/*******************************************************************
 *
 *  t1gload.c                                                   1.0
 *
 *    Type1 Glyph Loader.
 *
 *  Copyright 1996-1999 by
 *  David Turner, Robert Wilhelm, and Werner Lemberg.
 *
 *  This file is part of the FreeType project, and may only be used
 *  modified and distributed under the terms of the FreeType project
 *  license, LICENSE.TXT.  By continuing to use, modify, or distribute
 *  this file you indicate that you have read the license and
 *  understand and accept it fully.
 *
 ******************************************************************/

#include <t1gload.h>
#include <ftdebug.h>
#include <t1encode.h>
#include <ftstream.h>

#ifndef T1_CONFIG_OPTION_DISABLE_HINTER
#include <t1hinter.h>
#endif

  /**********************************************************************/
  /**********************************************************************/
  /**********************************************************************/
  /**********                                                   *********/
  /**********                                                   *********/
  /**********           GENERIC CHARSTRINGS PARSING             *********/
  /**********                                                   *********/
  /**********                                                   *********/
  /**********************************************************************/
  /**********************************************************************/
  /**********************************************************************/

/*********************************************************************
 *
 * <Function>
 *    T1_Init_Builder
 *
 * <Description>
 *    Initialise a given glyph builder.
 *
 * <Input>
 *    builder :: glyph builder to initialise
 *    face    :: current face object
 *    size    :: current size object
 *    glyph   :: current glyph object
 *    funcs   :: glyph builder functions (or "methods").
 *
 *********************************************************************/

  EXPORT_FUNC
  void  T1_Init_Builder( T1_Builder*             builder,
                         T1_Face                 face,
                         T1_Size                 size,
                         T1_GlyphSlot            glyph,
                         const T1_Builder_Funcs* funcs )
  {
    builder->funcs       = *funcs;
    builder->path_begun  = 0;
    builder->load_points = 1;

    builder->face   = face;
    builder->size   = size;
    builder->glyph  = glyph;
    builder->memory = face->root.memory;

    if (glyph)
    {
      builder->base         = glyph->root.outline;
      builder->max_points   = glyph->max_points;
      builder->max_contours = glyph->max_contours;
    }

    if (size)
    {
      builder->scale_x = size->root.metrics.x_scale;
      builder->scale_y = size->root.metrics.y_scale;
    }

    builder->pos_x = 0;
    builder->pos_y = 0;

    builder->left_bearing.x = 0;
    builder->left_bearing.y = 0;
    builder->advance.x      = 0;
    builder->advance.y      = 0;

    builder->base.n_points   = 0;
    builder->base.n_contours = 0;
    builder->current         = builder->base;

    builder->pass       = 0;
    builder->hint_point = 0;
  }


/*********************************************************************
 *
 * <Function>
 *    T1_Done_Builder
 *
 * <Description>
 *    Finalise a given glyph builder. Its content can still be
 *    used after the call, but the function saves important information
 *    within the corresponding glyph slot.
 *
 * <Input>
 *    builder :: glyph builder to initialise
 *
 *********************************************************************/

  EXPORT_FUNC
  void T1_Done_Builder( T1_Builder*  builder )
  {
    T1_GlyphSlot  glyph = builder->glyph;

    if (glyph)
    {
      glyph->root.outline = builder->base;
      glyph->max_points   = builder->max_points;
      glyph->max_contours = builder->max_contours;
    }
  }


/*********************************************************************
 *
 * <Function>
 *    T1_Init_Decoder
 *
 * <Description>
 *    Initialise a given Type 1 decoder for parsing
 *
 * <Input>
 *    decoder :: Type 1 decoder to initialise
 *    funcs   :: hinter functions interface
 *
 *********************************************************************/

  EXPORT_FUNC
  void  T1_Init_Decoder( T1_Decoder*             decoder,
                         const T1_Hinter_Funcs*  funcs )
  {
    decoder->hinter = *funcs;    /* copy hinter interface */
    decoder->top    = 0;
    decoder->zone   = 0;

    decoder->flex_state       = 0;
    decoder->num_flex_vectors = 0;

    /* Clear loader */
    MEM_Set( &decoder->builder, 0, sizeof(decoder->builder) );
  }


/*********************************************************************
 *
 * <Function>
 *    lookup_glyph_by_stdcharcode
 *
 * <Description>
 *    Lookup a given glyph by its StandardEncoding charcode. Used
 *    to implement the SEAC Type 1 operator.
 *
 * <Input>
 *    face     :: current face object         
 *    charcode :: charcode to look for
 *
 * <Return>
 *    glyph index in font face. Returns -1 if the corresponding
 *    glyph wasn't found.
 *
 *********************************************************************/

  static
  T1_Int    lookup_glyph_by_stdcharcode( T1_Face  face,
                                         T1_Int   charcode )
  {
    T1_Int            n;
    const T1_String*  glyph_name;
    
    /* check range of standard char code */
    if (charcode < 0 || charcode > 255)
      return -1;
      
    glyph_name = t1_standard_strings[t1_standard_encoding[charcode]];
    
    for ( n = 0; n < face->num_glyphs; n++ )
    {
      T1_String*  name = (T1_String*)face->glyph_names[n];
      
      if ( name && strcmp(name,glyph_name) == 0 )
        return n;
    }

    return -1;
  }


/*********************************************************************
 *
 * <Function>
 *    t1operator_seac
 *
 * <Description>
 *    Implements the "seac" Type 1 operator for a Type 1 decoder
 *
 * <Input>
 *    decoder  :: current Type 1 decoder
 *    asb      :: accent's side bearing
 *    adx      :: horizontal position of accent
 *    ady      :: vertical position of accent
 *    bchar    :: base character's StandardEncoding charcode
 *    achar    :: accent character's StandardEncoding charcode
 *
 * <Return>
 *    Error code. 0 means success.                               
 *
 *********************************************************************/

  static
  T1_Error  t1operator_seac( T1_Decoder*  decoder,
                             T1_Pos       asb,
                             T1_Pos       adx,
                             T1_Pos       ady,
                             T1_Int       bchar,
                             T1_Int       achar )
  {
    T1_Error     error;
    T1_Face      face = decoder->builder.face;
    T1_Int       bchar_index, achar_index, n_base_points;
    FT_Outline*  cur  = &decoder->builder.current;
    FT_Outline*  base = &decoder->builder.base;
    T1_Vector    left_bearing, advance;
    
    bchar_index = lookup_glyph_by_stdcharcode( face, bchar );
    achar_index = lookup_glyph_by_stdcharcode( face, achar );
    
    if (bchar_index < 0 || achar_index < 0)
    {
      FT_ERROR(( "T1.Parse_Seac : invalid seac character code arguments\n" ));
      return T1_Err_Syntax_Error;
    }

    /* First load "bchar" in builder */
    /* now load the unscaled outline */
    cur->n_points   = 0;
    cur->n_contours = 0;
    cur->points     = base->points   + base->n_points;
    cur->flags      = base->flags    + base->n_points;
    cur->contours   = base->contours + base->n_contours;

    error = T1_Parse_CharStrings( decoder,
                                  face->charstrings    [bchar_index],
                                  face->charstrings_len[bchar_index],
                                  face->num_subrs,
                                  face->subrs,
                                  face->subrs_len );
    if (error) return error;

    n_base_points   = cur->n_points;

    /* save the left bearing and width of the base character */
    /* as they will be erase by the next load..              */
    left_bearing = decoder->builder.left_bearing;
    advance      = decoder->builder.advance;

    decoder->builder.left_bearing.x = 0;
    decoder->builder.left_bearing.y = 0;    

    /* Now load "achar" on top of */
    /* the base outline           */
    /*                            */ 
    cur->n_points   = 0;
    cur->n_contours = 0;
    cur->points     = base->points   + base->n_points;
    cur->flags      = base->flags    + base->n_points;
    cur->contours   = base->contours + base->n_contours;

    error = T1_Parse_CharStrings( decoder,
                                  face->charstrings    [achar_index],
                                  face->charstrings_len[achar_index],
                                  face->num_subrs,
                                  face->subrs,
                                  face->subrs_len );
    if (error) return error;

    /* adjust contours in accented character outline */
    {
      T1_Int  n;

      for ( n = 0; n < cur->n_contours; n++ )
        cur->contours[n] += n_base_points;
    }

    /* restore the left side bearing and   */
    /* advance width of the base character */
    decoder->builder.left_bearing = left_bearing;
    decoder->builder.advance      = advance;

    /* Finally, move the accent */
    FT_Translate_Outline( cur, adx - asb, ady );
    
    (void)asb;           /* ignore this parameter */
    return T1_Err_Ok;
  }

/*********************************************************************
 *
 * <Function>
 *    t1operator_flex
 *
 * <Description>
 *    Implements the "flex" Type 1 operator for a Type 1 decoder
 *
 * <Input>
 *    decoder   :: current Type 1 decoder
 *    threshold :: threshold
 *    end_x     :: position of final flex point
 *    end_y     :: position of final flex point
 *
 * <Return>
 *    Error code. 0 means success.                               
 *
 *********************************************************************/

  static
  T1_Error  t1operator_flex( T1_Decoder*  decoder,
                             T1_Pos       threshold,
                             T1_Pos       end_x,
                             T1_Pos       end_y )
  {
    T1_Vector    vec;
    T1_Vector*   flex  = decoder->flex_vectors;
    T1_Int       n;

    /* we don't even try to test the threshold in the non-hinting  */
    /* builder, even if the flex operator is said to be a path      */
    /* construction statement in the specification. This is better */
    /* left to the hinter..                                        */

    flex = decoder->flex_vectors;
    vec  = *flex++;

    for ( n = 0; n < 6; n++ )
    {
      flex->x += vec.x;
      flex->y += vec.y;

      vec = *flex++;
    }


    (void)threshold;
    (void)end_x;
    (void)end_y;

    flex  = decoder->flex_vectors;

    return  decoder->builder.funcs.rcurve_to( &decoder->builder,
                                              flex[0].x, flex[0].y,
                                              flex[1].x, flex[1].y,
                                              flex[2].x, flex[2].y ) ||

            decoder->builder.funcs.rcurve_to( &decoder->builder,
                                              flex[3].x, flex[3].y,
                                              flex[4].x, flex[4].y,
                                              flex[5].x, flex[5].y );
  }


/*********************************************************************
 *
 * <Function>
 *    T1_Parse_CharStrings
 *
 * <Description>
 *    Parses a given Type 1 charstrings program
 *
 * <Input>
 *    decoder          :: current Type 1 decoder
 *    charstring_base  :: base of the charstring stream
 *    charstring_len   :: length in bytes of the charstring stream
 *    num_subrs        :: number of sub-routines
 *    subrs_base       :: array of sub-routines addresses
 *    subrs_len        :: array of sub-routines lengths
 *
 * <Return>
 *    Error code. 0 means success.                               
 *
 *********************************************************************/

  EXPORT_FUNC
  T1_Error   T1_Parse_CharStrings( T1_Decoder*  decoder,
                                   T1_Byte*     charstring_base,
                                   T1_Int       charstring_len,
                                   T1_Int       num_subrs,
                                   T1_Byte**    subrs_base,
                                   T1_Int*      subrs_len )
  {
    T1_Error            error;
    T1_Decoder_Zone*    zone;
    T1_Byte*            ip;
    T1_Byte*            limit;
    T1_Builder*         builder = &decoder->builder;
    T1_Builder_Funcs*   builds  = &builder->funcs;
    T1_Hinter_Funcs*    hints   = &decoder->hinter;

    static const T1_Int  args_count[ op_max ] = 
    {
      0, /* none */
      0, /* endchar */
      2, /* hsbw */
      5, /* seac */
      4, /* sbw */
      0, /* closepath */
      1, /* hlineto */
      1, /* hmoveto */
      4, /* hvcurveto */
      2, /* rlineto */
      2, /* rmoveto */
      6, /* rrcurveto */
      4, /* vhcurveto */
      1, /* vlineto */
      1, /* vmoveto */
      0, /* dotsection */
      2, /* hstem */
      6, /* hstem3 */
      2, /* vstem */
      6, /* vstem3 */
      2, /* div */
     -1, /* callothersubr */
      1, /* callsubr */
      0, /* pop */
      0, /* return */
      2  /* setcurrentpoint */
    };

    /* First of all, initialise the decoder */
    decoder->top  = decoder->stack;
    decoder->zone = decoder->zones;
    zone          = decoder->zones;

    builder->path_begun  = 0;

    zone->base           = charstring_base;
    limit = zone->limit  = charstring_base + charstring_len;
    ip    = zone->cursor = zone->base;

    error = T1_Err_Ok;

    /* now, execute loop */
    while ( ip < limit )
    {
      T1_Int*      top      = decoder->top;
      T1_Operator  op       = op_none;
      T1_Long      value    = 0;

      /* First of all, decompress operator or value */
      switch (*ip++)
      {
        case 1:  op = op_hstem;     break;

        case 3:  op = op_vstem;     break;
        case 4:  op = op_vmoveto;   break;
        case 5:  op = op_rlineto;   break;
        case 6:  op = op_hlineto;   break;
        case 7:  op = op_vlineto;   break;
        case 8:  op = op_rrcurveto; break;
        case 9:  op = op_closepath; break;
        case 10: op = op_callsubr;  break;
        case 11: op = op_return;    break;

        case 13: op = op_hsbw;      break;
        case 14: op = op_endchar;   break;

        case 21: op = op_rmoveto;   break;
        case 22: op = op_hmoveto;   break;

        case 30: op = op_vhcurveto; break;
        case 31: op = op_hvcurveto; break;

        case 12:
          {
            if (ip > limit)
            {
              FT_ERROR(( "T1.Parse_CharStrings : invalid escape (12+EOF)\n" ));
              goto Syntax_Error;
            }

            switch (*ip++)
            {
              case 0:  op = op_dotsection;      break;
              case 1:  op = op_vstem3;          break;
              case 2:  op = op_hstem3;          break;
              case 6:  op = op_seac;            break;
              case 7:  op = op_sbw;             break;
              case 12: op = op_div;             break;
              case 16: op = op_callothersubr;   break;
              case 17: op = op_pop;             break;
              case 33: op = op_setcurrentpoint; break;

              default:
                FT_ERROR(( "T1.Parse_CharStrings : invalid escape (12+%d)\n",
                         ip[-1] ));
                goto Syntax_Error;
            }
          }
          break;

        case 255:    /* four bytes integer */
          {
            if (ip+4 > limit)
            {
              FT_ERROR(( "T1.Parse_CharStrings : unexpected EOF in integer\n" ));
              goto Syntax_Error;
            }

            value = ((long)ip[0] << 24) |
                    ((long)ip[1] << 16) |
                    ((long)ip[2] << 8)  |
                           ip[3];
            ip += 4;
          }
          break;

        default:
          if (ip[-1] >= 32)
          {
            if (ip[-1] < 247)
              value = (long)ip[-1] - 139;
            else
            {
              if (++ip > limit)
              {
                FT_ERROR(( "T1.Parse_CharStrings : unexpected EOF in integer\n" ));
                goto Syntax_Error;
              }

              if (ip[-2] < 251)
                value =  ((long)(ip[-2]-247) << 8) + ip[-1] + 108;
              else
                value = -((((long)ip[-2]-251) << 8) + ip[-1] + 108 );
            }
          }
          else
          {
            FT_ERROR(( "T1.Parse_CharStrings : invalid byte (%d)\n",
                     ip[-1] ));
            goto Syntax_Error;
          }
      }

      /* push value if needed */
      if ( op == op_none )
      {
        if ( top - decoder->stack >= T1_MAX_CHARSTRINGS_OPERANDS )
        {
          FT_ERROR(( "T1.Parse_CharStrings : Stack overflow !!\n" ));
          goto Syntax_Error;
        }

        *top++       = value;
        decoder->top = top;
      }

      else if ( op == op_callothersubr ) /* check arguments differently */
      {
        if ( top - decoder->stack < 2)
          goto Stack_Underflow;

        top -= 2;

        switch (top[1])
        {
          case 1:   /* start flex feature ----------------------------- */
            {
              if (top[0] != 0) goto Unexpected_OtherSubr;

              decoder->flex_state        = 1;
              decoder->num_flex_vectors  = 0;
              decoder->flex_vectors[0].x = 0;
              decoder->flex_vectors[0].y = 0;
            }
            break;


          case 2:   /* add flex vector ------------------------------- */
            {
              T1_Int      index;
              T1_Vector*  flex;

              if (top[0] != 0) goto Unexpected_OtherSubr;

              top -= 2;
              if (top < decoder->stack) goto Stack_Underflow;

              index = decoder->num_flex_vectors++;
              if (index >= 7)
              {
                FT_ERROR(( "T1.Parse_CharStrings: too many flex vectors !\n" ));
                goto Syntax_Error;
              }

              flex = decoder->flex_vectors + index;
              flex->x += top[0];
              flex->y += top[1];

            }
            break;


          case 0:   /* end flex feature ------------------------------ */
            {
              if ( decoder->flex_state       == 0 ||
                   decoder->num_flex_vectors != 7 )
              {
                FT_ERROR(( "T1.Parse_CharStrings: unexpected flex end\n" ));
                goto Syntax_Error;
              }

              if (top[0] != 3) goto Unexpected_OtherSubr;

              top -= 3;
              if (top < decoder->stack) goto Stack_Underflow;

              /* now consume the remaining "pop pop setcurrentpoint" */
              if ( ip+6 > limit ||
                   ip[0] != 12  || ip[1] != 17 ||   /* pop */
                   ip[2] != 12  || ip[3] != 17 ||   /* pop */
                   ip[4] != 12  || ip[5] != 33 )    /* setcurrentpoint */
              {
                FT_ERROR(( "T1.Parse_CharStrings: invalid flex charstring\n" ));
                goto Syntax_Error;
              }

              decoder->flex_state = 0;
              decoder->top        = top;

              error = t1operator_flex( decoder, top[0], top[1], top[2] );
            }
            break;


          case 3:  /* change hints ------------------------------------ */
            {
              if (top[0] != 1) goto Unexpected_OtherSubr;

              /* eat the following "pop" */
              if (ip+2 > limit)
              {
                FT_ERROR(( "T1.Parse_CharStrings: invalid escape (12+%d)\n",
                         ip[-1] ));
                goto Syntax_Error;
              }

              if (ip[0] != 12 || ip[1] != 17)
              {
                FT_ERROR(( "T1.Parse_CharStrings: 'pop' expected, found (%d %d)\n",
                         ip[0], ip[1] ));
                goto Syntax_Error;
              }

              ip    += 2;
              error  = hints->change_hints(builder);
            }
            break;


          default:
            /* invalid OtherSubrs call */
          Unexpected_OtherSubr:
            FT_ERROR(( "T1.Parse_CharStrings: unexpected OtherSubrs [%d %d]\n",
                     top[0], top[1] ));
            goto Syntax_Error;
        }
        decoder->top = top;
      }
      else
      {
        T1_Int  num_args = args_count[op];

        if ( top - decoder->stack < num_args )
          goto Stack_Underflow;

        top -= num_args;

        switch (op)
        {
          case op_endchar:
            error = builds->end_char( builder );
            break;

          case op_hsbw:
            error = builds->set_bearing_point( builder, top[0], 0,
                                                         top[1], 0 );
            break;

          case op_seac:
            /* return immediately after the processing */
            return t1operator_seac( decoder, top[0], top[1],
                                             top[2], top[3], top[4] );

          case op_sbw:
            error = builds->set_bearing_point( builder, top[0], top[1],
                                                        top[2], top[3] );
            break;

          case op_closepath:
            error = builds->close_path( builder );
            break;

          case op_hlineto:
            error = builds->rline_to( builder, top[0], 0 );
            break;

          case op_hmoveto:
            error = builds->rmove_to( builder, top[0], 0 );
            break;

          case op_hvcurveto:
            error = builds->rcurve_to( builder, top[0], 0,
                                                top[1], top[2],
                                                0,      top[3] );
            break;

          case op_rlineto:
            error = builds->rline_to( builder, top[0], top[1] );
            break;

          case op_rmoveto:
            /* ignore operator when in flex mode */
            if (decoder->flex_state == 0)
              error = builds->rmove_to( builder, top[0], top[1] );
            else
              top += 2;
            break;

          case op_rrcurveto:
            {
              error = builds->rcurve_to( builder, top[0], top[1],
                                                  top[2], top[3],
                                                  top[4], top[5] );
            }
            break;

          case op_vhcurveto:
            error = builds->rcurve_to( builder,      0, top[0],
                                                top[1], top[2],
                                                top[3],      0 );
            break;

          case op_vlineto:
            error = builds->rline_to( builder, 0, top[0] );
            break;

          case op_vmoveto:
            error = builds->rmove_to( builder, 0, top[0] );
            break;

          case op_dotsection:
            error = hints->dot_section( builder );
            break;

          case op_hstem:
            error = hints->stem( builder, top[0], top[1], 0 );
            break;

          case op_hstem3:
            error = hints->stem3( builder, top[0], top[1], top[2],
                                           top[3], top[4], top[5], 0 );
            break;

          case op_vstem:
            error = hints->stem( builder, top[0], top[1], 1 );
            break;

          case op_vstem3:
            error = hints->stem3( builder, top[0], top[1], top[2],
                                           top[3], top[4], top[5], 1 );
            break;

          case op_div:
            if (top[1])
              *top++ = top[0] / top[1];
            else
            {
              FT_ERROR(( "T1.Parse_CHarStrings : division by 0\n" ));
              goto Syntax_Error;
            }
            break;

          case op_callsubr:
            {
              T1_Int  index = top[0];

              if ( index < 0 || index >= num_subrs )
              {
                FT_ERROR(( "T1.Parse_CharStrings : invalid subrs index\n" ));
                goto Syntax_Error;
              }

              if ( zone - decoder->zones >= T1_MAX_SUBRS_CALLS )
              {
                FT_ERROR(( "T1.Parse_CharStrings : too many nested subrs\n" ));
                goto Syntax_Error;
              }

              zone->cursor = ip;  /* save current instruction pointer */

              zone++;
              zone->base    = subrs_base[index];
              zone->limit   = zone->base + subrs_len[index];
              zone->cursor  = zone->base;

              if (!zone->base)
              {
                FT_ERROR(( "T1.Parse_CharStrings : invoking empty subrs !!\n" ));
                goto Syntax_Error;
              }

              decoder->zone = zone;
              ip            = zone->base;
              limit         = zone->limit;
            }
            break;

          case op_pop:
            FT_ERROR(( "T1.Parse_CharStrings : unexpected POP\n" ));
            goto Syntax_Error;


          case op_return:
            if ( zone <= decoder->zones )
            {
              FT_ERROR(( "T1.Parse_CharStrings : unexpected return\n" ));
              goto Syntax_Error;
            }

            zone--;
            ip            = zone->cursor;
            limit         = zone->limit;
            decoder->zone = zone;
            break;

          case op_setcurrentpoint:
            FT_ERROR(( "T1.Parse_CharStrings : unexpected SETCURRENTPOINT\n" ));
            goto Syntax_Error;
            break;

          default:
            FT_ERROR(( "T1.Parse_CharStrings : unhandled opcode %d\n", op ));
            goto Syntax_Error;
        }

        decoder->top = top;
      }
    }

    return error;

  Syntax_Error:
    return T1_Err_Syntax_Error;

  Stack_Underflow:
    return T1_Err_Stack_Underflow;
  }


/*************************************************************************/
/*                                                                       */
/* <Function> T1_Add_Points                                              */
/*                                                                       */
/* <Description>                                                         */
/*    Checks that there is enough room in the current load glyph outline */
/*    to accept "num_points" additional outline points. If not, this     */
/*    function grows the load outline's arrays accordingly..             */
/*                                                                       */
/* <Input>                                                               */
/*    builder    :: pointer to glyph builder object                      */
/*    num_points :: number of points that will be added later            */
/*                                                                       */
/* <Return>                                                              */
/*    Type1 error code. 0 means success                                  */
/*                                                                       */
/* <Note>                                                                */
/*    This function does NOT update the points count in the glyph builder*/
/*    This must be done by the caller itself, after this function is     */
/*    invoked..                                                          */
/*                                                                       */
  LOCAL_FUNC
  T1_Error  T1_Add_Points( T1_Builder*  builder,
                           T1_Int       num_points )
  {
    T1_Int    new_points;

    new_points = builder->base.n_points +
                 builder->current.n_points +
                 num_points;

    if ( new_points > builder->max_points )
    {
      FT_Memory  memory    = builder->memory;
      T1_Error   error;
      T1_Int     increment = builder->current.points - builder->base.points;
      T1_Int     current   = builder->max_points;

      while ( builder->max_points < new_points )
        builder->max_points += 16;

      if ( REALLOC_ARRAY( builder->base.points,
                          current, builder->max_points, T1_Vector )  ||
  
           REALLOC_ARRAY( builder->base.flags,
                          current, builder->max_points, T1_Byte )    )
        return error;
    
      builder->current.points = builder->base.points + increment;
      builder->current.flags  = builder->base.flags  + increment;
    }

    return T1_Err_Ok;
  }

/*************************************************************************/
/*                                                                       */
/* <Function> T1_Add_Contours                                            */
/*                                                                       */
/* <Description>                                                         */
/*    Checks that there is enough room in the current load glyph outline */
/*    to accept "num_contours" additional contours. If not, this func    */
/*    the load outline's arrays accordingly..                            */
/*                                                                       */
/* <Input>                                                               */
/*    builder       :: pointer to glyph builder object                   */
/*    num_contours :: number of contours that will be added later        */
/*                                                                       */
/* <Return>                                                              */
/*    Type1 error code. 0 means success                                  */
/*                                                                       */
/* <Note>                                                                */
/*    This function does NOT update the contours count in the load glyph */
/*    This must be done by the caller itself, after this function is     */
/*    invoked..                                                          */
/*                                                                       */
  LOCAL_FUNC
  T1_Error  T1_Add_Contours( T1_Builder*  builder,
                             T1_Int       num_contours )
  {
    T1_Int    new_contours;

    new_contours = builder->base.n_contours +
                   builder->current.n_contours +
                   num_contours;

    if ( new_contours > builder->max_contours && builder->load_points )
    {
      T1_Error  error;
      FT_Memory memory = builder->memory;
      T1_Int    increment = builder->current.contours - builder->base.contours;
      T1_Int    current   = builder->max_contours;

      while ( builder->max_contours < new_contours )
        builder->max_contours += 4;

      if ( REALLOC_ARRAY( builder->base.contours,
                          current, builder->max_contours, T1_Short ) )
        return error;
  
      builder->current.contours = builder->base.contours + increment;
    }

    return T1_Err_Ok;
  }


  /**********************************************************************/
  /**********************************************************************/
  /**********************************************************************/
  /**********                                                   *********/
  /**********                                                   *********/
  /**********           COMPUTE THE MAXIMUM ADVANCE WIDTH       *********/
  /**********                                                   *********/
  /**********   The following code is in charge of computing    *********/
  /**********   the maximum advance width of the font. It       *********/
  /**********   quickly process each glyph charstring to        *********/
  /**********   extract the value from either a "sbw" or "seac" *********/
  /**********   operator.                                       *********/
  /**********                                                   *********/
  /**********************************************************************/
  /**********************************************************************/
  /**********************************************************************/


  static
  T1_Error  maxadv_sbw( T1_Decoder*  decoder,
                        T1_Pos       sbx,
                        T1_Pos       sby,
                        T1_Pos       wx,
                        T1_Pos       wy )
  {
    if (wx > decoder->builder.advance.x)
      decoder->builder.advance.x = wx;

    (void)sbx;
    (void)sby;
    (void)wy;
    return -1;    /* return an error code to exit the Type 1 parser */
                  /* immediately.                                   */
  }


  static
  T1_Int  maxadv_error( void )
  {
    /* we should never reach this code, unless with a buggy font */
    return -2;
  }

  /* the maxadv_gbuilder_interface is used when computing the maximum  */
  /* advance width of all glyphs in a given font. We only process the */
  /* 'sbw' operator here, and return an error for all others..        */

  /* Note that "seac" is processed by the T1_Decoder                  */
  static
  const T1_Builder_Funcs  maxadv_builder_interface =
  {
    (T1_Builder_EndChar)     maxadv_error,
    (T1_Builder_Sbw)         maxadv_sbw,
    (T1_Builder_ClosePath)   maxadv_error,
    (T1_Builder_RLineTo)     maxadv_error,
    (T1_Builder_RMoveTo)     maxadv_error,
    (T1_Builder_RCurveTo)    maxadv_error
  };


  /* the maxadv_interface is used when computing the maximum advance */
  /* with of the set of glyphs in a given font file. We only process */
  /* the "seac" operator and return immediately..                    */
  static
  const T1_Hinter_Funcs  maxadv_hinter_interface =
  {
    (T1_Hinter_DotSection)   maxadv_error,
    (T1_Hinter_ChangeHints)  maxadv_error,
    (T1_Hinter_Stem)         maxadv_error,
    (T1_Hinter_Stem3)        maxadv_error,
  };


  LOCAL_FUNC
  T1_Error  T1_Compute_Max_Advance( T1_Face  face,
                                    T1_Int  *max_advance )
  {
    T1_Error    error;
    T1_Decoder  decoder;
    T1_Int      glyph_index;

    *max_advance = 0;

    /* Initialise load decoder */
    T1_Init_Decoder( &decoder, &maxadv_hinter_interface );

    T1_Init_Builder( &decoder.builder, face, 0, 0,
                     &maxadv_builder_interface );

    /* For each glyph, parse the glyph charstring and extract */
    /* the advance width..                                    */
    for ( glyph_index = 0; glyph_index < face->num_glyphs; glyph_index++ )
    {
      /* now get load the unscaled outline */
      error = T1_Parse_CharStrings( &decoder,
                                    face->charstrings    [glyph_index],
                                    face->charstrings_len[glyph_index],
                                    face->num_subrs,
                                    face->subrs,
                                    face->subrs_len );
      /* ignore the error if one occured - skip to next glyph */
      (void)error;
    }

    *max_advance = decoder.builder.advance.x;
    return T1_Err_Ok;
  }


  /**********************************************************************/
  /**********************************************************************/
  /**********************************************************************/
  /**********                                                   *********/
  /**********                                                   *********/
  /**********              UNHINTED GLYPH LOADER                *********/
  /**********                                                   *********/
  /**********   The following code is in charge of loading a    *********/
  /**********   single outline. It completely ignores hinting   *********/
  /**********   and is used when FT_LOAD_NO_HINTING is set.     *********/
  /**********                                                   *********/
  /**********     The Type 1 hinter is located in "t1hint.c"    *********/
  /**********                                                   *********/
  /**********************************************************************/
  /**********************************************************************/
  /**********************************************************************/


  static
  T1_Error  close_open_path( T1_Builder*  builder )
  {
    T1_Error     error;
    FT_Outline*  cur = &builder->current;
    T1_Int       num_points;
    T1_Int       first_point;
      
    /* Some fonts, like Hershey, are made of "open paths" which are    */
    /* now managed directly by FreeType. In this case, it is necessary */
    /* to close the path by duplicating its points in reverse order,   */
    /* which is precisely the purpose of this function                 */

    /* first compute the number of points to duplicate..           */
    if (cur->n_contours > 1)
      first_point = cur->contours[ cur->n_contours-2 ]+1;
    else
      first_point = 0;
        
    num_points = cur->n_points - first_point - 2;
    if ( num_points > 0 )
    {
      T1_Vector*  source_point;
      char*       source_flags;
      T1_Vector*  point;
      char*       flags;
              
      error = T1_Add_Points( builder, num_points );
      if (error) return error;

      point = cur->points + cur->n_points;
      flags = cur->flags  + cur->n_points;
        
      source_point   = point - 2;
      source_flags   = flags - 2;

      cur->n_points += num_points;

      if ( builder->load_points )  
        do
        {
          *point++ = *source_point--;
          *flags++ = *source_flags--;
          num_points--;
        }
        while (num_points > 0);
    }

    builder->path_begun = 0;
    return T1_Err_Ok;
  }


  static
  T1_Error  gload_closepath( T1_Builder*  builder )
  {
    FT_Outline*  cur = &builder->current;

    /* save current contour, if any */
    if ( cur->n_contours > 0 )
      cur->contours[cur->n_contours-1] = cur->n_points-1;

#ifndef T1_CONFIG_OPTION_DISABLE_HINTER
    /* hint latest points if needed - this is not strictly required      */
    /* there, but it helps for debugging, and doesn't affect performance */
    if ( builder->pass == 1 )
      T1_Hint_Points( builder );
#endif

    builder->path_begun = 0;
    return T1_Err_Ok;
  }


  static
  T1_Error  gload_endchar( T1_Builder*  builder )
  {
    FT_Outline*  cur = &builder->current;
    T1_Error     error;

    /* close path if needed */
    if (builder->path_begun)
    {
      error = close_open_path( builder );
      if (error) return error;
    }

    error = gload_closepath( builder );  

    builder->base.n_points   += cur->n_points;
    builder->base.n_contours += cur->n_contours;

    return error;
  }


  static
  T1_Error  gload_sbw( T1_Builder*  builder,
                       T1_Pos       sbx,
                       T1_Pos       sby,
                       T1_Pos       wx,
                       T1_Pos       wy )
  {
    builder->left_bearing.x += sbx;
    builder->left_bearing.y += sby;
    builder->advance.x       = wx;
    builder->advance.y       = wy;

    builder->last.x = sbx;
    builder->last.y = sby;
    return 0;
  }


  static
  T1_Error  gload_rlineto( T1_Builder*  builder,
                           T1_Pos       dx,
                           T1_Pos       dy )
  {
    T1_Error     error;
    FT_Outline*  cur = &builder->current;
    T1_Vector    vec;

    /* grow buffer if necessary */
    error = T1_Add_Points  ( builder, 1 );
    if (error) return error;

    if ( builder->load_points )
    {
      /* save point */
      vec.x = builder->last.x + dx;
      vec.y = builder->last.y + dy;

      cur->points[cur->n_points] = vec;
      cur->flags [cur->n_points] = FT_Curve_Tag_On;

      builder->last = vec;
    }
    cur->n_points++;

    builder->path_begun  = 1;
    return T1_Err_Ok;
  }


  static
  T1_Error  gload_rmoveto( T1_Builder*  builder,
                           T1_Pos       dx,
                           T1_Pos       dy )
  {
    T1_Error     error;
    FT_Outline*  cur = &builder->current;
    T1_Vector    vec;

    /* in the case where "path_begun" is set, we have a rmoveto    */
    /* after some normal path definition. When the face's paint    */
    /* type is set to 1, this means that we have an "open path",   */
    /* also called a 'stroke'. The FreeType raster doesn't support */
    /* opened path, so we'll close it explicitely there..          */
    if ( builder->path_begun && builder->face->paint_type == 1 )
    {
      if ( builder->face->paint_type == 1 )
      {
        error = close_open_path( builder );
        if (error) return error;
      }
    }
    
    /* grow buffer if necessary */
    error = T1_Add_Contours( builder, 1 ) ||
            T1_Add_Points  ( builder, 1 );
    if (error) return error;

    /* save current contour, if any */
    if ( cur->n_contours > 0 )
      cur->contours[cur->n_contours-1] = cur->n_points-1;

    if ( builder->load_points )
    {
      /* save point */
      vec.x = builder->last.x + dx;
      vec.y = builder->last.y + dy;
      cur->points[cur->n_points] = vec;
      cur->flags [cur->n_points] = FT_Curve_Tag_On;

      builder->last = vec;
    }

    cur->n_contours++;
    cur->n_points++;

    return T1_Err_Ok;
  }


  static
  T1_Error  gload_rrcurveto( T1_Builder*  builder,
                             T1_Pos       dx1,
                             T1_Pos       dy1,
                             T1_Pos       dx2,
                             T1_Pos       dy2,
                             T1_Pos       dx3,
                             T1_Pos       dy3 )
  {
    T1_Error     error;
    FT_Outline*  cur = &builder->current;
    T1_Vector    vec;
    T1_Vector*   points;
    char*        flags;

    /* grow buffer if necessary */
    error = T1_Add_Points  ( builder, 3 );
    if (error) return error;

    if ( builder->load_points )
    {
      /* save point */
      points = cur->points + cur->n_points;
      flags  = cur->flags  + cur->n_points;

      vec.x = builder->last.x + dx1;
      vec.y = builder->last.y + dy1;
      points[0] = vec;  flags[0] = FT_Curve_Tag_Cubic;

      vec.x += dx2;
      vec.y += dy2;
      points[1] = vec;  flags[1] = FT_Curve_Tag_Cubic;

      vec.x += dx3;
      vec.y += dy3;
      points[2] = vec;  flags[2] = FT_Curve_Tag_On;

      builder->last = vec;
    }
    
    cur->n_points      += 3;
    builder->path_begun = 1;
    return T1_Err_Ok;
  }


  static
  T1_Error  gload_ignore( void )
  {
    return 0;
  }


  static
  const T1_Builder_Funcs  gload_builder_interface =
  {
    gload_endchar,
    gload_sbw,
    gload_closepath,
    gload_rlineto,
    gload_rmoveto,
    gload_rrcurveto
  };


  static
  const T1_Builder_Funcs  gload_builder_interface_null =
  {
    (T1_Builder_EndChar)    gload_ignore,
    (T1_Builder_Sbw)        gload_sbw,      /* record left bearing */
    (T1_Builder_ClosePath)  gload_ignore,
    (T1_Builder_RLineTo)    gload_ignore,
    (T1_Builder_RMoveTo)    gload_ignore,
    (T1_Builder_RCurveTo)   gload_ignore
  };


  static
  const T1_Hinter_Funcs   gload_hinter_interface =
  {
    (T1_Hinter_DotSection)   gload_ignore,   /* dotsection         */
    (T1_Hinter_ChangeHints)  gload_ignore,   /* changehints        */
    (T1_Hinter_Stem)         gload_ignore,   /* hstem & vstem      */
    (T1_Hinter_Stem3)        gload_ignore,   /* hstem3 & vestem3   */
  };


  LOCAL_FUNC
  T1_Error  T1_Load_Glyph( T1_GlyphSlot  glyph,
                           T1_Size       size,
                           T1_Int        glyph_index,
                           T1_Int        load_flags )
  {
    T1_Error        error;
    T1_Decoder      decoder;
    T1_Face         face = (T1_Face)glyph->root.face;
    T1_Bool         hinting;

    glyph->x_scale = size->root.metrics.x_scale;
    glyph->y_scale = size->root.metrics.y_scale;

    glyph->root.outline.n_points   = 0;
    glyph->root.outline.n_contours = 0;

    hinting = ( load_flags & FT_LOAD_NO_SCALE   ) == 0 &&
              ( load_flags & FT_LOAD_NO_HINTING ) == 0;

    glyph->root.format = ft_glyph_format_none;

#ifndef T1_CONFIG_OPTION_DISABLE_HINTER
    /*****************************************************************/
    /*                                                               */
    /*  Hinter overview :                                            */
    /*                                                               */
    /*    This is a two-pass hinter. On the first pass, the hints    */
    /*    are all recorded by the hinter, and no point is loaded     */
    /*    in the outline.                                            */
    /*                                                               */
    /*    When the first pass is finished, all stems hints are       */
    /*    grid-fitted at once.                                       */
    /*                                                               */
    /*    Then, a second pass is performed to load the outline       */
    /*    points as well as hint/scale them correctly.               */
    /*                                                               */

    if ( hinting )
    {
      /* Pass 1 - don't record points, simply stem hints */
      T1_Init_Decoder( &decoder, &t1_hinter_funcs );
      T1_Init_Builder( &decoder.builder, face, size, glyph,
                       &gload_builder_interface_null );

      glyph->hints->hori_stems.num_stems = 0;
      glyph->hints->vert_stems.num_stems = 0;

      error = T1_Parse_CharStrings( &decoder,
                                    face->charstrings    [glyph_index],
                                    face->charstrings_len[glyph_index],
                                    face->num_subrs,
                                    face->subrs,
                                    face->subrs_len );

      /* All right, pass 1 is finished, now grid-fit all stem hints */
      T1_Hint_Stems( &decoder.builder );

      /* Pass 2 - record and scale/hint the points */
      T1_Init_Decoder( &decoder, &t1_hinter_funcs );
      T1_Init_Builder( &decoder.builder, face, size, glyph,
                       &gload_builder_interface );

      decoder.builder.pass = 1;

      error = T1_Parse_CharStrings( &decoder,
                                    face->charstrings    [glyph_index],
                                    face->charstrings_len[glyph_index],
                                    face->num_subrs,
                                    face->subrs,
                                    face->subrs_len );

      /* save new glyph tables */
      T1_Done_Builder( &decoder.builder );
    }
    else
#endif
    {
      T1_Init_Decoder( &decoder, &gload_hinter_interface );

      T1_Init_Builder( &decoder.builder, face, size, glyph,
                       &gload_builder_interface );
  
      /* now load the unscaled outline */
      error = T1_Parse_CharStrings( &decoder,
                                    face->charstrings    [glyph_index],
                                    face->charstrings_len[glyph_index],
                                    face->num_subrs,
                                    face->subrs,
                                    face->subrs_len );
  
      /* save new glyph tables */
      T1_Done_Builder( &decoder.builder );
    }


    /* Now, set the metrics.. - this is rather simple, as : */
    /* the left side bearing is the xMin, and the top side  */
    /* bearing the yMax..                                   */
    if (!error)
    {
      FT_BBox           cbox;
      FT_Glyph_Metrics* metrics = &glyph->root.metrics;

      FT_Get_Outline_CBox( &glyph->root.outline, &cbox );

      /* grid fit the bounding box if necessary */
      if (hinting)
      {
        cbox.xMin &= -64;
        cbox.yMin &= -64;
        cbox.xMax = ( cbox.xMax+63 ) & -64;
        cbox.yMax = ( cbox.yMax+63 ) & -64;
      }

      metrics->width  = cbox.xMax - cbox.xMin;
      metrics->height = cbox.yMax - cbox.yMin;

      metrics->horiBearingX = cbox.xMin;
      metrics->horiBearingY = cbox.yMax;

      /* copy the _unscaled_ advance width */
      metrics->horiAdvance  = decoder.builder.advance.x;

      /* make up vertical metrics */
      metrics->vertBearingX = 0;
      metrics->vertBearingY = 0;
      metrics->vertAdvance  = 0;

      glyph->root.format = ft_glyph_format_outline;

      glyph->root.outline.second_pass    = TRUE;
      glyph->root.outline.high_precision = ( size->root.metrics.y_ppem < 24 );
      glyph->root.outline.dropout_mode   = 2;

      if ( hinting )
      {
        /* adjust the advance width                  */
        /* XXX : TODO : consider stem hints grid-fit */
        metrics->horiAdvance  = FT_MulFix( metrics->horiAdvance,
                                           glyph->x_scale );
      }
      else if ( (load_flags & FT_LOAD_NO_SCALE) == 0 )
      {
        /* scale the outline and the metrics */
        T1_Int       n;
        FT_Outline*  cur = &decoder.builder.base;
        T1_Vector*   vec = cur->points;
        T1_Fixed     x_scale = glyph->x_scale;
        T1_Fixed     y_scale = glyph->y_scale;

        /* First of all, scale the points */
        for ( n = cur->n_points; n > 0; n--, vec++ )
        {
          vec->x = FT_MulFix( vec->x, x_scale );
          vec->y = FT_MulFix( vec->y, y_scale );
        }

        /* Then scale the metrics */
        metrics->width  = FT_MulFix( metrics->width,  x_scale );
        metrics->height = FT_MulFix( metrics->height, y_scale );

        metrics->horiBearingX = FT_MulFix( metrics->horiBearingX, x_scale );
        metrics->horiBearingY = FT_MulFix( metrics->horiBearingY, y_scale );
        metrics->horiAdvance  = FT_MulFix( metrics->horiAdvance,  x_scale );

        metrics->vertBearingX = FT_MulFix( metrics->vertBearingX, x_scale );
        metrics->vertBearingY = FT_MulFix( metrics->vertBearingY, y_scale );
        metrics->vertAdvance  = FT_MulFix( metrics->vertAdvance,  x_scale );

      }
    }

    return error;
  }