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// Copyright 2013 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.
//
// Helpers common across multiple parts of woff2
#include <algorithm>
#include "./woff2_common.h"
namespace woff2 {
uint32_t ComputeULongSum(const uint8_t* buf, size_t size) {
uint32_t checksum = 0;
size_t aligned_size = size & ~3;
for (size_t i = 0; i < aligned_size; i += 4) {
#if (defined(__BYTE_ORDER__) && (__BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__))
uint32_t v = *reinterpret_cast<const uint32_t*>(buf + i);
checksum += (((v & 0xFF) << 24) | ((v & 0xFF00) << 8) |
((v & 0xFF0000) >> 8) | ((v & 0xFF000000) >> 24));
#elif (defined(__BYTE_ORDER__) && (__BYTE_ORDER__ == __ORDER_BIG_ENDIAN__))
checksum += *reinterpret_cast<const uint32_t*>(buf + i);
#else
checksum += (buf[i] << 24) | (buf[i + 1] << 16) |
(buf[i + 2] << 8) | buf[i + 3];
#endif
}
// treat size not aligned on 4 as if it were padded to 4 with 0's
if (size != aligned_size) {
uint32_t v = 0;
for (size_t i = aligned_size; i < size; ++i) {
v |= buf[i] << (24 - 8 * (i & 3));
}
checksum += v;
}
return checksum;
}
size_t CollectionHeaderSize(uint32_t header_version, uint32_t num_fonts) {
size_t 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;
}
} // namespace woff2
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