[thirdparty/git.git] / vcs-svn / line_buffer.txt

line_buffer API
===============

The line_buffer library provides a convenient interface for
mostly-line-oriented input.

Each line is not permitted to exceed 10000 bytes.  The provided
functions are not thread-safe or async-signal-safe, and like
`fgets()`, they generally do not function correctly if interrupted
by a signal without SA_RESTART set.

Calling sequence
----------------

The calling program:

 - initializes a `struct line_buffer` to LINE_BUFFER_INIT
 - specifies a file to read with `buffer_init`
 - processes input with `buffer_read_line`, `buffer_read_string`,
   `buffer_skip_bytes`, and `buffer_copy_bytes`
 - closes the file with `buffer_deinit`, perhaps to start over and
   read another file.

When finished, the caller can use `buffer_reset` to deallocate
resources.

Functions
---------

`buffer_init`::
	Open the named file for input.  If filename is NULL,
	start reading from stdin.  On failure, returns -1 (with
	errno indicating the nature of the failure).

`buffer_deinit`::
	Stop reading from the current file (closing it unless
	it was stdin).  Returns nonzero if `fclose` fails or
	the error indicator was set.

`buffer_read_line`::
	Read a line and strip off the trailing newline.
	On failure or end of file, returns NULL.

`buffer_read_string`::
	Read `len` characters of input or up to the end of the
	file, whichever comes first.  Returns NULL on error.
	Returns whatever characters were read (possibly "")
	for end of file.

`buffer_copy_bytes`::
	Read `len` bytes of input and dump them to the standard output
	stream.  Returns early for error or end of file.

`buffer_skip_bytes`::
	Discards `len` bytes from the input stream (stopping early
	if necessary because of an error or eof).

`buffer_reset`::
	Deallocates non-static buffers.
Commit	Line	Data
3bbaec00 DB	1	line_buffer API
	2	===============
	3
	4	The line_buffer library provides a convenient interface for
	5	mostly-line-oriented input.
	6
	7	Each line is not permitted to exceed 10000 bytes. The provided
	8	functions are not thread-safe or async-signal-safe, and like
	9	`fgets()`, they generally do not function correctly if interrupted
	10	by a signal without SA_RESTART set.
	11
	12	Calling sequence
	13	----------------
	14
	15	The calling program:
	16
e5e45ca1	17	- initializes a `struct line_buffer` to LINE_BUFFER_INIT
3bbaec00 DB	18	- specifies a file to read with `buffer_init`
	19	- processes input with `buffer_read_line`, `buffer_read_string`,
	20	`buffer_skip_bytes`, and `buffer_copy_bytes`
	21	- closes the file with `buffer_deinit`, perhaps to start over and
	22	read another file.
	23
e5e45ca1 JN	24	When finished, the caller can use `buffer_reset` to deallocate
e5e45ca1 JN	25	resources.
3bbaec00 DB	26
	27	Functions
	28	---------
	29
	30	`buffer_init`::
	31	Open the named file for input. If filename is NULL,
	32	start reading from stdin. On failure, returns -1 (with
	33	errno indicating the nature of the failure).
	34
	35	`buffer_deinit`::
	36	Stop reading from the current file (closing it unless
	37	it was stdin). Returns nonzero if `fclose` fails or
	38	the error indicator was set.
	39
	40	`buffer_read_line`::
	41	Read a line and strip off the trailing newline.
	42	On failure or end of file, returns NULL.
	43
	44	`buffer_read_string`::
	45	Read `len` characters of input or up to the end of the
	46	file, whichever comes first. Returns NULL on error.
	47	Returns whatever characters were read (possibly "")
	48	for end of file.
	49
	50	`buffer_copy_bytes`::
	51	Read `len` bytes of input and dump them to the standard output
	52	stream. Returns early for error or end of file.
	53
	54	`buffer_skip_bytes`::
	55	Discards `len` bytes from the input stream (stopping early
	56	if necessary because of an error or eof).
	57
	58	`buffer_reset`::
	59	Deallocates non-static buffers.