File ‹str2long.c›
/*
* Copyright 2020, Data61, CSIRO (ABN 41 687 119 230)
*
* SPDX-License-Identifier: BSD-2-Clause
*/
/* http://blog.regehr.org/archives/909 */
long long LONG_MAX = 9223372036854775807L;
long long LONG_MIN = -9223372036854775807L - 1L;
int error = 0;
extern int error;
long str2long(const char *);
long str2long(const char *s)
{
long val = 0;
int negative = 0;
if (*s == '-') {
negative = 1;
s++;
}
if (*s == '\0') {
error = 1;
return -1;
}
for (; *s != '\0'; s++) {
if (*s < '0' || *s > '9') {
/* Non-numeric character; bail out. */
error = 1;
return -1;
} else {
long d = *s - '0'; /* digit value */
if (negative) {
if ((LONG_MIN + d) / 10 > val) {
/* We're about to underflow. */
error = 1;
return -1;
}
val = val * 10 - d;
} else {
if ((LONG_MAX - d) / 10 < val) {
/* We're about to overflow. */
error = 1;
return -1;
}
val = val * 10 + d;
}
}
}
return val;
}