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Diffstat (limited to 'timer_group.c')
| -rw-r--r-- | timer_group.c | 557 |
1 files changed, 557 insertions, 0 deletions
diff --git a/timer_group.c b/timer_group.c new file mode 100644 index 0000000..f6d7a5a --- /dev/null +++ b/timer_group.c @@ -0,0 +1,557 @@ +/* $Id: timer_group.c 1136 2010-11-28 16:07:16Z mzuther $ + * $URL: https://ssl.bulix.org/svn/lcd4linux/trunk/timer_group.c $ + * + * Generic grouping of widgets that have been set to the same update + * interval, thus allowing synchronized updates. + * + * Copyright (C) 2010 Martin Zuther <code@mzuther.de> + * Copyright (C) 2010 The LCD4Linux Team <lcd4linux-devel@users.sourceforge.net> + * + * Based on "timer.c" which is + * Copyright (C) 2003, 2004 Michael Reinelt <michael@reinelt.co.at> + * Copyright (C) 2004 The LCD4Linux Team <lcd4linux-devel@users.sourceforge.net> + * + * 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, or (at your option) + * 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. + * + */ + +/* + * Exported functions: + * + * void timer_process_group(void *data) + * + * Process all widgets of a timer group; if the timer group only + * contains one-shot timers, it will be deleted after processing. + * + * + * void timer_exit_group(void) + * + * Release all timer groups and widgets and free the associated + * memory blocks. + * + * + * int timer_add_widget(void (*callback) (void *data), void *data, + * const int interval, const int one_shot) + * + * Add widget to timer group of the specified update interval + * (also creates a new timer group if necessary). + * + * + * int timer_remove_widget(void (*callback) (void *data), void *data) + * + * Remove widget from the timer group with the specified update + * interval (also removes corresponding timer group if empty). + * + */ + + +#include "config.h" + +#include <stdlib.h> +#include <stdio.h> +#include <string.h> + +#include "debug.h" +#include "cfg.h" +#include "timer.h" +#include "timer_group.h" + +#ifdef WITH_DMALLOC +#include <dmalloc.h> +#endif + + +/* structure for storing all relevant data of a single timer group */ +typedef struct TIMER_GROUP { + /* pointer to the group's triggering interval in milliseconds; + this will be used to identify a specific timer group and also + as callback data for the underlying generic timer */ + int *interval; + + /* marks timer group as being active (so it will get processed) or + inactive (which means the timer group has been deleted and its + allocated memory may be re-used) */ + int active; +} TIMER_GROUP; + +/* number of allocated timer group slots */ +int nTimerGroups = 0; + +/* pointer to memory allocated for storing the timer group slots */ +TIMER_GROUP *TimerGroups = NULL; + + +/* structure for storing all relevant timer data of a single widget */ +typedef struct TIMER_GROUP_WIDGET { + /* pointer to function of type void func(void *data) that will be + called when the timer is processed; it will also be used to + identify a specific widget */ + void (*callback) (void *data); + + /* pointer to data which will be passed to the callback function; + it will also be used to identify a specific widget */ + void *data; + + /* specifies the timer's triggering interval in milliseconds; it + will also be used to identify a specific widget */ + int interval; + + /* specifies whether the timer should trigger indefinitely until + it is deleted (value of 0) or only once (all other values) */ + int one_shot; + + /* marks timer as being active (so it will get processed) or + inactive (which means the timer has been deleted and its + allocated memory may be re-used) */ + int active; +} TIMER_GROUP_WIDGET; + +/* number of allocated widget slots */ +int nTimerGroupWidgets = 0; + +/* pointer to memory allocated for storing the widget slots */ +TIMER_GROUP_WIDGET *TimerGroupWidgets = NULL; + + +int timer_group_exists(const int interval) +/* Check whether a timer group for the specified interval exists. + + interval (integer): the sought-after triggering interval in + milliseconds + + return value (integer): returns a value of 1 if timer group + exists; otherwise returns a value of 0 +*/ +{ + int group; /* current timer group's ID */ + + /* loop through the timer group slots to search for one that + matches the specified interval */ + for (group = 0; group < nTimerGroups; group++) { + /* skip inactive (i.e. deleted) timer groups */ + if (TimerGroups[group].active == 0) + continue; + + if (*TimerGroups[group].interval == interval) { + /* matching timer group found, so signal success by returning + a value of 1 */ + return 1; + } + } + + /* matching timer group not found, so signal failure by returning + a value of 0 */ + return 0; +} + + +int timer_add_group(const int interval) +/* Create a new timer group (unless it already exists) and link it to + the timer queue. + + interval (integer): the new timer group's triggering interval in + milliseconds + + return value (integer): returns a value of 0 on successful timer + group creation; otherwise returns a value of -1 +*/ +{ + /* if timer group for update interval already exists, signal + success by returning a value of 0 */ + if (timer_group_exists(interval)) + return 0; + + /* display an info message to inform the user that a new timer + group is being created */ + info("Creating new timer group (%d ms)", interval); + + int group; /* current timer group's ID */ + + /* try to minimize memory usage by looping through timer group + slots and looking for an inactive timer group */ + for (group = 0; group < nTimerGroups; group++) { + if (TimerGroups[group].active == 0) { + /* we've just found one, so let's reuse it ("group" holds its + ID) by breaking the loop */ + break; + } + } + + /* no inactive timer groups (or none at all) found, so we have to + add a new timer group slot */ + if (group >= nTimerGroups) { + /* increment number of timer groups and (re-)allocate memory used + for storing the timer group slots */ + nTimerGroups++; + TimerGroups = realloc(TimerGroups, nTimerGroups * sizeof(*TimerGroups)); + + /* make sure "group" points to valid memory */ + group = nTimerGroups - 1; + + /* realloc() has failed */ + if (TimerGroups == NULL) { + /* restore old number of timer groups */ + nTimerGroups--; + + /* signal unsuccessful timer group creation */ + return -1; + } + + /* allocate memory for the underlying generic timer's callback + data (i.e. the group's triggering interval in milliseconds) */ + TimerGroups[group].interval = malloc(sizeof(int)); + + /* malloc() has failed */ + if (TimerGroups[group].interval == NULL) { + /* signal unsuccessful timer group creation */ + return -1; + } + } + + /* initialize timer group's interval */ + *TimerGroups[group].interval = interval; + + /* set timer group to active so that it is processed and not + overwritten by the memory optimization routine above */ + TimerGroups[group].active = 1; + + /* finally, request a generic timer that calls this group and + signal success or failure */ + return timer_add(timer_process_group, TimerGroups[group].interval, interval, 0); +} + + +int timer_remove_group(const int interval) +/* Remove a timer group and unlink it from the timer queue (also + removes all remaining widget slots in this timer group). + + interval (integer): triggering interval in milliseconds; here, it + will be used to identify the timer group + + return value (integer): returns a value of 0 on successful timer + group removal; otherwise returns a value of -1 +*/ +{ + /* display an info message to inform the user that a timer group + is being removed */ + info("Removing timer group (%d ms)", interval); + + int group; /* current timer group's ID */ + int widget; /* current widget's ID */ + + /* loop through the widget slots to look for remaining widgets + with the specified update interval */ + for (widget = 0; widget < nTimerGroupWidgets; widget++) { + /* skip inactive (i.e. deleted) widget slots */ + if (TimerGroupWidgets[widget].active == 0) + continue; + + if (TimerGroupWidgets[widget].interval == interval) { + /* we have found a matching widget slot, so mark it as being + inactive; we will not actually delete the slot, so its + allocated memory may be re-used */ + TimerGroupWidgets[widget].active = 0; + } + } + + /* loop through timer group slots and try to find the specified + timer group slot by looking for its settings */ + for (group = 0; group < nTimerGroups; group++) { + /* skip inactive (i.e. deleted) timer groups */ + if (TimerGroups[group].active == 0) + continue; + + if (*TimerGroups[group].interval == interval) { + /* we have found the timer group slot, so mark it as being + inactive; we will not actually delete the slot, so its + allocated memory may be re-used */ + TimerGroups[group].active = 0; + + /* remove the generic timer that calls this group */ + if (timer_remove(timer_process_group, TimerGroups[group].interval)) { + /* signal successful removal of timer group */ + return 0; + } else { + /* an error occurred on generic timer removal, so signal + failure by returning a value of -1 */ + return -1; + } + } + } + + /* we have NOT found the timer group slot, so signal failure by + returning a value of -1 */ + return -1; +} + + +int timer_remove_empty_group(const int interval) +/* Remove timer group *only* if it contains no more widget slots. + + interval (integer): triggering interval in milliseconds; here, it + will be used to identify the timer group + + return value (integer): returns a value of 0 on successful + processing; otherwise returns a value of -1 +*/ +{ + int widget; /* current widget's ID */ + + /* loop through the widget slots to look for widgets with the + specified update interval */ + for (widget = 0; widget < nTimerGroupWidgets; widget++) { + /* skip inactive (i.e. deleted) widget slots */ + if (TimerGroupWidgets[widget].active == 0) + continue; + + /* at least one other widget with specified update interval + exists, so signal success by returning a value of 0 */ + if (TimerGroupWidgets[widget].interval == interval) + return 0; + } + + /* no other widgets with specified update interval exist, so + remove corresponding timer group and signal success or + failure */ + return timer_remove_group(interval); +} + + +void timer_process_group(void *data) +/* Process all widgets of a timer group; if the timer group only + contains one-shot timers, it will be deleted after processing. + + data (void pointer): points to an integer holding the triggering + interval in milliseconds; here, it will be used to identify the + timer group + + return value: void +*/ +{ + int widget; /* current widget's ID */ + + /* convert callback data to integer (triggering interval in + milliseconds) */ + int interval = *((int *) data); + + /* sanity check; by now, at least one timer group should be + instantiated */ + if (nTimerGroups <= 0) { + /* otherwise, print an error and return early */ + error("Huh? Not even a single timer group to process? Dazed and confused..."); + return; + } + + /* sanity check; by now, at least one widget slot should be + instantiated */ + if (nTimerGroupWidgets <= 0) { + /* otherwise, print an error and return early */ + error("Huh? Not even a single widget slot to process? Dazed and confused..."); + return; + } + + /* loop through widgets and search for those matching the timer + group's update interval */ + for (widget = 0; widget < nTimerGroupWidgets; widget++) { + /* skip inactive (i.e. deleted) widgets */ + if (TimerGroupWidgets[widget].active == 0) + continue; + + /* the current widget belongs to the specified timer group */ + if (TimerGroupWidgets[widget].interval == interval) { + /* if the widget's callback function has been set, call it and + pass the corresponding data */ + if (TimerGroupWidgets[widget].callback != NULL) + TimerGroupWidgets[widget].callback(TimerGroupWidgets[widget].data); + + /* mark one-shot widget as inactive (which means the it has + been deleted and its allocated memory may be re-used) */ + if (TimerGroupWidgets[widget].one_shot) { + TimerGroupWidgets[widget].active = 0; + + /* also remove the corresponding timer group if it is empty */ + timer_remove_empty_group(interval); + } + } + } +} + + +int timer_add_widget(void (*callback) (void *data), void *data, const int interval, const int one_shot) +/* Add widget to timer group of the specified update interval + (also creates a new timer group if necessary). + + callback (void pointer): function of type void func(void *data) + which will be called whenever the timer group triggers; this + pointer will also be used to identify a specific widget + + data (void pointer): data which will be passed to the callback + function; this pointer will also be used to identify a specific + widget + + interval (integer): specifies the timer's triggering interval in + milliseconds + + one_shot (integer): specifies whether the timer should trigger + indefinitely until it is deleted (value of 0) or only once (all + other values) + + return value (integer): returns a value of 0 on successful widget + addition; otherwise returns a value of -1 +*/ +{ + int widget; /* current widget's ID */ + + /* if no timer group for update interval exists, create one */ + if (!timer_group_exists(interval)) { + /* creation of new timer group failed, so signal failure by + returning a value of -1 */ + if (timer_add_group(interval) != 0) + return -1; + } + + /* try to minimize memory usage by looping through the widget + slots and looking for an inactive widget slot */ + for (widget = 0; widget < nTimerGroupWidgets; widget++) { + if (TimerGroupWidgets[widget].active == 0) { + /* we've just found one, so let's reuse it ("widget" holds its + ID) by breaking the loop */ + break; + } + } + + /* no inactive widget slots (or none at all) found, so we have to + add a new widget slot */ + if (widget >= nTimerGroupWidgets) { + /* increment number of widget slots and (re-)allocate memory used + for storing the widget slots */ + nTimerGroupWidgets++; + TimerGroupWidgets = realloc(TimerGroupWidgets, nTimerGroupWidgets * sizeof(*TimerGroupWidgets)); + + /* make sure "widget" points to valid memory */ + widget = nTimerGroupWidgets - 1; + + /* realloc() has failed */ + if (TimerGroupWidgets == NULL) { + /* restore old number of widget slots */ + nTimerGroupWidgets--; + + /* signal unsuccessful creation of widget slot */ + return -1; + } + } + + /* initialize widget slot */ + TimerGroupWidgets[widget].callback = callback; + TimerGroupWidgets[widget].data = data; + TimerGroupWidgets[widget].interval = interval; + TimerGroupWidgets[widget].one_shot = one_shot; + + /* set widget slot to active so that it is processed and not + overwritten by the memory optimization routine above */ + TimerGroupWidgets[widget].active = 1; + + /* signal successful addition of widget slot */ + return 0; +} + + +int timer_remove_widget(void (*callback) (void *data), void *data) +/* Remove widget from the timer group with the specified update + interval (also removes corresponding timer group if empty). + + callback (void pointer): function of type void func(void *data); + here, it will be used to identify a specific widget + + data (void pointer): data which will be passed to the callback + function; here, it will be used to identify a specific widget + + return value (integer): returns a value of 0 on successful widget + removal; otherwise returns a value of -1 +*/ +{ + int widget; /* current widget's ID */ + int interval = -1; /* specified widget's triggering interval in + milliseconds */ + + /* loop through the widget slots and try to find the specified + widget slot by looking for its settings */ + for (widget = 0; widget < nTimerGroupWidgets; widget++) { + /* skip inactive (i.e. deleted) widget slots */ + if (TimerGroupWidgets[widget].active == 0) + continue; + + if (TimerGroupWidgets[widget].callback == callback && TimerGroupWidgets[widget].data == data) { + /* we have found the widget slot, so mark it as being + inactive; we will not actually delete the slot, so its + allocated memory may be re-used */ + TimerGroupWidgets[widget].active = 0; + + /* store the widget's triggering interval for later use and + break the loop */ + interval = TimerGroupWidgets[widget].interval; + break; + } + } + + /* if no matching widget was found, signal an error by returning + a value of -1 */ + if (interval < 0) + return -1; + + /* if no other widgets with specified update interval exist, + remove corresponding timer group and signal success or + failure */ + return timer_remove_empty_group(interval); +} + + +void timer_exit_group(void) +/* Release all timer groups and widgets and free the associated + memory blocks. + + return value: void +*/ +{ + int group; /* current timer group's ID */ + + /* loop through all timer groups and remove them one by one */ + for (group = 0; group < nTimerGroups; group++) { + /* remove generic timer */ + timer_remove(timer_process_group, TimerGroups[group].interval); + + /* free memory allocated for callback data (i.e. the group's + triggering interval in milliseconds) */ + free(TimerGroups[group].interval); + } + + /* reset number of allocated timer groups */ + nTimerGroups = 0; + + /* free allocated memory containing the timer group slots */ + if (TimerGroups != NULL) { + free(TimerGroups); + TimerGroups = NULL; + } + + /* reset number of allocated widget slots */ + nTimerGroupWidgets = 0; + + /* free allocated memory containing the widget slots */ + if (TimerGroupWidgets != NULL) { + free(TimerGroupWidgets); + TimerGroupWidgets = NULL; + } +} |