readFixed

fn readFixed(bc: *BitcodeReader, comptime T: type, bits: u7) !T {
    var result: T = 0;
    var shift: std.math.Log2IntCeil(T) = 0;
    var remaining = bits;
    while (remaining > 0) {
        if (bc.bit_offset == 0) bc.bit_buffer = try bc.read32Bits();
        const chunk_len = @min(@as(u6, 32) - bc.bit_offset, remaining);
        const chunk_mask = @as(u32, std.math.maxInt(u32)) >> @intCast(32 - chunk_len);
        result |= @as(T, @intCast(bc.bit_buffer >> bc.bit_offset & chunk_mask)) << @intCast(shift);
        shift += @intCast(chunk_len);
        remaining -= chunk_len;
        bc.bit_offset = @truncate(bc.bit_offset + chunk_len);
    }
    return result;
}