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      1 /****************************************************************************
      2  *
      3  * ftgloadr.c
      4  *
      5  *   The FreeType glyph loader (body).
      6  *
      7  * Copyright (C) 2002-2020 by
      8  * David Turner, Robert Wilhelm, and Werner Lemberg
      9  *
     10  * This file is part of the FreeType project, and may only be used,
     11  * modified, and distributed under the terms of the FreeType project
     12  * license, LICENSE.TXT.  By continuing to use, modify, or distribute
     13  * this file you indicate that you have read the license and
     14  * understand and accept it fully.
     15  *
     16  */
     17 
     18 
     19 #include <freetype/internal/ftdebug.h>
     20 #include <freetype/internal/ftgloadr.h>
     21 #include <freetype/internal/ftmemory.h>
     22 #include <freetype/internal/ftobjs.h>
     23 
     24 #undef  FT_COMPONENT
     25 #define FT_COMPONENT  gloader
     26 
     27 
     28   /*************************************************************************/
     29   /*************************************************************************/
     30   /*************************************************************************/
     31   /*****                                                               *****/
     32   /*****                                                               *****/
     33   /*****                    G L Y P H   L O A D E R                    *****/
     34   /*****                                                               *****/
     35   /*****                                                               *****/
     36   /*************************************************************************/
     37   /*************************************************************************/
     38   /*************************************************************************/
     39 
     40   /**************************************************************************
     41    *
     42    * The glyph loader is a simple object which is used to load a set of
     43    * glyphs easily.  It is critical for the correct loading of composites.
     44    *
     45    * Ideally, one can see it as a stack of abstract `glyph' objects.
     46    *
     47    *   loader.base     Is really the bottom of the stack.  It describes a
     48    *                   single glyph image made of the juxtaposition of
     49    *                   several glyphs (those `in the stack').
     50    *
     51    *   loader.current  Describes the top of the stack, on which a new
     52    *                   glyph can be loaded.
     53    *
     54    *   Rewind          Clears the stack.
     55    *   Prepare         Set up `loader.current' for addition of a new glyph
     56    *                   image.
     57    *   Add             Add the `current' glyph image to the `base' one,
     58    *                   and prepare for another one.
     59    *
     60    * The glyph loader is now a base object.  Each driver used to
     61    * re-implement it in one way or the other, which wasted code and
     62    * energy.
     63    *
     64    */
     65 
     66 
     67   /* create a new glyph loader */
     68   FT_BASE_DEF( FT_Error )
     69   FT_GlyphLoader_New( FT_Memory        memory,
     70                       FT_GlyphLoader  *aloader )
     71   {
     72     FT_GlyphLoader  loader = NULL;
     73     FT_Error        error;
     74 
     75 
     76     if ( !FT_NEW( loader ) )
     77     {
     78       loader->memory = memory;
     79       *aloader       = loader;
     80     }
     81     return error;
     82   }
     83 
     84 
     85   /* rewind the glyph loader - reset counters to 0 */
     86   FT_BASE_DEF( void )
     87   FT_GlyphLoader_Rewind( FT_GlyphLoader  loader )
     88   {
     89     FT_GlyphLoad  base    = &loader->base;
     90     FT_GlyphLoad  current = &loader->current;
     91 
     92 
     93     base->outline.n_points   = 0;
     94     base->outline.n_contours = 0;
     95     base->outline.flags      = 0;
     96     base->num_subglyphs      = 0;
     97 
     98     *current = *base;
     99   }
    100 
    101 
    102   /* reset glyph loader, free all allocated tables, */
    103   /* and start from zero                            */
    104   FT_BASE_DEF( void )
    105   FT_GlyphLoader_Reset( FT_GlyphLoader  loader )
    106   {
    107     FT_Memory  memory = loader->memory;
    108 
    109 
    110     FT_FREE( loader->base.outline.points );
    111     FT_FREE( loader->base.outline.tags );
    112     FT_FREE( loader->base.outline.contours );
    113     FT_FREE( loader->base.extra_points );
    114     FT_FREE( loader->base.subglyphs );
    115 
    116     loader->base.extra_points2 = NULL;
    117 
    118     loader->max_points    = 0;
    119     loader->max_contours  = 0;
    120     loader->max_subglyphs = 0;
    121 
    122     FT_GlyphLoader_Rewind( loader );
    123   }
    124 
    125 
    126   /* delete a glyph loader */
    127   FT_BASE_DEF( void )
    128   FT_GlyphLoader_Done( FT_GlyphLoader  loader )
    129   {
    130     if ( loader )
    131     {
    132       FT_Memory  memory = loader->memory;
    133 
    134 
    135       FT_GlyphLoader_Reset( loader );
    136       FT_FREE( loader );
    137     }
    138   }
    139 
    140 
    141   /* re-adjust the `current' outline fields */
    142   static void
    143   FT_GlyphLoader_Adjust_Points( FT_GlyphLoader  loader )
    144   {
    145     FT_Outline*  base    = &loader->base.outline;
    146     FT_Outline*  current = &loader->current.outline;
    147 
    148 
    149     current->points   = FT_OFFSET( base->points,   base->n_points );
    150     current->tags     = FT_OFFSET( base->tags,     base->n_points );
    151     current->contours = FT_OFFSET( base->contours, base->n_contours );
    152 
    153     /* handle extra points table - if any */
    154     if ( loader->use_extra )
    155     {
    156       loader->current.extra_points  = loader->base.extra_points +
    157                                       base->n_points;
    158 
    159       loader->current.extra_points2 = loader->base.extra_points2 +
    160                                       base->n_points;
    161     }
    162   }
    163 
    164 
    165   FT_BASE_DEF( FT_Error )
    166   FT_GlyphLoader_CreateExtra( FT_GlyphLoader  loader )
    167   {
    168     FT_Error   error;
    169     FT_Memory  memory = loader->memory;
    170 
    171 
    172     if ( loader->max_points == 0           ||
    173          loader->base.extra_points != NULL )
    174       return FT_Err_Ok;
    175 
    176     if ( !FT_NEW_ARRAY( loader->base.extra_points, 2 * loader->max_points ) )
    177     {
    178       loader->use_extra          = 1;
    179       loader->base.extra_points2 = loader->base.extra_points +
    180                                    loader->max_points;
    181 
    182       FT_GlyphLoader_Adjust_Points( loader );
    183     }
    184     return error;
    185   }
    186 
    187 
    188   /* re-adjust the `current' subglyphs field */
    189   static void
    190   FT_GlyphLoader_Adjust_Subglyphs( FT_GlyphLoader  loader )
    191   {
    192     FT_GlyphLoad  base    = &loader->base;
    193     FT_GlyphLoad  current = &loader->current;
    194 
    195 
    196     current->subglyphs = FT_OFFSET( base->subglyphs, base->num_subglyphs );
    197   }
    198 
    199 
    200   /* Ensure that we can add `n_points' and `n_contours' to our glyph.      */
    201   /* This function reallocates its outline tables if necessary.  Note that */
    202   /* it DOESN'T change the number of points within the loader!             */
    203   /*                                                                       */
    204   FT_BASE_DEF( FT_Error )
    205   FT_GlyphLoader_CheckPoints( FT_GlyphLoader  loader,
    206                               FT_UInt         n_points,
    207                               FT_UInt         n_contours )
    208   {
    209     FT_Memory    memory  = loader->memory;
    210     FT_Error     error   = FT_Err_Ok;
    211     FT_Outline*  base    = &loader->base.outline;
    212     FT_Outline*  current = &loader->current.outline;
    213     FT_Bool      adjust  = 0;
    214 
    215     FT_UInt      new_max, old_max;
    216 
    217 
    218     error = FT_GlyphLoader_CreateExtra( loader );
    219     if ( error )
    220       return error;
    221 
    222     /* check points & tags */
    223     new_max = (FT_UInt)base->n_points + (FT_UInt)current->n_points +
    224               n_points;
    225     old_max = loader->max_points;
    226 
    227     if ( new_max > old_max )
    228     {
    229       new_max = FT_PAD_CEIL( new_max, 8 );
    230 
    231       if ( new_max > FT_OUTLINE_POINTS_MAX )
    232         return FT_THROW( Array_Too_Large );
    233 
    234       if ( FT_RENEW_ARRAY( base->points, old_max, new_max ) ||
    235            FT_RENEW_ARRAY( base->tags,   old_max, new_max ) )
    236         goto Exit;
    237 
    238       if ( loader->use_extra )
    239       {
    240         if ( FT_RENEW_ARRAY( loader->base.extra_points,
    241                              old_max * 2, new_max * 2 ) )
    242           goto Exit;
    243 
    244         FT_ARRAY_MOVE( loader->base.extra_points + new_max,
    245                        loader->base.extra_points + old_max,
    246                        old_max );
    247 
    248         loader->base.extra_points2 = loader->base.extra_points + new_max;
    249       }
    250 
    251       adjust = 1;
    252       loader->max_points = new_max;
    253     }
    254 
    255     error = FT_GlyphLoader_CreateExtra( loader );
    256     if ( error )
    257       return error;
    258 
    259     /* check contours */
    260     old_max = loader->max_contours;
    261     new_max = (FT_UInt)base->n_contours + (FT_UInt)current->n_contours +
    262               n_contours;
    263     if ( new_max > old_max )
    264     {
    265       new_max = FT_PAD_CEIL( new_max, 4 );
    266 
    267       if ( new_max > FT_OUTLINE_CONTOURS_MAX )
    268         return FT_THROW( Array_Too_Large );
    269 
    270       if ( FT_RENEW_ARRAY( base->contours, old_max, new_max ) )
    271         goto Exit;
    272 
    273       adjust = 1;
    274       loader->max_contours = new_max;
    275     }
    276 
    277     if ( adjust )
    278       FT_GlyphLoader_Adjust_Points( loader );
    279 
    280   Exit:
    281     if ( error )
    282       FT_GlyphLoader_Reset( loader );
    283 
    284     return error;
    285   }
    286 
    287 
    288   /* Ensure that we can add `n_subglyphs' to our glyph. this function */
    289   /* reallocates its subglyphs table if necessary.  Note that it DOES */
    290   /* NOT change the number of subglyphs within the loader!            */
    291   /*                                                                  */
    292   FT_BASE_DEF( FT_Error )
    293   FT_GlyphLoader_CheckSubGlyphs( FT_GlyphLoader  loader,
    294                                  FT_UInt         n_subs )
    295   {
    296     FT_Memory     memory = loader->memory;
    297     FT_Error      error  = FT_Err_Ok;
    298     FT_UInt       new_max, old_max;
    299 
    300     FT_GlyphLoad  base    = &loader->base;
    301     FT_GlyphLoad  current = &loader->current;
    302 
    303 
    304     new_max = base->num_subglyphs + current->num_subglyphs + n_subs;
    305     old_max = loader->max_subglyphs;
    306     if ( new_max > old_max )
    307     {
    308       new_max = FT_PAD_CEIL( new_max, 2 );
    309       if ( FT_RENEW_ARRAY( base->subglyphs, old_max, new_max ) )
    310         goto Exit;
    311 
    312       loader->max_subglyphs = new_max;
    313 
    314       FT_GlyphLoader_Adjust_Subglyphs( loader );
    315     }
    316 
    317   Exit:
    318     return error;
    319   }
    320 
    321 
    322   /* prepare loader for the addition of a new glyph on top of the base one */
    323   FT_BASE_DEF( void )
    324   FT_GlyphLoader_Prepare( FT_GlyphLoader  loader )
    325   {
    326     FT_GlyphLoad  current = &loader->current;
    327 
    328 
    329     current->outline.n_points   = 0;
    330     current->outline.n_contours = 0;
    331     current->num_subglyphs      = 0;
    332 
    333     FT_GlyphLoader_Adjust_Points   ( loader );
    334     FT_GlyphLoader_Adjust_Subglyphs( loader );
    335   }
    336 
    337 
    338   /* add current glyph to the base image -- and prepare for another */
    339   FT_BASE_DEF( void )
    340   FT_GlyphLoader_Add( FT_GlyphLoader  loader )
    341   {
    342     FT_GlyphLoad  base;
    343     FT_GlyphLoad  current;
    344 
    345     FT_Int        n_curr_contours;
    346     FT_Int        n_base_points;
    347     FT_Int        n;
    348 
    349 
    350     if ( !loader )
    351       return;
    352 
    353     base    = &loader->base;
    354     current = &loader->current;
    355 
    356     n_curr_contours = current->outline.n_contours;
    357     n_base_points   = base->outline.n_points;
    358 
    359     base->outline.n_points =
    360       (short)( base->outline.n_points + current->outline.n_points );
    361     base->outline.n_contours =
    362       (short)( base->outline.n_contours + current->outline.n_contours );
    363 
    364     base->num_subglyphs += current->num_subglyphs;
    365 
    366     /* adjust contours count in newest outline */
    367     for ( n = 0; n < n_curr_contours; n++ )
    368       current->outline.contours[n] =
    369         (short)( current->outline.contours[n] + n_base_points );
    370 
    371     /* prepare for another new glyph image */
    372     FT_GlyphLoader_Prepare( loader );
    373   }
    374 
    375 
    376 /* END */
    377