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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., 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>
/**
* 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 ) {
return ( linebuf->ready ? linebuf->data : NULL );
}
/**
* 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->ready = 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 rc Return status code
*
* If line_buffer() returns >0, 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()).
*
* @c data and @c len will be updated to reflect the data consumed by
* 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;
/* Free any completed line from previous iteration */
if ( linebuf->ready )
empty_line_buffer ( linebuf );
/* Search for line terminator */
if ( ( eol = memchr ( *data, '\n', *len ) ) ) {
consume = ( eol - *data + 1 );
} else {
consume = *len;
}
/* 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;
/* Update data and len */
*data += consume;
*len -= consume;
/* If we have reached end of line, trim the line and mark as ready */
if ( eol ) {
linebuf->data[--linebuf->len] = '\0'; /* trim NL */
if ( linebuf->data[linebuf->len - 1] == '\r' )
linebuf->data[--linebuf->len] = '\0'; /* trim CR */
linebuf->ready = 1;
}
return 0;
}
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