XZ Utils  5.1.0alpha
Data Structures | Macros | Functions
file_io.h File Reference

I/O types and functions. More...

Data Structures

union  io_buf
struct  file_pair

Macros

#define IO_BUFFER_SIZE   8192

Functions

void io_init (void)
 Initialize the I/O module.
void io_no_sparse (void)
 Disable creation of sparse files when decompressing.
file_pairio_open_src (const char *src_name)
 Open the source file.
bool io_open_dest (file_pair *pair)
 Open the destination file.
void io_close (file_pair *pair, bool success)
 Closes the file descriptors and frees possible allocated memory.
size_t io_read (file_pair *pair, io_buf *buf, size_t size)
 Reads from the source file to a buffer.
void io_fix_src_pos (file_pair *pair, size_t rewind_size)
 Fix the position in src_fd.
bool io_pread (file_pair *pair, io_buf *buf, size_t size, off_t pos)
 Read from source file from given offset to a buffer.
bool io_write (file_pair *pair, const io_buf *buf, size_t size)
 Writes a buffer to the destination file.

Detailed Description

I/O types and functions.


Function Documentation

void io_init ( void  )

Initialize the I/O module.

void io_no_sparse ( void  )

Disable creation of sparse files when decompressing.

References try_sparse.

file_pair* io_open_src ( const char *  src_name)
bool io_open_dest ( file_pair pair)

Open the destination file.

References signals_block(), and signals_unblock().

Referenced by coder_run().

void io_close ( file_pair pair,
bool  success 
)

Closes the file descriptors and frees possible allocated memory.

The success argument determines if source or destination file gets unlinked:

  • false: The destination file is unlinked.
  • true: The source file is unlinked unless writing to stdout or –keep was used.

References file_pair::dest_fd, file_pair::dest_name, file_pair::dest_pending_sparse, file_pair::dest_try_sparse, io_close_dest(), io_close_src(), io_copy_attrs(), message_error(), signals_block(), and signals_unblock().

Referenced by coder_run(), and list_file().

size_t io_read ( file_pair pair,
io_buf buf,
size_t  size 
)

Reads from the source file to a buffer.

Parameters:
pairFile pair having the source file open for reading
bufDestination buffer to hold the read data
sizeSize of the buffer; assumed be smaller than SSIZE_MAX
Returns:
On success, number of bytes read is returned. On end of file zero is returned and pair->src_eof set to true. On error, SIZE_MAX is returned and error message printed.

References message_error(), file_pair::src_eof, file_pair::src_fd, file_pair::src_name, and user_abort.

Referenced by coder_normal(), coder_passthru(), coder_run(), and io_pread().

void io_fix_src_pos ( file_pair pair,
size_t  rewind_size 
)

Fix the position in src_fd.

This is used when –single-thream has been specified and decompression is successful. If the input file descriptor supports seeking, this function fixes the input position to point to the next byte after the decompressed stream.

Parameters:
pairFile pair having the source file open for reading
rewind_sizeHow many bytes of extra have been read i.e. how much to seek backwards.

References file_pair::src_fd.

Referenced by coder_normal().

bool io_pread ( file_pair pair,
io_buf buf,
size_t  size,
off_t  pos 
)

Read from source file from given offset to a buffer.

This is remotely similar to standard pread(). This uses lseek() though, so the read offset is changed on each call.

Parameters:
pairSeekable source file
bufDestination buffer
sizeAmount of data to read
posOffset relative to the beginning of the file, from which the data should be read.
Returns:
On success, false is returned. On error, error message is printed and true is returned.

References io_read(), message_error(), file_pair::src_fd, and file_pair::src_name.

Referenced by parse_block_header(), parse_check_value(), and parse_indexes().

bool io_write ( file_pair pair,
const io_buf buf,
size_t  size 
)

Writes a buffer to the destination file.

Parameters:
pairFile pair having the destination file open for writing
bufBuffer containing the data to be written
sizeSize of the buffer; assumed be smaller than SSIZE_MAX
Returns:
On success, zero is returned. On error, -1 is returned and error message printed.

References file_pair::dest_fd, file_pair::dest_name, file_pair::dest_pending_sparse, file_pair::dest_try_sparse, and message_error().

Referenced by coder_normal(), and coder_passthru().