1/*
2 * Copyright © 2018 Google, Inc.
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 * Google Author(s): Garret Rieger
25 */
26
27#ifndef HB_OT_HDMX_TABLE_HH
28#define HB_OT_HDMX_TABLE_HH
29
30#include "hb-open-type.hh"
31
32/*
33 * hdmx -- Horizontal Device Metrics
34 * https://docs.microsoft.com/en-us/typography/opentype/spec/hdmx
35 */
36#define HB_OT_TAG_hdmx HB_TAG('h','d','m','x')
37
38
39namespace OT {
40
41
42struct DeviceRecord
43{
44 static unsigned int get_size (unsigned count)
45 { return hb_ceil_to_4 (min_size + count * HBUINT8::static_size); }
46
47 template<typename Iterator,
48 hb_requires (hb_is_iterator (Iterator))>
49 bool serialize (hb_serialize_context_t *c, unsigned pixelSize, Iterator it)
50 {
51 TRACE_SERIALIZE (this);
52
53 unsigned length = it.len ();
54
55 if (unlikely (!c->extend (*this, length))) return_trace (false);
56
57 this->pixelSize = pixelSize;
58 this->maxWidth =
59 + it
60 | hb_reduce (hb_max, 0u);
61
62 + it
63 | hb_sink (widthsZ.as_array (length));
64
65 return_trace (true);
66 }
67
68 bool sanitize (hb_sanitize_context_t *c, unsigned sizeDeviceRecord) const
69 {
70 TRACE_SANITIZE (this);
71 return_trace (likely (c->check_struct (this) &&
72 c->check_range (this, sizeDeviceRecord)));
73 }
74
75 HBUINT8 pixelSize; /* Pixel size for following widths (as ppem). */
76 HBUINT8 maxWidth; /* Maximum width. */
77 UnsizedArrayOf<HBUINT8> widthsZ; /* Array of widths (numGlyphs is from the 'maxp' table). */
78 public:
79 DEFINE_SIZE_ARRAY (2, widthsZ);
80};
81
82
83struct hdmx
84{
85 static constexpr hb_tag_t tableTag = HB_OT_TAG_hdmx;
86
87 unsigned int get_size () const
88 { return min_size + numRecords * sizeDeviceRecord; }
89
90 const DeviceRecord& operator [] (unsigned int i) const
91 {
92 /* XXX Null(DeviceRecord) is NOT safe as it's num-glyphs lengthed.
93 * https://github.com/harfbuzz/harfbuzz/issues/1300 */
94 if (unlikely (i >= numRecords)) return Null (DeviceRecord);
95 return StructAtOffset<DeviceRecord> (&this->firstDeviceRecord, i * sizeDeviceRecord);
96 }
97
98 template<typename Iterator,
99 hb_requires (hb_is_iterator (Iterator))>
100 bool serialize (hb_serialize_context_t *c, unsigned version, Iterator it)
101 {
102 TRACE_SERIALIZE (this);
103
104 if (unlikely (!c->extend_min ((*this)))) return_trace (false);
105
106 this->version = version;
107 this->numRecords = it.len ();
108 this->sizeDeviceRecord = DeviceRecord::get_size (it ? (*it).second.len () : 0);
109
110 for (const hb_item_type<Iterator>& _ : +it)
111 c->start_embed<DeviceRecord> ()->serialize (c, _.first, _.second);
112
113 return_trace (c->successful);
114 }
115
116
117 bool subset (hb_subset_context_t *c) const
118 {
119 TRACE_SUBSET (this);
120
121 hdmx *hdmx_prime = c->serializer->start_embed <hdmx> ();
122 if (unlikely (!hdmx_prime)) return_trace (false);
123
124 auto it =
125 + hb_range ((unsigned) numRecords)
126 | hb_map ([c, this] (unsigned _)
127 {
128 const DeviceRecord *device_record =
129 &StructAtOffset<DeviceRecord> (&firstDeviceRecord,
130 _ * sizeDeviceRecord);
131 auto row =
132 + hb_range (c->plan->num_output_glyphs ())
133 | hb_map (c->plan->reverse_glyph_map)
134 | hb_map ([this, c, device_record] (hb_codepoint_t _)
135 {
136 if (c->plan->is_empty_glyph (_))
137 return Null (HBUINT8);
138 return device_record->widthsZ.as_array (get_num_glyphs ()) [_];
139 })
140 ;
141 return hb_pair ((unsigned) device_record->pixelSize, +row);
142 })
143 ;
144
145 hdmx_prime->serialize (c->serializer, version, it);
146 return_trace (true);
147 }
148
149 unsigned get_num_glyphs () const
150 {
151 return sizeDeviceRecord - DeviceRecord::min_size;
152 }
153
154 bool sanitize (hb_sanitize_context_t *c) const
155 {
156 TRACE_SANITIZE (this);
157 return_trace (c->check_struct (this) &&
158 !hb_unsigned_mul_overflows (numRecords, sizeDeviceRecord) &&
159 sizeDeviceRecord >= DeviceRecord::min_size &&
160 c->check_range (this, get_size ()));
161 }
162
163 protected:
164 HBUINT16 version; /* Table version number (0) */
165 HBUINT16 numRecords; /* Number of device records. */
166 HBUINT32 sizeDeviceRecord;
167 /* Size of a device record, 32-bit aligned. */
168 DeviceRecord firstDeviceRecord;
169 /* Array of device records. */
170 public:
171 DEFINE_SIZE_MIN (8);
172};
173
174} /* namespace OT */
175
176
177#endif /* HB_OT_HDMX_TABLE_HH */
178