Home | History | Annotate | Download | only in src
      1 /*
      2  * Copyright  1998-2004  David Turner and Werner Lemberg
      3  * Copyright  2004,2007,2009  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_H_IN
     31 #error "Include <hb.h> instead."
     32 #endif
     33 
     34 #ifndef HB_BUFFER_H
     35 #define HB_BUFFER_H
     36 
     37 #include "hb-common.h"
     38 #include "hb-unicode.h"
     39 #include "hb-font.h"
     40 
     41 HB_BEGIN_DECLS
     42 
     43 /**
     44  * hb_glyph_info_t:
     45  * @codepoint: either a Unicode code point (before shaping) or a glyph index
     46  *             (after shaping).
     47  * @cluster: the index of the character in the original text that corresponds
     48  *           to this #hb_glyph_info_t, or whatever the client passes to
     49  *           hb_buffer_add(). More than one #hb_glyph_info_t can have the same
     50  *           @cluster value, if they resulted from the same character (e.g. one
     51  *           to many glyph substitution), and when more than one character gets
     52  *           merged in the same glyph (e.g. many to one glyph substitution) the
     53  *           #hb_glyph_info_t will have the smallest cluster value of them.
     54  *           By default some characters are merged into the same cluster
     55  *           (e.g. combining marks have the same cluster as their bases)
     56  *           even if they are separate glyphs, hb_buffer_set_cluster_level()
     57  *           allow selecting more fine-grained cluster handling.
     58  *
     59  * The #hb_glyph_info_t is the structure that holds information about the
     60  * glyphs and their relation to input text.
     61  */
     62 typedef struct hb_glyph_info_t
     63 {
     64   hb_codepoint_t codepoint;
     65   /*< private >*/
     66   hb_mask_t      mask;
     67   /*< public >*/
     68   uint32_t       cluster;
     69 
     70   /*< private >*/
     71   hb_var_int_t   var1;
     72   hb_var_int_t   var2;
     73 } hb_glyph_info_t;
     74 
     75 /**
     76  * hb_glyph_flags_t:
     77  * @HB_GLYPH_FLAG_UNSAFE_TO_BREAK: Indicates that if input text is broken at the
     78  * 				   beginning of the cluster this glyph is part of,
     79  * 				   then both sides need to be re-shaped, as the
     80  * 				   result might be different.  On the flip side,
     81  * 				   it means that when this flag is not present,
     82  * 				   then it's safe to break the glyph-run at the
     83  * 				   beginning of this cluster, and the two sides
     84  * 				   represent the exact same result one would get
     85  * 				   if breaking input text at the beginning of
     86  * 				   this cluster and shaping the two sides
     87  * 				   separately.  This can be used to optimize
     88  * 				   paragraph layout, by avoiding re-shaping
     89  * 				   of each line after line-breaking, or limiting
     90  * 				   the reshaping to a small piece around the
     91  * 				   breaking point only.
     92  * @HB_GLYPH_FLAG_DEFINED: All the currently defined flags.
     93  *
     94  * Since: 1.5.0
     95  */
     96 typedef enum { /*< flags >*/
     97   HB_GLYPH_FLAG_UNSAFE_TO_BREAK		= 0x00000001,
     98 
     99   HB_GLYPH_FLAG_DEFINED			= 0x00000001 /* OR of all defined flags */
    100 } hb_glyph_flags_t;
    101 
    102 HB_EXTERN hb_glyph_flags_t
    103 hb_glyph_info_get_glyph_flags (const hb_glyph_info_t *info);
    104 
    105 #define hb_glyph_info_get_glyph_flags(info) \
    106 	((hb_glyph_flags_t) ((unsigned int) (info)->mask & HB_GLYPH_FLAG_DEFINED))
    107 
    108 
    109 /**
    110  * hb_glyph_position_t:
    111  * @x_advance: how much the line advances after drawing this glyph when setting
    112  *             text in horizontal direction.
    113  * @y_advance: how much the line advances after drawing this glyph when setting
    114  *             text in vertical direction.
    115  * @x_offset: how much the glyph moves on the X-axis before drawing it, this
    116  *            should not affect how much the line advances.
    117  * @y_offset: how much the glyph moves on the Y-axis before drawing it, this
    118  *            should not affect how much the line advances.
    119  *
    120  * The #hb_glyph_position_t is the structure that holds the positions of the
    121  * glyph in both horizontal and vertical directions. All positions in
    122  * #hb_glyph_position_t are relative to the current point.
    123  *
    124  */
    125 typedef struct hb_glyph_position_t {
    126   hb_position_t  x_advance;
    127   hb_position_t  y_advance;
    128   hb_position_t  x_offset;
    129   hb_position_t  y_offset;
    130 
    131   /*< private >*/
    132   hb_var_int_t   var;
    133 } hb_glyph_position_t;
    134 
    135 /**
    136  * hb_segment_properties_t:
    137  * @direction: the #hb_direction_t of the buffer, see hb_buffer_set_direction().
    138  * @script: the #hb_script_t of the buffer, see hb_buffer_set_script().
    139  * @language: the #hb_language_t of the buffer, see hb_buffer_set_language().
    140  *
    141  * The structure that holds various text properties of an #hb_buffer_t. Can be
    142  * set and retrieved using hb_buffer_set_segment_properties() and
    143  * hb_buffer_get_segment_properties(), respectively.
    144  */
    145 typedef struct hb_segment_properties_t {
    146   hb_direction_t  direction;
    147   hb_script_t     script;
    148   hb_language_t   language;
    149   /*< private >*/
    150   void           *reserved1;
    151   void           *reserved2;
    152 } hb_segment_properties_t;
    153 
    154 #define HB_SEGMENT_PROPERTIES_DEFAULT {HB_DIRECTION_INVALID, \
    155 				       HB_SCRIPT_INVALID, \
    156 				       HB_LANGUAGE_INVALID, \
    157 				       (void *) 0, \
    158 				       (void *) 0}
    159 
    160 HB_EXTERN hb_bool_t
    161 hb_segment_properties_equal (const hb_segment_properties_t *a,
    162 			     const hb_segment_properties_t *b);
    163 
    164 HB_EXTERN unsigned int
    165 hb_segment_properties_hash (const hb_segment_properties_t *p);
    166 
    167 
    168 
    169 /**
    170  * hb_buffer_t:
    171  *
    172  * The main structure holding the input text and its properties before shaping,
    173  * and output glyphs and their information after shaping.
    174  */
    175 
    176 typedef struct hb_buffer_t hb_buffer_t;
    177 
    178 HB_EXTERN hb_buffer_t *
    179 hb_buffer_create (void);
    180 
    181 HB_EXTERN hb_buffer_t *
    182 hb_buffer_get_empty (void);
    183 
    184 HB_EXTERN hb_buffer_t *
    185 hb_buffer_reference (hb_buffer_t *buffer);
    186 
    187 HB_EXTERN void
    188 hb_buffer_destroy (hb_buffer_t *buffer);
    189 
    190 HB_EXTERN hb_bool_t
    191 hb_buffer_set_user_data (hb_buffer_t        *buffer,
    192 			 hb_user_data_key_t *key,
    193 			 void *              data,
    194 			 hb_destroy_func_t   destroy,
    195 			 hb_bool_t           replace);
    196 
    197 HB_EXTERN void *
    198 hb_buffer_get_user_data (hb_buffer_t        *buffer,
    199 			 hb_user_data_key_t *key);
    200 
    201 
    202 /**
    203  * hb_buffer_content_type_t:
    204  * @HB_BUFFER_CONTENT_TYPE_INVALID: Initial value for new buffer.
    205  * @HB_BUFFER_CONTENT_TYPE_UNICODE: The buffer contains input characters (before shaping).
    206  * @HB_BUFFER_CONTENT_TYPE_GLYPHS: The buffer contains output glyphs (after shaping).
    207  */
    208 typedef enum {
    209   HB_BUFFER_CONTENT_TYPE_INVALID = 0,
    210   HB_BUFFER_CONTENT_TYPE_UNICODE,
    211   HB_BUFFER_CONTENT_TYPE_GLYPHS
    212 } hb_buffer_content_type_t;
    213 
    214 HB_EXTERN void
    215 hb_buffer_set_content_type (hb_buffer_t              *buffer,
    216 			    hb_buffer_content_type_t  content_type);
    217 
    218 HB_EXTERN hb_buffer_content_type_t
    219 hb_buffer_get_content_type (hb_buffer_t *buffer);
    220 
    221 
    222 HB_EXTERN void
    223 hb_buffer_set_unicode_funcs (hb_buffer_t        *buffer,
    224 			     hb_unicode_funcs_t *unicode_funcs);
    225 
    226 HB_EXTERN hb_unicode_funcs_t *
    227 hb_buffer_get_unicode_funcs (hb_buffer_t        *buffer);
    228 
    229 HB_EXTERN void
    230 hb_buffer_set_direction (hb_buffer_t    *buffer,
    231 			 hb_direction_t  direction);
    232 
    233 HB_EXTERN hb_direction_t
    234 hb_buffer_get_direction (hb_buffer_t *buffer);
    235 
    236 HB_EXTERN void
    237 hb_buffer_set_script (hb_buffer_t *buffer,
    238 		      hb_script_t  script);
    239 
    240 HB_EXTERN hb_script_t
    241 hb_buffer_get_script (hb_buffer_t *buffer);
    242 
    243 HB_EXTERN void
    244 hb_buffer_set_language (hb_buffer_t   *buffer,
    245 			hb_language_t  language);
    246 
    247 
    248 HB_EXTERN hb_language_t
    249 hb_buffer_get_language (hb_buffer_t *buffer);
    250 
    251 HB_EXTERN void
    252 hb_buffer_set_segment_properties (hb_buffer_t *buffer,
    253 				  const hb_segment_properties_t *props);
    254 
    255 HB_EXTERN void
    256 hb_buffer_get_segment_properties (hb_buffer_t *buffer,
    257 				  hb_segment_properties_t *props);
    258 
    259 HB_EXTERN void
    260 hb_buffer_guess_segment_properties (hb_buffer_t *buffer);
    261 
    262 
    263 /**
    264  * hb_buffer_flags_t:
    265  * @HB_BUFFER_FLAG_DEFAULT: the default buffer flag.
    266  * @HB_BUFFER_FLAG_BOT: flag indicating that special handling of the beginning
    267  *                      of text paragraph can be applied to this buffer. Should usually
    268  *                      be set, unless you are passing to the buffer only part
    269  *                      of the text without the full context.
    270  * @HB_BUFFER_FLAG_EOT: flag indicating that special handling of the end of text
    271  *                      paragraph can be applied to this buffer, similar to
    272  *                      @HB_BUFFER_FLAG_BOT.
    273  * @HB_BUFFER_FLAG_PRESERVE_DEFAULT_IGNORABLES:
    274  *                      flag indication that character with Default_Ignorable
    275  *                      Unicode property should use the corresponding glyph
    276  *                      from the font, instead of hiding them (done by
    277  *                      replacing them with the space glyph and zeroing the
    278  *                      advance width.)  This flag takes precedence over
    279  *                      @HB_BUFFER_FLAG_REMOVE_DEFAULT_IGNORABLES.
    280  * @HB_BUFFER_FLAG_REMOVE_DEFAULT_IGNORABLES:
    281  *                      flag indication that character with Default_Ignorable
    282  *                      Unicode property should be removed from glyph string
    283  *                      instead of hiding them (done by replacing them with the
    284  *                      space glyph and zeroing the advance width.)
    285  *                      @HB_BUFFER_FLAG_PRESERVE_DEFAULT_IGNORABLES takes
    286  *                      precedence over this flag. Since: 1.8.0
    287  *
    288  * Since: 0.9.20
    289  */
    290 typedef enum { /*< flags >*/
    291   HB_BUFFER_FLAG_DEFAULT			= 0x00000000u,
    292   HB_BUFFER_FLAG_BOT				= 0x00000001u, /* Beginning-of-text */
    293   HB_BUFFER_FLAG_EOT				= 0x00000002u, /* End-of-text */
    294   HB_BUFFER_FLAG_PRESERVE_DEFAULT_IGNORABLES	= 0x00000004u,
    295   HB_BUFFER_FLAG_REMOVE_DEFAULT_IGNORABLES	= 0x00000008u
    296 } hb_buffer_flags_t;
    297 
    298 HB_EXTERN void
    299 hb_buffer_set_flags (hb_buffer_t       *buffer,
    300 		     hb_buffer_flags_t  flags);
    301 
    302 HB_EXTERN hb_buffer_flags_t
    303 hb_buffer_get_flags (hb_buffer_t *buffer);
    304 
    305 /**
    306  * hb_buffer_cluster_level_t:
    307  * @HB_BUFFER_CLUSTER_LEVEL_MONOTONE_GRAPHEMES: Return cluster values grouped by graphemes into
    308  *   monotone order.
    309  * @HB_BUFFER_CLUSTER_LEVEL_MONOTONE_CHARACTERS: Return cluster values grouped into monotone order.
    310  * @HB_BUFFER_CLUSTER_LEVEL_CHARACTERS: Don't group cluster values.
    311  * @HB_BUFFER_CLUSTER_LEVEL_DEFAULT: Default cluster level,
    312  *   equal to @HB_BUFFER_CLUSTER_LEVEL_MONOTONE_GRAPHEMES.
    313  *
    314  * Since: 0.9.42
    315  */
    316 typedef enum {
    317   HB_BUFFER_CLUSTER_LEVEL_MONOTONE_GRAPHEMES	= 0,
    318   HB_BUFFER_CLUSTER_LEVEL_MONOTONE_CHARACTERS	= 1,
    319   HB_BUFFER_CLUSTER_LEVEL_CHARACTERS		= 2,
    320   HB_BUFFER_CLUSTER_LEVEL_DEFAULT = HB_BUFFER_CLUSTER_LEVEL_MONOTONE_GRAPHEMES
    321 } hb_buffer_cluster_level_t;
    322 
    323 HB_EXTERN void
    324 hb_buffer_set_cluster_level (hb_buffer_t               *buffer,
    325 			     hb_buffer_cluster_level_t  cluster_level);
    326 
    327 HB_EXTERN hb_buffer_cluster_level_t
    328 hb_buffer_get_cluster_level (hb_buffer_t *buffer);
    329 
    330 /**
    331  * HB_BUFFER_REPLACEMENT_CODEPOINT_DEFAULT:
    332  *
    333  * The default code point for replacing invalid characters in a given encoding.
    334  * Set to U+FFFD REPLACEMENT CHARACTER.
    335  *
    336  * Since: 0.9.31
    337  */
    338 #define HB_BUFFER_REPLACEMENT_CODEPOINT_DEFAULT 0xFFFDu
    339 
    340 HB_EXTERN void
    341 hb_buffer_set_replacement_codepoint (hb_buffer_t    *buffer,
    342 				     hb_codepoint_t  replacement);
    343 
    344 HB_EXTERN hb_codepoint_t
    345 hb_buffer_get_replacement_codepoint (hb_buffer_t    *buffer);
    346 
    347 HB_EXTERN void
    348 hb_buffer_set_invisible_glyph (hb_buffer_t    *buffer,
    349 			       hb_codepoint_t  invisible);
    350 
    351 HB_EXTERN hb_codepoint_t
    352 hb_buffer_get_invisible_glyph (hb_buffer_t    *buffer);
    353 
    354 
    355 HB_EXTERN void
    356 hb_buffer_reset (hb_buffer_t *buffer);
    357 
    358 HB_EXTERN void
    359 hb_buffer_clear_contents (hb_buffer_t *buffer);
    360 
    361 HB_EXTERN hb_bool_t
    362 hb_buffer_pre_allocate (hb_buffer_t  *buffer,
    363 		        unsigned int  size);
    364 
    365 
    366 HB_EXTERN hb_bool_t
    367 hb_buffer_allocation_successful (hb_buffer_t  *buffer);
    368 
    369 HB_EXTERN void
    370 hb_buffer_reverse (hb_buffer_t *buffer);
    371 
    372 HB_EXTERN void
    373 hb_buffer_reverse_range (hb_buffer_t *buffer,
    374 			 unsigned int start, unsigned int end);
    375 
    376 HB_EXTERN void
    377 hb_buffer_reverse_clusters (hb_buffer_t *buffer);
    378 
    379 
    380 /* Filling the buffer in */
    381 
    382 HB_EXTERN void
    383 hb_buffer_add (hb_buffer_t    *buffer,
    384 	       hb_codepoint_t  codepoint,
    385 	       unsigned int    cluster);
    386 
    387 HB_EXTERN void
    388 hb_buffer_add_utf8 (hb_buffer_t  *buffer,
    389 		    const char   *text,
    390 		    int           text_length,
    391 		    unsigned int  item_offset,
    392 		    int           item_length);
    393 
    394 HB_EXTERN void
    395 hb_buffer_add_utf16 (hb_buffer_t    *buffer,
    396 		     const uint16_t *text,
    397 		     int             text_length,
    398 		     unsigned int    item_offset,
    399 		     int             item_length);
    400 
    401 HB_EXTERN void
    402 hb_buffer_add_utf32 (hb_buffer_t    *buffer,
    403 		     const uint32_t *text,
    404 		     int             text_length,
    405 		     unsigned int    item_offset,
    406 		     int             item_length);
    407 
    408 HB_EXTERN void
    409 hb_buffer_add_latin1 (hb_buffer_t   *buffer,
    410 		      const uint8_t *text,
    411 		      int            text_length,
    412 		      unsigned int   item_offset,
    413 		      int            item_length);
    414 
    415 HB_EXTERN void
    416 hb_buffer_add_codepoints (hb_buffer_t          *buffer,
    417 			  const hb_codepoint_t *text,
    418 			  int                   text_length,
    419 			  unsigned int          item_offset,
    420 			  int                   item_length);
    421 
    422 HB_EXTERN void
    423 hb_buffer_append (hb_buffer_t *buffer,
    424 		  hb_buffer_t *source,
    425 		  unsigned int start,
    426 		  unsigned int end);
    427 
    428 HB_EXTERN hb_bool_t
    429 hb_buffer_set_length (hb_buffer_t  *buffer,
    430 		      unsigned int  length);
    431 
    432 HB_EXTERN unsigned int
    433 hb_buffer_get_length (hb_buffer_t *buffer);
    434 
    435 /* Getting glyphs out of the buffer */
    436 
    437 HB_EXTERN hb_glyph_info_t *
    438 hb_buffer_get_glyph_infos (hb_buffer_t  *buffer,
    439                            unsigned int *length);
    440 
    441 HB_EXTERN hb_glyph_position_t *
    442 hb_buffer_get_glyph_positions (hb_buffer_t  *buffer,
    443                                unsigned int *length);
    444 
    445 
    446 HB_EXTERN void
    447 hb_buffer_normalize_glyphs (hb_buffer_t *buffer);
    448 
    449 
    450 /*
    451  * Serialize
    452  */
    453 
    454 /**
    455  * hb_buffer_serialize_flags_t:
    456  * @HB_BUFFER_SERIALIZE_FLAG_DEFAULT: serialize glyph names, clusters and positions.
    457  * @HB_BUFFER_SERIALIZE_FLAG_NO_CLUSTERS: do not serialize glyph cluster.
    458  * @HB_BUFFER_SERIALIZE_FLAG_NO_POSITIONS: do not serialize glyph position information.
    459  * @HB_BUFFER_SERIALIZE_FLAG_NO_GLYPH_NAMES: do no serialize glyph name.
    460  * @HB_BUFFER_SERIALIZE_FLAG_GLYPH_EXTENTS: serialize glyph extents.
    461  * @HB_BUFFER_SERIALIZE_FLAG_GLYPH_FLAGS: serialize glyph flags. Since: 1.5.0
    462  * @HB_BUFFER_SERIALIZE_FLAG_NO_ADVANCES: do not serialize glyph advances,
    463  *  glyph offsets will reflect absolute glyph positions. Since: 1.8.0
    464  *
    465  * Flags that control what glyph information are serialized in hb_buffer_serialize_glyphs().
    466  *
    467  * Since: 0.9.20
    468  */
    469 typedef enum { /*< flags >*/
    470   HB_BUFFER_SERIALIZE_FLAG_DEFAULT		= 0x00000000u,
    471   HB_BUFFER_SERIALIZE_FLAG_NO_CLUSTERS		= 0x00000001u,
    472   HB_BUFFER_SERIALIZE_FLAG_NO_POSITIONS		= 0x00000002u,
    473   HB_BUFFER_SERIALIZE_FLAG_NO_GLYPH_NAMES	= 0x00000004u,
    474   HB_BUFFER_SERIALIZE_FLAG_GLYPH_EXTENTS	= 0x00000008u,
    475   HB_BUFFER_SERIALIZE_FLAG_GLYPH_FLAGS		= 0x00000010u,
    476   HB_BUFFER_SERIALIZE_FLAG_NO_ADVANCES		= 0x00000020u
    477 } hb_buffer_serialize_flags_t;
    478 
    479 /**
    480  * hb_buffer_serialize_format_t:
    481  * @HB_BUFFER_SERIALIZE_FORMAT_TEXT: a human-readable, plain text format.
    482  * @HB_BUFFER_SERIALIZE_FORMAT_JSON: a machine-readable JSON format.
    483  * @HB_BUFFER_SERIALIZE_FORMAT_INVALID: invalid format.
    484  *
    485  * The buffer serialization and de-serialization format used in
    486  * hb_buffer_serialize_glyphs() and hb_buffer_deserialize_glyphs().
    487  *
    488  * Since: 0.9.2
    489  */
    490 typedef enum {
    491   HB_BUFFER_SERIALIZE_FORMAT_TEXT	= HB_TAG('T','E','X','T'),
    492   HB_BUFFER_SERIALIZE_FORMAT_JSON	= HB_TAG('J','S','O','N'),
    493   HB_BUFFER_SERIALIZE_FORMAT_INVALID	= HB_TAG_NONE
    494 } hb_buffer_serialize_format_t;
    495 
    496 HB_EXTERN hb_buffer_serialize_format_t
    497 hb_buffer_serialize_format_from_string (const char *str, int len);
    498 
    499 HB_EXTERN const char *
    500 hb_buffer_serialize_format_to_string (hb_buffer_serialize_format_t format);
    501 
    502 HB_EXTERN const char **
    503 hb_buffer_serialize_list_formats (void);
    504 
    505 HB_EXTERN unsigned int
    506 hb_buffer_serialize_glyphs (hb_buffer_t *buffer,
    507 			    unsigned int start,
    508 			    unsigned int end,
    509 			    char *buf,
    510 			    unsigned int buf_size,
    511 			    unsigned int *buf_consumed,
    512 			    hb_font_t *font,
    513 			    hb_buffer_serialize_format_t format,
    514 			    hb_buffer_serialize_flags_t flags);
    515 
    516 HB_EXTERN hb_bool_t
    517 hb_buffer_deserialize_glyphs (hb_buffer_t *buffer,
    518 			      const char *buf,
    519 			      int buf_len,
    520 			      const char **end_ptr,
    521 			      hb_font_t *font,
    522 			      hb_buffer_serialize_format_t format);
    523 
    524 
    525 /*
    526  * Compare buffers
    527  */
    528 
    529 typedef enum { /*< flags >*/
    530   HB_BUFFER_DIFF_FLAG_EQUAL			= 0x0000,
    531 
    532   /* Buffers with different content_type cannot be meaningfully compared
    533    * in any further detail. */
    534   HB_BUFFER_DIFF_FLAG_CONTENT_TYPE_MISMATCH	= 0x0001,
    535 
    536   /* For buffers with differing length, the per-glyph comparison is not
    537    * attempted, though we do still scan reference for dottedcircle / .notdef
    538    * glyphs. */
    539   HB_BUFFER_DIFF_FLAG_LENGTH_MISMATCH		= 0x0002,
    540 
    541   /* We want to know if dottedcircle / .notdef glyphs are present in the
    542    * reference, as we may not care so much about other differences in this
    543    * case. */
    544   HB_BUFFER_DIFF_FLAG_NOTDEF_PRESENT		= 0x0004,
    545   HB_BUFFER_DIFF_FLAG_DOTTED_CIRCLE_PRESENT	= 0x0008,
    546 
    547   /* If the buffers have the same length, we compare them glyph-by-glyph
    548    * and report which aspect(s) of the glyph info/position are different. */
    549   HB_BUFFER_DIFF_FLAG_CODEPOINT_MISMATCH	= 0x0010,
    550   HB_BUFFER_DIFF_FLAG_CLUSTER_MISMATCH		= 0x0020,
    551   HB_BUFFER_DIFF_FLAG_GLYPH_FLAGS_MISMATCH	= 0x0040,
    552   HB_BUFFER_DIFF_FLAG_POSITION_MISMATCH		= 0x0080
    553 
    554 } hb_buffer_diff_flags_t;
    555 
    556 /* Compare the contents of two buffers, report types of differences. */
    557 HB_EXTERN hb_buffer_diff_flags_t
    558 hb_buffer_diff (hb_buffer_t *buffer,
    559 		hb_buffer_t *reference,
    560 		hb_codepoint_t dottedcircle_glyph,
    561 		unsigned int position_fuzz);
    562 
    563 
    564 /*
    565  * Debugging.
    566  */
    567 
    568 typedef hb_bool_t	(*hb_buffer_message_func_t)	(hb_buffer_t *buffer,
    569 							 hb_font_t   *font,
    570 							 const char  *message,
    571 							 void        *user_data);
    572 
    573 HB_EXTERN void
    574 hb_buffer_set_message_func (hb_buffer_t *buffer,
    575 			    hb_buffer_message_func_t func,
    576 			    void *user_data, hb_destroy_func_t destroy);
    577 
    578 
    579 HB_END_DECLS
    580 
    581 #endif /* HB_BUFFER_H */
    582