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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-19 00:47:55 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-19 00:47:55 +0000
commit26a029d407be480d791972afb5975cf62c9360a6 (patch)
treef435a8308119effd964b339f76abb83a57c29483 /gfx/harfbuzz/src/hb-buffer.h
parentInitial commit. (diff)
downloadfirefox-26a029d407be480d791972afb5975cf62c9360a6.tar.xz
firefox-26a029d407be480d791972afb5975cf62c9360a6.zip
Adding upstream version 124.0.1.upstream/124.0.1
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'gfx/harfbuzz/src/hb-buffer.h')
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1 files changed, 799 insertions, 0 deletions
diff --git a/gfx/harfbuzz/src/hb-buffer.h b/gfx/harfbuzz/src/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);
+
+
+/*
+ * 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 */