Merge pull request #4845 from xackus/fix-parseFloat

fix overflow in parseFloat and cleanup
This commit is contained in:
Andrew Kelley 2020-03-29 22:40:32 -04:00 committed by GitHub
commit b717df786b
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2 changed files with 54 additions and 76 deletions

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@ -30,6 +30,7 @@
// - Does not handle denormals
const std = @import("../std.zig");
const ascii = std.ascii;
const max_digits = 25;
@ -190,14 +191,6 @@ const ParseResult = enum {
MinusInf,
};
inline fn isDigit(c: u8) bool {
return c >= '0' and c <= '9';
}
inline fn isSpace(c: u8) bool {
return (c >= 0x09 and c <= 0x13) or c == 0x20;
}
fn parseRepr(s: []const u8, n: *FloatRepr) !ParseResult {
var digit_index: usize = 0;
var negative = false;
@ -207,52 +200,49 @@ fn parseRepr(s: []const u8, n: *FloatRepr) !ParseResult {
var state = State.MaybeSign;
var i: usize = 0;
loop: while (i < s.len) {
while (i < s.len) {
const c = s[i];
switch (state) {
State.MaybeSign => {
state = State.LeadingMantissaZeros;
.MaybeSign => {
state = .LeadingMantissaZeros;
if (c == '+') {
i += 1;
} else if (c == '-') {
n.negative = true;
i += 1;
} else if (isDigit(c) or c == '.') {
} else if (ascii.isDigit(c) or c == '.') {
// continue
} else {
return error.InvalidCharacter;
}
},
State.LeadingMantissaZeros => {
.LeadingMantissaZeros => {
if (c == '0') {
i += 1;
} else if (c == '.') {
i += 1;
state = State.LeadingFractionalZeros;
state = .LeadingFractionalZeros;
} else {
state = State.MantissaIntegral;
state = .MantissaIntegral;
}
},
State.LeadingFractionalZeros => {
.LeadingFractionalZeros => {
if (c == '0') {
i += 1;
if (n.exponent > std.math.minInt(i32)) {
n.exponent -= 1;
}
} else {
state = State.MantissaFractional;
state = .MantissaFractional;
}
},
State.MantissaIntegral => {
if (isDigit(c)) {
.MantissaIntegral => {
if (ascii.isDigit(c)) {
if (digit_index < max_digits) {
n.mantissa *%= 10;
n.mantissa += s[i] - '0';
n.mantissa += c - '0';
digit_index += 1;
} else if (n.exponent < std.math.maxInt(i32)) {
n.exponent += 1;
@ -261,14 +251,13 @@ fn parseRepr(s: []const u8, n: *FloatRepr) !ParseResult {
i += 1;
} else if (c == '.') {
i += 1;
state = State.MantissaFractional;
state = .MantissaFractional;
} else {
state = State.MantissaFractional;
state = .MantissaFractional;
}
},
State.MantissaFractional => {
if (isDigit(c)) {
.MantissaFractional => {
if (ascii.isDigit(c)) {
if (digit_index < max_digits) {
n.mantissa *%= 10;
n.mantissa += c - '0';
@ -279,13 +268,12 @@ fn parseRepr(s: []const u8, n: *FloatRepr) !ParseResult {
i += 1;
} else if (c == 'e' or c == 'E') {
i += 1;
state = State.ExponentSign;
state = .ExponentSign;
} else {
state = State.ExponentSign;
state = .ExponentSign;
}
},
State.ExponentSign => {
.ExponentSign => {
if (c == '+') {
i += 1;
} else if (c == '-') {
@ -293,20 +281,18 @@ fn parseRepr(s: []const u8, n: *FloatRepr) !ParseResult {
i += 1;
}
state = State.LeadingExponentZeros;
state = .LeadingExponentZeros;
},
State.LeadingExponentZeros => {
.LeadingExponentZeros => {
if (c == '0') {
i += 1;
} else {
state = State.Exponent;
state = .Exponent;
}
},
State.Exponent => {
if (isDigit(c)) {
if (exponent < std.math.maxInt(i32)) {
.Exponent => {
if (ascii.isDigit(c)) {
if (exponent < std.math.maxInt(i32) / 10) {
exponent *= 10;
exponent += @intCast(i32, c - '0');
}
@ -323,29 +309,21 @@ fn parseRepr(s: []const u8, n: *FloatRepr) !ParseResult {
n.exponent += exponent;
if (n.mantissa == 0) {
return if (n.negative) ParseResult.MinusZero else ParseResult.PlusZero;
return if (n.negative) .MinusZero else .PlusZero;
} else if (n.exponent > 309) {
return if (n.negative) ParseResult.MinusInf else ParseResult.PlusInf;
return if (n.negative) .MinusInf else .PlusInf;
} else if (n.exponent < -328) {
return if (n.negative) ParseResult.MinusZero else ParseResult.PlusZero;
return if (n.negative) .MinusZero else .PlusZero;
}
return ParseResult.Ok;
}
inline fn isLower(c: u8) bool {
return c -% 'a' < 26;
}
inline fn toUpper(c: u8) u8 {
return if (isLower(c)) (c & 0x5f) else c;
return .Ok;
}
fn caseInEql(a: []const u8, b: []const u8) bool {
if (a.len != b.len) return false;
for (a) |_, i| {
if (toUpper(a[i]) != toUpper(b[i])) {
if (ascii.toUpper(a[i]) != ascii.toUpper(b[i])) {
return false;
}
}
@ -373,11 +351,11 @@ pub fn parseFloat(comptime T: type, s: []const u8) !T {
};
return switch (try parseRepr(s, &r)) {
ParseResult.Ok => convertRepr(T, r),
ParseResult.PlusZero => 0.0,
ParseResult.MinusZero => -@as(T, 0.0),
ParseResult.PlusInf => std.math.inf(T),
ParseResult.MinusInf => -std.math.inf(T),
.Ok => convertRepr(T, r),
.PlusZero => 0.0,
.MinusZero => -@as(T, 0.0),
.PlusInf => std.math.inf(T),
.MinusInf => -std.math.inf(T),
};
}
@ -396,26 +374,28 @@ test "fmt.parseFloat" {
testing.expectError(error.InvalidCharacter, parseFloat(T, "1abc"));
expectEqual(try parseFloat(T, "0"), 0.0);
expectEqual((try parseFloat(T, "0")), 0.0);
expectEqual((try parseFloat(T, "+0")), 0.0);
expectEqual((try parseFloat(T, "-0")), 0.0);
expectEqual(try parseFloat(T, "0"), 0.0);
expectEqual(try parseFloat(T, "+0"), 0.0);
expectEqual(try parseFloat(T, "-0"), 0.0);
expectEqual((try parseFloat(T, "0e0")), 0);
expectEqual((try parseFloat(T, "2e3")), 2000.0);
expectEqual((try parseFloat(T, "1e0")), 1.0);
expectEqual((try parseFloat(T, "-2e3")), -2000.0);
expectEqual((try parseFloat(T, "-1e0")), -1.0);
expectEqual((try parseFloat(T, "1.234e3")), 1234);
expectEqual(try parseFloat(T, "0e0"), 0);
expectEqual(try parseFloat(T, "2e3"), 2000.0);
expectEqual(try parseFloat(T, "1e0"), 1.0);
expectEqual(try parseFloat(T, "-2e3"), -2000.0);
expectEqual(try parseFloat(T, "-1e0"), -1.0);
expectEqual(try parseFloat(T, "1.234e3"), 1234);
expect(approxEq(T, try parseFloat(T, "3.141"), 3.141, epsilon));
expect(approxEq(T, try parseFloat(T, "-3.141"), -3.141, epsilon));
expectEqual((try parseFloat(T, "1e-700")), 0);
expectEqual((try parseFloat(T, "1e+700")), std.math.inf(T));
expectEqual(try parseFloat(T, "1e-700"), 0);
expectEqual(try parseFloat(T, "1e+700"), std.math.inf(T));
expectEqual(@bitCast(Z, try parseFloat(T, "nAn")), @bitCast(Z, std.math.nan(T)));
expectEqual((try parseFloat(T, "inF")), std.math.inf(T));
expectEqual((try parseFloat(T, "-INF")), -std.math.inf(T));
expectEqual(try parseFloat(T, "inF"), std.math.inf(T));
expectEqual(try parseFloat(T, "-INF"), -std.math.inf(T));
expectEqual(try parseFloat(T, "0.4e0066999999999999999999999999999999999999999999999999999"), std.math.inf(T));
if (T != f16) {
expect(approxEq(T, try parseFloat(T, "1e-2"), 0.01, epsilon));

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@ -1751,11 +1751,9 @@ test "i_number_double_huge_neg_exp" {
}
test "i_number_huge_exp" {
return error.SkipZigTest;
// FIXME Integer overflow in parseFloat
// any(
// \\[0.4e00669999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999969999999006]
// );
any(
\\[0.4e00669999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999969999999006]
);
}
test "i_number_neg_int_huge_exp" {