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46 lines
1.4 KiB
46 lines
1.4 KiB
// 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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