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#include "file.h"
#include "block_walker.h"
#include <assert.h>
#include <string.h>
#include <unistd.h>
#include <stdlib.h>
#include "defs.h"
uint16_t file_create(const char *disk_mem, mode_t mode)
{
uint16_t ipos = 0;
file *f = NULL;
bwalker *bw = NULL;
assert (disk_mem != NULL);
bw = bwalker_create (disk_mem, 0, 0);
ipos = inode_allocate_block(disk_mem);
f = (file *) disk_mem + INODEPOOL_OFFSET + (ipos * INODE_SIZE);
f->uid = getuid();
f->gid = getgid();
f->mode = mode;
f->size = 0;
f->type = I_FILE;
f->nlinks = 1;
f->ctime = NEW_TIME;
f->mtime = NEW_TIME;
f->atime = NEW_TIME;
bwalker_destroy (bw);
return (ipos);
}
size_t file_read (const char *disk_mem, file *f, char *buf,
size_t size, off_t offset)
{
size_t result = 0;
size_t len = 0;
bwalker *bw = NULL;
uint16_t *block;
uint16_t bnum;
assert (f != NULL);
assert (buf != NULL);
bw = bwalker_create (disk_mem, f->size, &(f->indirect));
while (size > 0 && (bnum = bwalker_next(bw)))
{
block = (uint16_t *) disk_mem + BLOCKPOOL_OFFSET + (bnum*BLOCK_SIZE);
if (offset >= BLOCK_SIZE){
/* Nos movemos (no escribimos) */
offset -= BLOCK_SIZE;
continue;
}
assert(offset < BLOCK_SIZE);
block += offset;
len = MIN(size,(BLOCK_SIZE - offset));
memcpy(buf, block, len);
result += len;
buf += len;
size -= len;
offset = 0;
if(bwalker_block_is_last(bw)){
break;
}
}
bwalker_destroy (bw);
return (result);
}
int file_truncate (const char *disk_mem, file *f, off_t size)
{
bwalker *walker;
uint16_t offset, i, fb_size, block=0;
assert(disk_mem != NULL);
assert(f != NULL);
walker=bwalker_create(disk_mem, f->size, &(f->indirect));
/*el tamaño en bytes de la cantidad de bloques que ocupa el file
* siempre es >= file_size*/
fb_size=(bwalker_direct_length(walker)*BLOCK_SIZE);
if(f->size < size){
/*si el pedacito que jode...*/
offset=size-f->size;
/*es menor que 512, y ademas el nuevo tamaño no pasa al fb_size
* no es neceasrio alocar bloques, solo se cambia el tamaño*/
if(offset<BLOCK_SIZE&&size<=fb_size){
f->size=size;
bwalker_destroy(walker);
return 0;
}
for(i=0; i<(DIV_CEIL(offset, BLOCK_SIZE)); i++){
/*aloca lo que necesita*/
block=bwalker_allocate_block(walker);
}
/*change size*/
f->size=size;
}else{
/*idem, pero al verez*/
offset=f->size-size;
f->size=size;
if(offset<BLOCK_SIZE&&size>=fb_size){
f->size=size;
bwalker_destroy(walker);
return 0;
}
for(i=0; i<(DIV_CEIL(offset, BLOCK_SIZE)); i++){
bwalker_free_block(walker);
}
f->size=size;
}
bwalker_destroy(walker);
return 0;
}
size_t file_write (const char *disk_mem, file *f, char *buf,
size_t size, off_t offset)
{
size_t result = 0;
size_t len = BLOCK_SIZE;
bwalker *bw = NULL;
uint16_t *block = NULL;
uint16_t bnum = 0;
time_t new_time = NEW_TIME;
assert (disk_mem != NULL);
assert (f != NULL);
bw = bwalker_create (disk_mem, f->size, &(f->indirect));
while (size > 0 && (bnum = bwalker_next(bw)))
{
assert(bnum != f->indirect);
if (offset >= BLOCK_SIZE){
/* Nos movemos (no escribimos) */
offset -= BLOCK_SIZE;
continue;
}
block = (uint16_t *) disk_mem + BLOCKPOOL_OFFSET + (bnum*BLOCK_SIZE);
assert(offset < BLOCK_SIZE);
block += offset;
len = MIN(size,(BLOCK_SIZE - offset));
memcpy(block, buf, len);
result += len;
buf += len;
size -= len;
offset = 0;
if(bwalker_direct_length(bw)<=1){
break;
}
}
f->atime = new_time;
f->mtime = new_time;
bwalker_destroy (bw);
return (result);
}
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