/*! 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.
 */

use dvec::DVec;
use std::serialization::{Serializable,
                         Deserializable,
                         Serializer,
                         Deserializer};

export filename;
export filemap;
export filemap_;
export span;
export file_substr;
export fss_none;
export fss_internal;
export fss_external;
export CodeMap;
export expn_info;
export expn_info_;
export expanded_from;
export new_filemap;
export new_filemap_w_substr;
export mk_substr_filename;
export lookup_char_pos;
export lookup_char_pos_adj;
export adjust_span;
export span_to_str;
export span_to_filename;
export span_to_lines;
export file_lines;
export get_line;
export next_line;
export span_to_snippet;
export loc;
export get_filemap;
export new_codemap;

type filename = ~str;

struct file_pos {
    ch: uint, byte: uint
}

impl file_pos : cmp::Eq {
    pure fn eq(other: &file_pos) -> bool {
        self.ch == (*other).ch && self.byte == (*other).byte
    }
    pure fn ne(other: &file_pos) -> bool { !self.eq(other) }
}

enum file_substr {
    fss_none,
    fss_internal(span),
    fss_external({filename: ~str, line: uint, col: uint})
}

struct filemap {
    name: filename,
    substr: file_substr,
    src: @~str,
    start_pos: file_pos,
    mut lines: ~[file_pos]
}

impl filemap {
    static fn new_w_substr(+filename: filename, +substr: file_substr,
                           src: @~str,
                           start_pos_ch: uint, start_pos_byte: uint)
        -> filemap {
        return filemap {
            name: filename, substr: substr, src: src,
            start_pos: file_pos {ch: start_pos_ch, byte: start_pos_byte},
            mut lines: ~[file_pos {ch: start_pos_ch, byte: start_pos_byte}]
        };
    }

    static fn new(+filename: filename, src: @~str,
                  start_pos_ch: uint, start_pos_byte: uint)
        -> filemap {
        return filemap::new_w_substr(filename, fss_none, src,
                                     start_pos_ch, start_pos_byte);
    }
}

struct CodeMap {
    files: DVec<@filemap>
}

struct loc {
    file: @filemap, line: uint, col: uint
}

fn new_codemap() -> CodeMap {
    CodeMap {
        files: DVec()
    }
}

fn mk_substr_filename(cm: @CodeMap, sp: span) -> ~str
{
    let pos = lookup_char_pos(cm, sp.lo);
    return fmt!("<%s:%u:%u>", pos.file.name, pos.line, pos.col);
}

fn next_line(file: @filemap, chpos: uint, byte_pos: uint) {
    file.lines.push(file_pos {ch: chpos, byte: byte_pos + file.start_pos.byte});
}

type lookup_fn = pure fn(file_pos) -> uint;

fn lookup_line(map: @CodeMap, pos: uint, lookup: lookup_fn)
    -> {fm: @filemap, line: uint}
{
    let len = map.files.len();
    let mut a = 0u;
    let mut b = len;
    while b - a > 1u {
        let m = (a + b) / 2u;
        if lookup(map.files[m].start_pos) > pos { b = m; } else { a = m; }
    }
    if (a >= len) {
        fail fmt!("position %u does not resolve to a source location", pos)
    }
    let f = map.files[a];
    a = 0u;
    b = vec::len(f.lines);
    while b - a > 1u {
        let m = (a + b) / 2u;
        if lookup(f.lines[m]) > pos { b = m; } else { a = m; }
    }
    return {fm: f, line: a};
}

fn lookup_pos(map: @CodeMap, pos: uint, lookup: lookup_fn) -> loc {
    let {fm: f, line: a} = lookup_line(map, pos, lookup);
    return loc {file: f, line: a + 1u, col: pos - lookup(f.lines[a])};
}

fn lookup_char_pos(map: @CodeMap, pos: uint) -> loc {
    pure fn lookup(pos: file_pos) -> uint { return pos.ch; }
    return lookup_pos(map, pos, lookup);
}

fn lookup_byte_pos(map: @CodeMap, pos: uint) -> loc {
    pure fn lookup(pos: file_pos) -> uint { return pos.byte; }
    return lookup_pos(map, pos, lookup);
}

fn lookup_char_pos_adj(map: @CodeMap, pos: uint)
    -> {filename: ~str, line: uint, col: uint, file: Option<@filemap>}
{
    let loc = lookup_char_pos(map, pos);
    match (loc.file.substr) {
      fss_none => {
        {filename: /* FIXME (#2543) */ copy loc.file.name,
         line: loc.line,
         col: loc.col,
         file: Some(loc.file)}
      }
      fss_internal(sp) => {
        lookup_char_pos_adj(map, sp.lo + (pos - loc.file.start_pos.ch))
      }
      fss_external(eloc) => {
        {filename: /* FIXME (#2543) */ copy eloc.filename,
         line: eloc.line + loc.line - 1u,
         col: if loc.line == 1u {eloc.col + loc.col} else {loc.col},
         file: None}
      }
    }
}

fn adjust_span(map: @CodeMap, sp: span) -> span {
    pure fn lookup(pos: file_pos) -> uint { return pos.ch; }
    let line = lookup_line(map, sp.lo, lookup);
    match (line.fm.substr) {
      fss_none => sp,
      fss_internal(s) => {
        adjust_span(map, span {lo: s.lo + (sp.lo - line.fm.start_pos.ch),
                               hi: s.lo + (sp.hi - line.fm.start_pos.ch),
                               expn_info: sp.expn_info})}
      fss_external(_) => sp
    }
}

enum expn_info_ {
    expanded_from({call_site: span,
                   callie: {name: ~str, span: Option<span>}})
}
type expn_info = Option<@expn_info_>;

struct span {lo: uint, hi: uint, expn_info: expn_info}

impl span : cmp::Eq {
    pure fn eq(other: &span) -> bool {
        return self.lo == (*other).lo && self.hi == (*other).hi;
    }
    pure fn ne(other: &span) -> bool { !self.eq(other) }
}

impl<S: Serializer> span: Serializable<S> {
    /* Note #1972 -- spans are serialized but not deserialized */
    fn serialize(&self, _s: &S) { }
}

impl<D: Deserializer> span: Deserializable<D> {
    static fn deserialize(_d: &D) -> span {
        ast_util::dummy_sp()
    }
}

fn span_to_str_no_adj(sp: span, cm: @CodeMap) -> ~str {
    let lo = lookup_char_pos(cm, sp.lo);
    let hi = lookup_char_pos(cm, sp.hi);
    return fmt!("%s:%u:%u: %u:%u", lo.file.name,
             lo.line, lo.col, hi.line, hi.col)
}

fn span_to_str(sp: span, cm: @CodeMap) -> ~str {
    let lo = lookup_char_pos_adj(cm, sp.lo);
    let hi = lookup_char_pos_adj(cm, sp.hi);
    return fmt!("%s:%u:%u: %u:%u", lo.filename,
             lo.line, lo.col, hi.line, hi.col)
}

struct file_lines {
    file: @filemap,
    lines: ~[uint]
}

fn span_to_filename(sp: span, cm: @codemap::CodeMap) -> filename {
    let lo = lookup_char_pos(cm, sp.lo);
    return /* FIXME (#2543) */ copy lo.file.name;
}

fn span_to_lines(sp: span, cm: @codemap::CodeMap) -> @file_lines {
    let lo = lookup_char_pos(cm, sp.lo);
    let hi = lookup_char_pos(cm, sp.hi);
    let mut lines = ~[];
    for uint::range(lo.line - 1u, hi.line as uint) |i| {
        lines.push(i);
    };
    return @file_lines {file: lo.file, lines: lines};
}

fn get_line(fm: @filemap, line: int) -> ~str unsafe {
    let begin: uint = fm.lines[line].byte - fm.start_pos.byte;
    let end = match str::find_char_from(*fm.src, '\n', begin) {
      Some(e) => e,
      None => str::len(*fm.src)
    };
    str::slice(*fm.src, begin, end)
}

fn lookup_byte_offset(cm: @codemap::CodeMap, chpos: uint)
    -> {fm: @filemap, pos: uint} {
    pure fn lookup(pos: file_pos) -> uint { return pos.ch; }
    let {fm, line} = lookup_line(cm, chpos, lookup);
    let line_offset = fm.lines[line].byte - fm.start_pos.byte;
    let col = chpos - fm.lines[line].ch;
    let col_offset = str::count_bytes(*fm.src, line_offset, col);
    {fm: fm, pos: line_offset + col_offset}
}

fn span_to_snippet(sp: span, cm: @codemap::CodeMap) -> ~str {
    let begin = lookup_byte_offset(cm, sp.lo);
    let end = lookup_byte_offset(cm, sp.hi);
    assert begin.fm.start_pos == end.fm.start_pos;
    return str::slice(*begin.fm.src, begin.pos, end.pos);
}

fn get_snippet(cm: @codemap::CodeMap, fidx: uint, lo: uint, hi: uint) -> ~str
{
    let fm = cm.files[fidx];
    return str::slice(*fm.src, lo, hi)
}

fn get_filemap(cm: @CodeMap, filename: ~str) -> @filemap {
    for cm.files.each |fm| { if fm.name == filename { return *fm; } }
    //XXjdm the following triggers a mismatched type bug
    //      (or expected function, found _|_)
    fail; // ("asking for " + filename + " which we don't know about");
}

//
// Local Variables:
// mode: rust
// fill-column: 78;
// indent-tabs-mode: nil
// c-basic-offset: 4
// buffer-file-coding-system: utf-8-unix
// End:
//