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#include "EXTERN.h"
#include "perl.h"
#include "XSUB.h"
/* set by scan_fat, used by next */
short *fat = NULL;
char *fat_flag_map = NULL;
unsigned int *fat_remap = NULL;
int fat_remap_size;
int type_size, nb_clusters, bad_cluster_value;
void free_all() {
#define FREE(p) if (p) free(p), p = NULL;
FREE(fat);
FREE(fat_flag_map);
FREE(fat_remap);
#undef FREE
}
unsigned int next(unsigned int cluster) {
short *p = fat + type_size * cluster;
if (!fat) {
free_all();
croak("fat::next: trying to use null pointer");
}
if (cluster >= nb_clusters + 2) {
free_all();
croak("fat::next: cluster %d outside filesystem", cluster);
}
return type_size == 1 ? *p : *((unsigned int *) p);
}
void set_next(unsigned int cluster, unsigned int val) {
short *p = fat + type_size * cluster;
if (!fat) {
free_all();
croak("fat::set_next: trying to use null pointer");
}
if (cluster >= nb_clusters + 2) {
free_all();
croak("fat::set_next: cluster %d outside filesystem", cluster);
}
type_size == 1 ? *p : *((unsigned int *) p) = val;
}
MODULE = resize_fat::c_rewritten PACKAGE = resize_fat::c_rewritten
PROTOTYPES: DISABLE
void
read_fat(fd, offset, size, magic)
int fd
int offset
int size
unsigned char magic
PPCODE:
{
fat = (short *) malloc(size);
if (!fat) {
free_all();
croak("read_fat: not enough memory");
}
if (lseek(fd, offset, SEEK_SET) != offset ||
read(fd, fat, size) != size) {
free_all();
croak("read_fat: reading FAT failed");
}
if (magic != *(unsigned char *) fat) {
free_all();
croak("read_fat: FAT has invalid signature");
}
}
void
write_fat(fd, size)
int fd
int size
PPCODE:
{
if (write(fd, fat, size) != size) {
free_all();
croak("write_fat: write failed");
}
}
void
free_all()
PPCODE:
free_all();
void
scan_fat(nb_clusters_, type_size_)
int nb_clusters_
int type_size_
PPCODE:
{
unsigned int v;
int free = 0, bad = 0, used = 0;
short *p;
type_size = type_size_; nb_clusters = nb_clusters_;
bad_cluster_value = type_size == 32 ? 0x0ffffff7 : 0xfff7;
if (type_size % 16) {
free_all();
croak("scan_fat: unable to handle FAT%d", type_size);
}
type_size /= 16;
for (p = fat + 2 * type_size; p < fat + type_size * (nb_clusters + 2); p += type_size) {
v = type_size == 1 ? *p : *((unsigned int *) p);
if (v == 0) free++;
else if (v == bad_cluster_value) bad++;
}
used = nb_clusters - free - bad;
EXTEND(SP, 3);
PUSHs(sv_2mortal(newSViv(free)));
PUSHs(sv_2mortal(newSViv(bad)));
PUSHs(sv_2mortal(newSViv(used)));
}
unsigned int
next(unused, cluster)
void *unused
unsigned int cluster
CODE:
RETVAL = next(cluster);
OUTPUT:
RETVAL
void
set_next(unused, cluster, val)
void *unused
unsigned int cluster
unsigned int val
CODE:
set_next(cluster, val);
void
allocate_fat_flag(size)
int size
CODE:
fat_flag_map = calloc(size, 1);
if (!fat_flag_map) {
free_all();
croak("allocate_fat_flag: not enough memory");
}
int
checkFat(cluster, type, name)
unsigned int cluster
int type
char *name
CODE:
int nb = 0;
if (!fat_flag_map) {
free_all();
croak("Bad FAT: trying to use null pointer");
}
for (; cluster < bad_cluster_value; cluster = next(cluster)) {
if (cluster == 0) {
free_all();
croak("Bad FAT: unterminated chain for %s\n", name);
}
if (cluster >= nb_clusters + 2) {
free_all();
croak("Bad FAT: chain outside filesystem for %s\n", name);
}
if (fat_flag_map[cluster]) {
free_all();
croak("Bad FAT: cluster %d is cross-linked for %s\n", cluster, name);
}
fat_flag_map[cluster] = type;
nb++;
}
RETVAL = nb;
OUTPUT:
RETVAL
unsigned int
flag(cluster)
unsigned int cluster
CODE:
if (!fat_flag_map) {
free_all();
croak("Bad FAT: trying to use null pointer");
}
if (cluster >= nb_clusters + 2) {
free_all();
croak("Bad FAT: going outside filesystem");
}
RETVAL = fat_flag_map[cluster];
OUTPUT:
RETVAL
void
set_flag(cluster, flag)
unsigned int cluster
int flag
CODE:
if (!fat_flag_map) {
free_all();
croak("Bad FAT: trying to use null pointer");
}
if (cluster >= nb_clusters + 2) {
free_all();
croak("Bad FAT: going outside filesystem");
}
fat_flag_map[cluster] = flag;
void
allocate_fat_remap(size)
int size
CODE:
fat_remap_size = size;
fat_remap = (unsigned int *) calloc(size, sizeof(unsigned int *));
if (!fat_remap) {
free_all();
croak("allocate_fat_remap: not enough memory");
}
unsigned int
fat_remap(cluster)
unsigned int cluster
CODE:
if (!fat_remap) {
free_all();
croak("fat_remap: trying to use null pointer");
}
if (cluster >= bad_cluster_value) {
RETVAL = cluster; /* special cases */
} else {
if (cluster >= fat_remap_size) {
free_all();
croak("fat_remap: cluster %d >= %d in fat_remap", cluster, fat_remap_size);
}
RETVAL = fat_remap[cluster];
}
OUTPUT:
RETVAL
void
set_fat_remap(cluster, val)
unsigned int cluster
unsigned int val
CODE:
if (!fat_remap) {
free_all();
croak("set_fat_remap: trying to use null pointer");
}
if (cluster >= fat_remap_size) {
free_all();
croak("set_fat_remap: cluster %d >= %d in set_fat_remap", cluster, fat_remap_size);
}
if (val < bad_cluster_value && val >= fat_remap_size) {
free_all();
croak("set_fat_remap: remapping cluster %d to cluster %d >= %d in set_fat_remap", cluster, val, fat_remap_size);
}
fat_remap[cluster] = val;
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