hb-buffer.h

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/*
 * Copyright © 1998-2004  David Turner and Werner Lemberg
 * Copyright © 2004,2007,2009  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
 */
 
#if !defined(HB_H_IN) && !defined(HB_NO_SINGLE_HEADER_ERROR)
#error "Include <hb.h> instead."
#endif
 
#ifndef HB_BUFFER_H
#define HB_BUFFER_H
 
#include "hb-common.h"
#include "hb-unicode.h"
#include "hb-font.h"
 
HB_BEGIN_DECLS
 
/**
 * hb_glyph_info_t:
 * @codepoint: either a Unicode code point (before shaping) or a glyph index
 *             (after shaping).
 * @cluster: the index of the character in the original text that corresponds
 *           to this #hb_glyph_info_t, or whatever the client passes to
 *           hb_buffer_add(). More than one #hb_glyph_info_t can have the same
 *           @cluster value, if they resulted from the same character (e.g. one
 *           to many glyph substitution), and when more than one character gets
 *           merged in the same glyph (e.g. many to one glyph substitution) the
 *           #hb_glyph_info_t will have the smallest cluster value of them.
 *           By default some characters are merged into the same cluster
 *           (e.g. combining marks have the same cluster as their bases)
 *           even if they are separate glyphs, hb_buffer_set_cluster_level()
 *           allow selecting more fine-grained cluster handling.
 *
 * The #hb_glyph_info_t is the structure that holds information about the
 * glyphs and their relation to input text.
 */
typedef struct hb_glyph_info_t {
  hb_codepoint_t codepoint;
  /*< private >*/
  hb_mask_t      mask;
  /*< public >*/
  uint32_t       cluster;
 
  /*< private >*/
  hb_var_int_t   var1;
  hb_var_int_t   var2;
} hb_glyph_info_t;
 
/**
 * hb_glyph_flags_t:
 * @HB_GLYPH_FLAG_UNSAFE_TO_BREAK: Indicates that if input text is broken at the
 *                 beginning of the cluster this glyph is part of,
 *                 then both sides need to be re-shaped, as the
 *                 result might be different.
 *                 On the flip side, it means that when this
 *                 flag is not present, then it is safe to break
 *                 the glyph-run at the beginning of this
 *                 cluster, and the two sides will represent the
 *                 exact same result one would get if breaking
 *                 input text at the beginning of this cluster
 *                 and shaping the two sides separately.
 *                 This can be used to optimize paragraph
 *                 layout, by avoiding re-shaping of each line
 *                 after line-breaking.
 * @HB_GLYPH_FLAG_UNSAFE_TO_CONCAT: Indicates that if input text is changed on one
 *                 side of the beginning of the cluster this glyph
 *                 is part of, then the shaping results for the
 *                 other side might change.
 *                 Note that the absence of this flag will NOT by
 *                 itself mean that it IS safe to concat text.
 *                 Only two pieces of text both of which clear of
 *                 this flag can be concatenated safely.
 *                 This can be used to optimize paragraph
 *                 layout, by avoiding re-shaping of each line
 *                 after line-breaking, by limiting the
 *                 reshaping to a small piece around the
 *                 breaking position only, even if the breaking
 *                 position carries the
 *                 #HB_GLYPH_FLAG_UNSAFE_TO_BREAK or when
 *                 hyphenation or other text transformation
 *                 happens at line-break position, in the following
 *                 way:
 *                 1. Iterate back from the line-break position
 *                 until the first cluster start position that is
 *                 NOT unsafe-to-concat, 2. shape the segment from
 *                 there till the end of line, 3. check whether the
 *                 resulting glyph-run also is clear of the
 *                 unsafe-to-concat at its start-of-text position;
 *                 if it is, just splice it into place and the line
 *                 is shaped; If not, move on to a position further
 *                 back that is clear of unsafe-to-concat and retry
 *                 from there, and repeat.
 *                 At the start of next line a similar algorithm can
 *                 be implemented. That is: 1. Iterate forward from
 *                 the line-break position until the first cluster
 *                 start position that is NOT unsafe-to-concat, 2.
 *                 shape the segment from beginning of the line to
 *                 that position, 3. check whether the resulting
 *                 glyph-run also is clear of the unsafe-to-concat
 *                 at its end-of-text position; if it is, just splice
 *                 it into place and the beginning is shaped; If not,
 *                 move on to a position further forward that is clear
 *                 of unsafe-to-concat and retry up to there, and repeat.
 *                 A slight complication will arise in the
 *                 implementation of the algorithm above,
 *                 because while our buffer API has a way to
 *                 return flags for position corresponding to
 *                 start-of-text, there is currently no position
 *                 corresponding to end-of-text.  This limitation
 *                 can be alleviated by shaping more text than needed
 *                 and looking for unsafe-to-concat flag within text
 *                 clusters.
 *                 The #HB_GLYPH_FLAG_UNSAFE_TO_BREAK flag will
 *                 always imply this flag.
 *                 To use this flag, you must enable the buffer flag
 *                 @HB_BUFFER_FLAG_PRODUCE_UNSAFE_TO_CONCAT during
 *                 shaping, otherwise the buffer flag will not be
 *                 reliably produced.
 *                 Since: 4.0.0
 * @HB_GLYPH_FLAG_SAFE_TO_INSERT_TATWEEL: In scripts that use elongation (Arabic,
                   Mongolian, Syriac, etc.), this flag signifies
                   that it is safe to insert a U+0640 TATWEEL
                   character before this cluster for elongation.
                   This flag does not determine the
                   script-specific elongation places, but only
                   when it is safe to do the elongation without
                   interrupting text shaping.
                   Since: 5.1.0
 * @HB_GLYPH_FLAG_DEFINED: All the currently defined flags.
 *
 * Flags for #hb_glyph_info_t.
 *
 * Since: 1.5.0
 */
typedef enum { /*< flags >*/
  HB_GLYPH_FLAG_UNSAFE_TO_BREAK         = 0x00000001,
  HB_GLYPH_FLAG_UNSAFE_TO_CONCAT        = 0x00000002,
  HB_GLYPH_FLAG_SAFE_TO_INSERT_TATWEEL      = 0x00000004,
 
  HB_GLYPH_FLAG_DEFINED             = 0x00000007 /* OR of all defined flags */
} hb_glyph_flags_t;
 
HB_EXTERN hb_glyph_flags_t
hb_glyph_info_get_glyph_flags (const hb_glyph_info_t *info);
 
#define hb_glyph_info_get_glyph_flags(info) \
    ((hb_glyph_flags_t) ((unsigned int) (info)->mask & HB_GLYPH_FLAG_DEFINED))
 
 
/**
 * hb_glyph_position_t:
 * @x_advance: how much the line advances after drawing this glyph when setting
 *             text in horizontal direction.
 * @y_advance: how much the line advances after drawing this glyph when setting
 *             text in vertical direction.
 * @x_offset: how much the glyph moves on the X-axis before drawing it, this
 *            should not affect how much the line advances.
 * @y_offset: how much the glyph moves on the Y-axis before drawing it, this
 *            should not affect how much the line advances.
 *
 * The #hb_glyph_position_t is the structure that holds the positions of the
 * glyph in both horizontal and vertical directions. All positions in
 * #hb_glyph_position_t are relative to the current point.
 *
 */
typedef struct hb_glyph_position_t {
  hb_position_t  x_advance;
  hb_position_t  y_advance;
  hb_position_t  x_offset;
  hb_position_t  y_offset;
 
  /*< private >*/
  hb_var_int_t   var;
} hb_glyph_position_t;
 
/**
 * hb_segment_properties_t:
 * @direction: the #hb_direction_t of the buffer, see hb_buffer_set_direction().
 * @script: the #hb_script_t of the buffer, see hb_buffer_set_script().
 * @language: the #hb_language_t of the buffer, see hb_buffer_set_language().
 *
 * The structure that holds various text properties of an #hb_buffer_t. Can be
 * set and retrieved using hb_buffer_set_segment_properties() and
 * hb_buffer_get_segment_properties(), respectively.
 */
typedef struct hb_segment_properties_t {
  hb_direction_t  direction;
  hb_script_t     script;
  hb_language_t   language;
  /*< private >*/
  void           *reserved1;
  void           *reserved2;
} hb_segment_properties_t;
 
/**
 * HB_SEGMENT_PROPERTIES_DEFAULT:
 *
 * The default #hb_segment_properties_t of of freshly created #hb_buffer_t.
 */
#define HB_SEGMENT_PROPERTIES_DEFAULT {HB_DIRECTION_INVALID, \
                       HB_SCRIPT_INVALID, \
                       HB_LANGUAGE_INVALID, \
                       (void *) 0, \
                       (void *) 0}
 
HB_EXTERN hb_bool_t
hb_segment_properties_equal (const hb_segment_properties_t *a,
                 const hb_segment_properties_t *b);
 
HB_EXTERN unsigned int
hb_segment_properties_hash (const hb_segment_properties_t *p);
 
HB_EXTERN void
hb_segment_properties_overlay (hb_segment_properties_t *p,
                   const hb_segment_properties_t *src);
 
 
/**
 * hb_buffer_t:
 *
 * The main structure holding the input text and its properties before shaping,
 * and output glyphs and their information after shaping.
 */
 
typedef struct hb_buffer_t hb_buffer_t;
 
HB_EXTERN hb_buffer_t *
hb_buffer_create (void);
 
HB_EXTERN hb_buffer_t *
hb_buffer_create_similar (const hb_buffer_t *src);
 
HB_EXTERN void
hb_buffer_reset (hb_buffer_t *buffer);
 
 
HB_EXTERN hb_buffer_t *
hb_buffer_get_empty (void);
 
HB_EXTERN hb_buffer_t *
hb_buffer_reference (hb_buffer_t *buffer);
 
HB_EXTERN void
hb_buffer_destroy (hb_buffer_t *buffer);
 
HB_EXTERN hb_bool_t
hb_buffer_set_user_data (hb_buffer_t        *buffer,
             hb_user_data_key_t *key,
             void *              data,
             hb_destroy_func_t   destroy,
             hb_bool_t           replace);
 
HB_EXTERN void *
hb_buffer_get_user_data (const hb_buffer_t  *buffer,
             hb_user_data_key_t *key);
 
 
/**
 * hb_buffer_content_type_t:
 * @HB_BUFFER_CONTENT_TYPE_INVALID: Initial value for new buffer.
 * @HB_BUFFER_CONTENT_TYPE_UNICODE: The buffer contains input characters (before shaping).
 * @HB_BUFFER_CONTENT_TYPE_GLYPHS: The buffer contains output glyphs (after shaping).
 *
 * The type of #hb_buffer_t contents.
 */
typedef enum {
  HB_BUFFER_CONTENT_TYPE_INVALID = 0,
  HB_BUFFER_CONTENT_TYPE_UNICODE,
  HB_BUFFER_CONTENT_TYPE_GLYPHS
} hb_buffer_content_type_t;
 
HB_EXTERN void
hb_buffer_set_content_type (hb_buffer_t              *buffer,
                hb_buffer_content_type_t  content_type);
 
HB_EXTERN hb_buffer_content_type_t
hb_buffer_get_content_type (const hb_buffer_t *buffer);
 
 
HB_EXTERN void
hb_buffer_set_unicode_funcs (hb_buffer_t        *buffer,
                 hb_unicode_funcs_t *unicode_funcs);
 
HB_EXTERN hb_unicode_funcs_t *
hb_buffer_get_unicode_funcs (const hb_buffer_t  *buffer);
 
HB_EXTERN void
hb_buffer_set_direction (hb_buffer_t    *buffer,
             hb_direction_t  direction);
 
HB_EXTERN hb_direction_t
hb_buffer_get_direction (const hb_buffer_t *buffer);
 
HB_EXTERN void
hb_buffer_set_script (hb_buffer_t *buffer,
              hb_script_t  script);
 
HB_EXTERN hb_script_t
hb_buffer_get_script (const hb_buffer_t *buffer);
 
HB_EXTERN void
hb_buffer_set_language (hb_buffer_t   *buffer,
            hb_language_t  language);
 
 
HB_EXTERN hb_language_t
hb_buffer_get_language (const hb_buffer_t *buffer);
 
HB_EXTERN void
hb_buffer_set_segment_properties (hb_buffer_t *buffer,
                  const hb_segment_properties_t *props);
 
HB_EXTERN void
hb_buffer_get_segment_properties (const hb_buffer_t *buffer,
                  hb_segment_properties_t *props);
 
HB_EXTERN void
hb_buffer_guess_segment_properties (hb_buffer_t *buffer);
 
 
/**
 * hb_buffer_flags_t:
 * @HB_BUFFER_FLAG_DEFAULT: the default buffer flag.
 * @HB_BUFFER_FLAG_BOT: flag indicating that special handling of the beginning
 *                      of text paragraph can be applied to this buffer. Should usually
 *                      be set, unless you are passing to the buffer only part
 *                      of the text without the full context.
 * @HB_BUFFER_FLAG_EOT: flag indicating that special handling of the end of text
 *                      paragraph can be applied to this buffer, similar to
 *                      @HB_BUFFER_FLAG_BOT.
 * @HB_BUFFER_FLAG_PRESERVE_DEFAULT_IGNORABLES:
 *                      flag indication that character with Default_Ignorable
 *                      Unicode property should use the corresponding glyph
 *                      from the font, instead of hiding them (done by
 *                      replacing them with the space glyph and zeroing the
 *                      advance width.)  This flag takes precedence over
 *                      @HB_BUFFER_FLAG_REMOVE_DEFAULT_IGNORABLES.
 * @HB_BUFFER_FLAG_REMOVE_DEFAULT_IGNORABLES:
 *                      flag indication that character with Default_Ignorable
 *                      Unicode property should be removed from glyph string
 *                      instead of hiding them (done by replacing them with the
 *                      space glyph and zeroing the advance width.)
 *                      @HB_BUFFER_FLAG_PRESERVE_DEFAULT_IGNORABLES takes
 *                      precedence over this flag. Since: 1.8.0
 * @HB_BUFFER_FLAG_DO_NOT_INSERT_DOTTED_CIRCLE:
 *                      flag indicating that a dotted circle should
 *                      not be inserted in the rendering of incorrect
 *                      character sequences (such at <0905 093E>). Since: 2.4.0
 * @HB_BUFFER_FLAG_VERIFY:
 *                      flag indicating that the hb_shape() call and its variants
 *                      should perform various verification processes on the results
 *                      of the shaping operation on the buffer.  If the verification
 *                      fails, then either a buffer message is sent, if a message
 *                      handler is installed on the buffer, or a message is written
 *                      to standard error.  In either case, the shaping result might
 *                      be modified to show the failed output. Since: 3.4.0
 * @HB_BUFFER_FLAG_PRODUCE_UNSAFE_TO_CONCAT:
 *                      flag indicating that the @HB_GLYPH_FLAG_UNSAFE_TO_CONCAT
 *                      glyph-flag should be produced by the shaper. By default
 *                      it will not be produced since it incurs a cost. Since: 4.0.0
 * @HB_BUFFER_FLAG_PRODUCE_SAFE_TO_INSERT_TATWEEL:
 *                      flag indicating that the @HB_GLYPH_FLAG_SAFE_TO_INSERT_TATWEEL
 *                      glyph-flag should be produced by the shaper. By default
 *                      it will not be produced. Since: 5.1.0
 * @HB_BUFFER_FLAG_DEFINED: All currently defined flags: Since: 4.4.0
 *
 * Flags for #hb_buffer_t.
 *
 * Since: 0.9.20
 */
typedef enum { /*< flags >*/
  HB_BUFFER_FLAG_DEFAULT            = 0x00000000u,
  HB_BUFFER_FLAG_BOT                = 0x00000001u, /* Beginning-of-text */
  HB_BUFFER_FLAG_EOT                = 0x00000002u, /* End-of-text */
  HB_BUFFER_FLAG_PRESERVE_DEFAULT_IGNORABLES    = 0x00000004u,
  HB_BUFFER_FLAG_REMOVE_DEFAULT_IGNORABLES  = 0x00000008u,
  HB_BUFFER_FLAG_DO_NOT_INSERT_DOTTED_CIRCLE    = 0x00000010u,
  HB_BUFFER_FLAG_VERIFY             = 0x00000020u,
  HB_BUFFER_FLAG_PRODUCE_UNSAFE_TO_CONCAT   = 0x00000040u,
  HB_BUFFER_FLAG_PRODUCE_SAFE_TO_INSERT_TATWEEL = 0x00000080u,
 
  HB_BUFFER_FLAG_DEFINED            = 0x000000FFu
} hb_buffer_flags_t;
 
HB_EXTERN void
hb_buffer_set_flags (hb_buffer_t       *buffer,
             hb_buffer_flags_t  flags);
 
HB_EXTERN hb_buffer_flags_t
hb_buffer_get_flags (const hb_buffer_t *buffer);
 
/**
 * hb_buffer_cluster_level_t:
 * @HB_BUFFER_CLUSTER_LEVEL_MONOTONE_GRAPHEMES: Return cluster values grouped by graphemes into
 *   monotone order.
 * @HB_BUFFER_CLUSTER_LEVEL_MONOTONE_CHARACTERS: Return cluster values grouped into monotone order.
 * @HB_BUFFER_CLUSTER_LEVEL_CHARACTERS: Don't group cluster values.
 * @HB_BUFFER_CLUSTER_LEVEL_DEFAULT: Default cluster level,
 *   equal to @HB_BUFFER_CLUSTER_LEVEL_MONOTONE_GRAPHEMES.
 * 
 * Data type for holding HarfBuzz's clustering behavior options. The cluster level
 * dictates one aspect of how HarfBuzz will treat non-base characters 
 * during shaping.
 *
 * In @HB_BUFFER_CLUSTER_LEVEL_MONOTONE_GRAPHEMES, non-base
 * characters are merged into the cluster of the base character that precedes them.
 *
 * In @HB_BUFFER_CLUSTER_LEVEL_MONOTONE_CHARACTERS, non-base characters are initially
 * assigned their own cluster values, which are not merged into preceding base
 * clusters. This allows HarfBuzz to perform additional operations like reorder
 * sequences of adjacent marks.
 *
 * @HB_BUFFER_CLUSTER_LEVEL_MONOTONE_GRAPHEMES is the default, because it maintains
 * backward compatibility with older versions of HarfBuzz. New client programs that
 * do not need to maintain such backward compatibility are recommended to use
 * @HB_BUFFER_CLUSTER_LEVEL_MONOTONE_CHARACTERS instead of the default.
 *
 * Since: 0.9.42
 */
typedef enum {
  HB_BUFFER_CLUSTER_LEVEL_MONOTONE_GRAPHEMES    = 0,
  HB_BUFFER_CLUSTER_LEVEL_MONOTONE_CHARACTERS   = 1,
  HB_BUFFER_CLUSTER_LEVEL_CHARACTERS        = 2,
  HB_BUFFER_CLUSTER_LEVEL_DEFAULT = HB_BUFFER_CLUSTER_LEVEL_MONOTONE_GRAPHEMES
} hb_buffer_cluster_level_t;
 
HB_EXTERN void
hb_buffer_set_cluster_level (hb_buffer_t               *buffer,
                 hb_buffer_cluster_level_t  cluster_level);
 
HB_EXTERN hb_buffer_cluster_level_t
hb_buffer_get_cluster_level (const hb_buffer_t *buffer);
 
/**
 * HB_BUFFER_REPLACEMENT_CODEPOINT_DEFAULT:
 *
 * The default code point for replacing invalid characters in a given encoding.
 * Set to U+FFFD REPLACEMENT CHARACTER.
 *
 * Since: 0.9.31
 */
#define HB_BUFFER_REPLACEMENT_CODEPOINT_DEFAULT 0xFFFDu
 
HB_EXTERN void
hb_buffer_set_replacement_codepoint (hb_buffer_t    *buffer,
                     hb_codepoint_t  replacement);
 
HB_EXTERN hb_codepoint_t
hb_buffer_get_replacement_codepoint (const hb_buffer_t *buffer);
 
HB_EXTERN void
hb_buffer_set_invisible_glyph (hb_buffer_t    *buffer,
                   hb_codepoint_t  invisible);
 
HB_EXTERN hb_codepoint_t
hb_buffer_get_invisible_glyph (const hb_buffer_t *buffer);
 
HB_EXTERN void
hb_buffer_set_not_found_glyph (hb_buffer_t    *buffer,
                   hb_codepoint_t  not_found);
 
HB_EXTERN hb_codepoint_t
hb_buffer_get_not_found_glyph (const hb_buffer_t *buffer);
 
HB_EXTERN void
hb_buffer_set_not_found_variation_selector_glyph (hb_buffer_t    *buffer,
                          hb_codepoint_t  not_found_variation_selector);
 
HB_EXTERN hb_codepoint_t
hb_buffer_get_not_found_variation_selector_glyph (const hb_buffer_t *buffer);
 
HB_EXTERN void
hb_buffer_set_random_state (hb_buffer_t    *buffer,
                unsigned        state);
 
HB_EXTERN unsigned
hb_buffer_get_random_state (const hb_buffer_t *buffer);
 
/*
 * Content API.
 */
 
HB_EXTERN void
hb_buffer_clear_contents (hb_buffer_t *buffer);
 
HB_EXTERN hb_bool_t
hb_buffer_pre_allocate (hb_buffer_t  *buffer,
            unsigned int  size);
 
 
HB_EXTERN hb_bool_t
hb_buffer_allocation_successful (hb_buffer_t  *buffer);
 
HB_EXTERN void
hb_buffer_reverse (hb_buffer_t *buffer);
 
HB_EXTERN void
hb_buffer_reverse_range (hb_buffer_t *buffer,
             unsigned int start, unsigned int end);
 
HB_EXTERN void
hb_buffer_reverse_clusters (hb_buffer_t *buffer);
 
 
/* Filling the buffer in */
 
HB_EXTERN void
hb_buffer_add (hb_buffer_t    *buffer,
           hb_codepoint_t  codepoint,
           unsigned int    cluster);
 
HB_EXTERN void
hb_buffer_add_utf8 (hb_buffer_t  *buffer,
            const char   *text,
            int           text_length,
            unsigned int  item_offset,
            int           item_length);
 
HB_EXTERN void
hb_buffer_add_utf16 (hb_buffer_t    *buffer,
             const uint16_t *text,
             int             text_length,
             unsigned int    item_offset,
             int             item_length);
 
HB_EXTERN void
hb_buffer_add_utf32 (hb_buffer_t    *buffer,
             const uint32_t *text,
             int             text_length,
             unsigned int    item_offset,
             int             item_length);
 
HB_EXTERN void
hb_buffer_add_latin1 (hb_buffer_t   *buffer,
              const uint8_t *text,
              int            text_length,
              unsigned int   item_offset,
              int            item_length);
 
HB_EXTERN void
hb_buffer_add_codepoints (hb_buffer_t          *buffer,
              const hb_codepoint_t *text,
              int                   text_length,
              unsigned int          item_offset,
              int                   item_length);
 
HB_EXTERN void
hb_buffer_append (hb_buffer_t *buffer,
          const hb_buffer_t *source,
          unsigned int start,
          unsigned int end);
 
HB_EXTERN hb_bool_t
hb_buffer_set_length (hb_buffer_t  *buffer,
              unsigned int  length);
 
HB_EXTERN unsigned int
hb_buffer_get_length (const hb_buffer_t *buffer);
 
/* Getting glyphs out of the buffer */
 
HB_EXTERN hb_glyph_info_t *
hb_buffer_get_glyph_infos (hb_buffer_t  *buffer,
               unsigned int *length);
 
HB_EXTERN hb_glyph_position_t *
hb_buffer_get_glyph_positions (hb_buffer_t  *buffer,
                   unsigned int *length);
 
HB_EXTERN hb_bool_t
hb_buffer_has_positions (hb_buffer_t  *buffer);
 
 
HB_EXTERN void
hb_buffer_normalize_glyphs (hb_buffer_t *buffer);
 
 
/*
 * Serialize
 */
 
/**
 * hb_buffer_serialize_flags_t:
 * @HB_BUFFER_SERIALIZE_FLAG_DEFAULT: serialize glyph names, clusters and positions.
 * @HB_BUFFER_SERIALIZE_FLAG_NO_CLUSTERS: do not serialize glyph cluster.
 * @HB_BUFFER_SERIALIZE_FLAG_NO_POSITIONS: do not serialize glyph position information.
 * @HB_BUFFER_SERIALIZE_FLAG_NO_GLYPH_NAMES: do no serialize glyph name.
 * @HB_BUFFER_SERIALIZE_FLAG_GLYPH_EXTENTS: serialize glyph extents.
 * @HB_BUFFER_SERIALIZE_FLAG_GLYPH_FLAGS: serialize glyph flags. Since: 1.5.0
 * @HB_BUFFER_SERIALIZE_FLAG_NO_ADVANCES: do not serialize glyph advances,
 *  glyph offsets will reflect absolute glyph positions. Since: 1.8.0
 * @HB_BUFFER_SERIALIZE_FLAG_DEFINED: All currently defined flags. Since: 4.4.0
 *
 * Flags that control what glyph information are serialized in hb_buffer_serialize_glyphs().
 *
 * Since: 0.9.20
 */
typedef enum { /*< flags >*/
  HB_BUFFER_SERIALIZE_FLAG_DEFAULT      = 0x00000000u,
  HB_BUFFER_SERIALIZE_FLAG_NO_CLUSTERS      = 0x00000001u,
  HB_BUFFER_SERIALIZE_FLAG_NO_POSITIONS     = 0x00000002u,
  HB_BUFFER_SERIALIZE_FLAG_NO_GLYPH_NAMES   = 0x00000004u,
  HB_BUFFER_SERIALIZE_FLAG_GLYPH_EXTENTS    = 0x00000008u,
  HB_BUFFER_SERIALIZE_FLAG_GLYPH_FLAGS      = 0x00000010u,
  HB_BUFFER_SERIALIZE_FLAG_NO_ADVANCES      = 0x00000020u,
 
  HB_BUFFER_SERIALIZE_FLAG_DEFINED      = 0x0000003Fu
} hb_buffer_serialize_flags_t;
 
/**
 * hb_buffer_serialize_format_t:
 * @HB_BUFFER_SERIALIZE_FORMAT_TEXT: a human-readable, plain text format.
 * @HB_BUFFER_SERIALIZE_FORMAT_JSON: a machine-readable JSON format.
 * @HB_BUFFER_SERIALIZE_FORMAT_INVALID: invalid format.
 *
 * The buffer serialization and de-serialization format used in
 * hb_buffer_serialize_glyphs() and hb_buffer_deserialize_glyphs().
 *
 * Since: 0.9.2
 */
typedef enum {
  HB_BUFFER_SERIALIZE_FORMAT_TEXT   = HB_TAG('T','E','X','T'),
  HB_BUFFER_SERIALIZE_FORMAT_JSON   = HB_TAG('J','S','O','N'),
  HB_BUFFER_SERIALIZE_FORMAT_INVALID    = HB_TAG_NONE
} hb_buffer_serialize_format_t;
 
HB_EXTERN hb_buffer_serialize_format_t
hb_buffer_serialize_format_from_string (const char *str, int len);
 
HB_EXTERN const char *
hb_buffer_serialize_format_to_string (hb_buffer_serialize_format_t format);
 
HB_EXTERN const char **
hb_buffer_serialize_list_formats (void);
 
HB_EXTERN unsigned int
hb_buffer_serialize_glyphs (hb_buffer_t *buffer,
                unsigned int start,
                unsigned int end,
                char *buf,
                unsigned int buf_size,
                unsigned int *buf_consumed,
                hb_font_t *font,
                hb_buffer_serialize_format_t format,
                hb_buffer_serialize_flags_t flags);
 
HB_EXTERN unsigned int
hb_buffer_serialize_unicode (hb_buffer_t *buffer,
                 unsigned int start,
                 unsigned int end,
                 char *buf,
                 unsigned int buf_size,
                 unsigned int *buf_consumed,
                 hb_buffer_serialize_format_t format,
                 hb_buffer_serialize_flags_t flags);
 
HB_EXTERN unsigned int
hb_buffer_serialize (hb_buffer_t *buffer,
             unsigned int start,
             unsigned int end,
             char *buf,
             unsigned int buf_size,
             unsigned int *buf_consumed,
             hb_font_t *font,
             hb_buffer_serialize_format_t format,
             hb_buffer_serialize_flags_t flags);
 
HB_EXTERN hb_bool_t
hb_buffer_deserialize_glyphs (hb_buffer_t *buffer,
                  const char *buf,
                  int buf_len,
                  const char **end_ptr,
                  hb_font_t *font,
                  hb_buffer_serialize_format_t format);
 
HB_EXTERN hb_bool_t
hb_buffer_deserialize_unicode (hb_buffer_t *buffer,
                   const char *buf,
                   int buf_len,
                   const char **end_ptr,
                   hb_buffer_serialize_format_t format);
 
 
 
/*
 * Compare buffers
 */
 
/**
 * hb_buffer_diff_flags_t:
 * @HB_BUFFER_DIFF_FLAG_EQUAL: equal buffers.
 * @HB_BUFFER_DIFF_FLAG_CONTENT_TYPE_MISMATCH: buffers with different
 *     #hb_buffer_content_type_t.
 * @HB_BUFFER_DIFF_FLAG_LENGTH_MISMATCH: buffers with differing length.
 * @HB_BUFFER_DIFF_FLAG_NOTDEF_PRESENT: `.notdef` glyph is present in the
 *     reference buffer.
 * @HB_BUFFER_DIFF_FLAG_DOTTED_CIRCLE_PRESENT: dotted circle glyph is present
 *     in the reference buffer.
 * @HB_BUFFER_DIFF_FLAG_CODEPOINT_MISMATCH: difference in #hb_glyph_info_t.codepoint
 * @HB_BUFFER_DIFF_FLAG_CLUSTER_MISMATCH: difference in #hb_glyph_info_t.cluster
 * @HB_BUFFER_DIFF_FLAG_GLYPH_FLAGS_MISMATCH: difference in #hb_glyph_flags_t.
 * @HB_BUFFER_DIFF_FLAG_POSITION_MISMATCH: difference in #hb_glyph_position_t.
 *
 * Flags from comparing two #hb_buffer_t's.
 *
 * Buffer with different #hb_buffer_content_type_t cannot be meaningfully
 * compared in any further detail.
 *
 * For buffers with differing length, the per-glyph comparison is not
 * attempted, though we do still scan reference buffer for dotted circle and
 * `.notdef` glyphs.
 *
 * If the buffers have the same length, we compare them glyph-by-glyph and
 * report which aspect(s) of the glyph info/position are different.
 *
 * Since: 1.5.0
 */
typedef enum { /*< flags >*/
  HB_BUFFER_DIFF_FLAG_EQUAL         = 0x0000,
 
  /* Buffers with different content_type cannot be meaningfully compared
   * in any further detail. */
  HB_BUFFER_DIFF_FLAG_CONTENT_TYPE_MISMATCH = 0x0001,
 
  /* For buffers with differing length, the per-glyph comparison is not
   * attempted, though we do still scan reference for dottedcircle / .notdef
   * glyphs. */
  HB_BUFFER_DIFF_FLAG_LENGTH_MISMATCH       = 0x0002,
 
  /* We want to know if dottedcircle / .notdef glyphs are present in the
   * reference, as we may not care so much about other differences in this
   * case. */
  HB_BUFFER_DIFF_FLAG_NOTDEF_PRESENT        = 0x0004,
  HB_BUFFER_DIFF_FLAG_DOTTED_CIRCLE_PRESENT = 0x0008,
 
  /* If the buffers have the same length, we compare them glyph-by-glyph
   * and report which aspect(s) of the glyph info/position are different. */
  HB_BUFFER_DIFF_FLAG_CODEPOINT_MISMATCH    = 0x0010,
  HB_BUFFER_DIFF_FLAG_CLUSTER_MISMATCH      = 0x0020,
  HB_BUFFER_DIFF_FLAG_GLYPH_FLAGS_MISMATCH  = 0x0040,
  HB_BUFFER_DIFF_FLAG_POSITION_MISMATCH     = 0x0080
 
} hb_buffer_diff_flags_t;
 
/* Compare the contents of two buffers, report types of differences. */
HB_EXTERN hb_buffer_diff_flags_t
hb_buffer_diff (hb_buffer_t *buffer,
        hb_buffer_t *reference,
        hb_codepoint_t dottedcircle_glyph,
        unsigned int position_fuzz);
 
 
/*
 * Tracing.
 */
 
/**
 * hb_buffer_message_func_t:
 * @buffer: An #hb_buffer_t to work upon
 * @font: The #hb_font_t the @buffer is shaped with
 * @message: `NULL`-terminated message passed to the function
 * @user_data: User data pointer passed by the caller
 *
 * A callback method for #hb_buffer_t. The method gets called with the
 * #hb_buffer_t it was set on, the #hb_font_t the buffer is shaped with and a
 * message describing what step of the shaping process will be performed.
 * Returning `false` from this method will skip this shaping step and move to
 * the next one.
 *
 * Return value: `true` to perform the shaping step, `false` to skip it.
 *
 * Since: 1.1.3
 */
typedef hb_bool_t   (*hb_buffer_message_func_t) (hb_buffer_t *buffer,
                             hb_font_t   *font,
                             const char  *message,
                             void        *user_data);
 
HB_EXTERN void
hb_buffer_set_message_func (hb_buffer_t *buffer,
                hb_buffer_message_func_t func,
                void *user_data, hb_destroy_func_t destroy);
 
 
HB_END_DECLS
 
#endif /* HB_BUFFER_H */