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vvfat: correctly generate numeric-tail of short file names

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More specifically:
- try without numeric-tail only if LFN didn't have invalid short chars
- start at ~1 (instead of ~0)
- handle case if numeric tail is more than one char (ie > 10)

Windows 9x Scandisk doesn't see anymore mismatches between short file names and
long file names for non-ASCII filenames.

Specification: "FAT: General overview of on-disk format" v1.03, page 31
Signed-off-by: Hervé Poussineau <hpoussin@reactos.org>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Hervé Poussineau 2017-05-22 23:12:02 +02:00 committed by Kevin Wolf
parent 0c36111f57
commit 339cebcc01
1 changed files with 31 additions and 34 deletions
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65
block/vvfat.c
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@ -528,13 +528,15 @@ static uint8_t to_valid_short_char(gunichar c)
}
static direntry_t *create_short_filename(BDRVVVFATState *s,
const char *filename)
const char *filename,
unsigned int directory_start)
{
int j = 0;
int i, j = 0;
direntry_t *entry = array_get_next(&(s->directory));
const gchar *p, *last_dot = NULL;
gunichar c;
bool lossy_conversion = false;
char tail[11];
if (!entry) {
return NULL;
@ -585,8 +587,32 @@ static direntry_t *create_short_filename(BDRVVVFATState *s,
}
}
}
(void)lossy_conversion;
return entry;
/* numeric-tail generation */
for (j = 0; j < 8; j++) {
if (entry->name[j] == ' ') {
break;
}
}
for (i = lossy_conversion ? 1 : 0; i < 999999; i++) {
direntry_t *entry1;
if (i > 0) {
int len = sprintf(tail, "~%d", i);
memcpy(entry->name + MIN(j, 8 - len), tail, len);
}
for (entry1 = array_get(&(s->directory), directory_start);
entry1 < entry; entry1++) {
if (!is_long_name(entry1) &&
!memcmp(entry1->name, entry->name, 11)) {
break; /* found dupe */
}
}
if (entry1 == entry) {
/* no dupe found */
return entry;
}
}
return NULL;
}
/* fat functions */
@ -699,36 +725,7 @@ static inline direntry_t* create_short_and_long_name(BDRVVVFATState* s,
}
entry_long=create_long_filename(s,filename);
entry = create_short_filename(s, filename);
/* mangle duplicates */
while(1) {
direntry_t* entry1=array_get(&(s->directory),directory_start);
int j;
for(;entry1<entry;entry1++)
if(!is_long_name(entry1) && !memcmp(entry1->name,entry->name,11))
break; /* found dupe */
if(entry1==entry) /* no dupe found */
break;
/* use all 8 characters of name */
if(entry->name[7]==' ') {
int j;
for(j=6;j>0 && entry->name[j]==' ';j--)
entry->name[j]='~';
}
/* increment number */
for(j=7;j>0 && entry->name[j]=='9';j--)
entry->name[j]='0';
if(j>0) {
if(entry->name[j]<'0' || entry->name[j]>'9')
entry->name[j]='0';
else
entry->name[j]++;
}
}
entry = create_short_filename(s, filename, directory_start);
/* calculate checksum; propagate to long name */
if(entry_long) {