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-object-private.hh"
  35 #include "hb-unicode-private.hh"
  36
  37
  38 ASSERT_STATIC (sizeof (hb_glyph_info_t) == 20);
  39 ASSERT_STATIC (sizeof (hb_glyph_info_t) == sizeof (hb_glyph_position_t));
  40
  41
  42 /*
  43  * hb_buffer_t
  44  */
  45
  46 struct hb_buffer_t {
  47   hb_object_header_t header;
  48   ASSERT_POD ();
  49
  50   /* Information about how the text in the buffer should be treated */
  51   hb_unicode_funcs_t *unicode; /* Unicode functions */
  52   hb_buffer_flags_t flags; /* BOT / EOT / etc. */
  53   hb_buffer_cluster_level_t cluster_level;
  54   hb_codepoint_t replacement; /* U+FFFD or something else. */
  55
  56   /* Buffer contents */
  57   hb_buffer_content_type_t content_type;
  58   hb_segment_properties_t props; /* Script, language, direction */
  59
  60   bool in_error; /* Allocation failed */
  61   bool have_output; /* Whether we have an output buffer going on */
  62   bool have_positions; /* Whether we have positions */
  63
  64   unsigned int idx; /* Cursor into ->info and ->pos arrays */
  65   unsigned int len; /* Length of ->info and ->pos arrays */
  66   unsigned int out_len; /* Length of ->out array if have_output */
  67
  68   unsigned int allocated; /* Length of allocated arrays */
  69   hb_glyph_info_t     *info;
  70   hb_glyph_info_t     *out_info;
  71   hb_glyph_position_t *pos;
  72
  73   inline hb_glyph_info_t &cur (unsigned int i = 0) { return info[idx + i]; }
  74   inline hb_glyph_info_t cur (unsigned int i = 0) const { return info[idx + i]; }
  75
  76   inline hb_glyph_position_t &cur_pos (unsigned int i = 0) { return pos[idx + i]; }
  77   inline hb_glyph_position_t cur_pos (unsigned int i = 0) const { return pos[idx + i]; }
  78
  79   inline hb_glyph_info_t &prev (void) { return out_info[out_len - 1]; }
  80   inline hb_glyph_info_t prev (void) const { return info[out_len - 1]; }
  81
  82   inline bool has_separate_output (void) const { return info != out_info; }
  83
  84   unsigned int serial;
  85
  86   /* These reflect current allocations of the bytes in glyph_info_t's var1 and var2. */
  87   uint8_t allocated_var_bytes[8];
  88   const char *allocated_var_owner[8];
  89
  90   /* Text before / after the main buffer contents.
  91    * Always in Unicode, and ordered outward.
  92    * Index 0 is for "pre-context", 1 for "post-context". */
  93   static const unsigned int CONTEXT_LENGTH = 5;
  94   hb_codepoint_t context[2][CONTEXT_LENGTH];
  95   unsigned int context_len[2];
  96
  97
  98   /* Methods */
  99
 100   HB_INTERNAL void reset (void);
 101   HB_INTERNAL void clear (void);
 102
 103   inline unsigned int backtrack_len (void) const
 104   { return have_output? out_len : idx; }
 105   inline unsigned int lookahead_len (void) const
 106   { return len - idx; }
 107   inline unsigned int next_serial (void) { return serial++; }
 108
 109   HB_INTERNAL void allocate_var (unsigned int byte_i, unsigned int count, const char *owner);
 110   HB_INTERNAL void deallocate_var (unsigned int byte_i, unsigned int count, const char *owner);
 111   HB_INTERNAL void assert_var (unsigned int byte_i, unsigned int count, const char *owner);
 112   HB_INTERNAL void deallocate_var_all (void);
 113
 114   HB_INTERNAL void add (hb_codepoint_t  codepoint,
 115                         unsigned int    cluster);
 116   HB_INTERNAL void add_info (const hb_glyph_info_t &glyph_info);
 117
 118   HB_INTERNAL void reverse_range (unsigned int start, unsigned int end);
 119   HB_INTERNAL void reverse (void);
 120   HB_INTERNAL void reverse_clusters (void);
 121   HB_INTERNAL void guess_segment_properties (void);
 122
 123   HB_INTERNAL void swap_buffers (void);
 124   HB_INTERNAL void remove_output (void);
 125   HB_INTERNAL void clear_output (void);
 126   HB_INTERNAL void clear_positions (void);
 127
 128   HB_INTERNAL void replace_glyphs (unsigned int num_in,
 129                                    unsigned int num_out,
 130                                    const hb_codepoint_t *glyph_data);
 131
 132   HB_INTERNAL void replace_glyph (hb_codepoint_t glyph_index);
 133   /* Makes a copy of the glyph at idx to output and replace glyph_index */
 134   HB_INTERNAL void output_glyph (hb_codepoint_t glyph_index);
 135   HB_INTERNAL void output_info (const hb_glyph_info_t &glyph_info);
 136   /* Copies glyph at idx to output but doesn't advance idx */
 137   HB_INTERNAL void copy_glyph (void);
 138   HB_INTERNAL bool move_to (unsigned int i); /* i is output-buffer index. */
 139   /* Copies glyph at idx to output and advance idx.
 140    * If there's no output, just advance idx. */
 141   inline void
 142   next_glyph (void)
 143   {
 144     if (have_output)
 145     {
 146       if (unlikely (out_info != info || out_len != idx)) {
 147         if (unlikely (!make_room_for (1, 1))) return;
 148         out_info[out_len] = info[idx];
 149       }
 150       out_len++;
 151     }
 152
 153     idx++;
 154   }
 155
 156   /* Advance idx without copying to output. */
 157   inline void skip_glyph (void) { idx++; }
 158
 159   inline void reset_masks (hb_mask_t mask)
 160   {
 161     for (unsigned int j = 0; j < len; j++)
 162       info[j].mask = mask;
 163   }
 164   inline void add_masks (hb_mask_t mask)
 165   {
 166     for (unsigned int j = 0; j < len; j++)
 167       info[j].mask |= mask;
 168   }
 169   HB_INTERNAL void set_masks (hb_mask_t value,
 170                               hb_mask_t mask,
 171                               unsigned int cluster_start,
 172                               unsigned int cluster_end);
 173
 174   HB_INTERNAL void merge_clusters (unsigned int start,
 175                                    unsigned int end)
 176   {
 177     if (end - start < 2)
 178       return;
 179     merge_clusters_impl (start, end);
 180   }
 181   HB_INTERNAL void merge_clusters_impl (unsigned int start,
 182                                         unsigned int end);
 183   HB_INTERNAL void merge_out_clusters (unsigned int start,
 184                                        unsigned int end);
 185   /* Merge clusters for deleting current glyph, and skip it. */
 186   HB_INTERNAL void delete_glyph (void);
 187
 188   /* Internal methods */
 189   HB_INTERNAL bool enlarge (unsigned int size);
 190
 191   inline bool ensure (unsigned int size)
 192   { return likely (!size || size < allocated) ? true : enlarge (size); }
 193
 194   inline bool ensure_inplace (unsigned int size)
 195   { return likely (!size || size < allocated); }
 196
 197   HB_INTERNAL bool make_room_for (unsigned int num_in, unsigned int num_out);
 198   HB_INTERNAL bool shift_forward (unsigned int count);
 199
 200   typedef long scratch_buffer_t;
 201   HB_INTERNAL scratch_buffer_t *get_scratch_buffer (unsigned int *size);
 202
 203   inline void clear_context (unsigned int side) { context_len[side] = 0; }
 204 };
 205
 206
 207 #define HB_BUFFER_XALLOCATE_VAR(b, func, var, owner) \
 208   b->func (offsetof (hb_glyph_info_t, var) - offsetof(hb_glyph_info_t, var1), \
 209            sizeof (b->info[0].var), owner)
 210 #define HB_BUFFER_ALLOCATE_VAR(b, var) \
 211         HB_BUFFER_XALLOCATE_VAR (b, allocate_var, var (), #var)
 212 #define HB_BUFFER_DEALLOCATE_VAR(b, var) \
 213         HB_BUFFER_XALLOCATE_VAR (b, deallocate_var, var (), #var)
 214 #define HB_BUFFER_ASSERT_VAR(b, var) \
 215         HB_BUFFER_XALLOCATE_VAR (b, assert_var, var (), #var)
 216
 217
 218 #endif /* HB_BUFFER_PRIVATE_HH */