import std._vec;

/* A codemap is a thing that maps uints to file/line/column positions
 * in a crate. This to make it possible to represent the positions
 * with single-word things, rather than passing records all over the
 * compiler.
 */

type filemap = @rec(str name,
                    uint start_pos,
                    mutable vec[uint] lines);
type codemap = @rec(mutable vec[filemap] files);
type loc = rec(str filename, uint line, uint col);

fn new_codemap() -> codemap {
    let vec[filemap] files = vec();
    ret @rec(mutable files=files);
}

fn new_filemap(str filename, uint start_pos) -> filemap {
    ret @rec(name=filename,
             start_pos=start_pos,
             mutable lines=vec(0u));
}

fn next_line(filemap file, uint pos) {
    _vec.push[uint](file.lines, pos);
}

fn lookup_pos(codemap map, uint pos) -> loc {
    auto a = 0u; auto b = _vec.len[filemap](map.files);
    while (b - a > 1u) {
        auto m = (a + b) / 2u;
        if (map.files.(m).start_pos > pos) { b = m; }
        else { a = m; }
    }
    auto f = map.files.(a);
    a = 0u; b = _vec.len[uint](f.lines);
    while (b - a > 1u) {
        auto m = (a + b) / 2u;
        if (f.lines.(m) > pos) { b = m; }
        else { a = m; }
    }
    ret rec(filename=f.name,
            line=a + 1u,
            col=pos - f.lines.(a));
}

//
// 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 $RBUILD 2>&1 | sed -e 's/\\/x\\//x:\\//g'";
// End:
//