1 /*
2 * Copyright (C) 2007 Michael Brown <mbrown@fensystems.co.uk>.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License as
6 * published by the Free Software Foundation; either version 2 of the
7 * License, or any later version.
8 *
9 * This program is distributed in the hope that it will be useful, but
10 * WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
17 */
18
19 FILE_LICENCE ( GPL2_OR_LATER );
20
21 /**
22 * @file
23 *
24 * Line buffering
25 *
26 */
27
28 #include <stdint.h>
29 #include <string.h>
30 #include <stdlib.h>
31 #include <errno.h>
32 #include <gpxe/linebuf.h>
33
34 /**
35 * Retrieve buffered-up line
36 *
37 * @v linebuf Line buffer
38 * @ret line Buffered line, or NULL if no line ready to read
39 */
buffered_line(struct line_buffer * linebuf)40 char * buffered_line ( struct line_buffer *linebuf ) {
41 return ( linebuf->ready ? linebuf->data : NULL );
42 }
43
44 /**
45 * Discard line buffer contents
46 *
47 * @v linebuf Line buffer
48 */
empty_line_buffer(struct line_buffer * linebuf)49 void empty_line_buffer ( struct line_buffer *linebuf ) {
50 free ( linebuf->data );
51 linebuf->data = NULL;
52 linebuf->len = 0;
53 linebuf->ready = 0;
54 }
55
56 /**
57 * Buffer up received data by lines
58 *
59 * @v linebuf Line buffer
60 * @v data New data to add
61 * @v len Length of new data to add
62 * @ret len Consumed length, or negative error number
63 *
64 * After calling line_buffer(), use buffered_line() to determine
65 * whether or not a complete line is available. Carriage returns and
66 * newlines will have been stripped, and the line will be
67 * NUL-terminated. This buffered line is valid only until the next
68 * call to line_buffer() (or to empty_line_buffer()).
69 *
70 * Note that line buffers use dynamically allocated storage; you
71 * should call empty_line_buffer() before freeing a @c struct @c
72 * line_buffer.
73 */
line_buffer(struct line_buffer * linebuf,const char * data,size_t len)74 ssize_t line_buffer ( struct line_buffer *linebuf,
75 const char *data, size_t len ) {
76 const char *eol;
77 size_t consume;
78 size_t new_len;
79 char *new_data;
80
81 /* Free any completed line from previous iteration */
82 if ( linebuf->ready )
83 empty_line_buffer ( linebuf );
84
85 /* Search for line terminator */
86 if ( ( eol = memchr ( data, '\n', len ) ) ) {
87 consume = ( eol - data + 1 );
88 } else {
89 consume = len;
90 }
91
92 /* Reallocate data buffer and copy in new data */
93 new_len = ( linebuf->len + consume );
94 new_data = realloc ( linebuf->data, ( new_len + 1 ) );
95 if ( ! new_data )
96 return -ENOMEM;
97 memcpy ( ( new_data + linebuf->len ), data, consume );
98 new_data[new_len] = '\0';
99 linebuf->data = new_data;
100 linebuf->len = new_len;
101
102 /* If we have reached end of line, trim the line and mark as ready */
103 if ( eol ) {
104 linebuf->data[--linebuf->len] = '\0'; /* trim NL */
105 if ( linebuf->data[linebuf->len - 1] == '\r' )
106 linebuf->data[--linebuf->len] = '\0'; /* trim CR */
107 linebuf->ready = 1;
108 }
109
110 return consume;
111 }
112