Update freetype sources (2.6.2) in third party.

third_party/freetype2/src/src/sfnt/ttkern.c

Index: third_party/freetype2/src/src/sfnt/ttkern.c
diff --git a/third_party/freetype2/src/src/sfnt/ttkern.c b/third_party/freetype2/src/src/sfnt/ttkern.c
new file mode 100644
index 0000000000000000000000000000000000000000..4fccc535cedc952ba99a6eb14d1e1db82aa267ea
--- /dev/null
+++ b/third_party/freetype2/src/src/sfnt/ttkern.c
@@ -0,0 +1,306 @@
+/***************************************************************************/
+/*                                                                         */
+/*  ttkern.c                                                               */
+/*                                                                         */
+/*    Load the basic TrueType kerning table.  This doesn't handle          */
+/*    kerning data within the GPOS table at the moment.                    */
+/*                                                                         */
+/*  Copyright 1996-2015 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 <ft2build.h>
+#include FT_INTERNAL_DEBUG_H
+#include FT_INTERNAL_STREAM_H
+#include FT_TRUETYPE_TAGS_H
+#include "ttkern.h"
+
+#include "sferrors.h"
+
+
+  /*************************************************************************/
+  /*                                                                       */
+  /* The macro FT_COMPONENT is used in trace mode.  It is an implicit      */
+  /* parameter of the FT_TRACE() and FT_ERROR() macros, used to print/log  */
+  /* messages during execution.                                            */
+  /*                                                                       */
+#undef  FT_COMPONENT
+#define FT_COMPONENT  trace_ttkern
+
+
+#undef  TT_KERN_INDEX
+#define TT_KERN_INDEX( g1, g2 )  ( ( (FT_ULong)(g1) << 16 ) | (g2) )
+
+
+  FT_LOCAL_DEF( FT_Error )
+  tt_face_load_kern( TT_Face    face,
+                     FT_Stream  stream )
+  {
+    FT_Error   error;
+    FT_ULong   table_size;
+    FT_Byte*   p;
+    FT_Byte*   p_limit;
+    FT_UInt    nn, num_tables;
+    FT_UInt32  avail = 0, ordered = 0;
+
+
+    /* the kern table is optional; exit silently if it is missing */
+    error = face->goto_table( face, TTAG_kern, stream, &table_size );
+    if ( error )
+      goto Exit;
+
+    if ( table_size < 4 )  /* the case of a malformed table */
+    {
+      FT_ERROR(( "tt_face_load_kern:"
+                 " kerning table is too small - ignored\n" ));
+      error = FT_THROW( Table_Missing );
+      goto Exit;
+    }
+
+    if ( FT_FRAME_EXTRACT( table_size, face->kern_table ) )
+    {
+      FT_ERROR(( "tt_face_load_kern:"
+                 " could not extract kerning table\n" ));
+      goto Exit;
+    }
+
+    face->kern_table_size = table_size;
+
+    p       = face->kern_table;
+    p_limit = p + table_size;
+
+    p         += 2; /* skip version */
+    num_tables = FT_NEXT_USHORT( p );
+
+    if ( num_tables > 32 ) /* we only support up to 32 sub-tables */
+      num_tables = 32;
+
+    for ( nn = 0; nn < num_tables; nn++ )
+    {
+      FT_UInt    num_pairs, length, coverage;
+      FT_Byte*   p_next;
+      FT_UInt32  mask = (FT_UInt32)1UL << nn;
+
+
+      if ( p + 6 > p_limit )
+        break;
+
+      p_next = p;
+
+      p += 2; /* skip version */
+      length   = FT_NEXT_USHORT( p );
+      coverage = FT_NEXT_USHORT( p );
+
+      if ( length <= 6 + 8 )
+        break;
+
+      p_next += length;
+
+      if ( p_next > p_limit )  /* handle broken table */
+        p_next = p_limit;
+
+      /* only use horizontal kerning tables */
+      if ( ( coverage & ~8U ) != 0x0001 ||
+           p + 8 > p_limit              )
+        goto NextTable;
+
+      num_pairs = FT_NEXT_USHORT( p );
+      p        += 6;
+
+      if ( ( p_next - p ) < 6 * (int)num_pairs ) /* handle broken count */
+        num_pairs = (FT_UInt)( ( p_next - p ) / 6 );
+
+      avail |= mask;
+
+      /*
+       *  Now check whether the pairs in this table are ordered.
+       *  We then can use binary search.
+       */
+      if ( num_pairs > 0 )
+      {
+        FT_ULong  count;
+        FT_ULong  old_pair;
+
+
+        old_pair = FT_NEXT_ULONG( p );
+        p       += 2;
+
+        for ( count = num_pairs - 1; count > 0; count-- )
+        {
+          FT_UInt32  cur_pair;
+
+
+          cur_pair = FT_NEXT_ULONG( p );
+          if ( cur_pair <= old_pair )
+            break;
+
+          p += 2;
+          old_pair = cur_pair;
+        }
+
+        if ( count == 0 )
+          ordered |= mask;
+      }
+
+    NextTable:
+      p = p_next;
+    }
+
+    face->num_kern_tables = nn;
+    face->kern_avail_bits = avail;
+    face->kern_order_bits = ordered;
+
+  Exit:
+    return error;
+  }
+
+
+  FT_LOCAL_DEF( void )
+  tt_face_done_kern( TT_Face  face )
+  {
+    FT_Stream  stream = face->root.stream;
+
+
+    FT_FRAME_RELEASE( face->kern_table );
+    face->kern_table_size = 0;
+    face->num_kern_tables = 0;
+    face->kern_avail_bits = 0;
+    face->kern_order_bits = 0;
+  }
+
+
+  FT_LOCAL_DEF( FT_Int )
+  tt_face_get_kerning( TT_Face  face,
+                       FT_UInt  left_glyph,
+                       FT_UInt  right_glyph )
+  {
+    FT_Int    result = 0;
+    FT_UInt   count, mask;
+    FT_Byte*  p       = face->kern_table;
+    FT_Byte*  p_limit = p + face->kern_table_size;
+
+
+    p   += 4;
+    mask = 0x0001;
+
+    for ( count = face->num_kern_tables;
+          count > 0 && p + 6 <= p_limit;
+          count--, mask <<= 1 )
+    {
+      FT_Byte* base     = p;
+      FT_Byte* next;
+      FT_UInt  version  = FT_NEXT_USHORT( p );
+      FT_UInt  length   = FT_NEXT_USHORT( p );
+      FT_UInt  coverage = FT_NEXT_USHORT( p );
+      FT_UInt  num_pairs;
+      FT_Int   value    = 0;
+
+      FT_UNUSED( version );
+
+
+      next = base + length;
+
+      if ( next > p_limit )  /* handle broken table */
+        next = p_limit;
+
+      if ( ( face->kern_avail_bits & mask ) == 0 )
+        goto NextTable;
+
+      if ( p + 8 > next )
+        goto NextTable;
+
+      num_pairs = FT_NEXT_USHORT( p );
+      p        += 6;
+
+      if ( ( next - p ) < 6 * (int)num_pairs )  /* handle broken count  */
+        num_pairs = (FT_UInt)( ( next - p ) / 6 );
+
+      switch ( coverage >> 8 )
+      {
+      case 0:
+        {
+          FT_ULong  key0 = TT_KERN_INDEX( left_glyph, right_glyph );
+
+
+          if ( face->kern_order_bits & mask )   /* binary search */
+          {
+            FT_UInt   min = 0;
+            FT_UInt   max = num_pairs;
+
+
+            while ( min < max )
+            {
+              FT_UInt   mid = ( min + max ) >> 1;
+              FT_Byte*  q   = p + 6 * mid;
+              FT_ULong  key;
+
+
+              key = FT_NEXT_ULONG( q );
+
+              if ( key == key0 )
+              {
+                value = FT_PEEK_SHORT( q );
+                goto Found;
+              }
+              if ( key < key0 )
+                min = mid + 1;
+              else
+                max = mid;
+            }
+          }
+          else /* linear search */
+          {
+            FT_UInt  count2;
+
+
+            for ( count2 = num_pairs; count2 > 0; count2-- )
+            {
+              FT_ULong  key = FT_NEXT_ULONG( p );
+
+
+              if ( key == key0 )
+              {
+                value = FT_PEEK_SHORT( p );
+                goto Found;
+              }
+              p += 2;
+            }
+          }
+        }
+        break;
+
+       /*
+        *  We don't support format 2 because we haven't seen a single font
+        *  using it in real life...
+        */
+
+      default:
+        ;
+      }
+
+      goto NextTable;
+
+    Found:
+      if ( coverage & 8 ) /* override or add */
+        result = value;
+      else
+        result += value;
+
+    NextTable:
+      p = next;
+    }
+
+    return result;
+  }
+
+#undef TT_KERN_INDEX
+
+/* END */