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Rewrite std.fmt.parseInt

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Alluet 2020-07-03 15:35:18 -04:00 committed by Andrew Kelley
parent 682fccaaf0
commit a0a93f2091
1 changed files with 61 additions and 26 deletions
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87
lib/std/fmt.zig
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@ -996,49 +996,77 @@ pub fn formatIntBuf(out_buf: []u8, value: var, base: u8, uppercase: bool, option
return fbs.pos;
}
pub fn parseInt(comptime T: type, buf: []const u8, radix: u8) !T {
if (!T.is_signed) return parseUnsigned(T, buf, radix);
if (buf.len == 0) return @as(T, 0);
if (buf[0] == '-') {
return math.negate(try parseUnsigned(T, buf[1..], radix));
} else if (buf[0] == '+') {
return parseUnsigned(T, buf[1..], radix);
} else {
return parseUnsigned(T, buf, radix);
}
}
test "parseInt" {
std.testing.expect((parseInt(i32, "-10", 10) catch unreachable) == -10);
std.testing.expect((parseInt(i32, "+10", 10) catch unreachable) == 10);
std.testing.expect(if (parseInt(i32, " 10", 10)) |_| false else |err| err == error.InvalidCharacter);
std.testing.expect(if (parseInt(i32, "10 ", 10)) |_| false else |err| err == error.InvalidCharacter);
std.testing.expect(if (parseInt(u32, "-10", 10)) |_| false else |err| err == error.InvalidCharacter);
std.testing.expect((parseInt(u8, "255", 10) catch unreachable) == 255);
std.testing.expect(if (parseInt(u8, "256", 10)) |_| false else |err| err == error.Overflow);
}
pub const ParseUnsignedError = error{
pub const ParseIntError = error{
/// The result cannot fit in the type specified
Overflow,
/// The input had a byte that was not a digit
/// The input was empty or had a byte that was not a digit
InvalidCharacter,
};
pub fn parseUnsigned(comptime T: type, buf: []const u8, radix: u8) ParseUnsignedError!T {
pub fn parseInt(comptime T: type, buf: []const u8, radix: u8) ParseIntError!T {
if (buf.len == 0) return error.InvalidCharacter;
if (buf[0] == '+') return parseWithSign(T, buf[1..], radix, .Pos);
if (buf[0] == '-') return parseWithSign(T, buf[1..], radix, .Neg);
return parseWithSign(T, buf, radix, .Pos);
}
test "parseInt" {
std.testing.expect((try parseInt(i32, "-10", 10)) == -10);
std.testing.expect((try parseInt(i32, "+10", 10)) == 10);
std.testing.expect((try parseInt(u32, "+10", 10)) == 10);
std.testing.expectError(error.Overflow, parseInt(u32, "-10", 10));
std.testing.expectError(error.InvalidCharacter, parseInt(u32, " 10", 10));
std.testing.expectError(error.InvalidCharacter, parseInt(u32, "10 ", 10));
std.testing.expect((try parseInt(u8, "255", 10)) == 255);
std.testing.expectError(error.Overflow, parseInt(u8, "256", 10));
// +0 and -0 should work for unsigned
std.testing.expect((try parseInt(u8, "-0", 10)) == 0);
std.testing.expect((try parseInt(u8, "+0", 10)) == 0);
// ensure minInt is parsed correctly
std.testing.expect((try parseInt(i8, "-128", 10)) == math.minInt(i8));
std.testing.expect((try parseInt(i43, "-4398046511104", 10)) == math.minInt(i43));
// empty string or bare +- is invalid
std.testing.expectError(error.InvalidCharacter, parseInt(u32, "", 10));
std.testing.expectError(error.InvalidCharacter, parseInt(i32, "", 10));
std.testing.expectError(error.InvalidCharacter, parseInt(u32, "+", 10));
std.testing.expectError(error.InvalidCharacter, parseInt(i32, "+", 10));
std.testing.expectError(error.InvalidCharacter, parseInt(u32, "-", 10));
std.testing.expectError(error.InvalidCharacter, parseInt(i32, "-", 10));
}
fn parseWithSign(
comptime T: type,
buf: []const u8,
radix: u8,
comptime sign: enum { Pos, Neg },
) ParseIntError!T {
if (buf.len == 0) return error.InvalidCharacter;
const add = switch (sign) {
.Pos => math.add,
.Neg => math.sub,
};
var x: T = 0;
for (buf) |c| {
const digit = try charToDigit(c, radix);
if (x != 0) x = try math.mul(T, x, try math.cast(T, radix));
x = try math.add(T, x, try math.cast(T, digit));
x = try add(T, x, try math.cast(T, digit));
}
return x;
}
pub fn parseUnsigned(comptime T: type, buf: []const u8, radix: u8) ParseIntError!T {
return parseWithSign(T, buf, radix, .Pos);
}
test "parseUnsigned" {
std.testing.expect((try parseUnsigned(u16, "050124", 10)) == 50124);
std.testing.expect((try parseUnsigned(u16, "65535", 10)) == 65535);
@ -1064,6 +1092,13 @@ test "parseUnsigned" {
std.testing.expect((try parseUnsigned(u1, "001", 16)) == 1);
std.testing.expect((try parseUnsigned(u2, "3", 16)) == 3);
std.testing.expectError(error.Overflow, parseUnsigned(u2, "4", 16));
// parseUnsigned does not expect a sign
std.testing.expectError(error.InvalidCharacter, parseUnsigned(u8, "+0", 10));
std.testing.expectError(error.InvalidCharacter, parseUnsigned(u8, "-0", 10));
// test empty string error
std.testing.expectError(error.InvalidCharacter, parseUnsigned(u8, "", 10));
}
pub const parseFloat = @import("fmt/parse_float.zig").parseFloat;