busybox/libbb/parse_number.c

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/* vi: set sw=4 ts=4: */
/*
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* bb_xparse_number implementation for busybox
*
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* Copyright (C) 2003 Manuel Novoa III <mjn3@codepoet.org>
*
* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
*/
#include <stdlib.h>
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#include <string.h>
#include <limits.h>
#include <errno.h>
#include <assert.h>
#include "libbb.h"
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unsigned long bb_xparse_number(const char *numstr,
const struct suffix_mult *suffixes)
{
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unsigned long int r;
char *e;
int old_errno;
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/* Since this is a lib function, we're not allowed to reset errno to 0.
* Doing so could break an app that is deferring checking of errno.
* So, save the old value so that we can restore it if successful. */
old_errno = errno;
errno = 0;
r = strtoul(numstr, &e, 10);
if ((numstr != e) && !errno) {
errno = old_errno; /* Ok. So restore errno. */
if (!*e) {
return r;
}
if (suffixes) {
assert(suffixes->suffix); /* No nul suffixes. */
do {
if (strcmp(suffixes->suffix, e) == 0) {
if (ULONG_MAX / suffixes->mult < r) { /* Overflow! */
break;
}
return r * suffixes->mult;
}
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++suffixes;
} while (suffixes->suffix);
}
}
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bb_error_msg_and_die("invalid number `%s'", numstr);
}