import std::vec;
import std::option::none;
import syntax::ast;
import lib::llvm::llvm::{ValueRef, TypeRef};
import back::abi;
import trans::{call_memmove, trans_shared_malloc, llsize_of, type_of_or_i8,
               INIT, copy_val, load_if_immediate, alloca, size_of,
               llderivedtydescs_block_ctxt, lazily_emit_tydesc_glue,
               get_tydesc, load_inbounds, move_val_if_temp, trans_lval,
               node_id_type, new_sub_block_ctxt, tps_normal, do_spill_noroot,
               GEPi, alloc_ty, dest};
import trans_build::*;
import trans_common::*;

fn get_fill(bcx: @block_ctxt, vptrptr: ValueRef) -> ValueRef {
    Load(bcx, GEPi(bcx, Load(bcx, vptrptr), [0, abi::vec_elt_fill as int]))
}
fn get_alloc(bcx: @block_ctxt, vptrptr: ValueRef) -> ValueRef {
    Load(bcx, GEPi(bcx, Load(bcx, vptrptr), [0, abi::vec_elt_alloc as int]))
}
fn get_dataptr(bcx: @block_ctxt, vptrptr: ValueRef, unit_ty: TypeRef) ->
   ValueRef {
    let ptr = GEPi(bcx, Load(bcx, vptrptr), [0, abi::vec_elt_elems as int]);
    PointerCast(bcx, ptr, T_ptr(unit_ty))
}

fn pointer_add(bcx: @block_ctxt, ptr: ValueRef, bytes: ValueRef) -> ValueRef {
    let old_ty = val_ty(ptr);
    let bptr = PointerCast(bcx, ptr, T_ptr(T_i8()));
    ret PointerCast(bcx, InBoundsGEP(bcx, bptr, [bytes]), old_ty);
}

fn alloc_raw(bcx: @block_ctxt, fill: ValueRef, alloc: ValueRef) -> result {
    let llvecty = T_opaque_vec();
    let vecsize = Add(bcx, alloc, llsize_of(llvecty));
    let {bcx: bcx, val: vecptr} =
        trans_shared_malloc(bcx, T_ptr(llvecty), vecsize);
    Store(bcx, fill,
          InBoundsGEP(bcx, vecptr, [C_int(0), C_uint(abi::vec_elt_fill)]));
    Store(bcx, alloc,
          InBoundsGEP(bcx, vecptr, [C_int(0), C_uint(abi::vec_elt_alloc)]));
    ret {bcx: bcx, val: vecptr};
}

type alloc_result =
    {bcx: @block_ctxt,
     val: ValueRef,
     unit_ty: ty::t,
     llunitsz: ValueRef,
     llunitty: TypeRef};

fn alloc(bcx: @block_ctxt, vec_ty: ty::t, elts: uint, dest: dest)
    -> alloc_result {
    let unit_ty = ty::sequence_element_type(bcx_tcx(bcx), vec_ty);
    let llunitty = type_of_or_i8(bcx, unit_ty);
    let llvecty = T_vec(llunitty);
    let {bcx: bcx, val: unit_sz} = size_of(bcx, unit_ty);

    let fill = Mul(bcx, C_uint(elts), unit_sz);
    let alloc = if elts < 4u { Mul(bcx, C_int(4), unit_sz) } else { fill };
    let {bcx: bcx, val: vptr} = alloc_raw(bcx, fill, alloc);
    let vptr = PointerCast(bcx, vptr, T_ptr(llvecty));

    let vptrptr = alt dest { trans::save_in(a) { a } };
    Store(bcx, vptr, vptrptr);
//    add_clean_temp(bcx, vptrptr, vec_ty);
    ret {bcx: bcx,
         val: vptrptr,
         unit_ty: unit_ty,
         llunitsz: unit_sz,
         llunitty: llunitty};
}

fn duplicate(bcx: @block_ctxt, vptrptr: ValueRef) -> @block_ctxt {
    let fill = get_fill(bcx, vptrptr);
    let vptr = Load(bcx, vptrptr);
    let size = Add(bcx, fill, llsize_of(T_opaque_vec()));
    let {bcx: bcx, val: newptr} =
        trans_shared_malloc(bcx, val_ty(vptr), size);
    let bcx = call_memmove(bcx, newptr, vptr, size).bcx;
    Store(bcx, fill,
          InBoundsGEP(bcx, newptr, [C_int(0), C_uint(abi::vec_elt_alloc)]));
    Store(bcx, newptr, vptrptr);
    ret bcx;
}
fn make_drop_glue(bcx: @block_ctxt, vptrptr: ValueRef, vec_ty: ty::t) ->
   @block_ctxt {
    let unit_ty = ty::sequence_element_type(bcx_tcx(bcx), vec_ty);
    let vptr = Load(bcx, vptrptr);
    let drop_cx = new_sub_block_ctxt(bcx, "drop");
    let next_cx = new_sub_block_ctxt(bcx, "next");
    let null_test = IsNull(bcx, vptr);
    CondBr(bcx, null_test, next_cx.llbb, drop_cx.llbb);
    if ty::type_needs_drop(bcx_tcx(bcx), unit_ty) {
        drop_cx = iter_vec(drop_cx, vptrptr, vec_ty, trans::drop_ty);
    }
    drop_cx = trans::trans_shared_free(drop_cx, vptr);
    Store(drop_cx, C_null(val_ty(vptr)), vptrptr);
    Br(drop_cx, next_cx.llbb);
    ret next_cx;
}

fn trans_vec(bcx: @block_ctxt, args: [@ast::expr], id: ast::node_id,
             dest: dest) -> @block_ctxt {
    if dest == trans::ignore {
        for arg in args {
            bcx = trans::trans_expr_dps(bcx, arg, trans::ignore);
        }
        ret bcx;
    }
    let vec_ty = node_id_type(bcx_ccx(bcx), id);
    let {bcx: bcx,
         val: vptrptr,
         llunitsz: llunitsz,
         unit_ty: unit_ty,
         llunitty: llunitty} =
        alloc(bcx, vec_ty, vec::len(args), dest);

    let vptr = Load(bcx, vptrptr);
    add_clean_free(bcx, vptr, true);
    // Store the individual elements.
    let dataptr = get_dataptr(bcx, vptrptr, llunitty);
    let i = 0u, temp_cleanups = [vptr];
    for e in args {
        let lv = trans_lval(bcx, e);
        bcx = lv.bcx;
        let lleltptr = if ty::type_has_dynamic_size(bcx_tcx(bcx), unit_ty) {
            InBoundsGEP(bcx, dataptr, [Mul(bcx, C_uint(i), llunitsz)])
        } else { InBoundsGEP(bcx, dataptr, [C_uint(i)]) };
        bcx = move_val_if_temp(bcx, INIT, lleltptr, lv, unit_ty);
        add_clean_temp_mem(bcx, lleltptr, unit_ty);
        temp_cleanups += [lleltptr];
        i += 1u;
    }
    for clean in temp_cleanups { revoke_clean(bcx, clean); }
    ret bcx;
}
fn trans_str(bcx: @block_ctxt, s: str, dest: dest) -> @block_ctxt {
    let veclen = std::str::byte_len(s) + 1u; // +1 for \0
    let {bcx: bcx, val: sptrptr, _} =
        alloc(bcx, ty::mk_str(bcx_tcx(bcx)), veclen, dest);

    let llcstr = C_cstr(bcx_ccx(bcx), s);
    let bcx =
        call_memmove(bcx, get_dataptr(bcx, sptrptr, T_i8()), llcstr,
                     C_uint(veclen)).bcx;
    ret bcx;
}

fn trans_append(cx: @block_ctxt, vec_ty: ty::t, lhsptr: ValueRef,
                rhsptr: ValueRef) -> @block_ctxt {
    // Cast to opaque interior vector types if necessary.
    let unit_ty = ty::sequence_element_type(bcx_tcx(cx), vec_ty);
    let dynamic = ty::type_has_dynamic_size(bcx_tcx(cx), unit_ty);
    if dynamic {
        lhsptr = PointerCast(cx, lhsptr, T_ptr(T_ptr(T_opaque_vec())));
        rhsptr = PointerCast(cx, rhsptr, T_ptr(T_ptr(T_opaque_vec())));
    }
    let strings =
        alt ty::struct(bcx_tcx(cx), vec_ty) {
          ty::ty_str. { true }
          ty::ty_vec(_) { false }
        };

    let {bcx: bcx, val: unit_sz} = size_of(cx, unit_ty);
    let llunitty = type_of_or_i8(cx, unit_ty);

    let rhs = Load(bcx, rhsptr);
    let lhs = Load(bcx, lhsptr);
    let self_append = ICmp(bcx, lib::llvm::LLVMIntEQ, lhs, rhs);
    let lfill = get_fill(bcx, lhsptr);
    let rfill = get_fill(bcx, rhsptr);
    let new_fill = Add(bcx, lfill, rfill);
    if strings { new_fill = Sub(bcx, new_fill, C_int(1)); }
    let opaque_lhs = PointerCast(bcx, lhsptr, T_ptr(T_ptr(T_opaque_vec())));
    Call(bcx, bcx_ccx(cx).upcalls.vec_grow,
         [cx.fcx.lltaskptr, opaque_lhs, new_fill]);
    // Was overwritten if we resized
    rhsptr = Select(bcx, self_append, lhsptr, rhsptr);

    let lhs_data = get_dataptr(bcx, lhsptr, llunitty);
    let lhs_off = lfill;
    if strings { lhs_off = Sub(bcx, lhs_off, C_int(1)); }
    let write_ptr = pointer_add(bcx, lhs_data, lhs_off);
    let write_ptr_ptr = do_spill_noroot(bcx, write_ptr);
    let bcx =
        iter_vec_raw(bcx, rhsptr, vec_ty, rfill,
                     // We have to increment by the dynamically-computed size.
                     {|bcx, addr, _ty|
                         let write_ptr = Load(bcx, write_ptr_ptr);
                         let bcx =
                             copy_val(bcx, INIT, write_ptr,
                                      load_if_immediate(bcx, addr, unit_ty),
                                      unit_ty);
                         let incr = dynamic ? unit_sz : C_int(1);
                         Store(bcx, InBoundsGEP(bcx, write_ptr, [incr]),
                               write_ptr_ptr);
                         ret bcx;
                     });
    ret bcx;
}

fn trans_append_literal(bcx: @block_ctxt, vptrptr: ValueRef, vec_ty: ty::t,
                        vals: [@ast::expr]) -> @block_ctxt {
    let elt_ty = ty::sequence_element_type(bcx_tcx(bcx), vec_ty);
    let ti = none;
    let {bcx: bcx, val: td} =
        get_tydesc(bcx, elt_ty, false, tps_normal, ti).result;
    trans::lazily_emit_tydesc_glue(bcx, abi::tydesc_field_take_glue, ti);
    let opaque_v = PointerCast(bcx, vptrptr, T_ptr(T_ptr(T_opaque_vec())));
    for val in vals {
        let {bcx: e_bcx, val: elt} = trans::trans_expr(bcx, val);
        bcx = e_bcx;
        let r = trans::spill_if_immediate(bcx, elt, elt_ty);
        let spilled = r.val;
        bcx = r.bcx;
        Call(bcx, bcx_ccx(bcx).upcalls.vec_push,
             [bcx.fcx.lltaskptr, opaque_v, td,
              PointerCast(bcx, spilled, T_ptr(T_i8()))]);
    }
    ret bcx;
}

fn trans_add(bcx: @block_ctxt, vec_ty: ty::t, lhsptr: ValueRef,
             rhsptr: ValueRef, dest: dest) -> @block_ctxt {
    let strings = alt ty::struct(bcx_tcx(bcx), vec_ty) {
      ty::ty_str. { true }
      ty::ty_vec(_) { false }
    };
    let unit_ty = ty::sequence_element_type(bcx_tcx(bcx), vec_ty);
    let llunitty = type_of_or_i8(bcx, unit_ty);
    let {bcx: bcx, val: llunitsz} = size_of(bcx, unit_ty);

    let lhs_fill = get_fill(bcx, lhsptr);
    if strings { lhs_fill = Sub(bcx, lhs_fill, C_int(1)); }
    let rhs_fill = get_fill(bcx, rhsptr);
    let new_fill = Add(bcx, lhs_fill, rhs_fill);
    let {bcx: bcx, val: new_vec_ptr} = alloc_raw(bcx, new_fill, new_fill);
    new_vec_ptr = PointerCast(bcx, new_vec_ptr, T_ptr(T_vec(llunitty)));
    let new_vec_ptr_ptr = alt dest { trans::save_in(a) { a } };
    Store(bcx, new_vec_ptr, new_vec_ptr_ptr);

    let write_ptr_ptr =
        do_spill_noroot(bcx, get_dataptr(bcx, new_vec_ptr_ptr, llunitty));
    let copy_fn =
        bind fn (bcx: @block_ctxt, addr: ValueRef, _ty: ty::t,
                 write_ptr_ptr: ValueRef, unit_ty: ty::t, llunitsz: ValueRef)
                -> @block_ctxt {
                 let write_ptr = Load(bcx, write_ptr_ptr);
                 let bcx =
                     copy_val(bcx, INIT, write_ptr,
                              load_if_immediate(bcx, addr, unit_ty), unit_ty);
                 let incr =
                     ty::type_has_dynamic_size(bcx_tcx(bcx), unit_ty) ?
                         llunitsz : C_int(1);
                 Store(bcx, InBoundsGEP(bcx, write_ptr, [incr]),
                       write_ptr_ptr);
                 ret bcx;
             }(_, _, _, write_ptr_ptr, unit_ty, llunitsz);

    let bcx = iter_vec_raw(bcx, lhsptr, vec_ty, lhs_fill, copy_fn);
    ret iter_vec_raw(bcx, rhsptr, vec_ty, rhs_fill, copy_fn);
}

type val_and_ty_fn = fn(@block_ctxt, ValueRef, ty::t) -> result;

type iter_vec_block = block(@block_ctxt, ValueRef, ty::t) -> @block_ctxt;

fn iter_vec_raw(bcx: @block_ctxt, vptrptr: ValueRef, vec_ty: ty::t,
                fill: ValueRef, f: iter_vec_block) -> @block_ctxt {
    let unit_ty = ty::sequence_element_type(bcx_tcx(bcx), vec_ty);
    let llunitty = type_of_or_i8(bcx, unit_ty);
    let {bcx: bcx, val: unit_sz} = size_of(bcx, unit_ty);
    vptrptr = PointerCast(bcx, vptrptr, T_ptr(T_ptr(T_vec(llunitty))));
    let data_ptr = get_dataptr(bcx, vptrptr, llunitty);

    // Calculate the last pointer address we want to handle.
    // TODO: Optimize this when the size of the unit type is statically
    // known to not use pointer casts, which tend to confuse LLVM.
    let data_end_ptr = pointer_add(bcx, data_ptr, fill);

    // Now perform the iteration.
    let header_cx = new_sub_block_ctxt(bcx, "iter_vec_loop_header");
    Br(bcx, header_cx.llbb);
    let data_ptr = Phi(header_cx, val_ty(data_ptr), [data_ptr], [bcx.llbb]);
    let not_yet_at_end =
        ICmp(header_cx, lib::llvm::LLVMIntULT, data_ptr, data_end_ptr);
    let body_cx = new_sub_block_ctxt(header_cx, "iter_vec_loop_body");
    let next_cx = new_sub_block_ctxt(header_cx, "iter_vec_next");
    CondBr(header_cx, not_yet_at_end, body_cx.llbb, next_cx.llbb);
    body_cx = f(body_cx, data_ptr, unit_ty);
    let increment =
        if ty::type_has_dynamic_size(bcx_tcx(bcx), unit_ty) {
            unit_sz
        } else { C_int(1) };
    AddIncomingToPhi(data_ptr, InBoundsGEP(body_cx, data_ptr, [increment]),
                     body_cx.llbb);
    Br(body_cx, header_cx.llbb);
    ret next_cx;
}

fn iter_vec(bcx: @block_ctxt, vptrptr: ValueRef, vec_ty: ty::t,
            f: iter_vec_block) -> @block_ctxt {
    vptrptr = PointerCast(bcx, vptrptr, T_ptr(T_ptr(T_opaque_vec())));
    ret iter_vec_raw(bcx, vptrptr, vec_ty, get_fill(bcx, vptrptr), f);
}

//
// 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:
//