parseNumberLiteral
Parse Zig number literal accepted by fmt.parseInt, fmt.parseFloat and big_int.setString. Valid for any input.
Function parameters
Parameters
- bytes:[]const u8
Type definitions in this namespace
Types
Parse Zig number literal accepted by fmt.parseInt, fmt.parseFloat and big_int.setString.
Functions
- parseNumberLiteral
- Parse Zig number literal accepted by fmt.parseInt, fmt.parseFloat and big_int.setString.
Error sets in this namespace
Error Sets
Source
Implementation
pub fn parseNumberLiteral(bytes: []const u8) Result {
var i: usize = 0;
var base: u8 = 10;
if (bytes.len >= 2 and bytes[0] == '0') switch (bytes[1]) {
'b' => {
base = 2;
i = 2;
},
'o' => {
base = 8;
i = 2;
},
'x' => {
base = 16;
i = 2;
},
'B', 'O', 'X' => return .{ .failure = .{ .upper_case_base = 1 } },
'.', 'e', 'E' => {},
else => return .{ .failure = .leading_zero },
};
if (bytes.len == 2 and base != 10) return .{ .failure = .digit_after_base };
var x: u64 = 0;
var overflow = false;
var underscore = false;
var period = false;
var special: u8 = 0;
var exponent = false;
var float = false;
while (i < bytes.len) : (i += 1) {
const c = bytes[i];
switch (c) {
'_' => {
if (i == 2 and base != 10) return .{ .failure = .{ .invalid_underscore_after_special = i } };
if (special != 0) return .{ .failure = .{ .invalid_underscore_after_special = i } };
if (underscore) return .{ .failure = .{ .repeated_underscore = i } };
underscore = true;
continue;
},
'e', 'E' => if (base == 10) {
float = true;
if (exponent) return .{ .failure = .{ .duplicate_exponent = i } };
if (underscore) return .{ .failure = .{ .exponent_after_underscore = i } };
special = c;
exponent = true;
continue;
},
'p', 'P' => if (base == 16) {
if (i == 2) {
return .{ .failure = .{ .digit_after_base = {} } };
}
float = true;
if (exponent) return .{ .failure = .{ .duplicate_exponent = i } };
if (underscore) return .{ .failure = .{ .exponent_after_underscore = i } };
special = c;
exponent = true;
continue;
},
'.' => {
if (exponent) {
const digit_index = i - ".e".len;
if (digit_index < bytes.len) {
switch (bytes[digit_index]) {
'0'...'9' => return .{ .failure = .{ .period_after_exponent = i } },
else => {},
}
}
}
float = true;
if (base != 10 and base != 16) return .{ .failure = .{ .invalid_float_base = 2 } };
if (period) return .{ .failure = .duplicate_period };
period = true;
if (underscore) return .{ .failure = .{ .special_after_underscore = i } };
special = c;
continue;
},
'+', '-' => {
switch (special) {
'p', 'P' => {},
'e', 'E' => if (base != 10) return .{ .failure = .{ .invalid_exponent_sign = i } },
else => return .{ .failure = .{ .invalid_exponent_sign = i } },
}
special = c;
continue;
},
else => {},
}
const digit = switch (c) {
'0'...'9' => c - '0',
'A'...'Z' => c - 'A' + 10,
'a'...'z' => c - 'a' + 10,
else => return .{ .failure = .{ .invalid_character = i } },
};
if (digit >= base) return .{ .failure = .{ .invalid_digit = .{ .i = i, .base = @as(Base, @enumFromInt(base)) } } };
if (exponent and digit >= 10) return .{ .failure = .{ .invalid_digit_exponent = i } };
underscore = false;
special = 0;
if (float) continue;
if (x != 0) {
const res = @mulWithOverflow(x, base);
if (res[1] != 0) overflow = true;
x = res[0];
}
const res = @addWithOverflow(x, digit);
if (res[1] != 0) overflow = true;
x = res[0];
}
if (underscore) return .{ .failure = .{ .trailing_underscore = bytes.len - 1 } };
if (special != 0) return .{ .failure = .{ .trailing_special = bytes.len - 1 } };
if (float) return .{ .float = @as(FloatBase, @enumFromInt(base)) };
if (overflow) return .{ .big_int = @as(Base, @enumFromInt(base)) };
return .{ .int = x };
}