/* $Id: plugin_sample.c,v 1.7 2004/06/26 09:27:21 reinelt Exp $ * * plugin template * * Copyright 2003 Michael Reinelt * Copyright 2004 The LCD4Linux Team * * This file is part of LCD4Linux. * * LCD4Linux 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, or (at your option) * any later version. * * LCD4Linux 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. * * * $Log: plugin_sample.c,v $ * Revision 1.7 2004/06/26 09:27:21 reinelt * * added '-W' to CFLAGS * changed all C++ comments to C ones ('//' => '/* */') * cleaned up a lot of signed/unsigned mistakes * * Revision 1.6 2004/06/01 06:04:25 reinelt * * made README.Plugins and plugin_sample up to date. * * Revision 1.5 2004/03/03 03:47:04 reinelt * big patch from Martin Hejl: * - use qprintf() where appropriate * - save CPU cycles on gettimeofday() * - add quit() functions to free allocated memory * - fixed lots of memory leaks * * Revision 1.4 2004/01/30 20:57:56 reinelt * HD44780 patch from Martin Hejl * dmalloc integrated * * Revision 1.3 2004/01/29 04:40:02 reinelt * every .c file includes "config.h" now * * Revision 1.2 2004/01/13 10:03:01 reinelt * new util 'hash' for associative arrays * new plugin 'cpuinfo' * * Revision 1.1 2004/01/06 17:33:45 reinelt * * Evaluator: functions with variable argument lists * Evaluator: plugin_sample.c and README.Plugins added * */ /* * exported functions: * * int plugin_init_sample (void) * adds various functions * */ /* define the include files you need */ #include "config.h" #include #include #include /* these should always be included */ #include "debug.h" #include "plugin.h" #ifdef WITH_DMALLOC #include #endif /* sample function 'mul2' */ /* takes one argument, a number */ /* multiplies the number by 2.0 */ /* Note: all local functions should be declared 'static' */ static void my_mul2 (RESULT *result, RESULT *arg1) { double param; double value; /* Get Parameter */ /* R2N stands for 'Result to Number' */ param = R2N(arg1); /* calculate value */ value = param*2.0; /* store result */ /* when called with R_NUMBER, it assumes the */ /* next parameter to be a pointer to double */ SetResult(&result, R_NUMBER, &value); } /* sample function 'mul3' */ /* takes one argument, a number */ /* multiplies the number by 3.0 */ /* same as 'mul2', but shorter */ static void my_mul3 (RESULT *result, RESULT *arg1) { /* do it all in one line */ double value = R2N(arg1) * 3.0; /* store result */ SetResult(&result, R_NUMBER, &value); } /* sample function 'diff' */ /* takes two arguments, both numbers */ /* returns |a-b| */ static void my_diff (RESULT *result, RESULT *arg1, RESULT *arg2) { /* do it all in one line */ double value = R2N(arg1) - R2N(arg2); /* some more calculations... */ if (value < 0) value = -value; /* store result */ SetResult(&result, R_NUMBER, &value); } /* sample function 'answer' */ /* takes no argument! */ /* returns the answer to all questions */ static void my_answer (RESULT *result) { /* we have to declare a variable because */ /* SetResult needs a pointer */ double value = 42; /* store result */ SetResult(&result, R_NUMBER, &value); } /* sample function 'length' */ /* takes one argument, a string */ /* returns the string length */ static void my_length (RESULT *result, RESULT *arg1) { /* Note #1: value *must* be double! */ /* Note #2: R2S stands for 'Result to String' */ double value = strlen(R2S(arg1)); /* store result */ SetResult(&result, R_NUMBER, &value); } /* sample function 'upcase' */ /* takes one argument, a string */ /* returns the string in upper case letters */ static void my_upcase (RESULT *result, RESULT *arg1) { char *value, *p; /* create a local copy of the argument */ /* Do *NOT* try to modify the original string! */ value = strdup(R2S(arg1)); /* process the string */ for (p = value; *p != '\0'; p++) *p = toupper(*p); /* store result */ /* when called with R_STRING, it assumes the */ /* next parameter to be a pointer to a string */ /* 'value' is already a char*, so use 'value', not '&value' */ SetResult(&result, R_STRING, value); /* free local copy again */ /* Note that SetResult() makes its own string copy */ free (value); } /* sample function 'cat' */ /* takes variable number of arguments, all strings */ /* returns all prameters concatenated */ static void my_concat (RESULT *result, int argc, RESULT *argv[]) { int i, len; char *value, *part; /* start with a empty string */ value = strdup(""); /* process all arguments */ for (i = 0; i < argc; i++) { part = R2S(argv[i]); len = strlen(value)+strlen(part); value = realloc(value, len+1); strcat(value, part); } /* store result */ SetResult(&result, R_STRING, value); /* free local string */ free (value); } /* plugin initialization */ /* MUST NOT be declared 'static'! */ int plugin_init_sample (void) { /* register all our cool functions */ /* the second parameter is the number of arguments */ /* -1 stands for variable argument list */ AddFunction ("mul2", 1, my_mul2); AddFunction ("mul3", 1, my_mul3); AddFunction ("answer", 0, my_answer); AddFunction ("diff", 2, my_diff); AddFunction ("length", 1, my_length); AddFunction ("upcase", 1, my_upcase); AddFunction ("concat", -1, my_concat); return 0; } void plugin_exit_sample(void) { /* free any allocated memory */ /* close filedescriptors */ }