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cdrom_id: unroll and simplify data check loop 

also removes this warning:

src/udev/cdrom_id/cdrom_id.c: In function ‘cd_media_info.isra.13’:
src/udev/cdrom_id/cdrom_id.c:612:12: warning: assuming signed overflow
does not occur when assuming that (X + c) >= X is always true
[-Wstrict-overflow]
 static int cd_media_info(struct udev *udev, int fd)
            ^
This commit is contained in:
Harald Hoyer 2015-03-27 13:47:32 +01:00
parent a7f7d1bde4
commit cb80d06c74
1 changed files with 14 additions and 13 deletions
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27
src/udev/cdrom_id/cdrom_id.c
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@ -650,8 +650,8 @@ static int cd_media_info(struct udev *udev, int fd)
* write protected; we need to check the contents if it is blank */
if ((cd_media_dvd_rw_ro || cd_media_dvd_plus_rw || cd_media_dvd_plus_rw_dl || cd_media_dvd_ram) && (header[2] & 3) > 1) {
unsigned char buffer[32 * 2048];
unsigned char result, len;
int block, offset;
unsigned char len;
int offset;
if (cd_media_dvd_ram) {
/* a write protected dvd-ram may report "complete" status */
@ -732,22 +732,23 @@ static int cd_media_info(struct udev *udev, int fd)
/* if any non-zero data is found in sector 16 (iso and udf) or
* eventually 0 (fat32 boot sector, ext2 superblock, etc), disc
* is assumed non-blank */
result = 0;
for (block = 32768; block >= 0 && !result; block -= 32768) {
offset = block;
while (offset < (block + 2048) && !result) {
result = buffer [offset];
offset++;
for (offset = 32768; offset < (32768 + 2048); offset++) {
if (buffer [offset]) {
log_debug("data in block 16, assuming complete");
goto determined;
}
}
if (!result) {
cd_media_state = media_status[0];
log_debug("no data in blocks 0 or 16, assuming blank");
} else {
log_debug("data in blocks 0 or 16, assuming complete");
for (offset = 0; offset < 2048; offset++) {
if (buffer [offset]) {
log_debug("data in block 0, assuming complete");
goto determined;
}
}
cd_media_state = media_status[0];
log_debug("no data in blocks 0 or 16, assuming blank");
}
determined: