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/*
* Copyright (C) 2006 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_LICENCE ( GPL2_OR_LATER );
#include <string.h>
#include <assert.h>
#include <gpxe/ansiesc.h>
/** @file
*
* ANSI escape sequences
*
*/
/**
* Call ANSI escape sequence handler
*
* @v handlers List of escape sequence handlers
* @v function Control function identifier
* @v count Parameter count
* @v params Parameter list
*/
static void ansiesc_call_handler ( struct ansiesc_handler *handlers,
unsigned int function, int count,
int params[] ) {
struct ansiesc_handler *handler;
for ( handler = handlers ; handler->function ; handler++ ) {
if ( handler->function == function ) {
handler->handle ( count, params );
break;
}
}
}
/**
* Process character that may be part of ANSI escape sequence
*
* @v ctx ANSI escape sequence context
* @v c Character
* @ret c Original character if not part of escape sequence
* @ret <0 Character was part of escape sequence
*
* ANSI escape sequences will be plucked out of the character stream
* and interpreted; once complete they will be passed to the
* appropriate handler if one exists in this ANSI escape sequence
* context.
*
* In the interests of code size, we are rather liberal about the
* sequences we are prepared to accept as valid.
*/
int ansiesc_process ( struct ansiesc_context *ctx, int c ) {
if ( ctx->count == 0 ) {
if ( c == ESC ) {
/* First byte of CSI : begin escape sequence */
ctx->count = 1;
memset ( ctx->params, 0xff, sizeof ( ctx->params ) );
ctx->function = 0;
return -1;
} else {
/* Normal character */
return c;
}
} else {
if ( c == '[' ) {
/* Second byte of CSI : do nothing */
} else if ( ( c >= '0' ) && ( c <= '9' ) ) {
/* Parameter Byte : part of a parameter value */
int *param = &ctx->params[ctx->count - 1];
if ( *param < 0 )
*param = 0;
*param = ( ( *param * 10 ) + ( c - '0' ) );
} else if ( c == ';' ) {
/* Parameter Byte : parameter delimiter */
ctx->count++;
if ( ctx->count > ( sizeof ( ctx->params ) /
sizeof ( ctx->params[0] ) ) ) {
/* Excessive parameters : abort sequence */
ctx->count = 0;
DBG ( "Too many parameters in ANSI escape "
"sequence\n" );
}
} else if ( ( c >= 0x20 ) && ( c <= 0x2f ) ) {
/* Intermediate Byte */
ctx->function <<= 8;
ctx->function |= c;
} else {
/* Treat as Final Byte. Zero ctx->count before
* calling handler to avoid potential infinite loops.
*/
int count = ctx->count;
ctx->count = 0;
ctx->function <<= 8;
ctx->function |= c;
ansiesc_call_handler ( ctx->handlers, ctx->function,
count, ctx->params );
}
return -1;
}
}
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