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| -rw-r--r-- | include/util_varbuf.h | 197 |
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diff --git a/include/util_varbuf.h b/include/util_varbuf.h new file mode 100644 index 0000000..8e45578 --- /dev/null +++ b/include/util_varbuf.h @@ -0,0 +1,197 @@ +/* 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 + * + * @defgroup APACHE_CORE_VARBUF Variable length buffer library + * @ingroup APACHE_CORE + * + * This set of functions provides resizable buffers. While the primary + * usage is with NUL-terminated strings, most functions also work with + * arbitrary binary data. + * + * @{ + */ + +#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 and + * to memory of the same lifetime as the pool otherwise. */ + 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 cleared. */ + 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 previously + * used ap_varbuf. The old buffer will be released when the corresponding + * pool is cleared. The buffer remains usable until the pool is cleared, + * even if the ap_varbuf was located on the stack and has gone out of scope. + * @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 the first 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 reallocations. + * @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 + * cleared. 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. vb->strlen determines where + * the string is appended in the buffer. If vb->strlen == AP_VARBUF_UNKNOWN, + * the string will be appended at the first NUL byte in the buffer. + * If len == 0, ap_varbuf_strmemcat() does nothing. + * @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 if len != 0, vb->buf will always be NUL-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. + * @note If vb->strlen equals AP_VARBUF_UNKNOWN, it will be set to + * strlen(vb->buf). + */ +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). + * @note If vb->strlen equals AP_VARBUF_UNKNOWN, it will be set to + * strlen(vb->buf) first. + */ +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 and append it to an ap_varbuf. + * @param vb Pointer to the ap_varbuf struct + * @param cfp 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 + * @note If vb->strlen equals AP_VARBUF_UNKNOWN, it will be set to + * strlen(vb->buf) first. + */ +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 */ +/** @} */ |