summaryrefslogtreecommitdiffstats
path: root/include/util_varbuf.h
blob: 1ae99f911e2b1fba440bb072b2930592249f4f58 (plain)
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
/* Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/**
 * @file util_varbuf.h
 * @brief Apache resizable variable length buffer library
 */

#ifndef AP_VARBUF_H
#define AP_VARBUF_H

#include "apr.h"
#include "apr_allocator.h"

#include "httpd.h"

#ifdef __cplusplus
extern "C" {
#endif

#define AP_VARBUF_UNKNOWN APR_SIZE_MAX
struct ap_varbuf_info;

/** A resizable buffer */
struct ap_varbuf {
    /** the actual buffer; will point to a const '\0' if avail == 0 */
    char *buf;

    /** allocated size of the buffer (minus one for the final \0);
     *  must only be changed using ap_varbuf_grow() */
    apr_size_t avail;

    /** length of string in buffer, or AP_VARBUF_UNKNOWN. This determines how
     *  much memory is copied by ap_varbuf_grow() and where
     *  ap_varbuf_strmemcat() will append to the buffer. */
    apr_size_t strlen;

    /** the pool for memory allocations and for registering the cleanup;
     *  the buffer memory will be released when this pool is destroyed */
    apr_pool_t *pool;

    /** opaque info for memory allocation */
    struct ap_varbuf_info *info;
};

/** initialize a resizable buffer. It is safe to re-initialize a prevously
 *  used ap_varbuf. The old buffer will be released when the corresponding
 *  pool is destroyed.
 * @param pool the pool to allocate small buffers from and to register the
 *        cleanup with
 * @param vb pointer to the ap_varbuf struct
 * @param init_size the initial size of the buffer (see ap_varbuf_grow() for details)
 */
AP_DECLARE(void) ap_varbuf_init(apr_pool_t *pool, struct ap_varbuf *vb,
                                apr_size_t init_size);

/** grow a resizable buffer. If the vb->buf cannot be grown in place, it will
 *  be reallocated and up to vb->strlen + 1 bytes of memory will be copied to
 *  the new location. If vb->strlen == AP_VARBUF_UNKNOWN, the whole buffer
 *  is copied.
 * @param vb pointer to the ap_varbuf struct
 * @param new_size the minimum new size of the buffer
 * @note ap_varbuf_grow() will usually at least double vb->buf's size with
 *       every invocation in order to reduce reallications.
 * @note ap_varbuf_grow() will use pool memory for small and allocator
 *       mem nodes for larger allocations.
 * @note ap_varbuf_grow() will call vb->pool's abort function if out of memory.
 */
AP_DECLARE(void) ap_varbuf_grow(struct ap_varbuf *vb, apr_size_t new_size);

/** Release memory from a ap_varbuf immediately, if possible.
 *  This allows to free large buffers before the corresponding pool is
 *  destroyed. Only larger allocations using mem nodes will be freed.
 * @param vb pointer to the ap_varbuf struct
 * @note After ap_varbuf_free(), vb must not be used unless ap_varbuf_init()
 *       is called again.
 */
AP_DECLARE(void) ap_varbuf_free(struct ap_varbuf *vb);

/** Concatenate a string to an ap_varbuf
 * @param vb pointer to the ap_varbuf struct
 * @param str the string to append; must be at least len bytes long
 * @param len the number of characters of *str to concatenate to the buf
 * @note vb->strlen will be set to the length of the new string
 * @note vb->buf will be null-terminated
 */
AP_DECLARE(void) ap_varbuf_strmemcat(struct ap_varbuf *vb, const char *str,
                                     int len);

/** Duplicate an ap_varbuf's content into pool memory
 * @param p the pool to allocate from
 * @param vb the ap_varbuf to copy from
 * @param prepend an optional buffer to prepend (may be NULL)
 * @param prepend_len length of prepend
 * @param append an optional buffer to append (may be NULL)
 * @param append_len length of append
 * @param new_len where to store the length of the resulting string
 *        (may be NULL)
 * @return the new string
 * @note ap_varbuf_pdup() uses vb->strlen to determine how much memory to
 *       copy. It works even if 0-bytes are embedded in vb->buf, prepend, or
 *       append
 */
AP_DECLARE(char *) ap_varbuf_pdup(apr_pool_t *p, struct ap_varbuf *vb,
                                  const char *prepend, apr_size_t prepend_len,
                                  const char *append, apr_size_t append_len,
                                  apr_size_t *new_len);


/** Concatenate a string to an ap_varbuf
 * @param vb pointer to the ap_varbuf struct
 * @param str the string to append
 * @note vb->strlen will be set to the length of the new string
 */
#define ap_varbuf_strcat(vb, str) ap_varbuf_strmemcat(vb, str, strlen(str))

/** Perform string substitutions based on regexp match, using an ap_varbuf.
 * This function behaves like ap_pregsub(), but appends to an ap_varbuf
 * instead of allocating the result from a pool.
 * @param vb The ap_varbuf to which the string will be appended
 * @param input An arbitrary string containing $1 through $9.  These are
 *              replaced with the corresponding matched sub-expressions
 * @param source The string that was originally matched to the regex
 * @param nmatch the nmatch returned from ap_pregex
 * @param pmatch the pmatch array returned from ap_pregex
 * @param maxlen the maximum string length to append to vb, 0 for unlimited
 * @return APR_SUCCESS if successful
 * @note Just like ap_pregsub(), this function does not copy the part of
 *       *source before the matching part (i.e. the first pmatch[0].rm_so
 *       characters).
 */
AP_DECLARE(apr_status_t) ap_varbuf_regsub(struct ap_varbuf *vb,
                                          const char *input,
                                          const char *source,
                                          apr_size_t nmatch,
                                          ap_regmatch_t pmatch[],
                                          apr_size_t maxlen);

/** Read a line from an ap_configfile_t into an ap_varbuf.
 * @param vb pointer to the ap_varbuf struct
 * @param cfg pointer to the ap_configfile_t
 * @param max_len maximum line length, including leading/trailing whitespace
 * @return see ap_cfg_getline()
 * @note vb->strlen will be set to the length of the line
 */
AP_DECLARE(apr_status_t) ap_varbuf_cfg_getline(struct ap_varbuf *vb,
                                               ap_configfile_t *cfp,
                                               apr_size_t max_len);

#ifdef __cplusplus
}
#endif

#endif  /* !AP_VARBUF_H */