com.itextpdf.io.font.woff2.Woff2Common Maven / Gradle / Ivy
// Copyright 2014 Google Inc. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
// This is part of java port of project hosted at https://github.com/google/woff2
package com.itextpdf.io.font.woff2;
import static com.itextpdf.io.font.woff2.JavaUnsignedUtil.asU8;
import static com.itextpdf.io.font.woff2.JavaUnsignedUtil.compareAsUnsigned;
// Common definition for WOFF2 encoding/decoding
// Helpers common across multiple parts of woff2
class Woff2Common {
public static final int kWoff2Signature = 0x774f4632; // "wOF2"
// Leave the first byte open to store flag_byte
public static final int kWoff2FlagsTransform = 1 << 8;
// TrueType Collection ID string: 'ttcf'
public static final int kTtcFontFlavor = 0x74746366;
public static final int kSfntHeaderSize = 12;
public static final int kSfntEntrySize = 16;
public static class Point {
public int x;
public int y;
public boolean on_curve;
public Point(int x, int y, boolean on_curve) {
this.x = x;
this.y = y;
this.on_curve = on_curve;
}
}
public static class Table implements Comparable {
public int tag;
public int flags;
public int src_offset;
public int src_length;
public int transform_length;
public int dst_offset;
public int dst_length;
@Override
public int compareTo(Table o) {
return compareAsUnsigned(tag, o.tag);
}
}
// Size of the collection header. 0 if version indicates this isn't a
// collection. Ref http://www.microsoft.com/typography/otspec/otff.htm,
// True Type Collections
public static int collectionHeaderSize(int header_version, int num_fonts) {
int size = 0;
if (header_version == 0x00020000) {
size += 12; // ulDsig{Tag,Length,Offset}
}
if (header_version == 0x00010000 || header_version == 0x00020000) {
size += 12 // TTCTag, Version, numFonts
+ 4 * num_fonts; // OffsetTable[numFonts]
}
return size;
}
// Compute checksum over size bytes of buf
public static int computeULongSum(byte[] buf, int offset, int size) {
int checksum = 0;
int aligned_size = (size & ~3);
for (int i = 0; i < aligned_size; i += 4) {
checksum += (asU8(buf[offset + i]) << 24) | (asU8(buf[offset + i + 1]) << 16) |
(asU8(buf[offset + i + 2]) << 8) | asU8(buf[offset + i + 3]);
}
// treat size not aligned on 4 as if it were padded to 4 with 0's
if (size != aligned_size) {
int v = 0;
for (int i = aligned_size; i < size; ++i) {
v |= asU8(buf[offset + i]) << (24 - 8 * (i & 3));
}
checksum += v;
}
return checksum;
}
}
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