1/*
2 * Copyright © 2018 Ebrahim Byagowi
3 *
4 * This is part of HarfBuzz, a text shaping library.
5 *
6 * Permission is hereby granted, without written agreement and without
7 * license or royalty fees, to use, copy, modify, and distribute this
8 * software and its documentation for any purpose, provided that the
9 * above copyright notice and the following two paragraphs appear in
10 * all copies of this software.
11 *
12 * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
13 * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
14 * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
15 * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
16 * DAMAGE.
17 *
18 * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
19 * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
20 * FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
21 * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
22 * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
23 */
24
25#ifndef HB_AAT_LAYOUT_FEAT_TABLE_HH
26#define HB_AAT_LAYOUT_FEAT_TABLE_HH
27
28#include "hb-aat-layout-common.hh"
29
30/*
31 * feat -- Feature Name
32 * https://developer.apple.com/fonts/TrueType-Reference-Manual/RM06/Chap6feat.html
33 */
34#define HB_AAT_TAG_feat HB_TAG('f','e','a','t')
35
36
37namespace AAT {
38
39
40struct SettingName
41{
42 friend struct FeatureName;
43
44 int cmp (hb_aat_layout_feature_selector_t key) const
45 { return (int) key - (int) setting; }
46
47 hb_aat_layout_feature_selector_t get_selector () const
48 { return (hb_aat_layout_feature_selector_t) (unsigned) setting; }
49
50 hb_aat_layout_feature_selector_info_t get_info (hb_aat_layout_feature_selector_t default_selector) const
51 {
52 return {
53 nameIndex,
54 (hb_aat_layout_feature_selector_t) (unsigned int) setting,
55 default_selector == HB_AAT_LAYOUT_FEATURE_SELECTOR_INVALID
56 ? (hb_aat_layout_feature_selector_t) (setting + 1)
57 : default_selector,
58 0
59 };
60 }
61
62 bool sanitize (hb_sanitize_context_t *c) const
63 {
64 TRACE_SANITIZE (this);
65 return_trace (c->check_struct (this));
66 }
67
68 protected:
69 HBUINT16 setting; /* The setting. */
70 NameID nameIndex; /* The name table index for the setting's name. */
71 public:
72 DEFINE_SIZE_STATIC (4);
73};
74DECLARE_NULL_NAMESPACE_BYTES (AAT, SettingName);
75
76struct feat;
77
78struct FeatureName
79{
80 int cmp (hb_aat_layout_feature_type_t key) const
81 { return (int) key - (int) feature; }
82
83 enum {
84 Exclusive = 0x8000, /* If set, the feature settings are mutually exclusive. */
85 NotDefault = 0x4000, /* If clear, then the setting with an index of 0 in
86 * the setting name array for this feature should
87 * be taken as the default for the feature
88 * (if one is required). If set, then bits 0-15 of this
89 * featureFlags field contain the index of the setting
90 * which is to be taken as the default. */
91 IndexMask = 0x00FF /* If bits 30 and 31 are set, then these sixteen bits
92 * indicate the index of the setting in the setting name
93 * array for this feature which should be taken
94 * as the default. */
95 };
96
97 unsigned int get_selector_infos (unsigned int start_offset,
98 unsigned int *selectors_count, /* IN/OUT. May be NULL. */
99 hb_aat_layout_feature_selector_info_t *selectors, /* OUT. May be NULL. */
100 unsigned int *pdefault_index, /* OUT. May be NULL. */
101 const void *base) const
102 {
103 hb_array_t< const SettingName> settings_table = (base+settingTableZ).as_array (nSettings);
104
105 static_assert (Index::NOT_FOUND_INDEX == HB_AAT_LAYOUT_NO_SELECTOR_INDEX, "");
106
107 hb_aat_layout_feature_selector_t default_selector = HB_AAT_LAYOUT_FEATURE_SELECTOR_INVALID;
108 unsigned int default_index = Index::NOT_FOUND_INDEX;
109 if (featureFlags & Exclusive)
110 {
111 default_index = (featureFlags & NotDefault) ? featureFlags & IndexMask : 0;
112 default_selector = settings_table[default_index].get_selector ();
113 }
114 if (pdefault_index)
115 *pdefault_index = default_index;
116
117 if (selectors_count)
118 {
119 + settings_table.sub_array (start_offset, selectors_count)
120 | hb_map ([=] (const SettingName& setting) { return setting.get_info (default_selector); })
121 | hb_sink (hb_array (selectors, *selectors_count))
122 ;
123 }
124 return settings_table.length;
125 }
126
127 hb_aat_layout_feature_type_t get_feature_type () const
128 { return (hb_aat_layout_feature_type_t) (unsigned int) feature; }
129
130 hb_ot_name_id_t get_feature_name_id () const { return nameIndex; }
131
132 bool is_exclusive () const { return featureFlags & Exclusive; }
133
134 /* A FeatureName with no settings is meaningless */
135 bool has_data () const { return nSettings; }
136
137 bool sanitize (hb_sanitize_context_t *c, const void *base) const
138 {
139 TRACE_SANITIZE (this);
140 return_trace (likely (c->check_struct (this) &&
141 (base+settingTableZ).sanitize (c, nSettings)));
142 }
143
144 protected:
145 HBUINT16 feature; /* Feature type. */
146 HBUINT16 nSettings; /* The number of records in the setting name array. */
147 NNOffset32To<UnsizedArrayOf<SettingName>>
148 settingTableZ; /* Offset in bytes from the beginning of this table to
149 * this feature's setting name array. The actual type of
150 * record this offset refers to will depend on the
151 * exclusivity value, as described below. */
152 HBUINT16 featureFlags; /* Single-bit flags associated with the feature type. */
153 HBINT16 nameIndex; /* The name table index for the feature's name.
154 * This index has values greater than 255 and
155 * less than 32768. */
156 public:
157 DEFINE_SIZE_STATIC (12);
158};
159
160struct feat
161{
162 static constexpr hb_tag_t tableTag = HB_AAT_TAG_feat;
163
164 bool has_data () const { return version.to_int (); }
165
166 unsigned int get_feature_types (unsigned int start_offset,
167 unsigned int *count,
168 hb_aat_layout_feature_type_t *features) const
169 {
170 if (count)
171 {
172 + namesZ.as_array (featureNameCount).sub_array (start_offset, count)
173 | hb_map (&FeatureName::get_feature_type)
174 | hb_sink (hb_array (features, *count))
175 ;
176 }
177 return featureNameCount;
178 }
179
180 bool exposes_feature (hb_aat_layout_feature_type_t feature_type) const
181 { return get_feature (feature_type).has_data (); }
182
183 const FeatureName& get_feature (hb_aat_layout_feature_type_t feature_type) const
184 { return namesZ.bsearch (featureNameCount, feature_type); }
185
186 hb_ot_name_id_t get_feature_name_id (hb_aat_layout_feature_type_t feature) const
187 { return get_feature (feature).get_feature_name_id (); }
188
189 unsigned int get_selector_infos (hb_aat_layout_feature_type_t feature_type,
190 unsigned int start_offset,
191 unsigned int *selectors_count, /* IN/OUT. May be NULL. */
192 hb_aat_layout_feature_selector_info_t *selectors, /* OUT. May be NULL. */
193 unsigned int *default_index /* OUT. May be NULL. */) const
194 {
195 return get_feature (feature_type).get_selector_infos (start_offset, selectors_count, selectors,
196 default_index, this);
197 }
198
199 bool sanitize (hb_sanitize_context_t *c) const
200 {
201 TRACE_SANITIZE (this);
202 return_trace (likely (c->check_struct (this) &&
203 version.major == 1 &&
204 namesZ.sanitize (c, featureNameCount, this)));
205 }
206
207 protected:
208 FixedVersion<>version; /* Version number of the feature name table
209 * (0x00010000 for the current version). */
210 HBUINT16 featureNameCount;
211 /* The number of entries in the feature name array. */
212 HBUINT16 reserved1; /* Reserved (set to zero). */
213 HBUINT32 reserved2; /* Reserved (set to zero). */
214 SortedUnsizedArrayOf<FeatureName>
215 namesZ; /* The feature name array. */
216 public:
217 DEFINE_SIZE_ARRAY (12, namesZ);
218};
219
220} /* namespace AAT */
221
222#endif /* HB_AAT_LAYOUT_FEAT_TABLE_HH */
223