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
37 namespace AAT {
38
39
40 struct 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 void get_info (hb_aat_layout_feature_selector_info_t *s,
51 hb_aat_layout_feature_selector_t default_selector) const
52 {
53 s->name_id = nameIndex;
54
55 s->enable = (hb_aat_layout_feature_selector_t) (unsigned int) setting;
56 s->disable = default_selector == HB_AAT_LAYOUT_FEATURE_SELECTOR_INVALID ?
57 (hb_aat_layout_feature_selector_t) (s->enable + 1) :
58 default_selector;
59
60 s->reserved = 0;
61 }
62
63 bool sanitize (hb_sanitize_context_t *c) const
64 {
65 TRACE_SANITIZE (this);
66 return_trace (likely (c->check_struct (this)));
67 }
68
69 protected:
70 HBUINT16 setting; /* The setting. */
71 NameID nameIndex; /* The name table index for the setting's name. */
72 public:
73 DEFINE_SIZE_STATIC (4);
74 };
75 DECLARE_NULL_NAMESPACE_BYTES (AAT, SettingName);
76
77 struct feat;
78
79 struct FeatureName
80 {
81 int cmp (hb_aat_layout_feature_type_t key) const
82 { return (int) key - (int) feature; }
83
84 enum {
85 Exclusive = 0x8000, /* If set, the feature settings are mutually exclusive. */
86 NotDefault = 0x4000, /* If clear, then the setting with an index of 0 in
87 * the setting name array for this feature should
88 * be taken as the default for the feature
89 * (if one is required). If set, then bits 0-15 of this
90 * featureFlags field contain the index of the setting
91 * which is to be taken as the default. */
92 IndexMask = 0x00FF /* If bits 30 and 31 are set, then these sixteen bits
93 * indicate the index of the setting in the setting name
94 * array for this feature which should be taken
95 * as the default. */
96 };
97
98 unsigned int get_selector_infos (unsigned int start_offset,
99 unsigned int *selectors_count, /* IN/OUT. May be NULL. */
100 hb_aat_layout_feature_selector_info_t *selectors, /* OUT. May be NULL. */
101 unsigned int *pdefault_index, /* OUT. May be NULL. */
102 const void *base) const
103 {
104 hb_array_t< const SettingName> settings_table = (base+settingTableZ).as_array (nSettings);
105
106 static_assert (Index::NOT_FOUND_INDEX == HB_AAT_LAYOUT_NO_SELECTOR_INDEX, "");
107
108 hb_aat_layout_feature_selector_t default_selector = HB_AAT_LAYOUT_FEATURE_SELECTOR_INVALID;
109 unsigned int default_index = Index::NOT_FOUND_INDEX;
110 if (featureFlags & Exclusive)
111 {
112 default_index = (featureFlags & NotDefault) ? featureFlags & IndexMask : 0;
113 default_selector = settings_table[default_index].get_selector ();
114 }
115 if (pdefault_index)
116 *pdefault_index = default_index;
117
118 if (selectors_count)
119 {
120 hb_array_t<const SettingName> arr = settings_table.sub_array (start_offset, selectors_count);
121 for (unsigned int i = 0; i < arr.length; i++)
122 settings_table[start_offset + i].get_info (&selectors[i], default_selector);
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 sanitize (hb_sanitize_context_t *c, const void *base) const
133 {
134 TRACE_SANITIZE (this);
135 return_trace (likely (c->check_struct (this) &&
136 (base+settingTableZ).sanitize (c, nSettings)));
137 }
138
139 protected:
140 HBUINT16 feature; /* Feature type. */
141 HBUINT16 nSettings; /* The number of records in the setting name array. */
142 LOffsetTo<UnsizedArrayOf<SettingName>, false>
143 settingTableZ; /* Offset in bytes from the beginning of this table to
144 * this feature's setting name array. The actual type of
145 * record this offset refers to will depend on the
146 * exclusivity value, as described below. */
147 HBUINT16 featureFlags; /* Single-bit flags associated with the feature type. */
148 HBINT16 nameIndex; /* The name table index for the feature's name.
149 * This index has values greater than 255 and
150 * less than 32768. */
151 public:
152 DEFINE_SIZE_STATIC (12);
153 };
154
155 struct feat
156 {
157 static constexpr hb_tag_t tableTag = HB_AAT_TAG_feat;
158
159 bool has_data () const { return version.to_int (); }
160
161 unsigned int get_feature_types (unsigned int start_offset,
162 unsigned int *count,
163 hb_aat_layout_feature_type_t *features) const
164 {
165 unsigned int feature_count = featureNameCount;
166 if (count && *count)
167 {
168 unsigned int len = MIN (feature_count - start_offset, *count);
169 for (unsigned int i = 0; i < len; i++)
170 features[i] = namesZ[i + start_offset].get_feature_type ();
171 *count = len;
172 }
173 return featureNameCount;
174 }
175
176 const FeatureName& get_feature (hb_aat_layout_feature_type_t feature_type) const
177 {
178 return namesZ.bsearch (featureNameCount, feature_type);
179 }
180
181 hb_ot_name_id_t get_feature_name_id (hb_aat_layout_feature_type_t feature) const
182 { return get_feature (feature).get_feature_name_id (); }
183
184 unsigned int get_selector_infos (hb_aat_layout_feature_type_t feature_type,
185 unsigned int start_offset,
186 unsigned int *selectors_count, /* IN/OUT. May be NULL. */
187 hb_aat_layout_feature_selector_info_t *selectors, /* OUT. May be NULL. */
188 unsigned int *default_index /* OUT. May be NULL. */) const
189 {
190 return get_feature (feature_type).get_selector_infos (start_offset, selectors_count, selectors,
191 default_index, this);
192 }
193
194 bool sanitize (hb_sanitize_context_t *c) const
195 {
196 TRACE_SANITIZE (this);
197 return_trace (likely (c->check_struct (this) &&
198 version.major == 1 &&
199 namesZ.sanitize (c, featureNameCount, this)));
200 }
201
202 protected:
203 FixedVersion<>version; /* Version number of the feature name table
204 * (0x00010000 for the current version). */
205 HBUINT16 featureNameCount;
206 /* The number of entries in the feature name array. */
207 HBUINT16 reserved1; /* Reserved (set to zero). */
208 HBUINT32 reserved2; /* Reserved (set to zero). */
209 SortedUnsizedArrayOf<FeatureName>
210 namesZ; /* The feature name array. */
211 public:
212 DEFINE_SIZE_STATIC (24);
213 };
214
215 } /* namespace AAT */
216
217 #endif /* HB_AAT_LAYOUT_FEAT_TABLE_HH */