1 /*
2 * Copyright (C) 2006 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 #include <string.h>
22 #include <assert.h>
23 #include <gpxe/ansiesc.h>
24
25 /** @file
26 *
27 * ANSI escape sequences
28 *
29 */
30
31 /**
32 * Call ANSI escape sequence handler
33 *
34 * @v handlers List of escape sequence handlers
35 * @v function Control function identifier
36 * @v count Parameter count
37 * @v params Parameter list
38 */
ansiesc_call_handler(struct ansiesc_handler * handlers,unsigned int function,int count,int params[])39 static void ansiesc_call_handler ( struct ansiesc_handler *handlers,
40 unsigned int function, int count,
41 int params[] ) {
42 struct ansiesc_handler *handler;
43
44 for ( handler = handlers ; handler->function ; handler++ ) {
45 if ( handler->function == function ) {
46 handler->handle ( count, params );
47 break;
48 }
49 }
50 }
51
52 /**
53 * Process character that may be part of ANSI escape sequence
54 *
55 * @v ctx ANSI escape sequence context
56 * @v c Character
57 * @ret c Original character if not part of escape sequence
58 * @ret <0 Character was part of escape sequence
59 *
60 * ANSI escape sequences will be plucked out of the character stream
61 * and interpreted; once complete they will be passed to the
62 * appropriate handler if one exists in this ANSI escape sequence
63 * context.
64 *
65 * In the interests of code size, we are rather liberal about the
66 * sequences we are prepared to accept as valid.
67 */
ansiesc_process(struct ansiesc_context * ctx,int c)68 int ansiesc_process ( struct ansiesc_context *ctx, int c ) {
69 if ( ctx->count == 0 ) {
70 if ( c == ESC ) {
71 /* First byte of CSI : begin escape sequence */
72 ctx->count = 1;
73 memset ( ctx->params, 0xff, sizeof ( ctx->params ) );
74 ctx->function = 0;
75 return -1;
76 } else {
77 /* Normal character */
78 return c;
79 }
80 } else {
81 if ( c == '[' ) {
82 /* Second byte of CSI : do nothing */
83 } else if ( ( c >= '0' ) && ( c <= '9' ) ) {
84 /* Parameter Byte : part of a parameter value */
85 int *param = &ctx->params[ctx->count - 1];
86 if ( *param < 0 )
87 *param = 0;
88 *param = ( ( *param * 10 ) + ( c - '0' ) );
89 } else if ( c == ';' ) {
90 /* Parameter Byte : parameter delimiter */
91 ctx->count++;
92 if ( ctx->count > ( sizeof ( ctx->params ) /
93 sizeof ( ctx->params[0] ) ) ) {
94 /* Excessive parameters : abort sequence */
95 ctx->count = 0;
96 DBG ( "Too many parameters in ANSI escape "
97 "sequence\n" );
98 }
99 } else if ( ( c >= 0x20 ) && ( c <= 0x2f ) ) {
100 /* Intermediate Byte */
101 ctx->function <<= 8;
102 ctx->function |= c;
103 } else {
104 /* Treat as Final Byte. Zero ctx->count before
105 * calling handler to avoid potential infinite loops.
106 */
107 int count = ctx->count;
108 ctx->count = 0;
109 ctx->function <<= 8;
110 ctx->function |= c;
111 ansiesc_call_handler ( ctx->handlers, ctx->function,
112 count, ctx->params );
113 }
114 return -1;
115 }
116 }
117