/*

 * Copyright © 2018 Adobe Inc.

 *

 *  This is part of HarfBuzz, a text shaping library.

 *

 * Permission is hereby granted, without written agreement and without

 * license or royalty fees, to use, copy, modify, and distribute this

 * software and its documentation for any purpose, provided that the

 * above copyright notice and the following two paragraphs appear in

 * all copies of this software.

 *

 * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR

 * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES

 * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN

 * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH

 * DAMAGE.

 *

 * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,

 * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND

 * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS

 * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO

 * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.

 *

 * Adobe Author(s): Michiharu Ariza

 */

#ifndef HB_CFF_INTERP_CS_COMMON_HH

#define HB_CFF_INTERP_CS_COMMON_HH

#include "hb.hh"

#include "hb-cff-interp-common.hh"

namespace CFF {

using namespace OT;

enum cs_type_t {

  CSType_CharString,

  CSType_GlobalSubr,

  CSType_LocalSubr

};

struct call_context_t

{

  void init (const byte_str_ref_t substr_=byte_str_ref_t (), cs_type_t type_=CSType_CharString, unsigned int subr_num_=0)

  {

    str_ref = substr_;

    type = type_;

    subr_num = subr_num_;

  }

  void fini () {}

  byte_str_ref_t  str_ref;

  cs_type_t       type;

  unsigned int    subr_num;

};

/* call stack */

const unsigned int kMaxCallLimit = 10;

struct call_stack_t : stack_t<call_context_t, kMaxCallLimit> {};

template <typename SUBRS>

struct biased_subrs_t

{

  void init (const SUBRS &subrs_)

  {

    subrs = &subrs_;

    unsigned int  nSubrs = get_count ();

    if (nSubrs < 1240)

      bias = 107;

    else if (nSubrs < 33900)

      bias = 1131;

    else

      bias = 32768;

  }

  void fini () {}

  unsigned int get_count () const { return (subrs == nullptr)? 0: subrs->count; }

  unsigned int get_bias () const { return bias; }

  byte_str_t operator [] (unsigned int index) const

  {

    if (unlikely ((subrs == nullptr) || index >= subrs->count))

      return Null(byte_str_t);

    else

      return (*subrs)[index];

  }

  protected:

  unsigned int  bias;

  const SUBRS   *subrs;

};

struct point_t

{

  void init ()

  {

    x.init ();

    y.init ();

  }

  void set_int (int _x, int _y)

  {

    x.set_int (_x);

    y.set_int (_y);

  }

  void move_x (const number_t &dx) { x += dx; }

  void move_y (const number_t &dy) { y += dy; }

  void move (const number_t &dx, const number_t &dy) { move_x (dx); move_y (dy); }

  void move (const point_t &d) { move_x (d.x); move_y (d.y); }

  number_t  x;

  number_t  y;

};

template <typename ARG, typename SUBRS>

struct cs_interp_env_t : interp_env_t<ARG>

{

  void init (const byte_str_t &str, const SUBRS &globalSubrs_, const SUBRS &localSubrs_)

  {

    interp_env_t<ARG>::init (str);

    context.init (str, CSType_CharString);

    seen_moveto = true;

    seen_hintmask = false;

    hstem_count = 0;

    vstem_count = 0;

    hintmask_size = 0;

    pt.init ();

    callStack.init ();

    globalSubrs.init (globalSubrs_);

    localSubrs.init (localSubrs_);

  }

  void fini ()

  {

    interp_env_t<ARG>::fini ();

    callStack.fini ();

    globalSubrs.fini ();

    localSubrs.fini ();

  }

  bool in_error () const

  {

    return callStack.in_error () || SUPER::in_error ();

  }

  bool popSubrNum (const biased_subrs_t<SUBRS>& biasedSubrs, unsigned int &subr_num)

  {

    int n = SUPER::argStack.pop_int ();

    n += biasedSubrs.get_bias ();

    if (unlikely ((n < 0) || ((unsigned int)n >= biasedSubrs.get_count ())))

      return false;

    subr_num = (unsigned int)n;

    return true;

  }

  void callSubr (const biased_subrs_t<SUBRS>& biasedSubrs, cs_type_t type)

  {

    unsigned int subr_num;

    if (unlikely (!popSubrNum (biasedSubrs, subr_num)

                 || callStack.get_count () >= kMaxCallLimit))

    {

      SUPER::set_error ();

      return;

    }

    context.str_ref = SUPER::str_ref;

    callStack.push (context);

    context.init ( biasedSubrs[subr_num], type, subr_num);

    SUPER::str_ref = context.str_ref;

  }

  void returnFromSubr ()

  {

    if (unlikely (SUPER::str_ref.in_error ()))

      SUPER::set_error ();

    context = callStack.pop ();

    SUPER::str_ref = context.str_ref;

  }

  void determine_hintmask_size ()

  {

    if (!seen_hintmask)

    {

      vstem_count += SUPER::argStack.get_count() / 2;

      hintmask_size = (hstem_count + vstem_count + 7) >> 3;

      seen_hintmask = true;

    }

  }

  void set_endchar (bool endchar_flag_) { endchar_flag = endchar_flag_; }

  bool is_endchar () const { return endchar_flag; }

  const number_t &get_x () const { return pt.x; }

  const number_t &get_y () const { return pt.y; }

  const point_t &get_pt () const { return pt; }

  void moveto (const point_t &pt_ ) { pt = pt_; }

  public:

  call_context_t   context;

  bool    endchar_flag;

  bool    seen_moveto;

  bool    seen_hintmask;

  unsigned int  hstem_count;

  unsigned int  vstem_count;

  unsigned int  hintmask_size;

  call_stack_t  callStack;

  biased_subrs_t<SUBRS>   globalSubrs;

  biased_subrs_t<SUBRS>   localSubrs;

  private:

  point_t        pt;

  typedef interp_env_t<ARG> SUPER;

};

template <typename ENV, typename PARAM>

struct path_procs_null_t

{

  static void rmoveto (ENV &env, PARAM& param) {}

  static void hmoveto (ENV &env, PARAM& param) {}

  static void vmoveto (ENV &env, PARAM& param) {}

  static void rlineto (ENV &env, PARAM& param) {}

  static void hlineto (ENV &env, PARAM& param) {}

  static void vlineto (ENV &env, PARAM& param) {}

  static void rrcurveto (ENV &env, PARAM& param) {}

  static void rcurveline (ENV &env, PARAM& param) {}

  static void rlinecurve (ENV &env, PARAM& param) {}

  static void vvcurveto (ENV &env, PARAM& param) {}

  static void hhcurveto (ENV &env, PARAM& param) {}

  static void vhcurveto (ENV &env, PARAM& param) {}

  static void hvcurveto (ENV &env, PARAM& param) {}

  static void moveto (ENV &env, PARAM& param, const point_t &pt) {}

  static void line (ENV &env, PARAM& param, const point_t &pt1) {}

  static void curve (ENV &env, PARAM& param, const point_t &pt1, const point_t &pt2, const point_t &pt3) {}

  static void hflex (ENV &env, PARAM& param) {}

  static void flex (ENV &env, PARAM& param) {}

  static void hflex1 (ENV &env, PARAM& param) {}

  static void flex1 (ENV &env, PARAM& param) {}

};

template <typename ARG, typename OPSET, typename ENV, typename PARAM, typename PATH=path_procs_null_t<ENV, PARAM> >

struct cs_opset_t : opset_t<ARG>

{

  static void process_op (op_code_t op, ENV &env, PARAM& param)

  {

    switch (op) {

      case OpCode_return:

        env.returnFromSubr ();

        break;

      case OpCode_endchar:

        OPSET::check_width (op, env, param);

        env.set_endchar (true);

        OPSET::flush_args_and_op (op, env, param);

        break;

      case OpCode_fixedcs:

        env.argStack.push_fixed_from_substr (env.str_ref);

        break;

      case OpCode_callsubr:

        env.callSubr (env.localSubrs, CSType_LocalSubr);

        break;

      case OpCode_callgsubr:

        env.callSubr (env.globalSubrs, CSType_GlobalSubr);

        break;

      case OpCode_hstem:

      case OpCode_hstemhm:

        OPSET::check_width (op, env, param);

        OPSET::process_hstem (op, env, param);

        break;

      case OpCode_vstem:

      case OpCode_vstemhm:

        OPSET::check_width (op, env, param);

        OPSET::process_vstem (op, env, param);

        break;

      case OpCode_hintmask:

      case OpCode_cntrmask:

        OPSET::check_width (op, env, param);

        OPSET::process_hintmask (op, env, param);

        break;

      case OpCode_rmoveto:

        OPSET::check_width (op, env, param);

        PATH::rmoveto (env, param);

        OPSET::process_post_move (op, env, param);

        break;

      case OpCode_hmoveto:

        OPSET::check_width (op, env, param);

        PATH::hmoveto (env, param);

        OPSET::process_post_move (op, env, param);

        break;

      case OpCode_vmoveto:

        OPSET::check_width (op, env, param);

        PATH::vmoveto (env, param);

        OPSET::process_post_move (op, env, param);

        break;

      case OpCode_rlineto:

        PATH::rlineto (env, param);

        process_post_path (op, env, param);

        break;

      case OpCode_hlineto:

        PATH::hlineto (env, param);

        process_post_path (op, env, param);

        break;

      case OpCode_vlineto:

        PATH::vlineto (env, param);

        process_post_path (op, env, param);

        break;

      case OpCode_rrcurveto:

        PATH::rrcurveto (env, param);

        process_post_path (op, env, param);

        break;

      case OpCode_rcurveline:

        PATH::rcurveline (env, param);

        process_post_path (op, env, param);

        break;

      case OpCode_rlinecurve:

        PATH::rlinecurve (env, param);

        process_post_path (op, env, param);

        break;

      case OpCode_vvcurveto:

        PATH::vvcurveto (env, param);

        process_post_path (op, env, param);

        break;

      case OpCode_hhcurveto:

        PATH::hhcurveto (env, param);

        process_post_path (op, env, param);

        break;

      case OpCode_vhcurveto:

        PATH::vhcurveto (env, param);

        process_post_path (op, env, param);

        break;

      case OpCode_hvcurveto:

        PATH::hvcurveto (env, param);

        process_post_path (op, env, param);

        break;

      case OpCode_hflex:

        PATH::hflex (env, param);

        OPSET::process_post_flex (op, env, param);

        break;

      case OpCode_flex:

        PATH::flex (env, param);

        OPSET::process_post_flex (op, env, param);

        break;

      case OpCode_hflex1:

        PATH::hflex1 (env, param);

        OPSET::process_post_flex (op, env, param);

        break;

      case OpCode_flex1:

        PATH::flex1 (env, param);

        OPSET::process_post_flex (op, env, param);

        break;

      default:

        SUPER::process_op (op, env);

        break;

    }

  }

  static void process_hstem (op_code_t op, ENV &env, PARAM& param)

  {

    env.hstem_count += env.argStack.get_count () / 2;

    OPSET::flush_args_and_op (op, env, param);

  }

  static void process_vstem (op_code_t op, ENV &env, PARAM& param)

  {

    env.vstem_count += env.argStack.get_count () / 2;

    OPSET::flush_args_and_op (op, env, param);

  }

  static void process_hintmask (op_code_t op, ENV &env, PARAM& param)

  {

    env.determine_hintmask_size ();

    if (likely (env.str_ref.avail (env.hintmask_size)))

    {

      OPSET::flush_hintmask (op, env, param);

      env.str_ref.inc (env.hintmask_size);

    }

  }

  static void process_post_flex (op_code_t op, ENV &env, PARAM& param)

  {

    OPSET::flush_args_and_op (op, env, param);

  }

  static void check_width (op_code_t op, ENV &env, PARAM& param)

  {}

  static void process_post_move (op_code_t op, ENV &env, PARAM& param)

  {

    if (!env.seen_moveto)

    {

      env.determine_hintmask_size ();

      env.seen_moveto = true;

    }

    OPSET::flush_args_and_op (op, env, param);

  }

  static void process_post_path (op_code_t op, ENV &env, PARAM& param)

  {

    OPSET::flush_args_and_op (op, env, param);

  }

  static void flush_args_and_op (op_code_t op, ENV &env, PARAM& param)

  {

    OPSET::flush_args (env, param);

    OPSET::flush_op (op, env, param);

  }

  static void flush_args (ENV &env, PARAM& param)

  {

    env.pop_n_args (env.argStack.get_count ());

  }

  static void flush_op (op_code_t op, ENV &env, PARAM& param)

  {

  }

  static void flush_hintmask (op_code_t op, ENV &env, PARAM& param)

  {

    OPSET::flush_args_and_op (op, env, param);

  }

  static bool is_number_op (op_code_t op)

  {

    switch (op)

    {

      case OpCode_shortint:

      case OpCode_fixedcs:

      case OpCode_TwoBytePosInt0: case OpCode_TwoBytePosInt1:

      case OpCode_TwoBytePosInt2: case OpCode_TwoBytePosInt3:

      case OpCode_TwoByteNegInt0: case OpCode_TwoByteNegInt1:

      case OpCode_TwoByteNegInt2: case OpCode_TwoByteNegInt3:

        return true;

      default:

        /* 1-byte integer */

        return (OpCode_OneByteIntFirst <= op) && (op <= OpCode_OneByteIntLast);

    }

  }

  protected:

  typedef opset_t<ARG>  SUPER;

};

template <typename PATH, typename ENV, typename PARAM>

struct path_procs_t

{

  static void rmoveto (ENV &env, PARAM& param)

  {

    point_t pt1 = env.get_pt ();

    const number_t &dy = env.pop_arg ();

    const number_t &dx = env.pop_arg ();

    pt1.move (dx, dy);

    PATH::moveto (env, param, pt1);

  }

  static void hmoveto (ENV &env, PARAM& param)

  {

    point_t pt1 = env.get_pt ();

    pt1.move_x (env.pop_arg ());

    PATH::moveto (env, param, pt1);

  }

  static void vmoveto (ENV &env, PARAM& param)

  {

    point_t pt1 = env.get_pt ();

    pt1.move_y (env.pop_arg ());

    PATH::moveto (env, param, pt1);

  }

  static void rlineto (ENV &env, PARAM& param)

  {

    for (unsigned int i = 0; i + 2 <= env.argStack.get_count (); i += 2)

    {

      point_t pt1 = env.get_pt ();

      pt1.move (env.eval_arg (i), env.eval_arg (i+1));

      PATH::line (env, param, pt1);

    }

  }

  static void hlineto (ENV &env, PARAM& param)

  {

    point_t pt1;

    unsigned int i = 0;

    for (; i + 2 <= env.argStack.get_count (); i += 2)

    {

      pt1 = env.get_pt ();

      pt1.move_x (env.eval_arg (i));

      PATH::line (env, param, pt1);

      pt1.move_y (env.eval_arg (i+1));

      PATH::line (env, param, pt1);

    }

    if (i < env.argStack.get_count ())

    {

      pt1 = env.get_pt ();

      pt1.move_x (env.eval_arg (i));

      PATH::line (env, param, pt1);

    }

  }

  static void vlineto (ENV &env, PARAM& param)

  {

    point_t pt1;

    unsigned int i = 0;

    for (; i + 2 <= env.argStack.get_count (); i += 2)

    {

      pt1 = env.get_pt ();

      pt1.move_y (env.eval_arg (i));

      PATH::line (env, param, pt1);

      pt1.move_x (env.eval_arg (i+1));

      PATH::line (env, param, pt1);

    }

    if (i < env.argStack.get_count ())