Apache Portable Runtime
apr_mmap.h
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15  */
16 
17 #ifndef APR_MMAP_H
18 #define APR_MMAP_H
19 
20 /**
21  * @file apr_mmap.h
22  * @brief APR MMAP routines
23  */
24 
25 #include "apr.h"
26 #include "apr_pools.h"
27 #include "apr_errno.h"
28 #include "apr_ring.h"
29 #include "apr_file_io.h" /* for apr_file_t */
30 
31 #ifdef BEOS
32 #include <kernel/OS.h>
33 #endif
34 
35 #ifdef __cplusplus
36 extern "C" {
37 #endif /* __cplusplus */
38 
39 /**
40  * @defgroup apr_mmap MMAP (Memory Map) Routines
41  * @ingroup APR
42  * @{
43  */
44 
45 /** MMap opened for reading */
46 #define APR_MMAP_READ 1
47 /** MMap opened for writing */
48 #define APR_MMAP_WRITE 2
49 
50 /** @see apr_mmap_t */
51 typedef struct apr_mmap_t apr_mmap_t;
52 
53 /**
54  * @remark
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
59  * Apache.
60  */
61 /** The MMAP structure */
62 struct apr_mmap_t {
63  /** The pool the mmap structure was allocated out of. */
65 #if defined(BEOS)
66  /** An area ID. Only valid on BeOS */
67  area_id area;
68 #elif defined(WIN32)
69  /** The handle of the file mapping */
70  HANDLE mhandle;
71  /** The start of the real memory page area (mapped view) */
72  void *mv;
73 #else
74  apr_off_t poffset;
75 #endif
76  /** The start of the memory mapped area */
77  void *mm;
78  /** The amount of data in the mmap */
79  apr_size_t size;
80  /** ring of apr_mmap_t's that reference the same
81  * mmap'ed region; acts in place of a reference count */
83 };
84 
85 #if APR_HAS_MMAP || defined(DOXYGEN)
86 
87 /** @def APR_MMAP_THRESHOLD
88  * Files have to be at least this big before they're mmap()d. This is to deal
89  * with systems where the expense of doing an mmap() and an munmap() outweighs
90  * the benefit for small files. It shouldn't be set lower than 1.
91  */
92 #ifdef MMAP_THRESHOLD
93 # define APR_MMAP_THRESHOLD MMAP_THRESHOLD
94 #else
95 # ifdef SUNOS4
96 # define APR_MMAP_THRESHOLD (8*1024)
97 # else
98 # define APR_MMAP_THRESHOLD 1
99 # endif /* SUNOS4 */
100 #endif /* MMAP_THRESHOLD */
101 
102 /** @def APR_MMAP_LIMIT
103  * Maximum size of MMap region
104  */
105 #ifdef MMAP_LIMIT
106 # define APR_MMAP_LIMIT MMAP_LIMIT
107 #else
108 # define APR_MMAP_LIMIT (4*1024*1024)
109 #endif /* MMAP_LIMIT */
110 
111 /** Can this file be MMaped */
112 #define APR_MMAP_CANDIDATE(filelength) \
113  ((filelength >= APR_MMAP_THRESHOLD) && (filelength < APR_MMAP_LIMIT))
114 
115 /* Function definitions */
116 
117 /**
118  * Create a new mmap'ed file out of an existing APR file.
119  * @param newmmap The newly created mmap'ed file.
120  * @param file The file to turn into an mmap.
121  * @param offset The offset into the file to start the data pointer at.
122  * @param size The size of the file
123  * @param flag bit-wise or of:
124  * <PRE>
125  * APR_MMAP_READ MMap opened for reading
126  * APR_MMAP_WRITE MMap opened for writing
127  * </PRE>
128  * @param cntxt The pool to use when creating the mmap.
129  */
131  apr_file_t *file, apr_off_t offset,
132  apr_size_t size, apr_int32_t flag,
133  apr_pool_t *cntxt);
134 
135 /**
136  * Duplicate the specified MMAP.
137  * @param new_mmap The structure to duplicate into.
138  * @param old_mmap The mmap to duplicate.
139  * @param p The pool to use for new_mmap.
140  */
142  apr_mmap_t *old_mmap,
143  apr_pool_t *p);
144 
145 /**
146  * Remove a mmap'ed.
147  * @param mm The mmap'ed file.
148  */
150 
151 /**
152  * Move the pointer into the mmap'ed file to the specified offset.
153  * @param addr The pointer to the offset specified.
154  * @param mm The mmap'ed file.
155  * @param offset The offset to move to.
156  */
158  apr_off_t offset);
159 
160 #endif /* APR_HAS_MMAP */
161 
162 /** @} */
163 
164 #ifdef __cplusplus
165 }
166 #endif
167 
168 #endif /* ! APR_MMAP_H */
APR Platform Definitions.
APR Error Codes.
APR File I/O Handling.
APR memory allocation.
APR Rings.
int apr_status_t
Definition: apr_errno.h:44
struct apr_file_t apr_file_t
Definition: apr_file_io.h:195
apr_status_t apr_mmap_delete(apr_mmap_t *mm)
apr_status_t apr_mmap_offset(void **addr, apr_mmap_t *mm, apr_off_t offset)
apr_status_t apr_mmap_dup(apr_mmap_t **new_mmap, apr_mmap_t *old_mmap, apr_pool_t *p)
apr_status_t apr_mmap_create(apr_mmap_t **newmmap, apr_file_t *file, apr_off_t offset, apr_size_t size, apr_int32_t flag, apr_pool_t *cntxt)
#define APR_DECLARE(type)
Definition: apr.h:516
struct apr_pool_t apr_pool_t
Definition: apr_pools.h:60
Definition: apr_mmap.h:62
apr_size_t size
Definition: apr_mmap.h:79
apr_pool_t * cntxt
Definition: apr_mmap.h:64
void * mm
Definition: apr_mmap.h:77
APR_RING_ENTRY(apr_mmap_t) link