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/*
* Copyright © 2024 Adobe, 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.
*
* Adobe Author(s): Skef Iterum
*/
#ifndef HB_SUBSET_DEPEND_H
#define HB_SUBSET_DEPEND_H
#if !defined(HB_SUBSET_H_IN) && !defined(HB_NO_SINGLE_HEADER_ERROR)
#error "Include <hb-subset.h> instead."
#endif
#include "hb.h"
HB_BEGIN_DECLS
/**
* hb_subset_depend_edge_flags_t:
* @HB_SUBSET_DEPEND_EDGE_FLAG_NONE: No flags set.
* @HB_SUBSET_DEPEND_EDGE_FLAG_FROM_CONTEXT_POSITION: Edge from a multi-position
* contextual rule (Context or ChainContext with inputCount > 1). Depend
* extraction records edges based on what glyphs could statically be at each
* position according to input coverage or class. However, at runtime lookups
* within the rule are applied sequentially: a lookup at an earlier position
* may transform the glyph at a later position, and two lookups at the same
* position may interact such that one produces a glyph that another
* immediately consumes as an "intermediate". A glyph that matches the static
* coverage may therefore not persist at that position when the rule actually
* fires, so this edge may not trigger during closure.
* @HB_SUBSET_DEPEND_EDGE_FLAG_FROM_NESTED_CONTEXT: Edge from a lookup invoked
* within another contextual lookup. The outer context's requirements are not
* propagated to this edge, so the edge may fire even when those requirements
* are not met.
*
* Flags on dependency edges returned by hb_subset_depend_lookup_glyph() that
* mark edges which may produce expected over-approximation when computing
* closure via the depend graph, relative to
* hb_ot_layout_lookups_substitute_closure(). These flags help distinguish
* known limitations of static dependency analysis (expected over-approximation)
* from bugs (unexpected over-approximation).
*
* Since: 14.3.0
*/
typedef enum { /*< flags >*/
HB_SUBSET_DEPEND_EDGE_FLAG_NONE = 0x00u,
HB_SUBSET_DEPEND_EDGE_FLAG_FROM_CONTEXT_POSITION = 0x01u,
HB_SUBSET_DEPEND_EDGE_FLAG_FROM_NESTED_CONTEXT = 0x02u,
} hb_subset_depend_edge_flags_t;
#define HB_SUBSET_DEPEND_EDGE_FLAGS_T_DEFINED
/* HB_MARK_AS_FLAG_T is applied in hb-depend-data.hh (internal header only) */
#ifndef HB_NO_SUBSET_DEPEND
/**
* hb_subset_depend_t:
*
* Data type for holding glyph dependency graphs.
*
* <warning>Highly experimental API. Subject to change.</warning>
*
* Since: 14.3.0
*/
typedef struct hb_subset_depend_t hb_subset_depend_t;
/**
* hb_subset_depend_entry_t:
* @table_tag: Source table (e.g. GSUB, glyf, CFF, COLR, MATH).
* @dependent: Target glyph ID.
* @layout_tag: Feature tag for GSUB edges; 0 otherwise.
* @ligature_set_index: Index into the sets array for ligature component
* glyphs, or #HB_CODEPOINT_INVALID if not a ligature edge.
* @context_set_index: Index into the sets array for context requirement
* glyphs, or #HB_CODEPOINT_INVALID if none. Use hb_subset_depend_lookup_set()
* to retrieve the set.
* @flags: Edge flags (#hb_subset_depend_edge_flags_t).
*
* A single dependency edge returned by hb_subset_depend_lookup_glyph().
*
* Since: 14.3.0
*/
typedef struct {
hb_tag_t table_tag;
hb_codepoint_t dependent;
hb_tag_t layout_tag;
hb_codepoint_t ligature_set_index;
hb_codepoint_t context_set_index;
hb_subset_depend_edge_flags_t flags;
} hb_subset_depend_entry_t;
HB_EXTERN hb_subset_depend_t *
hb_subset_depend_from_face_or_fail (hb_face_t *face);
HB_EXTERN unsigned int
hb_subset_depend_lookup_glyph (hb_subset_depend_t *depend,
hb_codepoint_t gid,
unsigned int start_offset,
unsigned int *entry_count, /* IN/OUT */
hb_subset_depend_entry_t *entries /* OUT */);
HB_EXTERN hb_bool_t
hb_subset_depend_lookup_set (hb_subset_depend_t *depend,
hb_codepoint_t index,
hb_set_t *out /* OUT */);
HB_EXTERN void
hb_subset_depend_destroy (hb_subset_depend_t *depend);
#endif
HB_END_DECLS
#endif /* HB_SUBSET_DEPEND_H */