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#include "android/utils/compiler.h"
22
23#include <stddef.h>
24#include <unistd.h>
25
26ANDROID_BEGIN_HEADER
27
28typedef struct MapFile MapFile;
29
30#ifdef WIN32
31/* Declare constants that are missing in Win32 headers. */
32#define PROT_READ   0x1
33#define PROT_WRITE  0x2
34#define PROT_EXEC   0x4
35#define PROT_NONE   0x0
36#endif
37
38/* Checks if file handle is a valid one.
39 * Return:
40 *  boolean: 1 if handle is valid, or 0 if it's not valid.
41 */
42static inline int
43mapfile_is_valid(MapFile* handle)
44{
45    return handle != (void*)(ptrdiff_t)-1;
46}
47
48/* Opens file in selected mode.
49 * Param:
50 *  path - Path to the file to open.
51 *  oflag - Defines mode in which file is to be opened. This value follows the
52 *      symantics of O_XXX flags defined for standard open routine.
53 *  share_mode Defines sharing mode for the opened file. This value follows the
54 *      symantics of S_IXXX flags defined for standard open routine.
55 * Return:
56 *  A valid handle to the opened file on success, or an invalid value on
57 *  failure. In case of failure errno contains error code.
58 */
59extern MapFile* mapfile_open(const char* path, int oflag, int share_mode);
60
61/* Closes a file handle opened with mapfile_open routine.
62 * Param:
63 *  handle - A handle to a file previously obtained via successful call to
64 *      mapfile_open routine.
65 * Return:
66 *  0 on success, or -1 on failure with errno containing the error code.
67 */
68extern int mapfile_close(MapFile* handle);
69
70/* Reads from a file opened with mapfile_open routine.
71 * Except for handle parameter, semantics of this call are the same as for
72 * the regualar read routine.
73 * Param:
74 *  handle - A handle to a file previously obtained via successful call to
75 *      mapfile_open routine.
76 */
77extern ssize_t mapfile_read(MapFile* handle, void* buf, size_t nbyte);
78
79/* Reads from a specific offset in a file opened with mapfile_open routine.
80 * Param:
81 *  handle - A handle to a file previously obtained via successful call to
82 *      mapfile_open routine.
83 *  offset - Offset in the file where to start reading from.
84 *  Rest of the parameters and return value are the same as in file_read.
85 */
86extern ssize_t mapfile_read_at(MapFile* handle,
87                               size_t offset,
88                               void* buf,
89                               size_t nbyte);
90
91/* Maps a section of a file to memory.
92 * Param:
93 *  handle - A handle to a file previously obtained via successful call to
94 *      mapfile_open routine.
95 *  offset - Offset in the file where mapping should begin.
96 *  size - Number of bytes starting with offset that should be mapped.
97 *  prot - Determines whether read, write, execute, or some combination of
98 *      accesses are permitted to the data being mapped. This parameter has the
99 *      same semantics as in regular mmap routene.
100 *  mapped_offset - Upon success, contains pointer to the requested offset
101 *      within the mapped section of the file.
102 *  size - Upon success, contains total number of bytes that were actually
103 *      mapped.
104 * Return:
105 *  Upon successful completion returns pointer to the beginning of memory
106 *  mapping, containing mapping of the requested section of a file. Note that
107 *  value returned from this routine doesn't necessarily points to the beginning
108 *  of the requested section mapping. Use value returned in mapped_offset
109 *  parameter to get actual pointer to the beginning of the requested section
110 *  mapping. Value returned from this routine must eventually be passed to
111 *  file_unmap_section reoutine to unmap section mapped with this routine.
112 *  This routine returns NULL on failure and sets errno to indicate the error.
113 */
114extern void* mapfile_map(MapFile* handle,
115                         size_t offset,
116                         size_t size,
117                         int prot,
118                         void** mapped_offset,
119                         size_t* mapped_size);
120
121/* Umaps section of a file previously mapped with mapfile_map routine.
122 * Param:
123 *  mapped_at - A pointer to the base address of the mapped section of a file
124 *      that is to be unmapped.
125 *  len - Byte size of the section that is to be unmapped.
126 * Return:
127 *  Upon successful completion returns 0. Otherwise, returns -1 and sets
128 *  errno to indicate the error.
129 */
130extern int mapfile_unmap(void* mapped_at, size_t len);
131
132ANDROID_END_HEADER
133
134#endif  // _ANDROID_UTILS_FILEIO_H
135