1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
|
#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);
}
if (type_size == 1)
*p = val;
else
*((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;
|
