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.
22 * @brief APR MMAP routines
26 #include "apr_pools.h"
27 #include "apr_errno.h"
29 #include "apr_file_io.h" /* for apr_file_t */
32 #include <kernel/OS.h>
37 #endif /* __cplusplus */
40 * @defgroup apr_mmap MMAP (Memory Map) Routines
45 /** MMap opened for reading */
46 #define APR_MMAP_READ 1
47 /** MMap opened for writing */
48 #define APR_MMAP_WRITE 2
50 /** @see apr_mmap_t */
51 typedef struct apr_mmap_t apr_mmap_t;
55 * As far as I can tell the only really sane way to store an MMAP is as a
56 * void * and a length. BeOS requires this area_id, but that's just a little
57 * something extra. I am exposing this type, because it doesn't make much
58 * sense to keep it private, and opening it up makes some stuff easier in
61 /** The MMAP structure */
63 /** The pool the mmap structure was allocated out of. */
66 /** An area ID. Only valid on BeOS */
70 /** The handle of the file mapping */
72 /** The start of the real memory page area (mapped view) */
74 /** The physical start, size and offset */
79 /** The start of the memory mapped area */
81 /** The amount of data in the mmap */
83 /** ring of apr_mmap_t's that reference the same
84 * mmap'ed region; acts in place of a reference count */
85 APR_RING_ENTRY(apr_mmap_t) link;
88 #if APR_HAS_MMAP || defined(DOXYGEN)
90 /** @def APR_MMAP_THRESHOLD
91 * Files have to be at least this big before they're mmap()d. This is to deal
92 * with systems where the expense of doing an mmap() and an munmap() outweighs
93 * the benefit for small files. It shouldn't be set lower than 1.
96 # define APR_MMAP_THRESHOLD MMAP_THRESHOLD
99 # define APR_MMAP_THRESHOLD (8*1024)
101 # define APR_MMAP_THRESHOLD 1
103 #endif /* MMAP_THRESHOLD */
105 /** @def APR_MMAP_LIMIT
106 * Maximum size of MMap region
109 # define APR_MMAP_LIMIT MMAP_LIMIT
111 # define APR_MMAP_LIMIT (4*1024*1024)
112 #endif /* MMAP_LIMIT */
114 /** Can this file be MMaped */
115 #define APR_MMAP_CANDIDATE(filelength) \
116 ((filelength >= APR_MMAP_THRESHOLD) && (filelength < APR_MMAP_LIMIT))
118 /* Function definitions */
121 * Create a new mmap'ed file out of an existing APR file.
122 * @param newmmap The newly created mmap'ed file.
123 * @param file The file to turn into an mmap.
124 * @param offset The offset into the file to start the data pointer at.
125 * @param size The size of the file
126 * @param flag bit-wise or of:
128 * APR_MMAP_READ MMap opened for reading
129 * APR_MMAP_WRITE MMap opened for writing
131 * @param cntxt The pool to use when creating the mmap.
133 APR_DECLARE(apr_status_t) apr_mmap_create(apr_mmap_t **newmmap,
134 apr_file_t *file, apr_off_t offset,
135 apr_size_t size, apr_int32_t flag,
139 * Duplicate the specified MMAP.
140 * @param new_mmap The structure to duplicate into.
141 * @param old_mmap The mmap to duplicate.
142 * @param p The pool to use for new_mmap.
144 APR_DECLARE(apr_status_t) apr_mmap_dup(apr_mmap_t **new_mmap,
145 apr_mmap_t *old_mmap,
150 * @param mm The mmap'ed file.
152 APR_DECLARE(apr_status_t) apr_mmap_delete(apr_mmap_t *mm);
155 * Move the pointer into the mmap'ed file to the specified offset.
156 * @param addr The pointer to the offset specified.
157 * @param mm The mmap'ed file.
158 * @param offset The offset to move to.
160 APR_DECLARE(apr_status_t) apr_mmap_offset(void **addr, apr_mmap_t *mm,
163 #endif /* APR_HAS_MMAP */
171 #endif /* ! APR_MMAP_H */