1 /* Copyright (C) 2007-2010 The Android Open Source Project
2 **
3 ** This software is licensed under the terms of the GNU General Public
4 ** License version 2, as published by the Free Software Foundation, and
5 ** may be copied, distributed, and modified under those terms.
6 **
7 ** This program is distributed in the hope that it will be useful,
8 ** but WITHOUT ANY WARRANTY; without even the implied warranty of
9 ** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
10 ** GNU General Public License for more details.
11 */
12
13 /*
14 * Contains declarations of routines that implement platform-independent
15 * file I/O.
16 */
17
18 #ifndef _ANDROID_UTILS_FILEIO_H
19 #define _ANDROID_UTILS_FILEIO_H
20
21 #ifdef __cplusplus
22 extern "C" {
23 #endif
24
25 typedef struct MapFile MapFile;
26
27 #ifdef WIN32
28 /* Declare constants that are missing in Win32 headers. */
29 #define PROT_READ 0x1
30 #define PROT_WRITE 0x2
31 #define PROT_EXEC 0x4
32 #define PROT_NONE 0x0
33 #endif
34
35 /* Checks if file handle is a valid one.
36 * Return:
37 * boolean: 1 if handle is valid, or 0 if it's not valid.
38 */
39 static inline int
mapfile_is_valid(MapFile * handle)40 mapfile_is_valid(MapFile* handle)
41 {
42 return handle != (void*)(ptrdiff_t)-1;
43 }
44
45 /* Opens file in selected mode.
46 * Param:
47 * path - Path to the file to open.
48 * oflag - Defines mode in which file is to be opened. This value follows the
49 * symantics of O_XXX flags defined for standard open routine.
50 * share_mode Defines sharing mode for the opened file. This value follows the
51 * symantics of S_IXXX flags defined for standard open routine.
52 * Return:
53 * A valid handle to the opened file on success, or an invalid value on
54 * failure. In case of failure errno contains error code.
55 */
56 extern MapFile* mapfile_open(const char* path, int oflag, int share_mode);
57
58 /* Closes a file handle opened with mapfile_open routine.
59 * Param:
60 * handle - A handle to a file previously obtained via successful call to
61 * mapfile_open routine.
62 * Return:
63 * 0 on success, or -1 on failure with errno containing the error code.
64 */
65 extern int mapfile_close(MapFile* handle);
66
67 /* Reads from a file opened with mapfile_open routine.
68 * Except for handle parameter, semantics of this call are the same as for
69 * the regualar read routine.
70 * Param:
71 * handle - A handle to a file previously obtained via successful call to
72 * mapfile_open routine.
73 */
74 extern ssize_t mapfile_read(MapFile* handle, void* buf, size_t nbyte);
75
76 /* Reads from a specific offset in a file opened with mapfile_open routine.
77 * Param:
78 * handle - A handle to a file previously obtained via successful call to
79 * mapfile_open routine.
80 * offset - Offset in the file where to start reading from.
81 * Rest of the parameters and return value are the same as in file_read.
82 */
83 extern ssize_t mapfile_read_at(MapFile* handle,
84 size_t offset,
85 void* buf,
86 size_t nbyte);
87
88 /* Maps a section of a file to memory.
89 * Param:
90 * handle - A handle to a file previously obtained via successful call to
91 * mapfile_open routine.
92 * offset - Offset in the file where mapping should begin.
93 * size - Number of bytes starting with offset that should be mapped.
94 * prot - Determines whether read, write, execute, or some combination of
95 * accesses are permitted to the data being mapped. This parameter has the
96 * same semantics as in regular mmap routene.
97 * mapped_offset - Upon success, contains pointer to the requested offset
98 * within the mapped section of the file.
99 * size - Upon success, contains total number of bytes that were actually
100 * mapped.
101 * Return:
102 * Upon successful completion returns pointer to the beginning of memory
103 * mapping, containing mapping of the requested section of a file. Note that
104 * value returned from this routine doesn't necessarily points to the beginning
105 * of the requested section mapping. Use value returned in mapped_offset
106 * parameter to get actual pointer to the beginning of the requested section
107 * mapping. Value returned from this routine must eventually be passed to
108 * file_unmap_section reoutine to unmap section mapped with this routine.
109 * This routine returns NULL on failure and sets errno to indicate the error.
110 */
111 extern void* mapfile_map(MapFile* handle,
112 size_t offset,
113 size_t size,
114 int prot,
115 void** mapped_offset,
116 size_t* mapped_size);
117
118 /* Umaps section of a file previously mapped with mapfile_map routine.
119 * Param:
120 * mapped_at - A pointer to the base address of the mapped section of a file
121 * that is to be unmapped.
122 * len - Byte size of the section that is to be unmapped.
123 * Return:
124 * Upon successful completion returns 0. Otherwise, returns -1 and sets
125 * errno to indicate the error.
126 */
127 extern int mapfile_unmap(void* mapped_at, size_t len);
128
129 #ifdef __cplusplus
130 } /* end of extern "C" */
131 #endif
132
133 #endif // _ANDROID_UTILS_FILEIO_H
134