45 lines
930 B
C
45 lines
930 B
C
|
#pragma once
|
||
|
|
|
||
|
|
#define isspace_fast(x) ((x) == ' ' || (x) == '\t' || (x) == '\n' || (x) == '\v' || (x) == '\f' || (x) == '\r')
|
||
|
|
|
||
|
|
int fast_atoi(const char *b)
|
||
|
|
{
|
||
|
|
int res = 0; // Initialize result
|
||
|
|
|
||
|
|
// Skip whitespace
|
||
|
|
for (; isspace_fast(*b); ++b);
|
||
|
|
|
||
|
|
if (*b == '-')
|
||
|
|
{
|
||
|
|
++b;
|
||
|
|
// Iterate through all characters of input string and update result
|
||
|
|
for (; ; ++b)
|
||
|
|
{
|
||
|
|
unsigned d = static_cast<unsigned>(*b) - '0';
|
||
|
|
if (d > 9)
|
||
|
|
{
|
||
|
|
return res;
|
||
|
|
}
|
||
|
|
res = res * 10 - d;
|
||
|
|
}
|
||
|
|
|
||
|
|
}
|
||
|
|
else if (*b == '+')
|
||
|
|
{
|
||
|
|
++b;
|
||
|
|
}
|
||
|
|
|
||
|
|
// Iterate through all characters of input string and update result
|
||
|
|
for (; ; ++b)
|
||
|
|
{
|
||
|
|
unsigned d = static_cast<unsigned>(*b) - '0';
|
||
|
|
if (d > 9)
|
||
|
|
{
|
||
|
|
return res;
|
||
|
|
}
|
||
|
|
res = res * 10 + d;
|
||
|
|
}
|
||
|
|
|
||
|
|
// unreachable
|
||
|
|
return res;
|
||
|
|
}
|