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This is an example of documentation generated by ZigDoc, an alternative to Zig's built-in Auto Doc feature. See also examples in other modes/formats. The project being documented here (as the example) is the Zig standard library. Public Function

setString

Doc Source

Public Function

std.math.big.int.Mutable.setString

pub fn setString(
        self: *Mutable,
        base: u8,
        value: []const u8,
    ) error

Set self from the string representation value.

value must contain only digits <= base and is case insensitive. Base prefixes are not allowed (e.g. 0x43 should simply be 43). Underscores in the input string are ignored and can be used as digit separators.

There must be enough memory for the value in self.limbs. An upper bound on number of limbs can be determined with calcSetStringLimbCount. Asserts the base is in the range [2, 36].

Returns an error if the value has invalid digits for the requested base.

Params

self: *Mutable
base: u8
value: []const u8

File

math/big/int.zig:363

    pub fn setString(
        self: *Mutable,
        base: u8,
        value: []const u8,
    ) error{InvalidCharacter}!void {
        assert(base >= 2);
        assert(base <= 36);

        var i: usize = 0;
        var positive = true;
        if (value.len > 0 and value[0] == '-') {
            positive = false;
            i += 1;
        }

        @memset(self.limbs, 0);
        self.len = 1;

        var limb: Limb = 0;
        var j: usize = 0;
        for (value[i..]) |ch| {
            if (ch == '_') {
                continue;
            }
            const d = try std.fmt.charToDigit(ch, base);
            limb *= base;
            limb += d;
            j += 1;

            if (j == constants.digits_per_limb[base]) {
                const len = @min(self.len + 1, self.limbs.len);
                // r = a * b = a + a * (b - 1)
                // we assert when self.limbs is not large enough to store the number
                assert(!llmulLimb(.add, self.limbs[0..len], self.limbs[0..len], constants.big_bases[base] - 1));
                assert(lladdcarry(self.limbs[0..len], self.limbs[0..len], &[1]Limb{limb}) == 0);

                if (self.limbs.len > self.len and self.limbs[self.len] != 0)
                    self.len += 1;
                j = 0;
                limb = 0;
            }
        }
        if (j > 0) {
            const len = @min(self.len + 1, self.limbs.len);
            // we assert when self.limbs is not large enough to store the number
            assert(!llmulLimb(.add, self.limbs[0..len], self.limbs[0..len], math.pow(Limb, base, j) - 1));
            assert(lladdcarry(self.limbs[0..len], self.limbs[0..len], &[1]Limb{limb}) == 0);

            if (self.limbs.len > self.len and self.limbs[self.len] != 0)
                self.len += 1;
        }
        self.positive = positive;
    }