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kc3-lang/harfbuzz/src/hb-cff-interp-common.hh

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  • Author : Behdad Esfahbod
    Date : 2023-06-03 22:52:16
    Hash : 054f966a
    Message : [subset/cff1] Don't allocate memory for retaingid holes 40% speedup in BM_subset/subset_glyphs/SourceHanSans-Regular_subset.otf/retaingids/10 benchmark.

  • src/hb-cff-interp-common.hh
  • /*
     * 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_COMMON_HH
    #define HB_CFF_INTERP_COMMON_HH
    
    extern HB_INTERNAL const unsigned char *endchar_str;
    
    namespace CFF {
    
    using namespace OT;
    
    typedef unsigned int op_code_t;
    
    
    /* === Dict operators === */
    
    /* One byte operators (0-31) */
    #define OpCode_version		  0 /* CFF Top */
    #define OpCode_Notice		  1 /* CFF Top */
    #define OpCode_FullName		  2 /* CFF Top */
    #define OpCode_FamilyName	  3 /* CFF Top */
    #define OpCode_Weight		  4 /* CFF Top */
    #define OpCode_FontBBox		  5 /* CFF Top */
    #define OpCode_BlueValues	  6 /* CFF Private, CFF2 Private */
    #define OpCode_OtherBlues	  7 /* CFF Private, CFF2 Private */
    #define OpCode_FamilyBlues	  8 /* CFF Private, CFF2 Private */
    #define OpCode_FamilyOtherBlues	  9 /* CFF Private, CFF2 Private */
    #define OpCode_StdHW		 10 /* CFF Private, CFF2 Private */
    #define OpCode_StdVW		 11 /* CFF Private, CFF2 Private */
    #define OpCode_escape		 12 /* All. Shared with CS */
    #define OpCode_UniqueID		 13 /* CFF Top */
    #define OpCode_XUID		 14 /* CFF Top */
    #define OpCode_charset		 15 /* CFF Top (0) */
    #define OpCode_Encoding		 16 /* CFF Top (0) */
    #define OpCode_CharStrings	 17 /* CFF Top, CFF2 Top */
    #define OpCode_Private		 18 /* CFF Top, CFF2 FD */
    #define OpCode_Subrs		 19 /* CFF Private, CFF2 Private */
    #define OpCode_defaultWidthX	 20 /* CFF Private (0) */
    #define OpCode_nominalWidthX	 21 /* CFF Private (0) */
    #define OpCode_vsindexdict	 22 /* CFF2 Private/CS */
    #define OpCode_blenddict	 23 /* CFF2 Private/CS */
    #define OpCode_vstore		 24 /* CFF2 Top */
    #define OpCode_reserved25	 25
    #define OpCode_reserved26	 26
    #define OpCode_reserved27	 27
    
    /* Numbers */
    #define OpCode_shortint		 28 /* 16-bit integer, All */
    #define OpCode_longintdict	 29 /* 32-bit integer, All */
    #define OpCode_BCD		 30 /* Real number, CFF2 Top/FD */
    #define OpCode_reserved31	 31
    
    /* 1-byte integers */
    #define OpCode_OneByteIntFirst	 32 /* All. beginning of the range of first byte ints */
    #define OpCode_OneByteIntLast	246 /* All. ending of the range of first byte int */
    
    /* 2-byte integers */
    #define OpCode_TwoBytePosInt0	247 /* All. first byte of two byte positive int (+108 to +1131) */
    #define OpCode_TwoBytePosInt1	248
    #define OpCode_TwoBytePosInt2	249
    #define OpCode_TwoBytePosInt3	250
    
    #define OpCode_TwoByteNegInt0	251 /* All. first byte of two byte negative int (-1131 to -108) */
    #define OpCode_TwoByteNegInt1	252
    #define OpCode_TwoByteNegInt2	253
    #define OpCode_TwoByteNegInt3	254
    
    /* Two byte escape operators 12, (0-41) */
    #define OpCode_ESC_Base		256
    #define Make_OpCode_ESC(byte2)	((op_code_t)(OpCode_ESC_Base + (byte2)))
    
    inline op_code_t Unmake_OpCode_ESC (op_code_t op)  { return (op_code_t)(op - OpCode_ESC_Base); }
    inline bool Is_OpCode_ESC (op_code_t op) { return op >= OpCode_ESC_Base; }
    inline unsigned int OpCode_Size (op_code_t op) { return Is_OpCode_ESC (op) ? 2: 1; }
    
    #define OpCode_Copyright	Make_OpCode_ESC(0) /* CFF Top */
    #define OpCode_isFixedPitch	Make_OpCode_ESC(1) /* CFF Top (false) */
    #define OpCode_ItalicAngle	Make_OpCode_ESC(2) /* CFF Top (0) */
    #define OpCode_UnderlinePosition Make_OpCode_ESC(3) /* CFF Top (-100) */
    #define OpCode_UnderlineThickness Make_OpCode_ESC(4) /* CFF Top (50) */
    #define OpCode_PaintType	Make_OpCode_ESC(5) /* CFF Top (0) */
    #define OpCode_CharstringType	Make_OpCode_ESC(6) /* CFF Top (2) */
    #define OpCode_FontMatrix	Make_OpCode_ESC(7) /* CFF Top, CFF2 Top (.001 0 0 .001 0 0)*/
    #define OpCode_StrokeWidth	Make_OpCode_ESC(8) /* CFF Top (0) */
    #define OpCode_BlueScale	Make_OpCode_ESC(9) /* CFF Private, CFF2 Private (0.039625) */
    #define OpCode_BlueShift	Make_OpCode_ESC(10) /* CFF Private, CFF2 Private (7) */
    #define OpCode_BlueFuzz		Make_OpCode_ESC(11) /* CFF Private, CFF2 Private (1) */
    #define OpCode_StemSnapH	Make_OpCode_ESC(12) /* CFF Private, CFF2 Private */
    #define OpCode_StemSnapV	Make_OpCode_ESC(13) /* CFF Private, CFF2 Private */
    #define OpCode_ForceBold	Make_OpCode_ESC(14) /* CFF Private (false) */
    #define OpCode_reservedESC15	Make_OpCode_ESC(15)
    #define OpCode_reservedESC16	Make_OpCode_ESC(16)
    #define OpCode_LanguageGroup	Make_OpCode_ESC(17) /* CFF Private, CFF2 Private (0) */
    #define OpCode_ExpansionFactor	Make_OpCode_ESC(18) /* CFF Private, CFF2 Private (0.06) */
    #define OpCode_initialRandomSeed Make_OpCode_ESC(19) /* CFF Private (0) */
    #define OpCode_SyntheticBase	Make_OpCode_ESC(20) /* CFF Top */
    #define OpCode_PostScript	Make_OpCode_ESC(21) /* CFF Top */
    #define OpCode_BaseFontName	Make_OpCode_ESC(22) /* CFF Top */
    #define OpCode_BaseFontBlend	Make_OpCode_ESC(23) /* CFF Top */
    #define OpCode_reservedESC24	Make_OpCode_ESC(24)
    #define OpCode_reservedESC25	Make_OpCode_ESC(25)
    #define OpCode_reservedESC26	Make_OpCode_ESC(26)
    #define OpCode_reservedESC27	Make_OpCode_ESC(27)
    #define OpCode_reservedESC28	Make_OpCode_ESC(28)
    #define OpCode_reservedESC29	Make_OpCode_ESC(29)
    #define OpCode_ROS		Make_OpCode_ESC(30) /* CFF Top_CID */
    #define OpCode_CIDFontVersion	Make_OpCode_ESC(31) /* CFF Top_CID (0) */
    #define OpCode_CIDFontRevision	Make_OpCode_ESC(32) /* CFF Top_CID (0) */
    #define OpCode_CIDFontType	Make_OpCode_ESC(33) /* CFF Top_CID (0) */
    #define OpCode_CIDCount		Make_OpCode_ESC(34) /* CFF Top_CID (8720) */
    #define OpCode_UIDBase		Make_OpCode_ESC(35) /* CFF Top_CID */
    #define OpCode_FDArray		Make_OpCode_ESC(36) /* CFF Top_CID, CFF2 Top */
    #define OpCode_FDSelect		Make_OpCode_ESC(37) /* CFF Top_CID, CFF2 Top */
    #define OpCode_FontName		Make_OpCode_ESC(38) /* CFF Top_CID */
    
    
    /* === CharString operators === */
    
    #define OpCode_hstem		  1 /* CFF, CFF2 */
    #define OpCode_Reserved2	  2
    #define OpCode_vstem		  3 /* CFF, CFF2 */
    #define OpCode_vmoveto		  4 /* CFF, CFF2 */
    #define OpCode_rlineto		  5 /* CFF, CFF2 */
    #define OpCode_hlineto		  6 /* CFF, CFF2 */
    #define OpCode_vlineto		  7 /* CFF, CFF2 */
    #define OpCode_rrcurveto	  8 /* CFF, CFF2 */
    #define OpCode_Reserved9	  9
    #define OpCode_callsubr		 10 /* CFF, CFF2 */
    #define OpCode_return		 11 /* CFF */
    //#define OpCode_escape		 12 /* CFF, CFF2 */
    #define OpCode_Reserved13	 13
    #define OpCode_endchar		 14 /* CFF */
    #define OpCode_vsindexcs	 15 /* CFF2 */
    #define OpCode_blendcs		 16 /* CFF2 */
    #define OpCode_Reserved17	 17
    #define OpCode_hstemhm		 18 /* CFF, CFF2 */
    #define OpCode_hintmask		 19 /* CFF, CFF2 */
    #define OpCode_cntrmask		 20 /* CFF, CFF2 */
    #define OpCode_rmoveto		 21 /* CFF, CFF2 */
    #define OpCode_hmoveto		 22 /* CFF, CFF2 */
    #define OpCode_vstemhm		 23 /* CFF, CFF2 */
    #define OpCode_rcurveline	 24 /* CFF, CFF2 */
    #define OpCode_rlinecurve	 25 /* CFF, CFF2 */
    #define OpCode_vvcurveto	 26 /* CFF, CFF2 */
    #define OpCode_hhcurveto	 27 /* CFF, CFF2 */
    //#define OpCode_shortint	 28 /* CFF, CFF2 */
    #define OpCode_callgsubr	 29 /* CFF, CFF2 */
    #define OpCode_vhcurveto	 30 /* CFF, CFF2 */
    #define OpCode_hvcurveto	 31 /* CFF, CFF2 */
    
    #define OpCode_fixedcs		255 /* 32-bit fixed */
    
    /* Two byte escape operators 12, (0-41) */
    #define OpCode_dotsection	Make_OpCode_ESC(0) /* CFF (obsoleted) */
    #define OpCode_ReservedESC1	Make_OpCode_ESC(1)
    #define OpCode_ReservedESC2	Make_OpCode_ESC(2)
    #define OpCode_and		Make_OpCode_ESC(3) /* CFF */
    #define OpCode_or		Make_OpCode_ESC(4) /* CFF */
    #define OpCode_not		Make_OpCode_ESC(5) /* CFF */
    #define OpCode_ReservedESC6	Make_OpCode_ESC(6)
    #define OpCode_ReservedESC7	Make_OpCode_ESC(7)
    #define OpCode_ReservedESC8	Make_OpCode_ESC(8)
    #define OpCode_abs		Make_OpCode_ESC(9) /* CFF */
    #define OpCode_add		Make_OpCode_ESC(10) /* CFF */
    #define OpCode_sub		Make_OpCode_ESC(11) /* CFF */
    #define OpCode_div		Make_OpCode_ESC(12) /* CFF */
    #define OpCode_ReservedESC13	Make_OpCode_ESC(13)
    #define OpCode_neg		Make_OpCode_ESC(14) /* CFF */
    #define OpCode_eq		Make_OpCode_ESC(15) /* CFF */
    #define OpCode_ReservedESC16	Make_OpCode_ESC(16)
    #define OpCode_ReservedESC17	Make_OpCode_ESC(17)
    #define OpCode_drop		Make_OpCode_ESC(18) /* CFF */
    #define OpCode_ReservedESC19	Make_OpCode_ESC(19)
    #define OpCode_put		Make_OpCode_ESC(20) /* CFF */
    #define OpCode_get		Make_OpCode_ESC(21) /* CFF */
    #define OpCode_ifelse		Make_OpCode_ESC(22) /* CFF */
    #define OpCode_random		Make_OpCode_ESC(23) /* CFF */
    #define OpCode_mul		Make_OpCode_ESC(24) /* CFF */
    //#define OpCode_reservedESC25	Make_OpCode_ESC(25)
    #define OpCode_sqrt		Make_OpCode_ESC(26) /* CFF */
    #define OpCode_dup		Make_OpCode_ESC(27) /* CFF */
    #define OpCode_exch		Make_OpCode_ESC(28) /* CFF */
    #define OpCode_index		Make_OpCode_ESC(29) /* CFF */
    #define OpCode_roll		Make_OpCode_ESC(30) /* CFF */
    #define OpCode_reservedESC31	Make_OpCode_ESC(31)
    #define OpCode_reservedESC32	Make_OpCode_ESC(32)
    #define OpCode_reservedESC33	Make_OpCode_ESC(33)
    #define OpCode_hflex		Make_OpCode_ESC(34) /* CFF, CFF2 */
    #define OpCode_flex		Make_OpCode_ESC(35) /* CFF, CFF2 */
    #define OpCode_hflex1		Make_OpCode_ESC(36) /* CFF, CFF2 */
    #define OpCode_flex1		Make_OpCode_ESC(37) /* CFF, CFF2 */
    
    
    #define OpCode_Invalid		0xFFFFu
    
    
    struct number_t
    {
      void set_int (int v)       { value = v; }
      int to_int () const        { return value; }
    
      void set_fixed (int32_t v) { value = v / 65536.0; }
      int32_t to_fixed () const  { return value * 65536.0; }
    
      void set_real (double v)   { value = v; }
      double to_real () const    { return value; }
    
      bool in_int_range () const
      { return ((double) (int16_t) to_int () == value); }
    
      bool operator >  (const number_t &n) const { return value > n.to_real (); }
      bool operator <  (const number_t &n) const { return n > *this; }
      bool operator >= (const number_t &n) const { return !(*this < n); }
      bool operator <= (const number_t &n) const { return !(*this > n); }
    
      const number_t &operator += (const number_t &n)
      {
        set_real (to_real () + n.to_real ());
    
        return *this;
      }
    
      protected:
      double value = 0.;
    };
    
    /* byte string */
    struct UnsizedByteStr : UnsizedArrayOf <HBUINT8>
    {
      hb_ubytes_t as_ubytes (unsigned l) const
      { return hb_ubytes_t ((const unsigned char *) this, l); }
    
      // encode 2-byte int (Dict/CharString) or 4-byte int (Dict)
      template <typename T, typename V>
      static bool serialize_int (hb_serialize_context_t *c, op_code_t intOp, V value)
      {
        TRACE_SERIALIZE (this);
    
        HBUINT8 *p = c->allocate_size<HBUINT8> (1);
        if (unlikely (!p)) return_trace (false);
        *p = intOp;
    
        T *ip = c->allocate_size<T> (T::static_size);
        if (unlikely (!ip)) return_trace (false);
        return_trace (c->check_assign (*ip, value, HB_SERIALIZE_ERROR_INT_OVERFLOW));
      }
    
      template <typename V>
      static bool serialize_int4 (hb_serialize_context_t *c, V value)
      { return serialize_int<HBINT32> (c, OpCode_longintdict, value); }
    
      template <typename V>
      static bool serialize_int2 (hb_serialize_context_t *c, V value)
      { return serialize_int<HBINT16> (c, OpCode_shortint, value); }
    
      /* Defining null_size allows a Null object may be created. Should be safe because:
       * A descendent struct Dict uses a Null pointer to indicate a missing table,
       * checked before access.
       */
      DEFINE_SIZE_MIN(0);
    };
    
    /* A byte string associated with the current offset and an error condition */
    struct byte_str_ref_t
    {
      byte_str_ref_t ()
        : str () {}
    
      byte_str_ref_t (const hb_ubytes_t &str_, unsigned int offset_ = 0)
        : str (str_) { set_offset (offset_); }
    
      void reset (const hb_ubytes_t &str_, unsigned int offset_ = 0)
      {
        str = str_;
        set_offset (offset_);
      }
    
      const unsigned char& operator [] (int i) {
        if (unlikely ((unsigned int) (get_offset () + i) >= str.length))
        {
          set_error ();
          return Null (unsigned char);
        }
        return str.arrayZ[get_offset () + i];
      }
    
      unsigned char head_unchecked () const { return str.arrayZ[get_offset ()]; }
    
      /* Conversion to hb_ubytes_t */
      operator hb_ubytes_t () const { return str.sub_array (get_offset ()); }
    
      hb_ubytes_t sub_array (unsigned int offset_, unsigned int len_) const
      { return str.sub_array (offset_, len_); }
    
      bool avail (unsigned int count=1) const
      { return get_offset () + count <= str.length; }
      void inc (unsigned int count=1)
      {
        /* Automatically puts us in error if count is out-of-range. */
        set_offset (get_offset () + count);
      }
    
      /* We (ab)use ubytes backwards_length as a cursor (called offset),
       * as well as to store error condition. */
    
      unsigned get_offset () const { return str.backwards_length; }
      void set_offset (unsigned offset) { str.backwards_length = offset; }
    
      void set_error ()      { str.backwards_length = str.length + 1; }
      bool in_error () const { return str.backwards_length > str.length; }
    
      unsigned total_size () const { return str.length; }
    
      protected:
      hb_ubytes_t       str;
    };
    
    using byte_str_array_t = hb_vector_t<hb_ubytes_t>;
    
    /* stack */
    template <typename ELEM, int LIMIT>
    struct cff_stack_t
    {
      ELEM& operator [] (unsigned int i)
      {
        if (unlikely (i >= count))
        {
          set_error ();
          return Crap (ELEM);
        }
        return elements[i];
      }
    
      void push (const ELEM &v)
      {
        if (likely (count < LIMIT))
          elements[count++] = v;
        else
          set_error ();
      }
      ELEM &push ()
      {
        if (likely (count < LIMIT))
          return elements[count++];
        else
        {
          set_error ();
          return Crap (ELEM);
        }
      }
    
      ELEM& pop ()
      {
        if (likely (count > 0))
          return elements[--count];
        else
        {
          set_error ();
          return Crap (ELEM);
        }
      }
      void pop (unsigned int n)
      {
        if (likely (count >= n))
          count -= n;
        else
          set_error ();
      }
    
      const ELEM& peek ()
      {
        if (unlikely (count == 0))
        {
          set_error ();
          return Null (ELEM);
        }
        return elements[count - 1];
      }
    
      void unpop ()
      {
        if (likely (count < LIMIT))
          count++;
        else
          set_error ();
      }
    
      void clear () { count = 0; }
    
      bool in_error () const { return (error); }
      void set_error ()      { error = true; }
    
      unsigned int get_count () const { return count; }
      bool is_empty () const          { return !count; }
    
      hb_array_t<const ELEM> sub_array (unsigned start, unsigned length) const
      { return hb_array_t<const ELEM> (elements).sub_array (start, length); }
    
      private:
      bool error = false;
      unsigned int count = 0;
      ELEM elements[LIMIT];
    };
    
    /* argument stack */
    template <typename ARG=number_t>
    struct arg_stack_t : cff_stack_t<ARG, 513>
    {
      void push_int (int v)
      {
        ARG &n = S::push ();
        n.set_int (v);
      }
    
      void push_fixed (int32_t v)
      {
        ARG &n = S::push ();
        n.set_fixed (v);
      }
    
      void push_real (double v)
      {
        ARG &n = S::push ();
        n.set_real (v);
      }
    
      ARG& pop_num () { return this->pop (); }
    
      int pop_int ()  { return this->pop ().to_int (); }
    
      unsigned int pop_uint ()
      {
        int i = pop_int ();
        if (unlikely (i < 0))
        {
          i = 0;
          S::set_error ();
        }
        return (unsigned) i;
      }
    
      void push_longint_from_substr (byte_str_ref_t& str_ref)
      {
        push_int ((str_ref[0] << 24) | (str_ref[1] << 16) | (str_ref[2] << 8) | (str_ref[3]));
        str_ref.inc (4);
      }
    
      bool push_fixed_from_substr (byte_str_ref_t& str_ref)
      {
        if (unlikely (!str_ref.avail (4)))
          return false;
        push_fixed ((int32_t)*(const HBUINT32*)&str_ref[0]);
        str_ref.inc (4);
        return true;
      }
    
      private:
      typedef cff_stack_t<ARG, 513> S;
    };
    
    /* an operator prefixed by its operands in a byte string */
    struct op_str_t
    {
      /* This used to have a hb_ubytes_t. Using a pointer and length
       * in a particular order, saves 8 bytes in this struct and more
       * in our parsed_cs_op_t subclass. */
    
      const unsigned char *ptr = nullptr;
    
      op_code_t  op = OpCode_Invalid;
    
      uint8_t length = 0;
    };
    
    /* base of OP_SERIALIZER */
    struct op_serializer_t
    {
      protected:
      bool copy_opstr (hb_serialize_context_t *c, const op_str_t& opstr) const
      {
        TRACE_SERIALIZE (this);
    
        unsigned char *d = c->allocate_size<unsigned char> (opstr.length);
        if (unlikely (!d)) return_trace (false);
        /* Faster than hb_memcpy for small strings. */
        for (unsigned i = 0; i < opstr.length; i++)
          d[i] = opstr.ptr[i];
        return_trace (true);
      }
    };
    
    template <typename VAL>
    struct parsed_values_t
    {
      void init ()
      {
        opStart = 0;
        values.init ();
      }
      void fini () { values.fini (); }
    
      void alloc (unsigned n)
      {
        values.alloc (n, true);
      }
    
      void add_op (op_code_t op, const byte_str_ref_t& str_ref = byte_str_ref_t (), const VAL &v = VAL ())
      {
        VAL *val = values.push (v);
        val->op = op;
        auto arr = str_ref.sub_array (opStart, str_ref.get_offset () - opStart);
        val->ptr = arr.arrayZ;
        val->length = arr.length;
        opStart = str_ref.get_offset ();
      }
    
      bool has_op (op_code_t op) const
      {
        for (const auto& v : values)
          if (v.op == op) return true;
        return false;
      }
    
      unsigned get_count () const { return values.length; }
      const VAL &operator [] (unsigned int i) const { return values[i]; }
    
      unsigned int       opStart;
      hb_vector_t<VAL>   values;
    };
    
    template <typename ARG=number_t>
    struct interp_env_t
    {
      interp_env_t () {}
      interp_env_t (const hb_ubytes_t &str_)
      {
        str_ref.reset (str_);
      }
      bool in_error () const
      { return str_ref.in_error () || argStack.in_error (); }
    
      void set_error () { str_ref.set_error (); }
    
      op_code_t fetch_op ()
      {
        op_code_t  op = OpCode_Invalid;
        if (unlikely (!str_ref.avail ()))
          return OpCode_Invalid;
        op = (op_code_t) str_ref.head_unchecked ();
        str_ref.inc ();
        if (op == OpCode_escape) {
          if (unlikely (!str_ref.avail ()))
    	return OpCode_Invalid;
          op = Make_OpCode_ESC (str_ref.head_unchecked ());
          str_ref.inc ();
        }
        return op;
      }
    
      const ARG& eval_arg (unsigned int i) { return argStack[i]; }
    
      ARG& pop_arg () { return argStack.pop (); }
      void pop_n_args (unsigned int n) { argStack.pop (n); }
    
      void clear_args () { pop_n_args (argStack.get_count ()); }
    
      byte_str_ref_t
    		str_ref;
      arg_stack_t<ARG>
    		argStack;
    };
    
    using num_interp_env_t =  interp_env_t<>;
    
    template <typename ARG=number_t>
    struct opset_t
    {
      static void process_op (op_code_t op, interp_env_t<ARG>& env)
      {
        switch (op) {
          case OpCode_shortint:
    	env.argStack.push_int ((int16_t)((env.str_ref[0] << 8) | env.str_ref[1]));
    	env.str_ref.inc (2);
    	break;
    
          case OpCode_TwoBytePosInt0: case OpCode_TwoBytePosInt1:
          case OpCode_TwoBytePosInt2: case OpCode_TwoBytePosInt3:
    	env.argStack.push_int ((int16_t)((op - OpCode_TwoBytePosInt0) * 256 + env.str_ref[0] + 108));
    	env.str_ref.inc ();
    	break;
    
          case OpCode_TwoByteNegInt0: case OpCode_TwoByteNegInt1:
          case OpCode_TwoByteNegInt2: case OpCode_TwoByteNegInt3:
    	env.argStack.push_int ((-(int16_t)(op - OpCode_TwoByteNegInt0) * 256 - env.str_ref[0] - 108));
    	env.str_ref.inc ();
    	break;
    
          default:
    	/* 1-byte integer */
    	if (likely ((OpCode_OneByteIntFirst <= op) && (op <= OpCode_OneByteIntLast)))
    	{
    	  env.argStack.push_int ((int)op - 139);
    	} else {
    	  /* invalid unknown operator */
    	  env.clear_args ();
    	  env.set_error ();
    	}
    	break;
        }
      }
    };
    
    template <typename ENV>
    struct interpreter_t
    {
      interpreter_t (ENV& env_) : env (env_) {}
      ENV& env;
    };
    
    } /* namespace CFF */
    
    #endif /* HB_CFF_INTERP_COMMON_HH */