store_16_le(val, p);
}
static inline void
k5_buf_add_uint32_be(struct k5buf *buf, uint32_t val)
{
void *p = k5_buf_get_space(buf, 4);
if (p != NULL)
store_32_be(val, p);
}
static inline void
k5_buf_add_uint32_le(struct k5buf *buf, uint32_t val)
{
void *p = k5_buf_get_space(buf, 4);
if (p != NULL)
store_32_le(val, p);
}
static inline void
k5_buf_add_uint64_be(struct k5buf *buf, uint64_t val)
{
void *p = k5_buf_get_space(buf, 8);
if (p != NULL)
store_64_be(val, p);
}
static inline void
k5_buf_add_uint64_le(struct k5buf *buf, uint64_t val)
{
void *p = k5_buf_get_space(buf, 8);
if (p != NULL)
store_64_le(val, p);
}
#endif /* K5_BUF_H */
|