chromium/third_party/harfbuzz-ng/src/src/hb-buffer.cc

/*
 * Copyright © 1998-2004  David Turner and Werner Lemberg
 * Copyright © 2004,2007,2009,2010  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
 */

#include "hb-buffer.hh"
#include "hb-utf.hh"


/**
 * SECTION: hb-buffer
 * @title: hb-buffer
 * @short_description: Input and output buffers
 * @include: hb.h
 *
 * Buffers serve a dual role in HarfBuzz; before shaping, they hold
 * the input characters that are passed to hb_shape(), and after
 * shaping they hold the output glyphs.
 *
 * The input buffer is a sequence of Unicode codepoints, with
 * associated attributes such as direction and script.  The output
 * buffer is a sequence of glyphs, with associated attributes such
 * as position and cluster.
 **/


/**
 * hb_segment_properties_equal:
 * @a: first #hb_segment_properties_t to compare.
 * @b: second #hb_segment_properties_t to compare.
 *
 * Checks the equality of two #hb_segment_properties_t's.
 *
 * Return value:
 * `true` if all properties of @a equal those of @b, `false` otherwise.
 *
 * Since: 0.9.7
 **/
hb_bool_t
hb_segment_properties_equal (const hb_segment_properties_t *a,
			     const hb_segment_properties_t *b)
{}

/**
 * hb_segment_properties_hash:
 * @p: #hb_segment_properties_t to hash.
 *
 * Creates a hash representing @p.
 *
 * Return value:
 * A hash of @p.
 *
 * Since: 0.9.7
 **/
unsigned int
hb_segment_properties_hash (const hb_segment_properties_t *p)
{}

/**
 * hb_segment_properties_overlay:
 * @p: #hb_segment_properties_t to fill in.
 * @src: #hb_segment_properties_t to fill in from.
 *
 * Fills in missing fields of @p from @src in a considered manner.
 *
 * First, if @p does not have direction set, direction is copied from @src.
 *
 * Next, if @p and @src have the same direction (which can be unset), if @p
 * does not have script set, script is copied from @src.
 *
 * Finally, if @p and @src have the same direction and script (which either
 * can be unset), if @p does not have language set, language is copied from
 * @src.
 *
 * Since: 3.3.0
 **/
void
hb_segment_properties_overlay (hb_segment_properties_t *p,
			       const hb_segment_properties_t *src)
{}

/* Here is how the buffer works internally:
 *
 * There are two info pointers: info and out_info.  They always have
 * the same allocated size, but different lengths.
 *
 * As an optimization, both info and out_info may point to the
 * same piece of memory, which is owned by info.  This remains the
 * case as long as out_len doesn't exceed i at any time.
 * In that case, sync() is mostly no-op and the glyph operations
 * operate mostly in-place.
 *
 * As soon as out_info gets longer than info, out_info is moved over
 * to an alternate buffer (which we reuse the pos buffer for), and its
 * current contents (out_len entries) are copied to the new place.
 *
 * This should all remain transparent to the user.  sync() then
 * switches info over to out_info and does housekeeping.
 */



/* Internal API */

bool
hb_buffer_t::enlarge (unsigned int size)
{}

bool
hb_buffer_t::make_room_for (unsigned int num_in,
			    unsigned int num_out)
{}

bool
hb_buffer_t::shift_forward (unsigned int count)
{}

hb_buffer_t::scratch_buffer_t *
hb_buffer_t::get_scratch_buffer (unsigned int *size)
{}



/* HarfBuzz-Internal API */

void
hb_buffer_t::similar (const hb_buffer_t &src)
{}

void
hb_buffer_t::reset ()
{}

void
hb_buffer_t::clear ()
{}

void
hb_buffer_t::enter ()
{}
void
hb_buffer_t::leave ()
{}


void
hb_buffer_t::add (hb_codepoint_t  codepoint,
		  unsigned int    cluster)
{}

void
hb_buffer_t::add_info (const hb_glyph_info_t &glyph_info)
{}


void
hb_buffer_t::clear_output ()
{}

void
hb_buffer_t::clear_positions ()
{}

bool
hb_buffer_t::sync ()
{}

int
hb_buffer_t::sync_so_far ()
{}

bool
hb_buffer_t::move_to (unsigned int i)
{}


void
hb_buffer_t::set_masks (hb_mask_t    value,
			hb_mask_t    mask,
			unsigned int cluster_start,
			unsigned int cluster_end)
{}

void
hb_buffer_t::merge_clusters_impl (unsigned int start,
				  unsigned int end)
{}
void
hb_buffer_t::merge_out_clusters (unsigned int start,
				 unsigned int end)
{}
void
hb_buffer_t::delete_glyph ()
{}

void
hb_buffer_t::delete_glyphs_inplace (bool (*filter) (const hb_glyph_info_t *info))
{}

void
hb_buffer_t::guess_segment_properties ()
{}


/* Public API */

DEFINE_NULL_INSTANCE (hb_buffer_t) =;


/**
 * hb_buffer_create:
 *
 * Creates a new #hb_buffer_t with all properties to defaults.
 *
 * Return value: (transfer full):
 * A newly allocated #hb_buffer_t with a reference count of 1. The initial
 * reference count should be released with hb_buffer_destroy() when you are done
 * using the #hb_buffer_t. This function never returns `NULL`. If memory cannot
 * be allocated, a special #hb_buffer_t object will be returned on which
 * hb_buffer_allocation_successful() returns `false`.
 *
 * Since: 0.9.2
 **/
hb_buffer_t *
hb_buffer_create ()
{}

/**
 * hb_buffer_create_similar:
 * @src: An #hb_buffer_t
 *
 * Creates a new #hb_buffer_t, similar to hb_buffer_create(). The only
 * difference is that the buffer is configured similarly to @src.
 *
 * Return value: (transfer full):
 * A newly allocated #hb_buffer_t, similar to hb_buffer_create().
 *
 * Since: 3.3.0
 **/
hb_buffer_t *
hb_buffer_create_similar (const hb_buffer_t *src)
{}

/**
 * hb_buffer_reset:
 * @buffer: An #hb_buffer_t
 *
 * Resets the buffer to its initial status, as if it was just newly created
 * with hb_buffer_create().
 *
 * Since: 0.9.2
 **/
void
hb_buffer_reset (hb_buffer_t *buffer)
{}

/**
 * hb_buffer_get_empty:
 *
 * Fetches an empty #hb_buffer_t.
 *
 * Return value: (transfer full): The empty buffer
 *
 * Since: 0.9.2
 **/
hb_buffer_t *
hb_buffer_get_empty ()
{}

/**
 * hb_buffer_reference: (skip)
 * @buffer: An #hb_buffer_t
 *
 * Increases the reference count on @buffer by one. This prevents @buffer from
 * being destroyed until a matching call to hb_buffer_destroy() is made.
 *
 * Return value: (transfer full):
 * The referenced #hb_buffer_t.
 *
 * Since: 0.9.2
 **/
hb_buffer_t *
hb_buffer_reference (hb_buffer_t *buffer)
{}

/**
 * hb_buffer_destroy: (skip)
 * @buffer: An #hb_buffer_t
 *
 * Deallocate the @buffer.
 * Decreases the reference count on @buffer by one. If the result is zero, then
 * @buffer and all associated resources are freed. See hb_buffer_reference().
 *
 * Since: 0.9.2
 **/
void
hb_buffer_destroy (hb_buffer_t *buffer)
{}

/**
 * hb_buffer_set_user_data: (skip)
 * @buffer: An #hb_buffer_t
 * @key: The user-data key
 * @data: A pointer to the user data
 * @destroy: (nullable): A callback to call when @data is not needed anymore
 * @replace: Whether to replace an existing data with the same key
 *
 * Attaches a user-data key/data pair to the specified buffer. 
 *
 * Return value: `true` if success, `false` otherwise
 *
 * Since: 0.9.2
 **/
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_buffer_get_user_data: (skip)
 * @buffer: An #hb_buffer_t
 * @key: The user-data key to query
 *
 * Fetches the user data associated with the specified key,
 * attached to the specified buffer.
 *
 * Return value: (transfer none): A pointer to the user data
 *
 * Since: 0.9.2
 **/
void *
hb_buffer_get_user_data (const hb_buffer_t  *buffer,
			 hb_user_data_key_t *key)
{}


/**
 * hb_buffer_set_content_type:
 * @buffer: An #hb_buffer_t
 * @content_type: The type of buffer contents to set
 *
 * Sets the type of @buffer contents. Buffers are either empty, contain
 * characters (before shaping), or contain glyphs (the result of shaping).
 *
 * You rarely need to call this function, since a number of other
 * functions transition the content type for you. Namely:
 *
 * - A newly created buffer starts with content type
 *   %HB_BUFFER_CONTENT_TYPE_INVALID. Calling hb_buffer_reset(),
 *   hb_buffer_clear_contents(), as well as calling hb_buffer_set_length()
 *   with an argument of zero all set the buffer content type to invalid
 *   as well.
 *
 * - Calling hb_buffer_add_utf8(), hb_buffer_add_utf16(),
 *   hb_buffer_add_utf32(), hb_buffer_add_codepoints() and
 *   hb_buffer_add_latin1() expect that buffer is either empty and
 *   have a content type of invalid, or that buffer content type is
 *   %HB_BUFFER_CONTENT_TYPE_UNICODE, and they also set the content
 *   type to Unicode if they added anything to an empty buffer.
 *
 * - Finally hb_shape() and hb_shape_full() expect that the buffer
 *   is either empty and have content type of invalid, or that buffer
 *   content type is %HB_BUFFER_CONTENT_TYPE_UNICODE, and upon
 *   success they set the buffer content type to
 *   %HB_BUFFER_CONTENT_TYPE_GLYPHS.
 *
 * The above transitions are designed such that one can use a buffer
 * in a loop of "reset : add-text : shape" without needing to ever
 * modify the content type manually.
 *
 * Since: 0.9.5
 **/
void
hb_buffer_set_content_type (hb_buffer_t              *buffer,
			    hb_buffer_content_type_t  content_type)
{}

/**
 * hb_buffer_get_content_type:
 * @buffer: An #hb_buffer_t
 *
 * Fetches the type of @buffer contents. Buffers are either empty, contain
 * characters (before shaping), or contain glyphs (the result of shaping).
 *
 * Return value:
 * The type of @buffer contents
 *
 * Since: 0.9.5
 **/
hb_buffer_content_type_t
hb_buffer_get_content_type (const hb_buffer_t *buffer)
{}


/**
 * hb_buffer_set_unicode_funcs:
 * @buffer: An #hb_buffer_t
 * @unicode_funcs: The Unicode-functions structure
 *
 * Sets the Unicode-functions structure of a buffer to
 * @unicode_funcs.
 *
 * Since: 0.9.2
 **/
void
hb_buffer_set_unicode_funcs (hb_buffer_t        *buffer,
			     hb_unicode_funcs_t *unicode_funcs)
{}

/**
 * hb_buffer_get_unicode_funcs:
 * @buffer: An #hb_buffer_t
 *
 * Fetches the Unicode-functions structure of a buffer.
 *
 * Return value: The Unicode-functions structure
 *
 * Since: 0.9.2
 **/
hb_unicode_funcs_t *
hb_buffer_get_unicode_funcs (const hb_buffer_t *buffer)
{}

/**
 * hb_buffer_set_direction:
 * @buffer: An #hb_buffer_t
 * @direction: the #hb_direction_t of the @buffer
 *
 * Set the text flow direction of the buffer. No shaping can happen without
 * setting @buffer direction, and it controls the visual direction for the
 * output glyphs; for RTL direction the glyphs will be reversed. Many layout
 * features depend on the proper setting of the direction, for example,
 * reversing RTL text before shaping, then shaping with LTR direction is not
 * the same as keeping the text in logical order and shaping with RTL
 * direction.
 *
 * Since: 0.9.2
 **/
void
hb_buffer_set_direction (hb_buffer_t    *buffer,
			 hb_direction_t  direction)
{}

/**
 * hb_buffer_get_direction:
 * @buffer: An #hb_buffer_t
 *
 * See hb_buffer_set_direction()
 *
 * Return value:
 * The direction of the @buffer.
 *
 * Since: 0.9.2
 **/
hb_direction_t
hb_buffer_get_direction (const hb_buffer_t *buffer)
{}

/**
 * hb_buffer_set_script:
 * @buffer: An #hb_buffer_t
 * @script: An #hb_script_t to set.
 *
 * Sets the script of @buffer to @script.
 *
 * Script is crucial for choosing the proper shaping behaviour for scripts that
 * require it (e.g. Arabic) and the which OpenType features defined in the font
 * to be applied.
 *
 * You can pass one of the predefined #hb_script_t values, or use
 * hb_script_from_string() or hb_script_from_iso15924_tag() to get the
 * corresponding script from an ISO 15924 script tag.
 *
 * Since: 0.9.2
 **/
void
hb_buffer_set_script (hb_buffer_t *buffer,
		      hb_script_t  script)
{}

/**
 * hb_buffer_get_script:
 * @buffer: An #hb_buffer_t
 *
 * Fetches the script of @buffer.
 *
 * Return value:
 * The #hb_script_t of the @buffer
 *
 * Since: 0.9.2
 **/
hb_script_t
hb_buffer_get_script (const hb_buffer_t *buffer)
{}

/**
 * hb_buffer_set_language:
 * @buffer: An #hb_buffer_t
 * @language: An hb_language_t to set
 *
 * Sets the language of @buffer to @language.
 *
 * Languages are crucial for selecting which OpenType feature to apply to the
 * buffer which can result in applying language-specific behaviour. Languages
 * are orthogonal to the scripts, and though they are related, they are
 * different concepts and should not be confused with each other.
 *
 * Use hb_language_from_string() to convert from BCP 47 language tags to
 * #hb_language_t.
 *
 * Since: 0.9.2
 **/
void
hb_buffer_set_language (hb_buffer_t   *buffer,
			hb_language_t  language)
{}

/**
 * hb_buffer_get_language:
 * @buffer: An #hb_buffer_t
 *
 * See hb_buffer_set_language().
 *
 * Return value: (transfer none):
 * The #hb_language_t of the buffer. Must not be freed by the caller.
 *
 * Since: 0.9.2
 **/
hb_language_t
hb_buffer_get_language (const hb_buffer_t *buffer)
{}

/**
 * hb_buffer_set_segment_properties:
 * @buffer: An #hb_buffer_t
 * @props: An #hb_segment_properties_t to use
 *
 * Sets the segment properties of the buffer, a shortcut for calling
 * hb_buffer_set_direction(), hb_buffer_set_script() and
 * hb_buffer_set_language() individually.
 *
 * Since: 0.9.7
 **/
void
hb_buffer_set_segment_properties (hb_buffer_t *buffer,
				  const hb_segment_properties_t *props)
{}

/**
 * hb_buffer_get_segment_properties:
 * @buffer: An #hb_buffer_t
 * @props: (out): The output #hb_segment_properties_t
 *
 * Sets @props to the #hb_segment_properties_t of @buffer.
 *
 * Since: 0.9.7
 **/
void
hb_buffer_get_segment_properties (const hb_buffer_t *buffer,
				  hb_segment_properties_t *props)
{}


/**
 * hb_buffer_set_flags:
 * @buffer: An #hb_buffer_t
 * @flags: The buffer flags to set
 *
 * Sets @buffer flags to @flags. See #hb_buffer_flags_t.
 *
 * Since: 0.9.7
 **/
void
hb_buffer_set_flags (hb_buffer_t       *buffer,
		     hb_buffer_flags_t  flags)
{}

/**
 * hb_buffer_get_flags:
 * @buffer: An #hb_buffer_t
 *
 * Fetches the #hb_buffer_flags_t of @buffer.
 *
 * Return value:
 * The @buffer flags
 *
 * Since: 0.9.7
 **/
hb_buffer_flags_t
hb_buffer_get_flags (const hb_buffer_t *buffer)
{}

/**
 * hb_buffer_set_cluster_level:
 * @buffer: An #hb_buffer_t
 * @cluster_level: The cluster level to set on the buffer
 *
 * Sets the cluster level of a buffer. The #hb_buffer_cluster_level_t
 * dictates one aspect of how HarfBuzz will treat non-base characters 
 * during shaping.
 *
 * Since: 0.9.42
 **/
void
hb_buffer_set_cluster_level (hb_buffer_t               *buffer,
			     hb_buffer_cluster_level_t  cluster_level)
{}

/**
 * hb_buffer_get_cluster_level:
 * @buffer: An #hb_buffer_t
 *
 * Fetches the cluster level of a buffer. The #hb_buffer_cluster_level_t
 * dictates one aspect of how HarfBuzz will treat non-base characters 
 * during shaping.
 *
 * Return value: The cluster level of @buffer
 *
 * Since: 0.9.42
 **/
hb_buffer_cluster_level_t
hb_buffer_get_cluster_level (const hb_buffer_t *buffer)
{}


/**
 * hb_buffer_set_replacement_codepoint:
 * @buffer: An #hb_buffer_t
 * @replacement: the replacement #hb_codepoint_t
 *
 * Sets the #hb_codepoint_t that replaces invalid entries for a given encoding
 * when adding text to @buffer.
 *
 * Default is #HB_BUFFER_REPLACEMENT_CODEPOINT_DEFAULT.
 *
 * Since: 0.9.31
 **/
void
hb_buffer_set_replacement_codepoint (hb_buffer_t    *buffer,
				     hb_codepoint_t  replacement)
{}

/**
 * hb_buffer_get_replacement_codepoint:
 * @buffer: An #hb_buffer_t
 *
 * Fetches the #hb_codepoint_t that replaces invalid entries for a given encoding
 * when adding text to @buffer.
 *
 * Return value:
 * The @buffer replacement #hb_codepoint_t
 *
 * Since: 0.9.31
 **/
hb_codepoint_t
hb_buffer_get_replacement_codepoint (const hb_buffer_t *buffer)
{}


/**
 * hb_buffer_set_invisible_glyph:
 * @buffer: An #hb_buffer_t
 * @invisible: the invisible #hb_codepoint_t
 *
 * Sets the #hb_codepoint_t that replaces invisible characters in
 * the shaping result.  If set to zero (default), the glyph for the
 * U+0020 SPACE character is used.  Otherwise, this value is used
 * verbatim.
 *
 * Since: 2.0.0
 **/
void
hb_buffer_set_invisible_glyph (hb_buffer_t    *buffer,
			       hb_codepoint_t  invisible)
{}

/**
 * hb_buffer_get_invisible_glyph:
 * @buffer: An #hb_buffer_t
 *
 * See hb_buffer_set_invisible_glyph().
 *
 * Return value:
 * The @buffer invisible #hb_codepoint_t
 *
 * Since: 2.0.0
 **/
hb_codepoint_t
hb_buffer_get_invisible_glyph (const hb_buffer_t *buffer)
{}

/**
 * hb_buffer_set_not_found_glyph:
 * @buffer: An #hb_buffer_t
 * @not_found: the not-found #hb_codepoint_t
 *
 * Sets the #hb_codepoint_t that replaces characters not found in
 * the font during shaping.
 *
 * The not-found glyph defaults to zero, sometimes known as the
 * ".notdef" glyph.  This API allows for differentiating the two.
 *
 * Since: 3.1.0
 **/
void
hb_buffer_set_not_found_glyph (hb_buffer_t    *buffer,
			       hb_codepoint_t  not_found)
{}

/**
 * hb_buffer_get_not_found_glyph:
 * @buffer: An #hb_buffer_t
 *
 * See hb_buffer_set_not_found_glyph().
 *
 * Return value:
 * The @buffer not-found #hb_codepoint_t
 *
 * Since: 3.1.0
 **/
hb_codepoint_t
hb_buffer_get_not_found_glyph (const hb_buffer_t *buffer)
{}

/**
 * hb_buffer_set_random_state:
 * @buffer: An #hb_buffer_t
 * @state: the new random state
 *
 * Sets the random state of the buffer. The state changes
 * every time a glyph uses randomness (eg. the `rand`
 * OpenType feature). This function together with
 * hb_buffer_get_random_state() allow for transferring
 * the current random state to a subsequent buffer, to
 * get better randomness distribution.
 *
 * Defaults to 1 and when buffer contents are cleared.
 * A value of 0 disables randomness during shaping.
 *
 * Since: 8.4.0
 **/
void
hb_buffer_set_random_state (hb_buffer_t    *buffer,
			    unsigned        state)
{}

/**
 * hb_buffer_get_random_state:
 * @buffer: An #hb_buffer_t
 *
 * See hb_buffer_set_random_state().
 *
 * Return value:
 * The @buffer random state
 *
 * Since: 8.4.0
 **/
unsigned
hb_buffer_get_random_state (const hb_buffer_t *buffer)
{}

/**
 * hb_buffer_clear_contents:
 * @buffer: An #hb_buffer_t
 *
 * Similar to hb_buffer_reset(), but does not clear the Unicode functions and
 * the replacement code point.
 *
 * Since: 0.9.11
 **/
void
hb_buffer_clear_contents (hb_buffer_t *buffer)
{}

/**
 * hb_buffer_pre_allocate:
 * @buffer: An #hb_buffer_t
 * @size: Number of items to pre allocate.
 *
 * Pre allocates memory for @buffer to fit at least @size number of items.
 *
 * Return value:
 * `true` if @buffer memory allocation succeeded, `false` otherwise
 *
 * Since: 0.9.2
 **/
hb_bool_t
hb_buffer_pre_allocate (hb_buffer_t *buffer, unsigned int size)
{}

/**
 * hb_buffer_allocation_successful:
 * @buffer: An #hb_buffer_t
 *
 * Check if allocating memory for the buffer succeeded.
 *
 * Return value:
 * `true` if @buffer memory allocation succeeded, `false` otherwise.
 *
 * Since: 0.9.2
 **/
hb_bool_t
hb_buffer_allocation_successful (hb_buffer_t  *buffer)
{}

/**
 * hb_buffer_add:
 * @buffer: An #hb_buffer_t
 * @codepoint: A Unicode code point.
 * @cluster: The cluster value of @codepoint.
 *
 * Appends a character with the Unicode value of @codepoint to @buffer, and
 * gives it the initial cluster value of @cluster. Clusters can be any thing
 * the client wants, they are usually used to refer to the index of the
 * character in the input text stream and are output in
 * #hb_glyph_info_t.cluster field.
 *
 * This function does not check the validity of @codepoint, it is up to the
 * caller to ensure it is a valid Unicode code point.
 *
 * Since: 0.9.7
 **/
void
hb_buffer_add (hb_buffer_t    *buffer,
	       hb_codepoint_t  codepoint,
	       unsigned int    cluster)
{}

/**
 * hb_buffer_set_length:
 * @buffer: An #hb_buffer_t
 * @length: The new length of @buffer
 *
 * Similar to hb_buffer_pre_allocate(), but clears any new items added at the
 * end.
 *
 * Return value:
 * `true` if @buffer memory allocation succeeded, `false` otherwise.
 *
 * Since: 0.9.2
 **/
hb_bool_t
hb_buffer_set_length (hb_buffer_t  *buffer,
		      unsigned int  length)
{}

/**
 * hb_buffer_get_length:
 * @buffer: An #hb_buffer_t
 *
 * Returns the number of items in the buffer.
 *
 * Return value:
 * The @buffer length.
 * The value valid as long as buffer has not been modified.
 *
 * Since: 0.9.2
 **/
unsigned int
hb_buffer_get_length (const hb_buffer_t *buffer)
{}

/**
 * hb_buffer_get_glyph_infos:
 * @buffer: An #hb_buffer_t
 * @length: (out): The output-array length.
 *
 * Returns @buffer glyph information array.  Returned pointer
 * is valid as long as @buffer contents are not modified.
 *
 * Return value: (transfer none) (array length=length):
 * The @buffer glyph information array.
 * The value valid as long as buffer has not been modified.
 *
 * Since: 0.9.2
 **/
hb_glyph_info_t *
hb_buffer_get_glyph_infos (hb_buffer_t  *buffer,
			   unsigned int *length)
{}

/**
 * hb_buffer_get_glyph_positions:
 * @buffer: An #hb_buffer_t
 * @length: (out): The output length
 *
 * Returns @buffer glyph position array.  Returned pointer
 * is valid as long as @buffer contents are not modified.
 *
 * If buffer did not have positions before, the positions will be
 * initialized to zeros, unless this function is called from
 * within a buffer message callback (see hb_buffer_set_message_func()),
 * in which case `NULL` is returned.
 *
 * Return value: (transfer none) (array length=length):
 * The @buffer glyph position array.
 * The value valid as long as buffer has not been modified.
 *
 * Since: 0.9.2
 **/
hb_glyph_position_t *
hb_buffer_get_glyph_positions (hb_buffer_t  *buffer,
			       unsigned int *length)
{}

/**
 * hb_buffer_has_positions:
 * @buffer: an #hb_buffer_t.
 *
 * Returns whether @buffer has glyph position data.
 * A buffer gains position data when hb_buffer_get_glyph_positions() is called on it,
 * and cleared of position data when hb_buffer_clear_contents() is called.
 *
 * Return value:
 * `true` if the @buffer has position array, `false` otherwise.
 *
 * Since: 2.7.3
 **/
HB_EXTERN hb_bool_t
hb_buffer_has_positions (hb_buffer_t  *buffer)
{}

/**
 * hb_glyph_info_get_glyph_flags:
 * @info: a #hb_glyph_info_t
 *
 * Returns glyph flags encoded within a #hb_glyph_info_t.
 *
 * Return value:
 * The #hb_glyph_flags_t encoded within @info
 *
 * Since: 1.5.0
 **/
hb_glyph_flags_t
(hb_glyph_info_get_glyph_flags) (const hb_glyph_info_t *info)
{}

/**
 * hb_buffer_reverse:
 * @buffer: An #hb_buffer_t
 *
 * Reverses buffer contents.
 *
 * Since: 0.9.2
 **/
void
hb_buffer_reverse (hb_buffer_t *buffer)
{}

/**
 * hb_buffer_reverse_range:
 * @buffer: An #hb_buffer_t
 * @start: start index
 * @end: end index
 *
 * Reverses buffer contents between @start and @end.
 *
 * Since: 0.9.41
 **/
void
hb_buffer_reverse_range (hb_buffer_t *buffer,
			 unsigned int start, unsigned int end)
{}

/**
 * hb_buffer_reverse_clusters:
 * @buffer: An #hb_buffer_t
 *
 * Reverses buffer clusters.  That is, the buffer contents are
 * reversed, then each cluster (consecutive items having the
 * same cluster number) are reversed again.
 *
 * Since: 0.9.2
 **/
void
hb_buffer_reverse_clusters (hb_buffer_t *buffer)
{}

/**
 * hb_buffer_guess_segment_properties:
 * @buffer: An #hb_buffer_t
 *
 * Sets unset buffer segment properties based on buffer Unicode
 * contents.  If buffer is not empty, it must have content type
 * #HB_BUFFER_CONTENT_TYPE_UNICODE.
 *
 * If buffer script is not set (ie. is #HB_SCRIPT_INVALID), it
 * will be set to the Unicode script of the first character in
 * the buffer that has a script other than #HB_SCRIPT_COMMON,
 * #HB_SCRIPT_INHERITED, and #HB_SCRIPT_UNKNOWN.
 *
 * Next, if buffer direction is not set (ie. is #HB_DIRECTION_INVALID),
 * it will be set to the natural horizontal direction of the
 * buffer script as returned by hb_script_get_horizontal_direction().
 * If hb_script_get_horizontal_direction() returns #HB_DIRECTION_INVALID,
 * then #HB_DIRECTION_LTR is used.
 *
 * Finally, if buffer language is not set (ie. is #HB_LANGUAGE_INVALID),
 * it will be set to the process's default language as returned by
 * hb_language_get_default().  This may change in the future by
 * taking buffer script into consideration when choosing a language.
 * Note that hb_language_get_default() is NOT threadsafe the first time
 * it is called.  See documentation for that function for details.
 *
 * Since: 0.9.7
 **/
void
hb_buffer_guess_segment_properties (hb_buffer_t *buffer)
{}

template <typename utf_t>
static inline void
hb_buffer_add_utf (hb_buffer_t  *buffer,
		   const typename utf_t::codepoint_t *text,
		   int           text_length,
		   unsigned int  item_offset,
		   int           item_length)
{}

/**
 * hb_buffer_add_utf8:
 * @buffer: An #hb_buffer_t
 * @text: (array length=text_length) (element-type uint8_t): An array of UTF-8
 *               characters to append.
 * @text_length: The length of the @text, or -1 if it is `NULL` terminated.
 * @item_offset: The offset of the first character to add to the @buffer.
 * @item_length: The number of characters to add to the @buffer, or -1 for the
 *               end of @text (assuming it is `NULL` terminated).
 *
 * See hb_buffer_add_codepoints().
 *
 * Replaces invalid UTF-8 characters with the @buffer replacement code point,
 * see hb_buffer_set_replacement_codepoint().
 *
 * Since: 0.9.2
 **/
void
hb_buffer_add_utf8 (hb_buffer_t  *buffer,
		    const char   *text,
		    int           text_length,
		    unsigned int  item_offset,
		    int           item_length)
{}

/**
 * hb_buffer_add_utf16:
 * @buffer: An #hb_buffer_t
 * @text: (array length=text_length): An array of UTF-16 characters to append
 * @text_length: The length of the @text, or -1 if it is `NULL` terminated
 * @item_offset: The offset of the first character to add to the @buffer
 * @item_length: The number of characters to add to the @buffer, or -1 for the
 *               end of @text (assuming it is `NULL` terminated)
 *
 * See hb_buffer_add_codepoints().
 *
 * Replaces invalid UTF-16 characters with the @buffer replacement code point,
 * see hb_buffer_set_replacement_codepoint().
 *
 * Since: 0.9.2
 **/
void
hb_buffer_add_utf16 (hb_buffer_t    *buffer,
		     const uint16_t *text,
		     int             text_length,
		     unsigned int    item_offset,
		     int             item_length)
{}

/**
 * hb_buffer_add_utf32:
 * @buffer: An #hb_buffer_t
 * @text: (array length=text_length): An array of UTF-32 characters to append
 * @text_length: The length of the @text, or -1 if it is `NULL` terminated
 * @item_offset: The offset of the first character to add to the @buffer
 * @item_length: The number of characters to add to the @buffer, or -1 for the
 *               end of @text (assuming it is `NULL` terminated)
 *
 * See hb_buffer_add_codepoints().
 *
 * Replaces invalid UTF-32 characters with the @buffer replacement code point,
 * see hb_buffer_set_replacement_codepoint().
 *
 * Since: 0.9.2
 **/
void
hb_buffer_add_utf32 (hb_buffer_t    *buffer,
		     const uint32_t *text,
		     int             text_length,
		     unsigned int    item_offset,
		     int             item_length)
{}

/**
 * hb_buffer_add_latin1:
 * @buffer: An #hb_buffer_t
 * @text: (array length=text_length) (element-type uint8_t): an array of UTF-8
 *               characters to append
 * @text_length: the length of the @text, or -1 if it is `NULL` terminated
 * @item_offset: the offset of the first character to add to the @buffer
 * @item_length: the number of characters to add to the @buffer, or -1 for the
 *               end of @text (assuming it is `NULL` terminated)
 *
 * Similar to hb_buffer_add_codepoints(), but allows only access to first 256
 * Unicode code points that can fit in 8-bit strings.
 *
 * <note>Has nothing to do with non-Unicode Latin-1 encoding.</note>
 *
 * Since: 0.9.39
 **/
void
hb_buffer_add_latin1 (hb_buffer_t   *buffer,
		      const uint8_t *text,
		      int            text_length,
		      unsigned int   item_offset,
		      int            item_length)
{}

/**
 * hb_buffer_add_codepoints:
 * @buffer: a #hb_buffer_t to append characters to.
 * @text: (array length=text_length): an array of Unicode code points to append.
 * @text_length: the length of the @text, or -1 if it is `NULL` terminated.
 * @item_offset: the offset of the first code point to add to the @buffer.
 * @item_length: the number of code points to add to the @buffer, or -1 for the
 *               end of @text (assuming it is `NULL` terminated).
 *
 * Appends characters from @text array to @buffer. The @item_offset is the
 * position of the first character from @text that will be appended, and
 * @item_length is the number of character. When shaping part of a larger text
 * (e.g. a run of text from a paragraph), instead of passing just the substring
 * corresponding to the run, it is preferable to pass the whole
 * paragraph and specify the run start and length as @item_offset and
 * @item_length, respectively, to give HarfBuzz the full context to be able,
 * for example, to do cross-run Arabic shaping or properly handle combining
 * marks at stat of run.
 *
 * This function does not check the validity of @text, it is up to the caller
 * to ensure it contains a valid Unicode scalar values.  In contrast,
 * hb_buffer_add_utf32() can be used that takes similar input but performs
 * sanity-check on the input.
 *
 * Since: 0.9.31
 **/
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_buffer_append:
 * @buffer: An #hb_buffer_t
 * @source: source #hb_buffer_t
 * @start: start index into source buffer to copy.  Use 0 to copy from start of buffer.
 * @end: end index into source buffer to copy.  Use @HB_FEATURE_GLOBAL_END to copy to end of buffer.
 *
 * Append (part of) contents of another buffer to this buffer.
 *
 * Since: 1.5.0
 **/
HB_EXTERN void
hb_buffer_append (hb_buffer_t *buffer,
		  const hb_buffer_t *source,
		  unsigned int start,
		  unsigned int end)
{}


static int
compare_info_codepoint (const hb_glyph_info_t *pa,
			const hb_glyph_info_t *pb)
{}

static inline void
normalize_glyphs_cluster (hb_buffer_t *buffer,
			  unsigned int start,
			  unsigned int end,
			  bool backward)
{}

/**
 * hb_buffer_normalize_glyphs:
 * @buffer: An #hb_buffer_t
 *
 * Reorders a glyph buffer to have canonical in-cluster glyph order / position.
 * The resulting clusters should behave identical to pre-reordering clusters.
 *
 * <note>This has nothing to do with Unicode normalization.</note>
 *
 * Since: 0.9.2
 **/
void
hb_buffer_normalize_glyphs (hb_buffer_t *buffer)
{}

void
hb_buffer_t::sort (unsigned int start, unsigned int end, int(*compar)(const hb_glyph_info_t *, const hb_glyph_info_t *))
{}


/*
 * Comparing buffers.
 */

/**
 * hb_buffer_diff:
 * @buffer: a buffer.
 * @reference: other buffer to compare to.
 * @dottedcircle_glyph: glyph id of U+25CC DOTTED CIRCLE, or (hb_codepoint_t) -1.
 * @position_fuzz: allowed absolute difference in position values.
 *
 * If dottedcircle_glyph is (hb_codepoint_t) -1 then #HB_BUFFER_DIFF_FLAG_DOTTED_CIRCLE_PRESENT
 * and #HB_BUFFER_DIFF_FLAG_NOTDEF_PRESENT are never returned.  This should be used by most
 * callers if just comparing two buffers is needed.
 *
 * Since: 1.5.0
 **/
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)
{}


/*
 * Debugging.
 */

#ifndef HB_NO_BUFFER_MESSAGE
/**
 * hb_buffer_set_message_func:
 * @buffer: An #hb_buffer_t
 * @func: (closure user_data) (destroy destroy) (scope notified): Callback function
 * @user_data: (nullable): Data to pass to @func
 * @destroy: (nullable): The function to call when @user_data is not needed anymore
 *
 * Sets the implementation function for #hb_buffer_message_func_t.
 *
 * Since: 1.1.3
 **/
void
hb_buffer_set_message_func (hb_buffer_t *buffer,
			    hb_buffer_message_func_t func,
			    void *user_data, hb_destroy_func_t destroy)
{}
bool
hb_buffer_t::message_impl (hb_font_t *font, const char *fmt, va_list ap)
{}
#endif