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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

fromBytes

Doc Source

Public Function

std.crypto.ff.Uint.fromBytes

pub fn fromBytes(bytes: []const u8, comptime endian: Endian) OverflowError!Self

Creates a new big integer from a byte array.

Params

bytes: []const u8
endian: Endian

Errors

Overflow

File

crypto/ff.zig:185

        pub fn fromBytes(bytes: []const u8, comptime endian: Endian) OverflowError!Self {
            if (bytes.len == 0) return Self.zero;
            var shift: usize = 0;
            var out = Self.zero;
            var out_i: usize = 0;
            var i: usize = switch (endian) {
                .big => bytes.len - 1,
                .little => 0,
            };
            while (true) {
                const bi = bytes[i];
                out.limbs()[out_i] |= math.shl(Limb, bi, shift);
                shift += 8;
                if (shift >= t_bits) {
                    shift -= t_bits;
                    out.limbs()[out_i] = @as(TLimb, @truncate(out.limbs()[out_i]));
                    const overflow = math.shr(Limb, bi, 8 - shift);
                    out_i += 1;
                    if (out_i >= out.limbs_len) {
                        if (overflow != 0 or i != 0) {
                            return error.Overflow;
                        }
                        break;
                    }
                    out.limbs()[out_i] = overflow;
                }
                switch (endian) {
                    .big => {
                        if (i == 0) break;
                        i -= 1;
                    },
                    .little => {
                        i += 1;
                        if (i == bytes.len) break;
                    },
                }
            }
            return out;
        }