Rust fast &str to i64 parser (x86_64 SIMD, SSE4.1)

Must be used when you are certain that the string contains only digits. If you pass not only digits, it will give you the wrong output (not error).

Examples

assert_eq!(atoi_simd::parse("0").unwrap(), 0_u64);
assert_eq!(atoi_simd::parse("1234").unwrap(), 1234_u64);

assert_eq!(atoi_simd::parse_i64("2345").unwrap(), 2345_i64);
assert_eq!(atoi_simd::parse_i64("-2345").unwrap(), -2345_i64);