jcs.org
Serenity Operating System
1/*
2 * Copyright (c) 2022, Nico Weber <thakis@chromium.org>
3 *
4 * SPDX-License-Identifier: BSD-2-Clause
5 */
6
7#include <LibGfx/Font/OpenType/Cmap.h>
8#include <LibTest/TestCase.h>
9
10TEST_CASE(test_cmap_format_4)
11{
12 // clang-format off
13 // Big endian.
14 u8 cmap_table[] =
15 {
16 // https://docs.microsoft.com/en-us/typography/opentype/spec/cmap#cmap-header
17 0, 0, // uint16 version
18 0, 1, // uint16 numTables
19
20 // https://docs.microsoft.com/en-us/typography/opentype/spec/cmap#encoding-records-and-encodings
21 0, 0, // uint16 platformID, 0 means "Unicode"
22 0, 3, // uint16 encodingID, 3 means "BMP only" for platformID==0.
23 0, 0, 0, 12, // Offset32 to encoding subtable.
24
25 // https://docs.microsoft.com/en-us/typography/opentype/spec/cmap#format-4-segment-mapping-to-delta-values
26 0, 4, // uint16 format = 4
27 0, 42, // uint16 length in bytes
28 0, 0, // uint16 language, must be 0
29 0, 6, // segCount * 2
30 0, 4, // searchRange
31 0, 1, // entrySelector
32 0, 2, // rangeShift
33
34 // endCode array, last entry must be 0xffff.
35 0, 128,
36 1, 0,
37 0xff, 0xff,
38
39 0, 0, // uint16 reservedPad
40
41 // startCode array
42 0, 16,
43 1, 0,
44 0xff, 0xff,
45
46 // delta array
47 0, 0,
48 0, 10,
49 0, 0,
50
51 // glyphID array
52 0, 0,
53 0, 0,
54 0, 0,
55 };
56 // clang-format on
57 auto cmap = OpenType::Cmap::from_slice({ cmap_table, sizeof cmap_table }).value();
58 cmap.set_active_index(0);
59
60 // Format 4 can't handle code points > 0xffff.
61
62 // First range is 16..128.
63 EXPECT_EQ(cmap.glyph_id_for_code_point(15), 0u);
64 EXPECT_EQ(cmap.glyph_id_for_code_point(16), 16u);
65 EXPECT_EQ(cmap.glyph_id_for_code_point(128), 128u);
66 EXPECT_EQ(cmap.glyph_id_for_code_point(129), 0u);
67
68 // Second range is 256..256, with delta 10.
69 EXPECT_EQ(cmap.glyph_id_for_code_point(255), 0u);
70 EXPECT_EQ(cmap.glyph_id_for_code_point(256), 266u);
71 EXPECT_EQ(cmap.glyph_id_for_code_point(257), 0u);
72
73 // Third range is 0xffff..0xffff.
74 // From https://docs.microsoft.com/en-us/typography/opentype/spec/cmap#format-4-segment-mapping-to-delta-values:
75 // "the final start code and endCode values must be 0xFFFF. This segment need not contain any valid mappings.
76 // (It can just map the single character code 0xFFFF to missingGlyph). However, the segment must be present."
77 // FIXME: Make OpenType::Cmap::from_slice() reject inputs where this isn't true.
78 EXPECT_EQ(cmap.glyph_id_for_code_point(0xfeff), 0u);
79 EXPECT_EQ(cmap.glyph_id_for_code_point(0xffff), 0xffffu);
80 EXPECT_EQ(cmap.glyph_id_for_code_point(0x1'0000), 0u);
81}