xref: /PHP-7.4/main/streams/php_stream_mmap.h (revision 19c84459)
1 /*
2   +----------------------------------------------------------------------+
3   | PHP Version 7                                                        |
4   +----------------------------------------------------------------------+
5   | Copyright (c) The PHP Group                                          |
6   +----------------------------------------------------------------------+
7   | This source file is subject to version 3.01 of the PHP license,      |
8   | that is bundled with this package in the file LICENSE, and is        |
9   | available through the world-wide-web at the following url:           |
10   | http://www.php.net/license/3_01.txt                                  |
11   | If you did not receive a copy of the PHP license and are unable to   |
12   | obtain it through the world-wide-web, please send a note to          |
13   | license@php.net so we can mail you a copy immediately.               |
14   +----------------------------------------------------------------------+
15   | Author: Wez Furlong <wez@thebrainroom.com>                           |
16   +----------------------------------------------------------------------+
17 */
18 
19 /* Memory Mapping interface for streams.
20  * The intention is to provide a uniform interface over the most common
21  * operations that are used within PHP itself, rather than a complete
22  * API for all memory mapping needs.
23  *
24  * ATM, we support only mmap(), but win32 memory mapping support will
25  * follow soon.
26  * */
27 
28 typedef enum {
29 	/* Does the stream support mmap ? */
30 	PHP_STREAM_MMAP_SUPPORTED,
31 	/* Request a range and offset to be mapped;
32 	 * while mapped, you MUST NOT use any read/write functions
33 	 * on the stream (win9x compatibility) */
34 	PHP_STREAM_MMAP_MAP_RANGE,
35 	/* Unmap the last range that was mapped for the stream */
36 	PHP_STREAM_MMAP_UNMAP
37 } php_stream_mmap_operation_t;
38 
39 typedef enum {
40 	PHP_STREAM_MAP_MODE_READONLY,
41 	PHP_STREAM_MAP_MODE_READWRITE,
42 	PHP_STREAM_MAP_MODE_SHARED_READONLY,
43 	PHP_STREAM_MAP_MODE_SHARED_READWRITE
44 } php_stream_mmap_access_t;
45 
46 typedef struct {
47 	/* requested offset and length.
48 	 * If length is 0, the whole file is mapped */
49 	size_t offset;
50 	size_t length;
51 
52 	php_stream_mmap_access_t mode;
53 
54 	/* returned mapped address */
55 	char *mapped;
56 
57 } php_stream_mmap_range;
58 
59 #define PHP_STREAM_MMAP_ALL 0
60 
61 #define PHP_STREAM_MMAP_MAX (512 * 1024 * 1024)
62 
63 #define php_stream_mmap_supported(stream)	(_php_stream_set_option((stream), PHP_STREAM_OPTION_MMAP_API, PHP_STREAM_MMAP_SUPPORTED, NULL) == 0 ? 1 : 0)
64 
65 /* Returns 1 if the stream in its current state can be memory mapped,
66  * 0 otherwise */
67 #define php_stream_mmap_possible(stream)			(!php_stream_is_filtered((stream)) && php_stream_mmap_supported((stream)))
68 
69 BEGIN_EXTERN_C()
70 PHPAPI char *_php_stream_mmap_range(php_stream *stream, size_t offset, size_t length, php_stream_mmap_access_t mode, size_t *mapped_len);
71 #define php_stream_mmap_range(stream, offset, length, mode, mapped_len)	_php_stream_mmap_range((stream), (offset), (length), (mode), (mapped_len))
72 
73 /* un-maps the last mapped range */
74 PHPAPI int _php_stream_mmap_unmap(php_stream *stream);
75 #define php_stream_mmap_unmap(stream)				_php_stream_mmap_unmap((stream))
76 
77 PHPAPI int _php_stream_mmap_unmap_ex(php_stream *stream, zend_off_t readden);
78 #define php_stream_mmap_unmap_ex(stream, readden)			_php_stream_mmap_unmap_ex((stream), (readden))
79 END_EXTERN_C()
80