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-rw-r--r--modules/woff2/src/woff2_common.cc65
1 files changed, 65 insertions, 0 deletions
diff --git a/modules/woff2/src/woff2_common.cc b/modules/woff2/src/woff2_common.cc
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index 000000000..9dc7cbd5c
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+++ b/modules/woff2/src/woff2_common.cc
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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) {
+ uint32_t v;
+ memcpy(&v, buf + i, 4);
+#if (defined(__BYTE_ORDER__) && (__BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__))
+ checksum += (((v & 0xFF) << 24) | ((v & 0xFF00) << 8) |
+ ((v & 0xFF0000) >> 8) | ((v & 0xFF000000) >> 24));
+#elif (defined(__BYTE_ORDER__) && (__BYTE_ORDER__ == __ORDER_BIG_ENDIAN__))
+ checksum += v;
+#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