2 * This file is part of DisOrder
3 * Copyright (C) 2010 Richard Kettlewell
5 * This program is free software: you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation, either version 3 of the License, or
8 * (at your option) any later version.
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
15 * You should have received a copy of the GNU General Public License
16 * along with this program. If not, see <http://www.gnu.org/licenses/>.
18 /** @file lib/hreader.h
19 * @brief Hands-off reader - read files without keeping them open
26 /** @brief A hands-off reader
28 * Allows files to be read without holding them open.
31 const char *path; /* file to read */
32 off_t size; /* file size */
33 off_t read_offset; /* for next hreader_read() */
34 off_t buf_offset; /* offset of start of buffer */
35 char *buffer; /* input buffer */
36 size_t bufsize; /* buffer size */
37 size_t bytes; /* size of last read */
40 /** @brief Initialize a hands-off reader
41 * @param path File to read
42 * @param h Reader to initialize
43 * @return 0 on success, -1 on error
45 int hreader_init(const char *path, struct hreader *h);
47 /** @brief Read some bytes
48 * @param h Reader to read from
49 * @param buffer Where to store bytes
50 * @param n Maximum bytes to read
51 * @return Bytes read, or 0 at EOF, or -1 on error
53 int hreader_read(struct hreader *h, void *buffer, size_t n);
55 /** @brief Read some bytes at a given offset
56 * @param h Reader to read from
57 * @param offset Offset to read at
58 * @param buffer Where to store bytes
59 * @param n Maximum bytes to read
60 * @return Bytes read, or 0 at EOF, or -1 on error
62 int hreader_pread(struct hreader *h, void *buffer, size_t n, off_t offset);
64 /** @brief Seek within a file
65 * @param h Reader to seek
66 * @param offset Offset
67 * @param whence SEEK_*
68 * @return Result offset
70 off_t hreader_seek(struct hreader *h, off_t offset, int whence);
72 #endif /* HREADER_H */