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
39 namespace OT {
40
41
42 struct DeviceRecord
43 {
44 struct SubsetView
45 {
46 const DeviceRecord *source_device_record;
47 unsigned int sizeDeviceRecord;
48 hb_subset_plan_t *subset_plan;
49
50 void init (const DeviceRecord *source_device_record,
51 unsigned int sizeDeviceRecord,
52 hb_subset_plan_t *subset_plan)
53 {
54 this->source_device_record = source_device_record;
55 this->sizeDeviceRecord = sizeDeviceRecord;
56 this->subset_plan = subset_plan;
57 }
58
59 unsigned int len () const
60 { return this->subset_plan->glyphs.length; }
61
62 const HBUINT8* operator [] (unsigned int i) const
63 {
64 if (unlikely (i >= len ())) return nullptr;
65 hb_codepoint_t gid = this->subset_plan->glyphs [i];
66
67 if (gid >= sizeDeviceRecord - DeviceRecord::min_size)
68 return nullptr;
69 return &(this->source_device_record->widthsZ[gid]);
70 }
71 };
72
73 static unsigned int get_size (unsigned int count)
74 { return hb_ceil_to_4 (min_size + count * HBUINT8::static_size); }
75
76 bool serialize (hb_serialize_context_t *c, const SubsetView &subset_view)
77 {
78 TRACE_SERIALIZE (this);
79
80 unsigned int size = get_size (subset_view.len ());
81 if (unlikely (!c->allocate_size<DeviceRecord> (size)))
82 {
83 DEBUG_MSG(SUBSET, nullptr, "Couldn't allocate enough space for DeviceRecord: %d.",
84 size);
85 return_trace (false);
86 }
87
88 this->pixelSize.set (subset_view.source_device_record->pixelSize);
89 this->maxWidth.set (subset_view.source_device_record->maxWidth);
90
91 for (unsigned int i = 0; i < subset_view.len (); i++)
92 {
93 const HBUINT8 *width = subset_view[i];
94 if (!width)
95 {
96 DEBUG_MSG(SUBSET, nullptr, "HDMX width for new gid %d is missing.", i);
97 return_trace (false);
98 }
99 widthsZ[i].set (*width);
100 }
101
102 return_trace (true);
103 }
104
105 bool sanitize (hb_sanitize_context_t *c, unsigned int sizeDeviceRecord) const
106 {
107 TRACE_SANITIZE (this);
108 return_trace (likely (c->check_struct (this) &&
109 c->check_range (this, sizeDeviceRecord)));
110 }
111
112 HBUINT8 pixelSize; /* Pixel size for following widths (as ppem). */
113 HBUINT8 maxWidth; /* Maximum width. */
114 UnsizedArrayOf<HBUINT8> widthsZ; /* Array of widths (numGlyphs is from the 'maxp' table). */
115 public:
116 DEFINE_SIZE_ARRAY (2, widthsZ);
117 };
118
119
120 struct hdmx
121 {
122 static constexpr hb_tag_t tableTag = HB_OT_TAG_hdmx;
123
124 unsigned int get_size () const
125 { return min_size + numRecords * sizeDeviceRecord; }
126
127 const DeviceRecord& operator [] (unsigned int i) const
128 {
129 /* XXX Null(DeviceRecord) is NOT safe as it's num-glyphs lengthed.
130 * https://github.com/harfbuzz/harfbuzz/issues/1300 */
131 if (unlikely (i >= numRecords)) return Null (DeviceRecord);
132 return StructAtOffset<DeviceRecord> (&this->firstDeviceRecord, i * sizeDeviceRecord);
133 }
134
135 bool serialize (hb_serialize_context_t *c, const hdmx *source_hdmx, hb_subset_plan_t *plan)
136 {
137 TRACE_SERIALIZE (this);
138
139 if (unlikely (!c->extend_min ((*this)))) return_trace (false);
140
141 this->version.set (source_hdmx->version);
142 this->numRecords.set (source_hdmx->numRecords);
143 this->sizeDeviceRecord.set (DeviceRecord::get_size (plan->glyphs.length));
144
145 for (unsigned int i = 0; i < source_hdmx->numRecords; i++)
146 {
147 DeviceRecord::SubsetView subset_view;
148 subset_view.init (&(*source_hdmx)[i], source_hdmx->sizeDeviceRecord, plan);
149
150 if (!c->start_embed<DeviceRecord> ()->serialize (c, subset_view))
151 return_trace (false);
152 }
153
154 return_trace (true);
155 }
156
157 static size_t get_subsetted_size (const hdmx *source_hdmx, hb_subset_plan_t *plan)
158 {
159 return min_size + source_hdmx->numRecords * DeviceRecord::get_size (plan->glyphs.length);
160 }
161
162 bool subset (hb_subset_plan_t *plan) const
163 {
164 size_t dest_size = get_subsetted_size (this, plan);
165 hdmx *dest = (hdmx *) malloc (dest_size);
166 if (unlikely (!dest))
167 {
168 DEBUG_MSG(SUBSET, nullptr, "Unable to alloc %lu for hdmx subset output.", (unsigned long) dest_size);
169 return false;
170 }
171
172 hb_serialize_context_t c (dest, dest_size);
173 hdmx *hdmx_prime = c.start_serialize<hdmx> ();
174 if (!hdmx_prime || !hdmx_prime->serialize (&c, this, plan))
175 {
176 free (dest);
177 DEBUG_MSG(SUBSET, nullptr, "Failed to serialize write new hdmx.");
178 return false;
179 }
180 c.end_serialize ();
181
182 hb_blob_t *hdmx_prime_blob = hb_blob_create ((const char *) dest,
183 dest_size,
184 HB_MEMORY_MODE_READONLY,
185 dest,
186 free);
187 bool result = plan->add_table (HB_OT_TAG_hdmx, hdmx_prime_blob);
188 hb_blob_destroy (hdmx_prime_blob);
189
190 return result;
191 }
192
193 bool sanitize (hb_sanitize_context_t *c) const
194 {
195 TRACE_SANITIZE (this);
196 return_trace (c->check_struct (this) &&
197 !hb_unsigned_mul_overflows (numRecords, sizeDeviceRecord) &&
198 sizeDeviceRecord >= DeviceRecord::min_size &&
199 c->check_range (this, get_size ()));
200 }
201
202 protected:
203 HBUINT16 version; /* Table version number (0) */
204 HBUINT16 numRecords; /* Number of device records. */
205 HBUINT32 sizeDeviceRecord; /* Size of a device record, 32-bit aligned. */
206 DeviceRecord firstDeviceRecord; /* Array of device records. */
207 public:
208 DEFINE_SIZE_MIN (8);
209 };
210
211 } /* namespace OT */
212
213
214 #endif /* HB_OT_HDMX_TABLE_HH */