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LibGfx: Use OpenType offset table structs when reading WOFF2 font data

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This commit is contained in:
Sam Atkins 2023-10-21 12:53:15 +01:00 • committed by Andreas Kling
parent b73b434f80
commit 8e96902c75
1 changed files with 30 additions and 25 deletions
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55
Userland/Libraries/LibGfx/Font/WOFF2/Font.cpp
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@ -917,15 +917,15 @@ ErrorOr<NonnullRefPtr<Font>> Font::try_load_from_externally_owned_memory(Seekabl
// We use it as an initial size of the font buffer and extend it as necessary.
auto font_buffer = TRY(ByteBuffer::create_zeroed(header.total_sfnt_size));
// ISO-IEC 14496-22:2019 4.5.1 Offset table
constexpr size_t OFFSET_TABLE_SIZE_IN_BYTES = 12;
TRY(font_buffer.try_ensure_capacity(OFFSET_TABLE_SIZE_IN_BYTES));
u16 search_range = pow_2_less_than_or_equal(header.num_tables);
be_u32(font_buffer.data() + 0, header.flavor);
be_u16(font_buffer.data() + 4, header.num_tables);
be_u16(font_buffer.data() + 6, search_range * 16);
be_u16(font_buffer.data() + 8, log2(search_range));
be_u16(font_buffer.data() + 10, header.num_tables * 16 - search_range * 16);
OpenType::TableDirectory table_directory {
.sfnt_version = header.flavor,
.num_tables = header.num_tables,
.search_range = search_range * 16,
.entry_selector = log2(search_range),
.range_shift = header.num_tables * 16 - search_range * 16,
};
font_buffer.overwrite(0, &table_directory, sizeof(table_directory));
Vector<TableDirectoryEntry> table_entries;
TRY(table_entries.try_ensure_capacity(header.num_tables));
@ -1042,12 +1042,13 @@ ErrorOr<NonnullRefPtr<Font>> Font::try_load_from_externally_owned_memory(Seekabl
if (font_buffer.size() < (font_buffer_offset + glyf_and_loca_buffer->glyf_table.size()))
TRY(font_buffer.try_resize(font_buffer_offset + glyf_and_loca_buffer->glyf_table.size()));
// ISO-IEC 14496-22:2019 4.5.2 Table directory
be_u32(font_buffer.data() + table_directory_offset, GLYF_TAG);
// FIXME: WOFF2 does not give us the original checksum.
be_u32(font_buffer.data() + table_directory_offset + 4, 0);
be_u32(font_buffer.data() + table_directory_offset + 8, font_buffer_offset);
be_u32(font_buffer.data() + table_directory_offset + 12, glyf_and_loca_buffer->glyf_table.size());
OpenType::TableRecord table_record {
.table_tag = GLYF_TAG,
.checksum = 0, // FIXME: WOFF2 does not give us the original checksum.
.offset = font_buffer_offset,
.length = glyf_and_loca_buffer->glyf_table.size(),
};
font_buffer.overwrite(table_directory_offset, &table_record, sizeof(table_record));
font_buffer.overwrite(font_buffer_offset, glyf_and_loca_buffer->glyf_table.data(), glyf_and_loca_buffer->glyf_table.size());
font_buffer_offset += glyf_and_loca_buffer->glyf_table.size();
@ -1057,11 +1058,14 @@ ErrorOr<NonnullRefPtr<Font>> Font::try_load_from_externally_owned_memory(Seekabl
if (font_buffer.size() < (font_buffer_offset + glyf_and_loca_buffer->loca_table.size()))
TRY(font_buffer.try_resize(font_buffer_offset + glyf_and_loca_buffer->loca_table.size()));
constexpr u32 LOCA_TAG = 0x6C6F6361;
be_u32(font_buffer.data() + table_directory_offset, LOCA_TAG);
// FIXME: WOFF2 does not give us the original checksum.
be_u32(font_buffer.data() + table_directory_offset + 4, 0);
be_u32(font_buffer.data() + table_directory_offset + 8, font_buffer_offset);
be_u32(font_buffer.data() + table_directory_offset + 12, glyf_and_loca_buffer->loca_table.size());
OpenType::TableRecord table_record {
.table_tag = LOCA_TAG,
.checksum = 0, // FIXME: WOFF2 does not give us the original checksum.
.offset = font_buffer_offset,
.length = glyf_and_loca_buffer->loca_table.size(),
};
font_buffer.overwrite(table_directory_offset, &table_record, sizeof(table_record));
font_buffer.overwrite(font_buffer_offset, glyf_and_loca_buffer->loca_table.data(), glyf_and_loca_buffer->loca_table.size());
font_buffer_offset += glyf_and_loca_buffer->loca_table.size();
@ -1071,12 +1075,13 @@ ErrorOr<NonnullRefPtr<Font>> Font::try_load_from_externally_owned_memory(Seekabl
return Error::from_string_literal("Unknown transformation");
}
} else {
// ISO-IEC 14496-22:2019 4.5.2 Table directory
be_u32(font_buffer.data() + table_directory_offset, table_entry.tag_to_u32());
// FIXME: WOFF2 does not give us the original checksum.
be_u32(font_buffer.data() + table_directory_offset + 4, 0);
be_u32(font_buffer.data() + table_directory_offset + 8, font_buffer_offset);
be_u32(font_buffer.data() + table_directory_offset + 12, length_to_read);
OpenType::TableRecord table_record {
.table_tag = table_entry.tag_to_u32(),
.checksum = 0, // FIXME: WOFF2 does not give us the original checksum.
.offset = font_buffer_offset,
.length = length_to_read,
};
font_buffer.overwrite(table_directory_offset, &table_record, sizeof(table_record));
if (font_buffer.size() < (font_buffer_offset + length_to_read))
TRY(font_buffer.try_resize(font_buffer_offset + length_to_read));