/*
* 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., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
/**
* @file
*
* Line buffering
*
*/
#include <stdint.h>
#include <string.h>
#include <stdlib.h>
#include <errno.h>
#include <gpxe/linebuf.h>
/**
* Line terminators
*
* These values are used in the @c skip_terminators bitmask.
*/
enum line_terminators {
TERM_CR = 1,
TERM_NL = 2,
TERM_NUL = 4,
};
/**
* Get terminator ID corresponding to character
*
* @v character Character
* @ret terminator_id Terminator ID, or -1
*/
static int terminator_id ( unsigned int character ) {
switch ( character ) {
case '\r':
return TERM_CR;
case '\n':
return TERM_NL;
case '\0':
return TERM_NUL;
default:
return -1;
}
}
/**
* 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;
}
/**
* 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 buffered Amount of data consumed and added to the buffer
* @ret <0 Out of memory
*
* If line_buffer() does not consume the entirety of the new data
* (i.e. if @c buffered is not equal to @c len), then an end of line
* has been reached and the buffered-up line can be obtained from
* buffered_line(). 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 ) {
size_t consume = 0;
size_t copy = 0;
size_t new_len;
char *new_data;
int terminator;
/* First, handle the termination of the previous line */
if ( linebuf->skip_terminators ) {
/* Free buffered string */
empty_line_buffer ( linebuf );
/* Skip over any terminators from the end of a previous line */
for ( ; consume < len ; consume++ ) {
terminator = terminator_id ( data[consume] );
if ( ( terminator < 0 ) ||
! ( linebuf->skip_terminators & terminator ) ) {
linebuf->skip_terminators = 0;
break;
}
linebuf->skip_terminators &= ~terminator;
}
}
/* Scan up to the next terminator, if any */
for ( ; consume < len ; consume++, copy++ ) {
if ( terminator_id ( data[consume] ) >= 0 ) {
linebuf->skip_terminators = -1U;
break;
}
}
/* Reallocate data buffer and copy in new data */
new_len = ( linebuf->len + copy );
new_data = realloc ( linebuf->data, ( new_len + 1 ) );
if ( ! new_data )
return -ENOMEM;
memcpy ( ( new_data + linebuf->len ), ( data + consume - copy ),
copy );
new_data[new_len] = '\0';
linebuf->data = new_data;
linebuf->len = new_len;
return consume;
}
