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#include <string.h>
#include "filesys/file.h"
#include "threads/thread.h"
#include "threads/vaddr.h"
#include "threads/malloc.h"
#include "threads/palloc.h"
#include "vm/mmap.h"
#include "vm/page.h"
static struct mmap_table_entry *mmap_table_get (struct mmap_table *table,
mapid_t mapid);
/* initialize memory mapped files table */
bool
mmap_table_init (struct mmap_table *table)
{
table->ids = palloc_get_page (PAL_ZERO);
if (table->ids == NULL)
return false;
table->id_cap = PGSIZE / sizeof (table->ids[0]);
table->id_free = 0;
table->id_max = -1;
return true;
}
/* frees the content of mmap table */
void
mmap_table_free (struct mmap_table *table)
{
//TODO
palloc_free_page (table->ids);
}
/* inserts a new mmap entry in the mmap table
returns -1 if entry is invalid or already in the table */
mapid_t
mmap_table_insert (struct mmap_table *table, void *addr, struct file *file,
off_t len)
{
off_t ofs = 0;
size_t page_read_bytes;
struct mmap_table_entry *mme;
mapid_t mapid;
/* no more entries left */
if (table->id_free >= table->id_cap)
return -1;
mme = malloc (sizeof *mme);
if (mme == NULL)
return -1;
mapid = table->id_free++;
mme->addr = addr;
mme->file = file;
table->ids[mapid] = mme;
/* create needed pages in page table */
while (len > 0)
{
page_read_bytes = (len < PGSIZE) ? len : PGSIZE;
if (!page_table_insert_segment (&thread_current ()->page_table, file, ofs,
addr, page_read_bytes, true))
return -1;
/* Advance. */
len -= PGSIZE;
ofs += page_read_bytes;
addr += PGSIZE;
}
/* update index of free/max mapid index */
if (mapid > table->id_max)
table->id_max = mapid;
while (table->ids[table->id_free] != NULL)
{
table->id_free++;
if (table->id_free >= table->id_cap)
break;
}
return mapid;
}
static struct mmap_table_entry *
mmap_table_get (struct mmap_table *table, mapid_t mapid)
{
if (mapid < 0 || mapid >= table->id_cap || !table->ids[mapid])
return NULL;
return table->ids[mapid];
}
bool
mmap_table_remove (struct mmap_table *table, mapid_t mapid)
{
struct mmap_table_entry *mme = mmap_table_get(table, mapid);
if (mme == NULL)
return false;
table->ids[mapid] = NULL;
//TODO
/* update index of free/max file descriptor index */
if (mapid < table->id_free)
table->id_free = mapid;
while (table->ids[table->id_max] == NULL)
{
table->id_max--;
if (table->id_max < 0)
break;
}
return true;
}
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