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/*
* Copyright (C) 2007 Michael Brown <mbrown@fensystems.co.uk>.
*
* 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 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., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301, USA.
*
* You can also choose to distribute this program under the terms of
* the Unmodified Binary Distribution Licence (as given in the file
* COPYING.UBDL), provided that you have satisfied its requirements.
*/
FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
/**
* @file
*
* Line buffering
*
*/
#include <stdint.h>
#include <string.h>
#include <stdlib.h>
#include <errno.h>
#include <ipxe/linebuf.h>
/**
* Retrieve buffered-up line
*
* @v linebuf Line buffer
* @ret line Buffered line, or NULL if no line ready to read
*/
char * buffered_line ( struct line_buffer *linebuf ) {
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;
}
/**
* Discard line buffer contents
*
* @v linebuf Line buffer
*/
void empty_line_buffer ( struct line_buffer *linebuf ) {
free ( linebuf->data );
linebuf->data = NULL;
linebuf->len = 0;
linebuf->consumed = 0;
}
/**
* Buffer up received data by lines
*
* @v linebuf Line buffer
* @v data New data to add
* @v len Length of new data to add
* @ret 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 @c struct @c
* line_buffer.
*/
int line_buffer ( struct line_buffer *linebuf, const char *data, size_t len ) {
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;
}
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