fn __zero_std_unicode_decode_raw(text: Span<u8>, index: usize) -> u64 {
    let len: usize = std.mem.len(text)
    if index >= len {
        return 0
    }
    let first: u8 = text[index]
    if first < 128_u8 {
        return 4294967296_u64 + (first as u64)
    }
    if first >= 194_u8 && first <= 223_u8 {
        if index + 2 > len {
            return 0
        }
        let second: u8 = text[index + 1]
        if second < 128_u8 || second > 191_u8 {
            return 0
        }
        let cp: u64 = ((first as u64) - 192_u64) * 64_u64 + ((second as u64) - 128_u64)
        return 2_u64 * 4294967296_u64 + cp
    }
    if first >= 224_u8 && first <= 239_u8 {
        if index + 3 > len {
            return 0
        }
        let second: u8 = text[index + 1]
        let third: u8 = text[index + 2]
        if second < 128_u8 || second > 191_u8 || (third < 128_u8 || third > 191_u8) {
            return 0
        }
        if first == 224_u8 && second < 160_u8 {
            return 0
        }
        if first == 237_u8 && second > 159_u8 {
            return 0
        }
        let cp: u64 = ((first as u64) - 224_u64) * 4096_u64 + ((second as u64) - 128_u64) * 64_u64 + ((third as u64) - 128_u64)
        return 3_u64 * 4294967296_u64 + cp
    }
    if first >= 240_u8 && first <= 244_u8 {
        if index + 4 > len {
            return 0
        }
        let second: u8 = text[index + 1]
        let third: u8 = text[index + 2]
        let fourth: u8 = text[index + 3]
        if second < 128_u8 || second > 191_u8 {
            return 0
        }
        if third < 128_u8 || third > 191_u8 || (fourth < 128_u8 || fourth > 191_u8) {
            return 0
        }
        if first == 240_u8 && second < 144_u8 {
            return 0
        }
        if first == 244_u8 && second > 143_u8 {
            return 0
        }
        let cp: u64 = ((first as u64) - 240_u64) * 262144_u64 + ((second as u64) - 128_u64) * 4096_u64 + ((third as u64) - 128_u64) * 64_u64 + ((fourth as u64) - 128_u64)
        return 4_u64 * 4294967296_u64 + cp
    }
    return 0
}

fn __zero_std_unicode_decode_at(text: Span<u8>, index: usize) -> Maybe<u32> {
    let raw: u64 = __zero_std_unicode_decode_raw(text, index)
    if raw == 0 {
        return null
    }
    return (raw % 4294967296_u64) as u32
}

fn __zero_std_unicode_decode_status_at(text: Span<u8>, index: usize) -> u32 {
    let len: usize = std.mem.len(text)
    if index >= len {
        return 1_u32
    }
    let first: u8 = text[index]
    if first < 128_u8 {
        return 0_u32
    }
    if first >= 128_u8 && first <= 191_u8 {
        return 2_u32
    }
    if first == 192_u8 || first == 193_u8 {
        return 6_u32
    }
    if first >= 194_u8 && first <= 223_u8 {
        if index + 2 > len {
            return 4_u32
        }
        let second: u8 = text[index + 1]
        if second < 128_u8 || second > 191_u8 {
            return 5_u32
        }
        return 0_u32
    }
    if first >= 224_u8 && first <= 239_u8 {
        if index + 3 > len {
            return 4_u32
        }
        let second: u8 = text[index + 1]
        let third: u8 = text[index + 2]
        if second < 128_u8 || second > 191_u8 {
            return 5_u32
        }
        if third < 128_u8 || third > 191_u8 {
            return 5_u32
        }
        if first == 224_u8 && second < 160_u8 {
            return 6_u32
        }
        if first == 237_u8 && second > 159_u8 {
            return 7_u32
        }
        return 0_u32
    }
    if first >= 240_u8 && first <= 244_u8 {
        if index + 4 > len {
            return 4_u32
        }
        let second: u8 = text[index + 1]
        let third: u8 = text[index + 2]
        let fourth: u8 = text[index + 3]
        if second < 128_u8 || second > 191_u8 {
            return 5_u32
        }
        if third < 128_u8 || third > 191_u8 {
            return 5_u32
        }
        if fourth < 128_u8 || fourth > 191_u8 {
            return 5_u32
        }
        if first == 240_u8 && second < 144_u8 {
            return 6_u32
        }
        if first == 244_u8 && second > 143_u8 {
            return 8_u32
        }
        return 0_u32
    }
    return 3_u32
}

fn __zero_std_unicode_status_name(status: u32) -> String {
    if status == 0_u32 {
        return "ok"
    }
    if status == 1_u32 {
        return "out of range"
    }
    if status == 2_u32 {
        return "unexpected continuation byte"
    }
    if status == 3_u32 {
        return "invalid leading byte"
    }
    if status == 4_u32 {
        return "truncated sequence"
    }
    if status == 5_u32 {
        return "invalid continuation byte"
    }
    if status == 6_u32 {
        return "overlong encoding"
    }
    if status == 7_u32 {
        return "surrogate codepoint"
    }
    if status == 8_u32 {
        return "codepoint above U+10FFFF"
    }
    return "unknown status"
}

fn __zero_std_unicode_next_index(text: Span<u8>, index: usize) -> Maybe<usize> {
    let width: Maybe<usize> = __zero_std_unicode_width_at(text, index)
    if width.has {
        return index + width.value
    }
    return null
}

fn __zero_std_unicode_invalid_index(text: Span<u8>) -> usize {
    var index: usize = 0
    while index < std.mem.len(text) {
        let next: Maybe<usize> = __zero_std_unicode_next_index(text, index)
        if !next.has {
            return index
        }
        index = next.value
    }
    return std.mem.len(text)
}

fn __zero_std_unicode_width_at(text: Span<u8>, index: usize) -> Maybe<usize> {
    let raw: u64 = __zero_std_unicode_decode_raw(text, index)
    if raw == 0 {
        return null
    }
    return (raw / 4294967296_u64) as usize
}

fn __zero_std_unicode_encoded_width(cp: u32) -> Maybe<usize> {
    if cp >= 55296_u32 && cp <= 57343_u32 {
        return null
    }
    if cp > 1114111_u32 {
        return null
    }
    if cp < 128_u32 {
        return 1_usize
    }
    if cp < 2048_u32 {
        return 2_usize
    }
    if cp < 65536_u32 {
        return 3_usize
    }
    return 4_usize
}

fn __zero_std_unicode_encode(buffer: MutSpan<u8>, cp: u32) -> Maybe<Span<u8>> {
    let width: Maybe<usize> = __zero_std_unicode_encoded_width(cp)
    if !width.has {
        return null
    }
    let needed: usize = width.value
    if needed > std.mem.len(buffer) {
        return null
    }
    if needed == 1 {
        buffer[0] = cp as u8
        return buffer[..1]
    }
    if needed == 2 {
        buffer[0] = (192_u32 + cp / 64_u32) as u8
        buffer[1] = (128_u32 + cp % 64_u32) as u8
        return buffer[..2]
    }
    if needed == 3 {
        buffer[0] = (224_u32 + cp / 4096_u32) as u8
        buffer[1] = (128_u32 + (cp / 64_u32) % 64_u32) as u8
        buffer[2] = (128_u32 + cp % 64_u32) as u8
        return buffer[..3]
    }
    buffer[0] = (240_u32 + cp / 262144_u32) as u8
    buffer[1] = (128_u32 + (cp / 4096_u32) % 64_u32) as u8
    buffer[2] = (128_u32 + (cp / 64_u32) % 64_u32) as u8
    buffer[3] = (128_u32 + cp % 64_u32) as u8
    return buffer[..4]
}

fn __zero_std_unicode_is_digit(cp: u32) -> Bool {
    return cp >= 48_u32 && cp <= 57_u32
}

fn __zero_std_unicode_is_word(cp: u32) -> Bool {
    return (cp >= 48_u32 && cp <= 57_u32) || ((cp >= 65_u32 && cp <= 90_u32) || (cp >= 97_u32 && cp <= 122_u32) || cp == 95_u32)
}

fn __zero_std_unicode_is_space(cp: u32) -> Bool {
    if cp == 9_u32 || cp == 10_u32 || (cp == 11_u32 || cp == 12_u32) || (cp == 13_u32 || cp == 32_u32) {
        return true
    }
    if cp == 160_u32 || cp == 5760_u32 || (cp == 8232_u32 || cp == 8233_u32) {
        return true
    }
    if cp >= 8192_u32 && cp <= 8202_u32 {
        return true
    }
    return cp == 8239_u32 || cp == 8287_u32 || (cp == 12288_u32 || cp == 65279_u32)
}