sbase/libutil/parseoffset.c

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/* See LICENSE file for copyright and license details. */
#include <ctype.h>
#include <inttypes.h>
#include <stdlib.h>
#include <string.h>
#include "../util.h"
off_t
parseoffset(const char *str)
{
off_t res;
size_t scale;
int base = 10;
char *end;
/* bases */
if (!strncasecmp(str, "0x", strlen("0x"))) {
base = 16;
} else if (*str == '0') {
str++;
base = 8;
}
res = strtol(str, &end, base);
if (res < 0) {
weprintf("invalid file offset: %s\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("invalid file offset suffix: %s\n", str);
return -1;
}
}
/* prevent overflow */
if (res > (SIZE_MAX / scale)) {
weprintf("file offset out of range: %s\n", str);
return -1;
}
return res;
}