Merge branch 'valyala:master' into validate-parse

fastfloat/parse.go

@@ -213,6 +213,12 @@ func ParseBestEffort(s string) float64 {
 		}
 	}
 
+	// the integer part might be elided to remain compliant
+	// with https://go.dev/ref/spec#Floating-point_literals
+	if s[i] == '.' && (i+1 >= uint(len(s)) || s[i+1] < '0' || s[i+1] > '9') {
+		return 0
+	}
+
 	d := uint64(0)
 	j := i
 	for i < uint(len(s)) {
@@ -232,7 +238,7 @@ func ParseBestEffort(s string) float64 {
 		}
 		break
 	}
-	if i <= j {
+	if i <= j && s[i] != '.' {
 		s = s[i:]
 		if strings.HasPrefix(s, "+") {
 			s = s[1:]
@@ -263,7 +269,9 @@ func ParseBestEffort(s string) float64 {
 		// Parse fractional part.
 		i++
 		if i >= uint(len(s)) {
-			return 0
+			// the fractional part may be elided to remain compliant
+			// with https://go.dev/ref/spec#Floating-point_literals
+			return f
 		}
 		k := i
 		for i < uint(len(s)) {
@@ -363,6 +371,12 @@ func Parse(s string) (float64, error) {
 		}
 	}
 
+	// the integer part might be elided to remain compliant
+	// with https://go.dev/ref/spec#Floating-point_literals
+	if s[i] == '.' && (i+1 >= uint(len(s)) || s[i+1] < '0' || s[i+1] > '9') {
+		return 0, fmt.Errorf("missing integer and fractional part in %q", s)
+	}
+
 	d := uint64(0)
 	j := i
 	for i < uint(len(s)) {
@@ -382,7 +396,7 @@ func Parse(s string) (float64, error) {
 		}
 		break
 	}
-	if i <= j {
+	if i <= j && s[i] != '.' {
 		ss := s[i:]
 		if strings.HasPrefix(ss, "+") {
 			ss = ss[1:]
@@ -413,7 +427,9 @@ func Parse(s string) (float64, error) {
 		// Parse fractional part.
 		i++
 		if i >= uint(len(s)) {
-			return 0, fmt.Errorf("cannot parse fractional part in %q", s)
+			// the fractional part might be elided to remain compliant
+			// with https://go.dev/ref/spec#Floating-point_literals
+			return f, nil
 		}
 		k := i
 		for i < uint(len(s)) {

fastfloat/parse_test.go

@@ -206,6 +206,7 @@ func TestParseBestEffort(t *testing.T) {
 	f("-", 0)
 	f("--", 0)
 	f("-.", 0)
+	f(".", 0)
 	f("-.e", 0)
 	f("+112", 0)
 	f("++", 0)
@@ -214,7 +215,6 @@ func TestParseBestEffort(t *testing.T) {
 	f("-e12", 0)
 	f(".", 0)
 	f("..34", 0)
-	f("-.32", 0)
 	f("-.e3", 0)
 	f(".e+3", 0)
 
@@ -224,7 +224,6 @@ func TestParseBestEffort(t *testing.T) {
 	f("12.34.56", 0)
 	f("13e34.56", 0)
 	f("12.34e56e4", 0)
-	f("12.", 0)
 	f("123..45", 0)
 	f("123ee34", 0)
 	f("123e", 0)
@@ -262,6 +261,9 @@ func TestParseBestEffort(t *testing.T) {
 	f("-0.1", -0.1)
 	f("-0.123", -0.123)
 	f("1.66", 1.66)
+	f("12.", 12)
+	f(".12", 0.12)
+	f("-.12", -0.12)
 	f("12345.12345678901", 12345.12345678901)
 	f("12345.123456789012", 12345.123456789012)
 	f("12345.1234567890123", 12345.1234567890123)
@@ -338,6 +340,7 @@ func TestParseFailure(t *testing.T) {
 	f(" bar ")
 	f("-")
 	f("--")
+	f(".")
 	f("-.")
 	f("-.e")
 	f("+112")
@@ -347,7 +350,6 @@ func TestParseFailure(t *testing.T) {
 	f("-e12")
 	f(".")
 	f("..34")
-	f("-.32")
 	f("-.e3")
 	f(".e+3")
 
@@ -357,7 +359,6 @@ func TestParseFailure(t *testing.T) {
 	f("12.34.56")
 	f("13e34.56")
 	f("12.34e56e4")
-	f("12.")
 	f("123..45")
 	f("123ee34")
 	f("123e")
@@ -413,6 +414,9 @@ func TestParseSuccess(t *testing.T) {
 	f("-0.1", -0.1)
 	f("-0.123", -0.123)
 	f("1.66", 1.66)
+	f("12.", 12)
+	f(".12", 0.12)
+	f("-.12", -0.12)
 	f("12345.12345678901", 12345.12345678901)
 	f("12345.123456789012", 12345.123456789012)
 	f("12345.1234567890123", 12345.1234567890123)
@@ -447,6 +451,8 @@ func TestParseSuccess(t *testing.T) {
 	f("-123.456E-10", -123.456e-10)
 	f("1.e4", 1.e4)
 	f("-1.E-10", -1.e-10)
+	f(".1e3", 100)
+	f("-.12e3", -120)
 
 	// inf and nan
 	f("12345678909123456789012e45678", math.Inf(1))

parser_test.go

@@ -35,6 +35,9 @@ func TestParseRawNumber(t *testing.T) {
 		f("-12.345E+67 tail", "-12.345E+67", " tail")
 		f("-12.345E-67,tail", "-12.345E-67", ",tail")
 		f("-1234567.8e+90tail", "-1234567.8e+90", "tail")
+		f("12.tail", "12.", "tail")
+		f(".2tail", ".2", "tail")
+		f("-.2tail", "-.2", "tail")
 		f("NaN", "NaN", "")
 		f("nantail", "nan", "tail")
 		f("inf", "inf", "")