D-Modem/pjproject-2.11.1/pjlib/include/pj/file_io.h

184 lines
6.3 KiB
C
Raw Permalink Normal View History

2021-10-30 02:41:03 +08:00
/* $Id$ */
/*
* Copyright (C) 2008-2011 Teluu Inc. (http://www.teluu.com)
* Copyright (C) 2003-2008 Benny Prijono <benny@prijono.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#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);
/**
* Flush file buffers.
*
* @param fd The file descriptor.
*
* @return PJ_SUCCESS or the appropriate error code on error.
*/
PJ_DECL(pj_status_t) pj_file_flush(pj_oshandle_t fd);
/** @} */
PJ_END_DECL
#endif /* __PJ_FILE_IO_H__ */