1 /* Licensed to the Apache Software Foundation (ASF) under one or more
2 * contributor license agreements. See the NOTICE file distributed with
3 * this work for additional information regarding copyright ownership.
4 * The ASF licenses this file to You under the Apache License, Version 2.0
5 * (the "License"); you may not use this file except in compliance with
6 * the License. You may obtain a copy of the License at
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
19 * @brief Apache resizable variable length buffer library
21 * @defgroup APACHE_CORE_VARBUF Variable length buffer library
22 * @ingroup APACHE_CORE
24 * This set of functions provides resizable buffers. While the primary
25 * usage is with NUL-terminated strings, most functions also work with
26 * arbitrary binary data.
35 #include "apr_allocator.h"
43 #define AP_VARBUF_UNKNOWN APR_SIZE_MAX
44 struct ap_varbuf_info;
46 /** A resizable buffer. */
48 /** The actual buffer; will point to a const '\\0' if avail == 0 and
49 * to memory of the same lifetime as the pool otherwise. */
52 /** Allocated size of the buffer (minus one for the final \\0);
53 * must only be changed using ap_varbuf_grow(). */
56 /** Length of string in buffer, or AP_VARBUF_UNKNOWN. This determines how
57 * much memory is copied by ap_varbuf_grow() and where
58 * ap_varbuf_strmemcat() will append to the buffer. */
61 /** The pool for memory allocations and for registering the cleanup;
62 * the buffer memory will be released when this pool is cleared. */
65 /** Opaque info for memory allocation. */
66 struct ap_varbuf_info *info;
70 * Initialize a resizable buffer. It is safe to re-initialize a previously
71 * used ap_varbuf. The old buffer will be released when the corresponding
72 * pool is cleared. The buffer remains usable until the pool is cleared,
73 * even if the ap_varbuf was located on the stack and has gone out of scope.
74 * @param pool The pool to allocate small buffers from and to register
76 * @param vb Pointer to the ap_varbuf struct
77 * @param init_size The initial size of the buffer (see ap_varbuf_grow() for
80 AP_DECLARE(void) ap_varbuf_init(apr_pool_t *pool, struct ap_varbuf *vb,
81 apr_size_t init_size);
84 * Grow a resizable buffer. If the vb->buf cannot be grown in place, it will
85 * be reallocated and the first vb->strlen + 1 bytes of memory will be copied
86 * to the new location. If vb->strlen == AP_VARBUF_UNKNOWN, the whole buffer
88 * @param vb Pointer to the ap_varbuf struct
89 * @param new_size The minimum new size of the buffer
90 * @note ap_varbuf_grow() will usually at least double vb->buf's size with
91 * every invocation in order to reduce reallocations.
92 * @note ap_varbuf_grow() will use pool memory for small and allocator
93 * mem nodes for larger allocations.
94 * @note ap_varbuf_grow() will call vb->pool's abort function if out of memory.
96 AP_DECLARE(void) ap_varbuf_grow(struct ap_varbuf *vb, apr_size_t new_size);
99 * Release memory from a ap_varbuf immediately, if possible.
100 * This allows to free large buffers before the corresponding pool is
101 * cleared. Only larger allocations using mem nodes will be freed.
102 * @param vb Pointer to the ap_varbuf struct
103 * @note After ap_varbuf_free(), vb must not be used unless ap_varbuf_init()
106 AP_DECLARE(void) ap_varbuf_free(struct ap_varbuf *vb);
109 * Concatenate a string to an ap_varbuf. vb->strlen determines where
110 * the string is appended in the buffer. If vb->strlen == AP_VARBUF_UNKNOWN,
111 * the string will be appended at the first NUL byte in the buffer.
112 * If len == 0, ap_varbuf_strmemcat() does nothing.
113 * @param vb Pointer to the ap_varbuf struct
114 * @param str The string to append; must be at least len bytes long
115 * @param len The number of characters of *str to concatenate to the buf
116 * @note vb->strlen will be set to the length of the new string
117 * @note if len != 0, vb->buf will always be NUL-terminated
119 AP_DECLARE(void) ap_varbuf_strmemcat(struct ap_varbuf *vb, const char *str,
123 * Duplicate an ap_varbuf's content into pool memory.
124 * @param p The pool to allocate from
125 * @param vb The ap_varbuf to copy from
126 * @param prepend An optional buffer to prepend (may be NULL)
127 * @param prepend_len Length of prepend
128 * @param append An optional buffer to append (may be NULL)
129 * @param append_len Length of append
130 * @param new_len Where to store the length of the resulting string
132 * @return The new string
133 * @note ap_varbuf_pdup() uses vb->strlen to determine how much memory to
134 * copy. It works even if 0-bytes are embedded in vb->buf, prepend, or
136 * @note If vb->strlen equals AP_VARBUF_UNKNOWN, it will be set to
139 AP_DECLARE(char *) ap_varbuf_pdup(apr_pool_t *p, struct ap_varbuf *vb,
140 const char *prepend, apr_size_t prepend_len,
141 const char *append, apr_size_t append_len,
142 apr_size_t *new_len);
146 * Concatenate a string to an ap_varbuf.
147 * @param vb Pointer to the ap_varbuf struct
148 * @param str The string to append
149 * @note vb->strlen will be set to the length of the new string
151 #define ap_varbuf_strcat(vb, str) ap_varbuf_strmemcat(vb, str, strlen(str))
154 * Perform string substitutions based on regexp match, using an ap_varbuf.
155 * This function behaves like ap_pregsub(), but appends to an ap_varbuf
156 * instead of allocating the result from a pool.
157 * @param vb The ap_varbuf to which the string will be appended
158 * @param input An arbitrary string containing $1 through $9. These are
159 * replaced with the corresponding matched sub-expressions
160 * @param source The string that was originally matched to the regex
161 * @param nmatch The nmatch returned from ap_pregex
162 * @param pmatch The pmatch array returned from ap_pregex
163 * @param maxlen The maximum string length to append to vb, 0 for unlimited
164 * @return APR_SUCCESS if successful
165 * @note Just like ap_pregsub(), this function does not copy the part of
166 * *source before the matching part (i.e. the first pmatch[0].rm_so
168 * @note If vb->strlen equals AP_VARBUF_UNKNOWN, it will be set to
169 * strlen(vb->buf) first.
171 AP_DECLARE(apr_status_t) ap_varbuf_regsub(struct ap_varbuf *vb,
175 ap_regmatch_t pmatch[],
179 * Read a line from an ap_configfile_t and append it to an ap_varbuf.
180 * @param vb Pointer to the ap_varbuf struct
181 * @param cfp Pointer to the ap_configfile_t
182 * @param max_len Maximum line length, including leading/trailing whitespace
183 * @return See ap_cfg_getline()
184 * @note vb->strlen will be set to the length of the line
185 * @note If vb->strlen equals AP_VARBUF_UNKNOWN, it will be set to
186 * strlen(vb->buf) first.
188 AP_DECLARE(apr_status_t) ap_varbuf_cfg_getline(struct ap_varbuf *vb,
189 ap_configfile_t *cfp,
196 #endif /* !AP_VARBUF_H */