diff --git a/src/numbers.rs b/src/numbers.rs
index 85a4190..29b24ec 100644
--- a/src/numbers.rs
+++ b/src/numbers.rs
@@ -2,35 +2,28 @@
 ///
 /// This is around 2x faster than using `str::parse::<i64>()`
 pub fn int_parse_str(s: &str) -> Option<i64> {
-    fast_parse_int(s.bytes())
+    int_parse_bytes(s.as_bytes())
 }
 
 /// Parse bytes as an int.
 pub fn int_parse_bytes(s: &[u8]) -> Option<i64> {
-    fast_parse_int(s.iter().copied())
-}
+    let (neg, first_digit, digits) = match s {
+        [b'-', first, digits @ ..] => (true, first, digits),
+        [b'+', first, digits @ ..] | [first, digits @ ..] => (false, first, digits),
+        _ => return None,
+    };
 
-pub fn fast_parse_int<I: Iterator>(mut bytes: I) -> Option<i64>
-where
-    I: Iterator<Item = u8>,
-{
-    let mut result: i64 = 0;
-    let neg = match bytes.next() {
-        Some(b'-') => true,
-        Some(b'+') => false,
-        Some(c) if c.is_ascii_digit() => {
-            result = (c & 0x0f) as i64;
-            false
-        }
+    let mut result = match first_digit {
+        b'0' => 0,
+        b'1'..=b'9' => (first_digit & 0x0f) as i64,
         _ => return None,
     };
 
-    for digit in bytes {
+    for digit in digits {
+        result = result.checked_mul(10)?;
         match digit {
-            b'0'..=b'9' => {
-                result = result.checked_mul(10)?;
-                result = result.checked_add((digit & 0x0f) as i64)?
-            }
+            b'0' => {}
+            b'1'..=b'9' => result = result.checked_add((digit & 0x0f) as i64)?,
             _ => return None,
         }
     }
@@ -58,30 +51,27 @@ impl IntFloat {
 ///
 /// This is around 2x faster than using `str::parse::<f64>()`
 pub fn float_parse_str(s: &str) -> IntFloat {
-    fast_parse_float(s.bytes())
+    float_parse_bytes(s.as_bytes())
 }
 
 /// Parse bytes as an float.
 pub fn float_parse_bytes(s: &[u8]) -> IntFloat {
-    fast_parse_float(s.iter().copied())
-}
+    let (neg, first_digit, digits) = match s {
+        [b'-', first, digits @ ..] => (true, first, digits),
+        [b'+', first, digits @ ..] | [first, digits @ ..] => (false, first, digits),
+        _ => return IntFloat::Err,
+    };
 
-pub fn fast_parse_float<I: Iterator>(mut bytes: I) -> IntFloat
-where
-    I: Iterator<Item = u8>,
-{
-    let mut int_part: i64 = 0;
-    let neg = match bytes.next() {
-        Some(b'-') => true,
-        Some(c) if c.is_ascii_digit() => {
-            int_part = (c & 0x0f) as i64;
-            false
-        }
+    let mut int_part = match first_digit {
+        b'0' => 0,
+        b'1'..=b'9' => (first_digit & 0x0f) as i64,
         _ => return IntFloat::Err,
     };
 
     let mut found_dot = false;
 
+    let mut bytes = digits.iter().copied();
+
     for digit in bytes.by_ref() {
         match digit {
             b'0'..=b'9' => {
diff --git a/tests/main.rs b/tests/main.rs
index 50a9df9..eb1a829 100644
--- a/tests/main.rs
+++ b/tests/main.rs
@@ -5,8 +5,8 @@ use chrono::{Datelike, FixedOffset as ChronoFixedOffset, NaiveDate, NaiveDateTim
 use strum::EnumMessage;
 
 use speedate::{
-    float_parse_str, int_parse_str, Date, DateTime, Duration, MicrosecondsPrecisionOverflowBehavior, ParseError, Time,
-    TimeConfig, TimeConfigBuilder,
+    float_parse_bytes, float_parse_str, int_parse_bytes, int_parse_str, Date, DateTime, Duration, IntFloat,
+    MicrosecondsPrecisionOverflowBehavior, ParseError, Time, TimeConfig, TimeConfigBuilder,
 };
 
 /// macro for expected values
@@ -1348,3 +1348,24 @@ fn test_time_config_builder() {
     );
     assert_eq!(TimeConfigBuilder::new().build(), TimeConfig::builder().build());
 }
+
+#[test]
+fn date_dash_err() {
+    let error = Date::parse_str("-").unwrap_err();
+    assert_eq!(error, ParseError::TooShort);
+    assert_eq!(error.to_string(), "too_short");
+    assert_eq!(error.get_documentation(), Some("input is too short"));
+}
+
+#[test]
+fn number_dash_err() {
+    assert!(int_parse_str("-").is_none());
+    assert!(int_parse_str("+").is_none());
+    assert!(int_parse_bytes(b"-").is_none());
+    assert!(int_parse_bytes(b"+").is_none());
+
+    assert!(matches!(float_parse_str("-"), IntFloat::Err));
+    assert!(matches!(float_parse_str("+"), IntFloat::Err));
+    assert!(matches!(float_parse_bytes(b"-"), IntFloat::Err));
+    assert!(matches!(float_parse_bytes(b"+"), IntFloat::Err));
+}