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 { get_sizeOT::DeviceRecord44 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))> serializeOT::DeviceRecord49 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 sanitizeOT::DeviceRecord68 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 83 struct hdmx 84 { 85 static constexpr hb_tag_t tableTag = HB_OT_TAG_hdmx; 86 get_sizeOT::hdmx87 unsigned int get_size () const 88 { return min_size + numRecords * sizeDeviceRecord; } 89 operator []OT::hdmx90 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))> serializeOT::hdmx100 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 subsetOT::hdmx117 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 get_num_glyphsOT::hdmx149 unsigned get_num_glyphs () const 150 { 151 return sizeDeviceRecord - DeviceRecord::min_size; 152 } 153 sanitizeOT::hdmx154 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