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Diffstat (limited to 'pjlib/include/pj/file_io.h')
-rw-r--r-- | pjlib/include/pj/file_io.h | 155 |
1 files changed, 155 insertions, 0 deletions
diff --git a/pjlib/include/pj/file_io.h b/pjlib/include/pj/file_io.h new file mode 100644 index 00000000..7e5fa3ea --- /dev/null +++ b/pjlib/include/pj/file_io.h @@ -0,0 +1,155 @@ +/* $Id$ */ +#ifndef __PJ_FILE_IO_H__ +#define __PJ_FILE_IO_H__ + +/** + * @file file_io.h + * @brief Simple file I/O abstraction. + */ +#include <pj/types.h> + +PJ_BEGIN_DECL + +/** + * @defgroup PJ_FILE_IO File I/O + * @ingroup PJ_IO + * @{ + * + * This file contains functionalities to perform file I/O. The file + * I/O can be implemented with various back-end, either using native + * file API or ANSI stream. + * + * @section pj_file_size_limit_sec Size Limits + * + * There may be limitation on the size that can be handled by the + * #pj_file_setpos() or #pj_file_getpos() functions. The API itself + * uses 64-bit integer for the file offset/position (where available); + * however some backends (such as ANSI) may only support signed 32-bit + * offset resolution. + * + * Reading and writing operation uses signed 32-bit integer to indicate + * the size. + * + * + */ + +/** + * These enumerations are used when opening file. Values PJ_O_RDONLY, + * PJ_O_WRONLY, and PJ_O_RDWR are mutually exclusive. Value PJ_O_APPEND + * can only be used when the file is opened for writing. + */ +enum pj_file_access +{ + PJ_O_RDONLY = 0x1101, /**< Open file for reading. */ + PJ_O_WRONLY = 0x1102, /**< Open file for writing. */ + PJ_O_RDWR = 0x1103, /**< Open file for reading and writing.
+ File will be truncated. */ + PJ_O_APPEND = 0x1108, /**< Append to existing file. */
+}; + +/** + * The seek directive when setting the file position with #pj_file_setpos. + */ +enum pj_file_seek_type +{ + PJ_SEEK_SET = 0x1201, /**< Offset from beginning of the file. */ + PJ_SEEK_CUR = 0x1202, /**< Offset from current position. */ + PJ_SEEK_END = 0x1203, /**< Size of the file plus offset. */ +}; + +/** + * Open the file as specified in \c pathname with the specified + * mode, and return the handle in \c fd. All files will be opened + * as binary. + * + * @param pool Pool to allocate memory for the new file descriptor. + * @param pathname The file name to open. + * @param flags Open flags, which is bitmask combination of + * #pj_file_access enum. The flag must be either + * PJ_O_RDONLY, PJ_O_WRONLY, or PJ_O_RDWR. When file + * writing is specified, existing file will be + * truncated unless PJ_O_APPEND is specified.
+ * @param fd The returned descriptor. + * + * @return PJ_SUCCESS or the appropriate error code on error. + */ +PJ_DECL(pj_status_t) pj_file_open(pj_pool_t *pool, + const char *pathname, + unsigned flags, + pj_oshandle_t *fd); + +/** + * Close an opened file descriptor. + * + * @param fd The file descriptor. + * + * @return PJ_SUCCESS or the appropriate error code on error. + */ +PJ_DECL(pj_status_t) pj_file_close(pj_oshandle_t fd); + +/** + * Write data with the specified size to an opened file. + * + * @param fd The file descriptor. + * @param data Data to be written to the file. + * @param size On input, specifies the size of data to be written. + * On return, it contains the number of data actually + * written to the file. + * + * @return PJ_SUCCESS or the appropriate error code on error. + */ +PJ_DECL(pj_status_t) pj_file_write(pj_oshandle_t fd, + const void *data, + pj_ssize_t *size); + +/** + * Read data from the specified file. When end-of-file condition is set,
+ * this function will return PJ_SUCCESS but the size will contain zero. + * + * @param fd The file descriptor. + * @param data Pointer to buffer to receive the data. + * @param size On input, specifies the maximum number of data to + * read from the file. On output, it contains the size + * of data actually read from the file. It will contain
+ * zero when EOF occurs. + * + * @return PJ_SUCCESS or the appropriate error code on error.
+ * When EOF occurs, the return is PJ_SUCCESS but size
+ * will report zero. + */ +PJ_DECL(pj_status_t) pj_file_read(pj_oshandle_t fd, + void *data, + pj_ssize_t *size); +
+/** + * Set file position to new offset according to directive \c whence. + * + * @param fd The file descriptor. + * @param offset The new file position to set. + * @param whence The directive. + * + * @return PJ_SUCCESS or the appropriate error code on error. + */ +PJ_DECL(pj_status_t) pj_file_setpos(pj_oshandle_t fd, + pj_off_t offset, + enum pj_file_seek_type whence); + +/** + * Get current file position. + * + * @param fd The file descriptor. + * @param pos On return contains the file position as measured + * from the beginning of the file. + * + * @return PJ_SUCCESS or the appropriate error code on error. + */ +PJ_DECL(pj_status_t) pj_file_getpos(pj_oshandle_t fd, + pj_off_t *pos); + +/** @} */ + + +PJ_END_DECL + +#endif /* __PJ_FILE_IO_H__ */ + |