sbase/libutil/parseoffset.c

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/* See LICENSE file for copyright and license details. */
#include <ctype.h>
#include <errno.h>
#include <inttypes.h>
#include <stdlib.h>
#include <string.h>
#include "../util.h"
off_t
parseoffset(const char *str)
{
off_t res, scale = 1;
char *end;
/* strictly check what strtol() usually would let pass */
if (!str || !*str || isspace(*str) || *str == '+' || *str == '-') {
weprintf("parseoffset %s: invalid value\n", str);
return -1;
}
errno = 0;
res = strtol(str, &end, 0);
if (errno) {
weprintf("parseoffset %s: invalid value\n", str);
return -1;
}
if (res < 0) {
weprintf("parseoffset %s: negative value\n", str);
return -1;
}
/* suffix */
if (*end) {
switch (toupper((int)*end)) {
case 'B':
scale = 512L;
break;
case 'K':
scale = 1024L;
break;
case 'M':
scale = 1024L * 1024L;
break;
case 'G':
scale = 1024L * 1024L * 1024L;
break;
default:
weprintf("parseoffset %s: invalid suffix '%s'\n", str, end);
return -1;
}
}
/* prevent overflow */
if (res > (SIZE_MAX / scale)) {
weprintf("parseoffset %s: out of range\n", str);
return -1;
}
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return res * scale;
}