import rustrt.sbuf;

import _vec.rustrt.vbuf;

native "rust" mod rustrt {
    type sbuf;
    fn str_buf(str s) -> sbuf;
    fn str_byte_len(str s) -> uint;
    fn str_alloc(uint n_bytes) -> str;
    fn str_from_vec(vec[mutable? u8] b) -> str;
    fn str_from_cstr(sbuf cstr) -> str;
    fn str_from_buf(sbuf buf, uint len) -> str;
    fn str_push_byte(str s, uint byte) -> str;
    fn refcount[T](str s) -> uint;
}

fn eq(&str a, &str b) -> bool {
    let uint i = byte_len(a);
    if (byte_len(b) != i) {
        ret false;
    }
    while (i > 0u) {
        i -= 1u;
        auto cha = a.(i);
        auto chb = b.(i);
        if (cha != chb) {
            ret false;
        }
    }
    ret true;
}

fn lteq(&str a, &str b) -> bool {
    let uint i = byte_len(a);
    let uint j = byte_len(b);
    let uint n = i;
    if (j < n) {
        n = j;
    }

    let uint x = 0u;
    while (x < n) {
        auto cha = a.(x);
        auto chb = b.(x);
        if (cha < chb) {
            ret true;
        }
        else if (cha > chb) {
            ret false;
        }
        x += 1u;
    }

    ret i <= j;
}


fn hash(&str s) -> uint {
    // djb hash.
    // FIXME: replace with murmur.
    let uint u = 5381u;
    for (u8 c in s) {
        u *= 33u;
        u += (c as uint);
    }
    ret u;
}

// UTF-8 tags and ranges
const u8 tag_cont_u8 = 0x80_u8;
const uint tag_cont = 0x80_u;
const uint max_one_b = 0x80_u;
const uint tag_two_b = 0xc0_u;
const uint max_two_b = 0x800_u;
const uint tag_three_b = 0xe0_u;
const uint max_three_b = 0x10000_u;
const uint tag_four_b = 0xf0_u;
const uint max_four_b = 0x200000_u;
const uint tag_five_b = 0xf8_u;
const uint max_five_b = 0x4000000_u;
const uint tag_six_b = 0xfc_u;

fn is_utf8(vec[u8] v) -> bool {
    auto i = 0u;
    auto total = _vec.len[u8](v);
    while (i < total) {
        auto chsize = utf8_char_width(v.(i));
        if (chsize == 0u) {ret false;}
        if (i + chsize > total) {ret false;}
        i += 1u;
        while (chsize > 1u) {
            if (v.(i) & 0xc0_u8 != tag_cont_u8) {ret false;}
            i += 1u;
            chsize -= 1u;
        }
    }
    ret true;
}

fn is_ascii(str s) -> bool {
    let uint i = byte_len(s);
    while (i > 0u) {
        i -= 1u;
        if ((s.(i) & 0x80_u8) != 0u8) {
            ret false;
        }
    }
    ret true;
}

fn alloc(uint n_bytes) -> str {
    ret rustrt.str_alloc(n_bytes);
}

// Returns the number of bytes (a.k.a. UTF-8 code units) in s.
// Contrast with a function that would return the number of code
// points (char's), combining character sequences, words, etc.  See
// http://icu-project.org/apiref/icu4c/classBreakIterator.html for a
// way to implement those.
fn byte_len(str s) -> uint {
    ret rustrt.str_byte_len(s);
}

fn buf(str s) -> sbuf {
    ret rustrt.str_buf(s);
}

fn bytes(str s) -> vec[u8] {
    fn ith(str s, uint i) -> u8 {
        ret s.(i);
    }
    ret _vec.init_fn[u8](bind ith(s, _), byte_len(s));
}

fn from_bytes(vec[u8] v) : is_utf8(v) -> str {
    ret rustrt.str_from_vec(v);
}

// FIXME temp thing
fn unsafe_from_bytes(vec[mutable? u8] v) -> str {
    ret rustrt.str_from_vec(v);
}

// FIXME even temp-er thing; rustc can use "unsafe_from_bytes" above
fn unsafe_from_mutable_bytes(vec[mutable u8] mv) -> str {
    let vec[u8] v = vec();
    for (mutable u8 b in mv) {
        v += vec(b);
    }
    ret rustrt.str_from_vec(v);
}

fn unsafe_from_byte(u8 u) -> str {
    ret rustrt.str_from_vec(vec(u));
}

unsafe fn str_from_cstr(sbuf cstr) -> str {
    ret rustrt.str_from_cstr(cstr);
}

unsafe fn str_from_buf(sbuf buf, uint len) -> str {
    ret rustrt.str_from_buf(buf, len);
}

fn push_utf8_bytes(&mutable str s, char ch) {
    auto code = ch as uint;
    if (code < max_one_b) {
        s = rustrt.str_push_byte(s, code);
    } else if (code < max_two_b) {
        s = rustrt.str_push_byte(s, ((code >> 6u) & 0x1f_u) | tag_two_b);
        s = rustrt.str_push_byte(s, (code & 0x3f_u) | tag_cont);
    } else if (code < max_three_b) {
        s = rustrt.str_push_byte(s, ((code >> 12u) & 0x0f_u) | tag_three_b);
        s = rustrt.str_push_byte(s, ((code >> 6u) & 0x3f_u) | tag_cont);
        s = rustrt.str_push_byte(s, (code & 0x3f_u) | tag_cont);
    } else if (code < max_four_b) {
        s = rustrt.str_push_byte(s, ((code >> 18u) & 0x07_u) | tag_four_b);
        s = rustrt.str_push_byte(s, ((code >> 12u) & 0x3f_u) | tag_cont);
        s = rustrt.str_push_byte(s, ((code >> 6u) & 0x3f_u) | tag_cont);
        s = rustrt.str_push_byte(s, (code & 0x3f_u) | tag_cont);
    } else if (code < max_five_b) {
        s = rustrt.str_push_byte(s, ((code >> 24u) & 0x03_u) | tag_five_b);
        s = rustrt.str_push_byte(s, ((code >> 18u) & 0x3f_u) | tag_cont);
        s = rustrt.str_push_byte(s, ((code >> 12u) & 0x3f_u) | tag_cont);
        s = rustrt.str_push_byte(s, ((code >> 6u) & 0x3f_u) | tag_cont);
        s = rustrt.str_push_byte(s, (code & 0x3f_u) | tag_cont);
    } else {
        s = rustrt.str_push_byte(s, ((code >> 30u) & 0x01_u) | tag_six_b);
        s = rustrt.str_push_byte(s, ((code >> 24u) & 0x3f_u) | tag_cont);
        s = rustrt.str_push_byte(s, ((code >> 18u) & 0x3f_u) | tag_cont);
        s = rustrt.str_push_byte(s, ((code >> 12u) & 0x3f_u) | tag_cont);
        s = rustrt.str_push_byte(s, ((code >> 6u) & 0x3f_u) | tag_cont);
        s = rustrt.str_push_byte(s, (code & 0x3f_u) | tag_cont);
    }
}

fn from_char(char ch) -> str {
    auto buf = "";
    push_utf8_bytes(buf, ch);
    ret buf;
}

fn from_chars(vec[char] chs) -> str {
    auto buf = "";
    for (char ch in chs) {push_utf8_bytes(buf, ch);}
    ret buf;
}

fn utf8_char_width(u8 b) -> uint {
    let uint byte = b as uint;
    if (byte < 0x80_u) {ret 1u;}
    if (byte < 0xc0_u) {ret 0u;} // Not a valid start byte
    if (byte < 0xe0_u) {ret 2u;}
    if (byte < 0xf0_u) {ret 3u;}
    if (byte < 0xf8_u) {ret 4u;}
    if (byte < 0xfc_u) {ret 5u;}
    ret 6u;
}

fn char_range_at(str s, uint i) -> tup(char, uint) {
    auto b0 = s.(i);
    auto w = utf8_char_width(b0);
    check(w != 0u);
    if (w == 1u) {ret tup(b0 as char, i + 1u);}
    auto val = 0u;
    auto end = i + w;
    i += 1u;
    while (i < end) {
        auto byte = s.(i);
        check(byte & 0xc0_u8 == tag_cont_u8);
        val <<= 6u;
        val += (byte & 0x3f_u8) as uint;
        i += 1u;
    }
    // Clunky way to get the right bits from the first byte. Uses two shifts,
    // the first to clip off the marker bits at the left of the byte, and then
    // a second (as uint) to get it to the right position.
    val += ((b0 << ((w + 1u) as u8)) as uint) << ((w - 1u) * 6u - w - 1u);
    ret tup(val as char, i);
}

fn char_at(str s, uint i) -> char {
    ret char_range_at(s, i)._0;
}

fn char_len(str s) -> uint {
    auto i = 0u;
    auto len = 0u;
    auto total = byte_len(s);
    while (i < total) {
        auto chsize = utf8_char_width(s.(i));
        check(chsize > 0u);
        len += 1u;
        i += chsize;
    }
    check(i == total);
    ret len;
}

fn to_chars(str s) -> vec[char] {
    let vec[char] buf = vec();
    auto i = 0u;
    auto len = byte_len(s);
    while (i < len) {
        auto cur = char_range_at(s, i);
        _vec.push[char](buf, cur._0);
        i = cur._1;
    }
    ret buf;
}

fn push_char(&mutable str s, char ch) {
    s += from_char(ch);
}

fn pop_char(&mutable str s) -> char {
    auto end = byte_len(s);
    while (end > 0u && s.(end - 1u) & 0xc0_u8 == tag_cont_u8) {end -= 1u;}
    check(end > 0u);
    auto ch = char_at(s, end - 1u);
    s = substr(s, 0u, end - 1u);
    ret ch;
}

fn shift_char(&mutable str s) -> char {
    auto r = char_range_at(s, 0u);
    s = substr(s, r._1, byte_len(s) - r._1);
    ret r._0;
}

fn unshift_char(&mutable str s, char ch) {
    // Workaround for rustboot order-of-evaluation issue -- if I put s
    // directly after the +, the string ends up containing (only) the
    // character, twice.
    auto x = s;
    s = from_char(ch) + x;
}

fn refcount(str s) -> uint {
    auto r = rustrt.refcount[u8](s);
    if (r == dbg.const_refcount) {
        ret r;
    } else {
        // -1 because calling this function incremented the refcount.
        ret  r - 1u;
    }
}


// Standard bits from the world of string libraries.

fn index(str s, u8 c) -> int {
    let int i = 0;
    for (u8 k in s) {
        if (k == c) {
            ret i;
        }
        i += 1;
    }
    ret -1;
}

fn rindex(str s, u8 c) -> int {
    let int n = _str.byte_len(s) as int;
    while (n >= 0) {
        if (s.(n) == c) {
            ret n;
        }
        n -= 1;
    }
    ret n;
}

fn find(str haystack, str needle) -> int {

    let int haystack_len = byte_len(haystack) as int;
    let int needle_len = byte_len(needle) as int;

    if (needle_len == 0) {
        ret 0;
    }

    fn match_at(&str haystack,
                &str needle,
                int i) -> bool {
        let int j = i;
        for (u8 c in needle) {
            if (haystack.(j) != c) {
                ret false;
            }
            j += 1;
        }
        ret true;
    }

    let int i = 0;
    while (i <= haystack_len - needle_len) {
        if (match_at(haystack, needle, i)) {
            ret i;
        }
        i += 1;
    }
    ret  -1;
}

fn starts_with(str haystack, str needle) -> bool {
    let uint haystack_len = byte_len(haystack);
    let uint needle_len = byte_len(needle);
    if (needle_len == 0u) {
        ret true;
    }
    if (needle_len > haystack_len) {
        ret false;
    }
    ret eq(substr(haystack, 0u, needle_len), needle);
}

fn ends_with(str haystack, str needle) -> bool {
    let uint haystack_len = byte_len(haystack);
    let uint needle_len = byte_len(needle);
    if (needle_len == 0u) {
        ret true;
    }
    if (needle_len > haystack_len) {
        ret false;
    }
    ret eq(substr(haystack,
                  haystack_len - needle_len,
                  needle_len),
           needle);
}

fn substr(str s, uint begin, uint len) -> str {
    let str accum = "";
    let uint i = begin;
    while (i < begin+len) {
        accum += unsafe_from_byte(s.(i));
        i += 1u;
    }
    ret accum;
}

fn shift_byte(&mutable str s) -> u8 {
    auto len = byte_len(s);
    check(len > 0u);
    auto b = s.(0);
    s = substr(s, 1u, len - 1u);
    ret b;
}

fn pop_byte(&mutable str s) -> u8 {
    auto len = byte_len(s);
    check(len > 0u);
    auto b = s.(len - 1u);
    s = substr(s, 0u, len - 1u);
    ret b;
}

fn push_byte(&mutable str s, u8 b) {
    s = rustrt.str_push_byte(s, b as uint);
}

fn unshift_byte(&mutable str s, u8 b) {
    auto res = alloc(byte_len(s) + 1u);
    res += unsafe_from_byte(b);
    res += s;
    s = res;
}

fn split(str s, u8 sep) -> vec[str] {
    let vec[str] v = vec();
    let str accum = "";
    let bool ends_with_sep = false;
    for (u8 c in s) {
        if (c == sep) {
            v += vec(accum);
            accum = "";
            ends_with_sep = true;
        } else {
            accum += unsafe_from_byte(c);
            ends_with_sep = false;
        }
    }
    if (_str.byte_len(accum) != 0u ||
        ends_with_sep) {
        v += vec(accum);
    }
    ret v;
}

fn concat(vec[str] v) -> str {
    let str s = "";
    for (str ss in v) {
        s += ss;
    }
    ret s;
}

fn connect(vec[str] v, str sep) -> str {
    let str s = "";
    let bool first = true;
    for (str ss in v) {
        if (first) {
            first = false;
        } else {
            s += sep;
        }
        s += ss;
    }
    ret s;
}

// FIXME: This only handles ASCII
fn to_upper(str s) -> str {
    auto outstr = "";
    auto ascii_a = 'a' as u8;
    auto ascii_z = 'z' as u8;
    auto diff = 32u8;
    for (u8 byte in s) {
        auto next;
        if (ascii_a <= byte && byte <= ascii_z) {
            next = byte - diff;
        } else {
            next = byte;
        }
        push_byte(outstr, next);
    }
    ret outstr;
}


// Local Variables:
// mode: rust;
// fill-column: 78;
// indent-tabs-mode: nil
// c-basic-offset: 4
// buffer-file-coding-system: utf-8-unix
// compile-command: "make -k -C .. 2>&1 | sed -e 's/\\/x\\//x:\\//g'";
// End: