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