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 /*

  * Copyright © 1998-2004  David Turner and Werner Lemberg

  * Copyright © 2004,2007,2009,2010  Red Hat, Inc.

  * Copyright © 2011,2012  Google, 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.

  *

  * Red Hat Author(s): Owen Taylor, Behdad Esfahbod

  * Google Author(s): Behdad Esfahbod

  */

 #ifndef HB_BUFFER_PRIVATE_HH

 #define HB_BUFFER_PRIVATE_HH

 #include "hb-private.hh"

 #include "hb-object-private.hh"

 #include "hb-unicode-private.hh"

 ASSERT_STATIC (sizeof (hb_glyph_info_t) == 20);

 ASSERT_STATIC (sizeof (hb_glyph_info_t) == sizeof (hb_glyph_position_t));

 /*

  * hb_buffer_t

  */

 struct hb_buffer_t {

   hb_object_header_t header;

   ASSERT_POD ();

   /* Information about how the text in the buffer should be treated */

   hb_unicode_funcs_t *unicode; /* Unicode functions */

   hb_segment_properties_t props; /* Script, language, direction */

   hb_buffer_flags_t flags; /* BOT / EOT / etc. */

   /* Buffer contents */

   hb_buffer_content_type_t content_type;

   bool in_error; /* Allocation failed */

   bool have_output; /* Whether we have an output buffer going on */

   bool have_positions; /* Whether we have positions */

   unsigned int idx; /* Cursor into ->info and ->pos arrays */

   unsigned int len; /* Length of ->info and ->pos arrays */

   unsigned int out_len; /* Length of ->out array if have_output */

   unsigned int allocated; /* Length of allocated arrays */

   hb_glyph_info_t     *info;

   hb_glyph_info_t     *out_info;

   hb_glyph_position_t *pos;

   inline hb_glyph_info_t &cur (unsigned int i = 0) { return info[idx + i]; }

   inline hb_glyph_info_t cur (unsigned int i = 0) const { return info[idx + i]; }

   inline hb_glyph_position_t &cur_pos (unsigned int i = 0) { return pos[idx + i]; }

   inline hb_glyph_position_t cur_pos (unsigned int i = 0) const { return pos[idx + i]; }

   inline hb_glyph_info_t &prev (void) { return out_info[out_len - 1]; }

   inline hb_glyph_info_t prev (void) const { return info[out_len - 1]; }

   inline bool has_separate_output (void) const { return info != out_info; }

   unsigned int serial;

   /* These reflect current allocations of the bytes in glyph_info_t's var1 and var2. */

   uint8_t allocated_var_bytes[8];

   const char *allocated_var_owner[8];

   /* Text before / after the main buffer contents.

    * Always in Unicode, and ordered outward.

    * Index 0 is for "pre-context", 1 for "post-context". */

   static const unsigned int CONTEXT_LENGTH = 5;

   hb_codepoint_t context[2][CONTEXT_LENGTH];

   unsigned int context_len[2];

   /* Methods */

   HB_INTERNAL void reset (void);

   HB_INTERNAL void clear (void);

   inline unsigned int backtrack_len (void) const

   { return have_output? out_len : idx; }

   inline unsigned int lookahead_len (void) const

   { return len - idx; }

   inline unsigned int next_serial (void) { return serial++; }

   HB_INTERNAL void allocate_var (unsigned int byte_i, unsigned int count, const char *owner);

   HB_INTERNAL void deallocate_var (unsigned int byte_i, unsigned int count, const char *owner);

   HB_INTERNAL void assert_var (unsigned int byte_i, unsigned int count, const char *owner);

   HB_INTERNAL void deallocate_var_all (void);

   HB_INTERNAL void add (hb_codepoint_t  codepoint,

 			unsigned int    cluster);

   HB_INTERNAL void add_info (const hb_glyph_info_t &glyph_info);

   HB_INTERNAL void reverse_range (unsigned int start, unsigned int end);

   HB_INTERNAL void reverse (void);

   HB_INTERNAL void reverse_clusters (void);

   HB_INTERNAL void guess_segment_properties (void);

   HB_INTERNAL void swap_buffers (void);

   HB_INTERNAL void remove_output (void);

   HB_INTERNAL void clear_output (void);

   HB_INTERNAL void clear_positions (void);

   HB_INTERNAL void replace_glyphs (unsigned int num_in,

 				   unsigned int num_out,

 				   const hb_codepoint_t *glyph_data);

   HB_INTERNAL void replace_glyph (hb_codepoint_t glyph_index);

   /* Makes a copy of the glyph at idx to output and replace glyph_index */

   HB_INTERNAL void output_glyph (hb_codepoint_t glyph_index);

   HB_INTERNAL void output_info (const hb_glyph_info_t &glyph_info);

   /* Copies glyph at idx to output but doesn't advance idx */

   HB_INTERNAL void copy_glyph (void);

   HB_INTERNAL bool move_to (unsigned int i); /* i is output-buffer index. */

   /* Copies glyph at idx to output and advance idx.

    * If there's no output, just advance idx. */

   inline void

   next_glyph (void)

   {

     if (have_output)

     {

       if (unlikely (out_info != info || out_len != idx)) {

 	if (unlikely (!make_room_for (1, 1))) return;

 	out_info[out_len] = info[idx];

       }

       out_len++;

     }

     idx++;

   }

   /* Advance idx without copying to output. */

   inline void skip_glyph (void) { idx++; }

   inline void reset_masks (hb_mask_t mask)

   {

     for (unsigned int j = 0; j < len; j++)

       info[j].mask = mask;

   }

   inline void add_masks (hb_mask_t mask)

   {

     for (unsigned int j = 0; j < len; j++)

       info[j].mask |= mask;

   }

   HB_INTERNAL void set_masks (hb_mask_t value,

 			      hb_mask_t mask,

 			      unsigned int cluster_start,

 			      unsigned int cluster_end);

   HB_INTERNAL void merge_clusters (unsigned int start,

 				   unsigned int end);

   HB_INTERNAL void merge_out_clusters (unsigned int start,

 				       unsigned int end);

   /* Internal methods */

   HB_INTERNAL bool enlarge (unsigned int size);

   inline bool ensure (unsigned int size)

   { return likely (!size || size < allocated) ? true : enlarge (size); }

   HB_INTERNAL bool make_room_for (unsigned int num_in, unsigned int num_out);

   HB_INTERNAL bool shift_forward (unsigned int count);

   typedef long scratch_buffer_t;

   HB_INTERNAL scratch_buffer_t *get_scratch_buffer (unsigned int *size);

   inline void clear_context (unsigned int side) { context_len[side] = 0; }

 };

 #define HB_BUFFER_XALLOCATE_VAR(b, func, var, owner) \

   b->func (offsetof (hb_glyph_info_t, var) - offsetof(hb_glyph_info_t, var1), \

 	   sizeof (b->info[0].var), owner)

 #define HB_BUFFER_ALLOCATE_VAR(b, var) \

 	HB_BUFFER_XALLOCATE_VAR (b, allocate_var, var (), #var)

 #define HB_BUFFER_DEALLOCATE_VAR(b, var) \

 	HB_BUFFER_XALLOCATE_VAR (b, deallocate_var, var (), #var)

 #define HB_BUFFER_ASSERT_VAR(b, var) \

 	HB_BUFFER_XALLOCATE_VAR (b, assert_var, var (), #var)

 #endif /* HB_BUFFER_PRIVATE_HH */