linebuf.h File Reference

Line buffering. More...

#include <stdint.h>
#include <stddef.h>

Go to the source code of this file.

Data Structures
struct	line_buffer
	A line buffer. More...

Functions
	FILE_LICENCE (GPL2_OR_LATER_OR_UBDL)
char *	buffered_line (struct line_buffer *linebuf)
	Retrieve buffered-up line. More...
int	line_buffer (struct line_buffer *linebuf, const char *data, size_t len)
	Buffer up received data by lines. More...
void	empty_line_buffer (struct line_buffer *linebuf)
	Discard line buffer contents. More...

Detailed Description

Line buffering.

Definition in file linebuf.h.

Function Documentation

FILE_LICENCE()

FILE_LICENCE

(

GPL2_OR_LATER_OR_UBDL

)

buffered_line()

char* buffered_line

(

struct line_buffer *

linebuf

)

Retrieve buffered-up line.

Parameters

linebuf

Line buffer

Return values

line	Buffered line, or NULL if no line ready to read

Definition at line 45 of file linebuf.c.

                                                     {
        char *line = &linebuf->data[ linebuf->len ];

        /* Fail unless we have a newly completed line to retrieve */
        if ( ( linebuf->len == 0 ) || ( linebuf->consumed == 0 ) ||
             ( *(--line) != '\0' ) )
                return NULL;

        /* Identify start of line */
        while ( ( line > linebuf->data ) && ( line[-1] != '\0' ) )
                line--;

        return line;
}

References line_buffer::consumed, line_buffer::data, line_buffer::len, and NULL.

Referenced by http_rx_chunk_len(), http_rx_headers(), http_rx_trailers(), linebuf_consume_okx(), linebuf_empty_okx(), and linebuf_init_okx().

line_buffer()

int line_buffer	(	struct line_buffer *	linebuf,
		const char *	data,
		size_t	len
	)

Buffer up received data by lines.

Parameters

linebuf	Line buffer
data	New data to add
len	Length of new data to add

Return values

len	Consumed length, or negative error number

After calling line_buffer(), use buffered_line() to determine whether or not a complete line is available. Carriage returns and newlines will have been stripped, and the line will be NUL-terminated. This buffered line is valid only until the next call to line_buffer() (or to empty_line_buffer()).

Note that line buffers use dynamically allocated storage; you should call empty_line_buffer() before freeing a struct line_buffer.

Definition at line 91 of file linebuf.c.

                                                                              {
        const char *eol;
        size_t consume;
        size_t new_len;
        char *new_data;
        char *lf;
        char *cr;

        /* Search for line terminator */
        if ( ( eol = memchr ( data, '\n', len ) ) ) {
                consume = ( eol - data + 1 );
        } else {
                consume = len;
        }

        /* Reject any embedded NULs within the data to be consumed */
        if ( memchr ( data, '\0', consume ) )
                return -EINVAL;

        /* Reallocate data buffer and copy in new data */
        new_len = ( linebuf->len + consume );
        new_data = realloc ( linebuf->data, ( new_len + 1 ) );
        if ( ! new_data )
                return -ENOMEM;
        memcpy ( ( new_data + linebuf->len ), data, consume );
        new_data[new_len] = '\0';
        linebuf->data = new_data;
        linebuf->len = new_len;

        /* If we have reached end of line, terminate the line */
        if ( eol ) {

                /* Overwrite trailing LF (which must exist at this point) */
                assert ( linebuf->len > 0 );
                lf = &linebuf->data[ linebuf->len - 1 ];
                assert ( *lf == '\n' );
                *lf = '\0';

                /* Trim (and overwrite) trailing CR, if present */
                if ( linebuf->len > 1 ) {
                        cr = ( lf - 1 );
                        if ( *cr == '\r' ) {
                                linebuf->len--;
                                *cr = '\0';
                        }
                }
        }

        /* Record consumed length */
        linebuf->consumed = consume;

        return consume;
}

References assert(), line_buffer::consumed, cr, line_buffer::data, data, EINVAL, ENOMEM, line_buffer::len, len, memchr(), memcpy(), and realloc().

Referenced by http_rx_linebuf(), and linebuf_consume_okx().

empty_line_buffer()

void empty_line_buffer

(

struct line_buffer *

linebuf

)

Discard line buffer contents.

Parameters

linebuf

Line buffer

Definition at line 65 of file linebuf.c.

                                                       {

        free ( linebuf->data );
        linebuf->data = NULL;
        linebuf->len = 0;
        linebuf->consumed = 0;
}

References line_buffer::consumed, line_buffer::data, free, line_buffer::len, and NULL.

Referenced by http_free(), http_rx_chunk_len(), http_rx_trailers(), http_tx_request(), and linebuf_empty_okx().