third_party/harfbuzz-ng/src/hb-buffer-private.hh

   1 /*
   2  * Copyright © 1998-2004  David Turner and Werner Lemberg
   3  * Copyright © 2004,2007,2009,2010  Red Hat, Inc.
   4  * Copyright © 2011,2012  Google, Inc.
   5  *
   6  *  This is part of HarfBuzz, a text shaping library.
   7  *
   8  * Permission is hereby granted, without written agreement and without
   9  * license or royalty fees, to use, copy, modify, and distribute this
  10  * software and its documentation for any purpose, provided that the
  11  * above copyright notice and the following two paragraphs appear in
  12  * all copies of this software.
  13  *
  14  * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
  15  * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
  16  * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
  17  * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
  18  * DAMAGE.
  19  *
  20  * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
  21  * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
  22  * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
  23  * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
  24  * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
  25  *
  26  * Red Hat Author(s): Owen Taylor, Behdad Esfahbod
  27  * Google Author(s): Behdad Esfahbod
  28  */
  29
  30 #ifndef HB_BUFFER_PRIVATE_HH
  31 #define HB_BUFFER_PRIVATE_HH
  32
  33 #include "hb-private.hh"
  34 #include "hb-buffer.h"
  35 #include "hb-object-private.hh"
  36 #include "hb-unicode-private.hh"
  37
  38
  39
  40 ASSERT_STATIC (sizeof (hb_glyph_info_t) == 20);
  41 ASSERT_STATIC (sizeof (hb_glyph_info_t) == sizeof (hb_glyph_position_t));
  42
  43
  44 /*
  45  * hb_segment_properties_t
  46  */
  47
  48 typedef struct hb_segment_properties_t {
  49     hb_direction_t      direction;
  50     hb_script_t         script;
  51     hb_language_t       language;
  52     ASSERT_POD ();
  53 } hb_segment_properties_t;
  54
  55 #define _HB_BUFFER_PROPS_DEFAULT { HB_DIRECTION_INVALID, HB_SCRIPT_INVALID, HB_LANGUAGE_INVALID }
  56
  57 static inline hb_bool_t
  58 hb_segment_properties_equal (const hb_segment_properties_t *a,
  59                              const hb_segment_properties_t *b)
  60 {
  61   return a->direction == b->direction &&
  62          a->script    == b->script    &&
  63          a->language  == b->language;
  64 }
  65
  66
  67 #if 0
  68 static inline unsigned int
  69 hb_segment_properties_hash (const hb_segment_properties_t *p)
  70 {
  71   /* TODO improve */
  72   return (unsigned int) p->direction +
  73          (unsigned int) p->script +
  74          (intptr_t) (p->language);
  75 }
  76 #endif
  77
  78
  79
  80 /*
  81  * hb_buffer_t
  82  */
  83
  84 struct hb_buffer_t {
  85   hb_object_header_t header;
  86   ASSERT_POD ();
  87
  88   /* Information about how the text in the buffer should be treated */
  89
  90   hb_unicode_funcs_t *unicode; /* Unicode functions */
  91   hb_segment_properties_t props; /* Script, language, direction */
  92
  93   /* Buffer contents */
  94
  95   hb_buffer_content_type_t content_type;
  96
  97   bool in_error; /* Allocation failed */
  98   bool have_output; /* Whether we have an output buffer going on */
  99   bool have_positions; /* Whether we have positions */
 100
 101   unsigned int idx; /* Cursor into ->info and ->pos arrays */
 102   unsigned int len; /* Length of ->info and ->pos arrays */
 103   unsigned int out_len; /* Length of ->out array if have_output */
 104
 105   unsigned int allocated; /* Length of allocated arrays */
 106   hb_glyph_info_t     *info;
 107   hb_glyph_info_t     *out_info;
 108   hb_glyph_position_t *pos;
 109
 110   inline hb_glyph_info_t &cur (unsigned int i = 0) { return info[idx + i]; }
 111   inline hb_glyph_info_t cur (unsigned int i = 0) const { return info[idx + i]; }
 112
 113   inline hb_glyph_position_t &cur_pos (unsigned int i = 0) { return pos[idx + i]; }
 114   inline hb_glyph_position_t cur_pos (unsigned int i = 0) const { return pos[idx + i]; }
 115
 116   inline hb_glyph_info_t &prev (void) { return out_info[out_len - 1]; }
 117   inline hb_glyph_info_t prev (void) const { return info[out_len - 1]; }
 118
 119   unsigned int serial;
 120
 121   /* These reflect current allocations of the bytes in glyph_info_t's var1 and var2. */
 122   uint8_t allocated_var_bytes[8];
 123   const char *allocated_var_owner[8];
 124
 125   /* Text before / after the main buffer contents.
 126    * Always in Unicode, and ordered outward.
 127    * Index 0 is for "pre-context", 1 for "post-context". */
 128   static const unsigned int CONTEXT_LENGTH = 5;
 129   hb_codepoint_t context[2][CONTEXT_LENGTH];
 130   unsigned int context_len[2];
 131
 132
 133   /* Methods */
 134
 135   HB_INTERNAL void reset (void);
 136
 137   inline unsigned int backtrack_len (void) const
 138   { return have_output? out_len : idx; }
 139   inline unsigned int next_serial (void) { return serial++; }
 140
 141   HB_INTERNAL void allocate_var (unsigned int byte_i, unsigned int count, const char *owner);
 142   HB_INTERNAL void deallocate_var (unsigned int byte_i, unsigned int count, const char *owner);
 143   HB_INTERNAL void assert_var (unsigned int byte_i, unsigned int count, const char *owner);
 144   HB_INTERNAL void deallocate_var_all (void);
 145
 146   HB_INTERNAL void add (hb_codepoint_t  codepoint,
 147                         hb_mask_t       mask,
 148                         unsigned int    cluster);
 149
 150   HB_INTERNAL void reverse_range (unsigned int start, unsigned int end);
 151   HB_INTERNAL void reverse (void);
 152   HB_INTERNAL void reverse_clusters (void);
 153   HB_INTERNAL void guess_properties (void);
 154
 155   HB_INTERNAL void swap_buffers (void);
 156   HB_INTERNAL void remove_output (void);
 157   HB_INTERNAL void clear_output (void);
 158   HB_INTERNAL void clear_positions (void);
 159
 160   HB_INTERNAL void replace_glyphs (unsigned int num_in,
 161                                    unsigned int num_out,
 162                                    const hb_codepoint_t *glyph_data);
 163
 164   HB_INTERNAL void replace_glyph (hb_codepoint_t glyph_index);
 165   /* Makes a copy of the glyph at idx to output and replace glyph_index */
 166   HB_INTERNAL void output_glyph (hb_codepoint_t glyph_index);
 167   HB_INTERNAL void output_info (hb_glyph_info_t &glyph_info);
 168   /* Copies glyph at idx to output but doesn't advance idx */
 169   HB_INTERNAL void copy_glyph (void);
 170   /* Copies glyph at idx to output and advance idx.
 171    * If there's no output, just advance idx. */
 172   inline void
 173   next_glyph (void)
 174   {
 175     if (have_output)
 176     {
 177       if (unlikely (out_info != info || out_len != idx)) {
 178         if (unlikely (!make_room_for (1, 1))) return;
 179         out_info[out_len] = info[idx];
 180       }
 181       out_len++;
 182     }
 183
 184     idx++;
 185   }
 186
 187   /* Advance idx without copying to output. */
 188   inline void skip_glyph (void) { idx++; }
 189
 190   inline void reset_masks (hb_mask_t mask)
 191   {
 192     for (unsigned int j = 0; j < len; j++)
 193       info[j].mask = mask;
 194   }
 195   inline void add_masks (hb_mask_t mask)
 196   {
 197     for (unsigned int j = 0; j < len; j++)
 198       info[j].mask |= mask;
 199   }
 200   HB_INTERNAL void set_masks (hb_mask_t value,
 201                               hb_mask_t mask,
 202                               unsigned int cluster_start,
 203                               unsigned int cluster_end);
 204
 205   HB_INTERNAL void merge_clusters (unsigned int start,
 206                                    unsigned int end);
 207   HB_INTERNAL void merge_out_clusters (unsigned int start,
 208                                        unsigned int end);
 209
 210   /* Internal methods */
 211   HB_INTERNAL bool enlarge (unsigned int size);
 212
 213   inline bool ensure (unsigned int size)
 214   { return likely (size < allocated) ? true : enlarge (size); }
 215
 216   HB_INTERNAL bool make_room_for (unsigned int num_in, unsigned int num_out);
 217
 218   HB_INTERNAL void *get_scratch_buffer (unsigned int *size);
 219
 220   inline void clear_context (unsigned int side) { context_len[side] = 0; }
 221 };
 222
 223
 224 #define HB_BUFFER_XALLOCATE_VAR(b, func, var, owner) \
 225   b->func (offsetof (hb_glyph_info_t, var) - offsetof(hb_glyph_info_t, var1), \
 226            sizeof (b->info[0].var), owner)
 227 #define HB_BUFFER_ALLOCATE_VAR(b, var) \
 228         HB_BUFFER_XALLOCATE_VAR (b, allocate_var, var (), #var)
 229 #define HB_BUFFER_DEALLOCATE_VAR(b, var) \
 230         HB_BUFFER_XALLOCATE_VAR (b, deallocate_var, var (), #var)
 231 #define HB_BUFFER_ASSERT_VAR(b, var) \
 232         HB_BUFFER_XALLOCATE_VAR (b, assert_var, var (), #var)
 233
 234
 235 #endif /* HB_BUFFER_PRIVATE_HH */