1 /* 2 * Copyright (C) 2006 Michael Brown <mbrown (at) 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 */ 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 */ 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
