1 // Copyright (c) 2009 The Chromium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4
5 #include "hdmx.h"
6 #include "head.h"
7 #include "maxp.h"
8
9 // hdmx - Horizontal Device Metrics
10 // http://www.microsoft.com/opentype/otspec/hdmx.htm
11
12 #define DROP_THIS_TABLE \
13 do { delete file->hdmx; file->hdmx = 0; } while (0)
14
15 namespace ots {
16
ots_hdmx_parse(OpenTypeFile * file,const uint8_t * data,size_t length)17 bool ots_hdmx_parse(OpenTypeFile *file, const uint8_t *data, size_t length) {
18 Buffer table(data, length);
19 file->hdmx = new OpenTypeHDMX;
20 OpenTypeHDMX * const hdmx = file->hdmx;
21
22 if (!file->head || !file->maxp) {
23 return OTS_FAILURE();
24 }
25
26 if ((file->head->flags & 0x14) == 0) {
27 // http://www.microsoft.com/typography/otspec/recom.htm
28 OTS_WARNING("the table should not be present when bit 2 and 4 of the "
29 "head->flags are not set");
30 DROP_THIS_TABLE;
31 return true;
32 }
33
34 int16_t num_recs;
35 if (!table.ReadU16(&hdmx->version) ||
36 !table.ReadS16(&num_recs) ||
37 !table.ReadS32(&hdmx->size_device_record)) {
38 return OTS_FAILURE();
39 }
40 if (hdmx->version != 0) {
41 OTS_WARNING("bad version: %u", hdmx->version);
42 DROP_THIS_TABLE;
43 return true;
44 }
45 if (num_recs <= 0) {
46 OTS_WARNING("bad num_recs: %d", num_recs);
47 DROP_THIS_TABLE;
48 return true;
49 }
50 const int32_t actual_size_device_record = file->maxp->num_glyphs + 2;
51 if (hdmx->size_device_record < actual_size_device_record) {
52 OTS_WARNING("bad hdmx->size_device_record: %d", hdmx->size_device_record);
53 DROP_THIS_TABLE;
54 return true;
55 }
56
57 hdmx->pad_len = hdmx->size_device_record - actual_size_device_record;
58 if (hdmx->pad_len > 3) {
59 return OTS_FAILURE();
60 }
61
62 uint8_t last_pixel_size = 0;
63 hdmx->records.reserve(num_recs);
64 for (int i = 0; i < num_recs; ++i) {
65 OpenTypeHDMXDeviceRecord rec;
66
67 if (!table.ReadU8(&rec.pixel_size) ||
68 !table.ReadU8(&rec.max_width)) {
69 return OTS_FAILURE();
70 }
71 if ((i != 0) &&
72 (rec.pixel_size <= last_pixel_size)) {
73 OTS_WARNING("records are not sorted");
74 DROP_THIS_TABLE;
75 return true;
76 }
77 last_pixel_size = rec.pixel_size;
78
79 rec.widths.reserve(file->maxp->num_glyphs);
80 for (unsigned j = 0; j < file->maxp->num_glyphs; ++j) {
81 uint8_t width;
82 if (!table.ReadU8(&width)) {
83 return OTS_FAILURE();
84 }
85 rec.widths.push_back(width);
86 }
87
88 if ((hdmx->pad_len > 0) &&
89 !table.Skip(hdmx->pad_len)) {
90 return OTS_FAILURE();
91 }
92
93 hdmx->records.push_back(rec);
94 }
95
96 return true;
97 }
98
ots_hdmx_should_serialise(OpenTypeFile * file)99 bool ots_hdmx_should_serialise(OpenTypeFile *file) {
100 if (!file->hdmx) return false;
101 if (!file->glyf) return false; // this table is not for CFF fonts.
102 return true;
103 }
104
ots_hdmx_serialise(OTSStream * out,OpenTypeFile * file)105 bool ots_hdmx_serialise(OTSStream *out, OpenTypeFile *file) {
106 OpenTypeHDMX * const hdmx = file->hdmx;
107
108 if (!out->WriteU16(hdmx->version) ||
109 !out->WriteS16(hdmx->records.size()) ||
110 !out->WriteS32(hdmx->size_device_record)) {
111 return OTS_FAILURE();
112 }
113
114 for (unsigned i = 0; i < hdmx->records.size(); ++i) {
115 const OpenTypeHDMXDeviceRecord& rec = hdmx->records[i];
116 if (!out->Write(&rec.pixel_size, 1) ||
117 !out->Write(&rec.max_width, 1) ||
118 !out->Write(&rec.widths[0], rec.widths.size())) {
119 return OTS_FAILURE();
120 }
121 if ((hdmx->pad_len > 0) &&
122 !out->Write((const uint8_t *)"\x00\x00\x00", hdmx->pad_len)) {
123 return OTS_FAILURE();
124 }
125 }
126
127 return true;
128 }
129
ots_hdmx_free(OpenTypeFile * file)130 void ots_hdmx_free(OpenTypeFile *file) {
131 delete file->hdmx;
132 }
133
134 } // namespace ots
135