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47 lines
1.4 KiB
47 lines
1.4 KiB
2 years ago
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// Copyright 2013 Google Inc. All Rights Reserved.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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//
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// Helpers common across multiple parts of woff2
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#include <algorithm>
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#include "./woff2_common.h"
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namespace woff2 {
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uint32_t ComputeULongSum(const uint8_t* buf, size_t size) {
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uint32_t checksum = 0;
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for (size_t i = 0; i < size; i += 4) {
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// We assume the addition is mod 2^32, which is valid because unsigned
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checksum += (buf[i] << 24) | (buf[i + 1] << 16) |
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(buf[i + 2] << 8) | buf[i + 3];
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}
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return checksum;
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}
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size_t CollectionHeaderSize(uint32_t header_version, uint32_t num_fonts) {
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size_t size = 0;
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if (header_version == 0x00020000) {
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size += 12; // ulDsig{Tag,Length,Offset}
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}
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if (header_version == 0x00010000 || header_version == 0x00020000) {
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size += 12 // TTCTag, Version, numFonts
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+ 4 * num_fonts; // OffsetTable[numFonts]
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}
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return size;
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}
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} // namespace woff2
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