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/* nbdkit
* Copyright Red Hat
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* * Neither the name of Red Hat nor the names of its contributors may be
* used to endorse or promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY RED HAT AND CONTRIBUTORS ''AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
* PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL RED HAT OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#ifndef NBDKIT_HUMAN_SIZE_H
#define NBDKIT_HUMAN_SIZE_H
#include <stdbool.h>
#include <stdint.h>
#include <inttypes.h>
#include <errno.h>
/* Attempt to parse a string with a possible scaling suffix, such as
* "2M". Disk sizes cannot usefully exceed off_t (which is signed)
* and cannot be negative.
*
* On error, returns -1 and sets *error and *pstr. You can form a
* final error message by appending "<error>: <pstr>".
*/
static inline int64_t
human_size_parse (const char *str,
const char **error, const char **pstr)
{
int64_t size;
char *end;
uint64_t scale = 1;
/* XXX Should we also parse things like '1.5M'? */
/* XXX Should we allow hex? If so, hex cannot use scaling suffixes,
* because some of them are valid hex digits.
*/
errno = 0;
size = strtoimax (str, &end, 10);
if (str == end) {
*error = "could not parse size string";
*pstr = str;
return -1;
}
if (size < 0) {
*error = "size cannot be negative";
*pstr = str;
return -1;
}
if (errno) {
*error = "size exceeds maximum value";
*pstr = str;
return -1;
}
switch (*end) {
/* No suffix */
case '\0':
end--; /* Safe, since we already filtered out empty string */
break;
/* Powers of 1024 */
case 'e': case 'E':
scale *= 1024;
/* fallthru */
case 'p': case 'P':
scale *= 1024;
/* fallthru */
case 't': case 'T':
scale *= 1024;
/* fallthru */
case 'g': case 'G':
scale *= 1024;
/* fallthru */
case 'm': case 'M':
scale *= 1024;
/* fallthru */
case 'k': case 'K':
scale *= 1024;
/* fallthru */
case 'b': case 'B':
break;
/* "sectors", ie. units of 512 bytes, even if that's not the real
* sector size
*/
case 's': case 'S':
scale = 512;
break;
default:
*error = "could not parse size: unknown suffix";
*pstr = end;
return -1;
}
/* XXX Maybe we should support 'MiB' as a synonym for 'M'; and 'MB'
* for powers of 1000, for similarity to GNU tools. But for now,
* anything beyond 'M' is dropped.
*/
if (end[1]) {
*error = "could not parse size: unknown suffix";
*pstr = end;
return -1;
}
if (INT64_MAX / scale < size) {
*error = "could not parse size: size * scale overflows";
*pstr = str;
return -1;
}
return size * scale;
}
/* If you allocate a buffer of at least this length in bytes and pass
* it as the first parameter to human_size, then it will not overrun.
*/
#define HUMAN_SIZE_LONGEST 64
/* Convert bytes to a human-readable string.
*
* This is roughly the opposite of nbdkit_parse_size. It will convert
* multiples of powers of 1024 to the appropriate human size with the
* right extension like 'M' or 'G'. Anything that cannot be converted
* is returned as bytes. The *human flag is set to true if the output
* was abbreviated to a human-readable size, or false if it is just
* bytes.
*
* If buf == NULL, a buffer is allocated and returned. In this case
* the returned buffer must be freed.
*
* buf may also be allocated by the caller, in which case it must be
* at least HUMAN_SIZE_LONGEST bytes.
*
* On error the function returns an error and sets errno.
*/
static inline char *
human_size (char *buf, uint64_t bytes, bool *human)
{
static const char ext[] = "EPTGMK";
size_t i;
if (buf == NULL) {
buf = malloc (HUMAN_SIZE_LONGEST);
if (buf == NULL)
return NULL;
}
/* Work out which extension to use, if any. */
i = 6;
while (bytes && (bytes & 1023) == 0) {
bytes >>= 10;
i--;
}
/* Set the flag to true if we're going to add a human-readable extension. */
if (human)
*human = ext[i] != '\0';
snprintf (buf, HUMAN_SIZE_LONGEST, "%" PRIu64 "%.1s", bytes, &ext[i]);
return buf;
}
#endif /* NBDKIT_HUMAN_SIZE_H */
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