/*
** Dining Philosophers Problem's scheduler
**    with state developper as a tableau method

** 連絡先： 琉球大学情報工学科 河野 真治
** （E-Mail Address: kono@ie.u-ryukyu.ac.jp）
**
**    このソースのいかなる複写，改変，修正も許諾します。ただし、
**    その際には、誰が貢献したを示すこの部分を残すこと。
**    再配布や雑誌の付録などの問い合わせも必要ありません。
**    営利利用も上記に反しない範囲で許可します。
**    バイナリの配布の際にはversion messageを保存することを条件とします。
**    このプログラムについては特に何の保証もしない、悪しからず。
**
**    Everyone is permitted to do anything on this program
**    including copying, modifying, improving,
**    as long as you don't try to pretend that you wrote it.
**    i.e., the above copyright notice has to appear in all copies.
**    Binary distribution requires original version messages.
**    You don't have to ask before copying, redistribution or publishing.
**    THE AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE.

*/
#include <stdlib.h>
#include <time.h>
#include "dpp2.h"
#include "queue.h"
#include "memory.h"
#include "state_db.h"

int NUM_PHILOSOPHER = 5;    /* A number of philosophers must be more than 2. */

static __code (*ret)(int);
static void *env;

static PhilsPtr phils_list = NULL;

static int max_step = 100;

static StateDB state_db;
static MemoryPtr mem;
static StateNode st;

int
list_length(TaskPtr list)
{
    int length;
    TaskPtr t;

    if (!list) return 0;
    t = list->next;

    for (length = 1; t && t != list; length++) {
	t = t->next;
    }
    return length;
}

TaskPtr
get_task(int num, TaskPtr list)
{
    while (num-- > 0) {
	list = list->next;
    }
    return list;
}


static TaskIteratorPtr task_iter;
static int depth,count;

/*
    Performe depth frist search
    Possible task iterleave is generated by TaskIterator
        (using task ring)
    State are recorded in StateDB
	all memory fragments are regsitered by add_memory_range()
	including task queue
 */


__code tableau(TaskPtr list)
{
    StateDB out;

    st.hash = get_memory_hash(mem,0);
    if (lookup_StateDB(&st, &state_db, &out)) {
	// found in the state database
	//printf("found %d\n",count);
	while(!(list = next_task_iterator(task_iter))) {
	    // no more branch, go back to the previous one
	    TaskIteratorPtr prev_iter = task_iter->prev;
	    if (!prev_iter) {
		printf("All done count %d\n",count);
		memory_usage();
		goto ret(0);
	    }
	    //printf("no more branch %d\n",count);
	    depth--;
	    free_task_iterator(task_iter);
	    task_iter = prev_iter;
	}
	// return to previous state
	//    here we assume task list is fixed, we don't have to
	//    recover task list itself
	restore_memory(task_iter->state->memory);
	//printf("restore list %x next %x\n",(int)list,(int)(list->next));
    } else {
	// one step further
	depth++;
	task_iter = create_task_iterator(list,out,task_iter);
    }
    //printf("depth %d count %d\n", depth, count++);
    count++;
    goto list->phils->next(list->phils,list);
}

__code get_next_task_fifo(TaskPtr list)
{
    TaskPtr t = list;
    TaskPtr e;

    if (max_step--<0) goto die("Simuration end.");

    list = list->next;
    goto list->phils->next(list->phils,list);
}

__code scheduler(PhilsPtr phils, TaskPtr list)
{
    goto tableau(list);
    // goto next_next_task_fifo(list);
}

__code task_entry1(int count, PhilsPtr self, TaskPtr list, TaskPtr last);

__code task_entry2(int count,PhilsPtr self, TaskPtr list,TaskPtr last, TaskPtr q)
{
    if (!q) {
	goto die("Can't allocate Task\n");
    } else {
	add_memory_range(q,sizeof(Task),&mem);
	goto enqueue(count, self, list, last, q, task_entry1);
    }
}

__code task_entry1(int count, PhilsPtr self, TaskPtr list, TaskPtr last)
{
    StateDB out;
    /*
    printf("int count %d, PhilsPtr self %x, TaskPtr list %x, TaskPtr last %x\n",
	count, self, list, last);
    */

    if (count++ < NUM_PHILOSOPHER) {
	self = self->left;
	goto create_queue(count,self,list,last,task_entry2);
    } else {
	// make circular task list
	last->next = list;
	st.memory = mem;
	st.hash = get_memory_hash(mem,0);
	lookup_StateDB(&st, &state_db, &out);
	task_iter = create_task_iterator(list,out,0);
	// start first task
	goto list->phils->next(list->phils,list);
    }
}

__code task_entry0(int count, PhilsPtr self, TaskPtr list, TaskPtr last, TaskPtr q)
{
    add_memory_range(q,sizeof(Task),&mem);
    goto task_entry1(count, self, q, q);
}

__code init_final(PhilsPtr self)
{
    self->right = phils_list;
    self->right_fork = phils_list->left_fork;
    //printf("init all\n");

    goto create_queue(1, self, 0, 0, task_entry0);
}

__code init_phils2(PhilsPtr self, int count, int id)
{
    PhilsPtr tmp_self;

    tmp_self = (PhilsPtr)malloc(sizeof(Phils));
    if (!tmp_self) {
	goto die("Can't allocate Phils\n");
    }
    self->right = tmp_self;
    tmp_self->id = id;
    tmp_self->right_fork = NULL;
    tmp_self->left_fork = self->right_fork;
    tmp_self->right = NULL;
    tmp_self->left = self;
    tmp_self->next = thinking;
    add_memory_range(tmp_self,sizeof(Phils),&mem);

    count--;
    id++;

    if (count == 0) {
	goto init_final(tmp_self);
    } else {
	goto init_fork2(tmp_self, count, id);
    }
}

__code init_fork2(PhilsPtr self, int count, int id)
{
    ForkPtr tmp_fork;

    tmp_fork = (ForkPtr)malloc(sizeof(Fork));
    if (!tmp_fork) {
	goto die("Can't allocate Fork\n");
    }
    tmp_fork->id = id;
    tmp_fork->owner = NULL;
    self->right_fork = tmp_fork;
    add_memory_range(tmp_fork,sizeof(Fork),&mem);

    goto init_phils2(self, count, id);
}

__code init_phils1(ForkPtr fork, int count, int id)
{
    PhilsPtr self;

    self = (PhilsPtr)malloc(sizeof(Phils));
    if (!self) {
	goto die("Can't allocate Phils\n");
    }
    phils_list = self;
    self->id = id;
    self->right_fork = NULL;
    self->left_fork = fork;
    self->right = NULL;
    self->left = NULL;
    self->next = thinking;
    add_memory_range(self,sizeof(Phils),&mem);

    count--;
    id++;

    goto init_fork2(self, count, id);
}

__code init_fork1(int count)
{
    ForkPtr fork;
    int id = 1;

    fork = (ForkPtr)malloc(sizeof(Fork));
    if (!fork) {
	goto die("Can't allocate Fork\n");
    }
    fork->id = id;
    fork->owner = NULL;
    add_memory_range(fork,sizeof(Fork),&mem);

    goto init_phils1(fork, count, id);
}

__code die(char *err)
{
    printf("%s\n", err);
    goto ret(1);
}

int main(int ac, char *av[])
{
    ret = __return;
    env = __environment;
    // srand((unsigned)time(NULL));
    // srandom((unsigned long)time(NULL));
    srandom(555);

    if (ac==2) {
	NUM_PHILOSOPHER = atoi(av[1]);
	if (NUM_PHILOSOPHER >10 ||NUM_PHILOSOPHER < 2) {
	    printf("illegal number of philosopher = %d\n", NUM_PHILOSOPHER );
	    return 1;
	}
	printf("number of philosopher = %d\n", NUM_PHILOSOPHER );
    }

    goto init_fork1(NUM_PHILOSOPHER);
}

/* end */