Utils_file
This module allows you to performs file operations such as to open, close, read, and write a file, and to obtain the file size. The filing system varies according to the hardware platform. The following limitations are imposed on a platform that uses the Serial Peripheral Interface Flash Filing System (SPIFFS):
Since:
1.0
Version:
1.0
Summary
Files
Macros
Defines the offset position used by UtilsFileSeek in a file to start offsetting from the file header. |
|
Defines the offset position used by UtilsFileSeek in a file to start offsetting from the current read and write position. |
|
Defines the offset position used by UtilsFileSeek in a file to start offsetting from the end of the file. |
|
Defines a flag used byUtilsFileOpen to open a file in read-only mode. |
|
Defines a flag used by UtilsFileOpen to open a file in write-only mode. |
|
Defines a flag used by UtilsFileOpen to open a file in read-and-write mode. |
|
Defines a flag used by UtilsFileOpen to create a file when the file to open does not exist. |
|
Defines a flag used by UtilsFileOpen to check whether the file to open exists when is already set. |
|
O_TRUNC_FS 01000 |
Defines a flag used by to clear the file content if the file exists and can be opened in write mode. |
O_APPEND_FS 02000 |
Defines a flag used by to start reading or writing from the end of a file. |
Functions
UtilsFileOpen (const char path, int oflag, int mode) |
|
UtilsFileRead (int fd, char buf, unsigned int len) |
Reads a specified length of data from a file with the specified file descriptor and writes the data into the buffer. |
Writes a specified length of data into a file with the specified file descriptor. |
|
UtilsFileDelete (const char path) |
|
UtilsFileSeek (int fd, int offset, unsigned int whence) |
|
UtilsFileMove (const char src, const char dest) |
Details
Macro Definition Documentation
O_APPEND_FS
Description:
Defines a flag used by UtilsFileOpen to start reading or writing from the end of a file.
O_CREAT_FS
Description:
Defines a flag used by UtilsFileOpen to create a file when the file to open does not exist.
#define O_EXCL_FS 0200
Description:
Defines a flag used by to check whether the file to open exists when O_CREAT_FS is already set.
If the file does not exist, a new file will be created. If the file exists, the file cannot be opened.
O_RDONLY_FS
#define O_RDONLY_FS 00
Description:
Defines a flag used byUtilsFileOpen to open a file in read-only mode.
O_RDWR_FS
#define O_RDWR_FS 02
Description:
Defines a flag used by UtilsFileOpen to open a file in read-and-write mode.
O_TRUNC_FS
#define O_TRUNC_FS 01000
Description:
Defines a flag used by UtilsFileOpen to clear the file content if the file exists and can be opened in write mode.
O_WRONLY_FS
Description:
Defines a flag used by UtilsFileOpen to open a file in write-only mode.
SEEK_CUR_FS
Description:
Defines the offset position used by UtilsFileSeek in a file to start offsetting from the current read and write position.
SEEK_END_FS
#define SEEK_END_FS 2
Description:
Defines the offset position used by UtilsFileSeek in a file to start offsetting from the end of the file.
SEEK_SET_FS
#define SEEK_SET_FS 0
Description:
Defines the offset position used by UtilsFileSeek in a file to start offsetting from the file header.
Function Documentation
int UtilsFileClose (int fd)
Description:
Closes a file with the specified file descriptor.
Parameters:
fd | Indicates the file descriptor of the file to close. |
Returns:
Returns 0 if the file is closed; returns -1 otherwise.
UtilsFileCopy()
int UtilsFileCopy (const char * src, const char * dest )
Description:
Copies the source file to a target file.
Parameters:
Attention:
If the number of opened files reaches the upper limit (32), close any two files first. Otherwise, the file cannot be copied.
Returns:
Returns 0 if the operation is successful; returns -1 otherwise.
UtilsFileDelete()
Description:
Deletes a specified file.
Parameters:
path | Indicates the file to delete. |
Attention:
If the number of opened files reaches the upper limit (32), close any of them first. Otherwise, the file cannot be deleted.
Returns:
Returns 0 if the file is deleted; returns -1 otherwise.
UtilsFileMove()
Description:
Moves the source file into a target file.
Parameters:
src | Indicates the source file. |
dest | Indicates the target file. |
Attention:
If the number of opened files reaches the upper limit (32), close any two files first. Otherwise, the file cannot be moved.
Returns:
Returns 0 if the operation is successful; returns -1 otherwise.
UtilsFileOpen()
int UtilsFileOpen (const char * path, int oflag, int mode )
Description:
Opens or creates a file.
Parameters:
path | Indicates the file to open or create. |
oflag | Indicates the mode of opening a file. The following modes are supported. These modes can be used together, with each of them identified by “or”. |
mode | Used for function compatibility. This parameter does not take effect in any scenario. |
Returns:
Returns the file descriptor if the file is opened or created; returns -1 otherwise.
UtilsFileRead()
int UtilsFileRead (int fd, char * buf, unsigned int len )
Description:
Reads a specified length of data from a file with the specified file descriptor and writes the data into the buffer.
Parameters:
fd | Indicates the file descriptor of the file to read. |
buf | Indicates the buffer that stores the read data. This is an output parameter. |
len | Indicates the length of the data to read. |
Returns:
Returns the number of bytes of the data if the data is read; returns -1 otherwise.
UtilsFileSeek()
int UtilsFileSeek (int fd, int offset, unsigned int whence )
Description:
Adjusts the read and write position offset in a file.
Parameters:
Returns:
Returns the current read and write position if the operation is successful; returns -1 otherwise.
UtilsFileStat()
Description:
Obtains the file size.
Parameters:
Returns:
Returns 0 if the file size is obtained; returns -1 otherwise.
UtilsFileWrite()
Description:
Writes a specified length of data into a file with the specified file descriptor.
Parameters:
fd | Indicates the file descriptor of the file where to write the data. |
buf | Indicates the data to write. |
len | Indicates the length of the data to write. |
Returns the number of bytes of the data if the data is written; returns -1 otherwise.