/*

 * 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_DICT_COMMON_HH

#define HB_CFF_INTERP_DICT_COMMON_HH

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

#include <math.h>

#include <float.h>

namespace CFF {

using namespace OT;

/* an opstr and the parsed out dict value(s) */

struct dict_val_t : op_str_t

{

  void init () { single_val.set_int (0); }

  void fini () {}

  number_t            single_val;

};

typedef dict_val_t num_dict_val_t;

template <typename VAL> struct dict_values_t : parsed_values_t<VAL> {};

template <typename OPSTR=op_str_t>

struct top_dict_values_t : dict_values_t<OPSTR>

{

  void init ()

  {

    dict_values_t<OPSTR>::init ();

    charStringsOffset = 0;

    FDArrayOffset = 0;

  }

  void fini () { dict_values_t<OPSTR>::fini (); }

  unsigned int calculate_serialized_op_size (const OPSTR& opstr) const

  {

    switch (opstr.op)

    {

      case OpCode_CharStrings:

      case OpCode_FDArray:

        return OpCode_Size (OpCode_longintdict) + 4 + OpCode_Size (opstr.op);

      default:

        return opstr.str.length;

    }

  }

  unsigned int  charStringsOffset;

  unsigned int  FDArrayOffset;

};

struct dict_opset_t : opset_t<number_t>

{

  static void process_op (op_code_t op, interp_env_t<number_t>& env)

  {

    switch (op) {

      case OpCode_longintdict:  /* 5-byte integer */

        env.argStack.push_longint_from_substr (env.str_ref);

        break;

      case OpCode_BCD:  /* real number */

        env.argStack.push_real (parse_bcd (env.str_ref));

        break;

      default:

        opset_t<number_t>::process_op (op, env);

        break;

    }

  }

  static double parse_bcd (byte_str_ref_t& str_ref)

  {

    bool    neg = false;

    double  int_part = 0;

    uint64_t frac_part = 0;

    uint32_t  frac_count = 0;

    bool    exp_neg = false;

    uint32_t  exp_part = 0;

    bool    exp_overflow = false;

    enum Part { INT_PART=0, FRAC_PART, EXP_PART } part = INT_PART;

    enum Nibble { DECIMAL=10, EXP_POS, EXP_NEG, RESERVED, NEG, END };

    const uint64_t MAX_FRACT = 0xFFFFFFFFFFFFFull; /* 1^52-1 */

    const uint32_t MAX_EXP = 0x7FFu; /* 1^11-1 */

    double  value = 0.0;

    unsigned char byte = 0;

    for (uint32_t i = 0;; i++)

    {

      char d;

      if ((i & 1) == 0)

      {

        if (!str_ref.avail ())

        {

          str_ref.set_error ();

          return 0.0;

        }

        byte = str_ref[0];

        str_ref.inc ();

        d = byte >> 4;

      }

      else

        d = byte & 0x0F;

      switch (d)

      {

        case RESERVED:

          str_ref.set_error ();

          return value;

        case END:

          value = (double)(neg? -int_part: int_part);

          if (frac_count > 0)

          {

            double frac = (frac_part / pow (10.0, (double)frac_count));

            if (neg) frac = -frac;

            value += frac;

          }

          if (unlikely (exp_overflow))

          {

            if (value == 0.0)

              return value;

            if (exp_neg)

              return neg? -DBL_MIN: DBL_MIN;

            else

              return neg? -DBL_MAX: DBL_MAX;

          }

          if (exp_part != 0)

          {

            if (exp_neg)

              value /= pow (10.0, (double)exp_part);

            else

              value *= pow (10.0, (double)exp_part);

          }

          return value;

        case NEG:

          if (i != 0)

          {

            str_ref.set_error ();

            return 0.0;

          }

          neg = true;

          break;

        case DECIMAL:

          if (part != INT_PART)

          {

            str_ref.set_error ();

            return value;

          }

          part = FRAC_PART;

          break;

        case EXP_NEG:

          exp_neg = true;

          HB_FALLTHROUGH;

        case EXP_POS:

          if (part == EXP_PART)

          {

            str_ref.set_error ();

            return value;

          }

          part = EXP_PART;

          break;

        default:

          switch (part) {

            default:

            case INT_PART:

              int_part = (int_part * 10) + d;

              break;

            case FRAC_PART:

              if (likely (frac_part <= MAX_FRACT / 10))

              {

                frac_part = (frac_part * 10) + (unsigned)d;

                frac_count++;

              }

              break;

            case EXP_PART:

              if (likely (exp_part * 10 + d <= MAX_EXP))

              {

                exp_part = (exp_part * 10) + d;

              }

              else

                exp_overflow = true;

              break;

          }

      }

    }

    return value;

  }

  static bool is_hint_op (op_code_t op)

  {

    switch (op)

    {

      case OpCode_BlueValues:

      case OpCode_OtherBlues:

      case OpCode_FamilyBlues:

      case OpCode_FamilyOtherBlues:

      case OpCode_StemSnapH:

      case OpCode_StemSnapV:

      case OpCode_StdHW:

      case OpCode_StdVW:

      case OpCode_BlueScale:

      case OpCode_BlueShift:

      case OpCode_BlueFuzz:

      case OpCode_ForceBold:

      case OpCode_LanguageGroup:

      case OpCode_ExpansionFactor:

        return true;

      default:

        return false;

    }

  }

};

template <typename VAL=op_str_t>

struct top_dict_opset_t : dict_opset_t

{

  static void process_op (op_code_t op, interp_env_t<number_t>& env, top_dict_values_t<VAL> & dictval)

  {

    switch (op) {

      case OpCode_CharStrings:

        dictval.charStringsOffset = env.argStack.pop_uint ();

        env.clear_args ();

        break;

      case OpCode_FDArray:

        dictval.FDArrayOffset = env.argStack.pop_uint ();

        env.clear_args ();

        break;

      case OpCode_FontMatrix:

        env.clear_args ();

        break;

      default:

        dict_opset_t::process_op (op, env);

        break;

    }

  }

};

template <typename OPSET, typename PARAM, typename ENV=num_interp_env_t>

struct dict_interpreter_t : interpreter_t<ENV>

{

  bool interpret (PARAM& param)

  {

    param.init ();

    while (SUPER::env.str_ref.avail ())

    {

      OPSET::process_op (SUPER::env.fetch_op (), SUPER::env, param);

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

        return false;

    }

    return true;

  }

  private:

  typedef interpreter_t<ENV> SUPER;

};

} /* namespace CFF */

#endif /* HB_CFF_INTERP_DICT_COMMON_HH */