Adding upstream version 124.0.1.upstream/124.0.1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 206 insertions, 0 deletions

diff --git a/gfx/2d/SFNTData.cpp b/gfx/2d/SFNTData.cpp
new file mode 100644
index 0000000000..42cf95c33c
--- /dev/null
+++ b/gfx/2d/SFNTData.cpp
@@ -0,0 +1,206 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "SFNTData.h"
+
+#include <algorithm>
+#include <numeric>
+
+#include "BigEndianInts.h"
+#include "Logging.h"
+#include "mozilla/HashFunctions.h"
+#include "mozilla/Span.h"
+
+namespace mozilla {
+namespace gfx {
+
+#define TRUETYPE_TAG(a, b, c, d) ((a) << 24 | (b) << 16 | (c) << 8 | (d))
+
+#pragma pack(push, 1)
+
+struct TTCHeader {
+  BigEndianUint32 ttcTag;   // Always 'ttcf'
+  BigEndianUint32 version;  // Fixed, 0x00010000
+  BigEndianUint32 numFonts;
+};
+
+struct OffsetTable {
+  BigEndianUint32 sfntVersion;  // Fixed, 0x00010000 for version 1.0.
+  BigEndianUint16 numTables;
+  BigEndianUint16 searchRange;    // (Maximum power of 2 <= numTables) x 16.
+  BigEndianUint16 entrySelector;  // Log2(maximum power of 2 <= numTables).
+  BigEndianUint16 rangeShift;     // NumTables x 16-searchRange.
+};
+
+struct TableDirEntry {
+  BigEndianUint32 tag;       // 4 -byte identifier.
+  BigEndianUint32 checkSum;  // CheckSum for this table.
+  BigEndianUint32 offset;    // Offset from beginning of TrueType font file.
+  BigEndianUint32 length;    // Length of this table.
+
+  friend bool operator<(const TableDirEntry& lhs, const uint32_t aTag) {
+    return lhs.tag < aTag;
+  }
+};
+
+#pragma pack(pop)
+
+class SFNTData::Font {
+ public:
+  Font(const OffsetTable* aOffsetTable, const uint8_t* aFontData,
+       uint32_t aDataLength)
+      : mFontData(aFontData),
+        mFirstDirEntry(
+            reinterpret_cast<const TableDirEntry*>(aOffsetTable + 1)),
+        mEndOfDirEntries(mFirstDirEntry + aOffsetTable->numTables),
+        mDataLength(aDataLength) {}
+
+  Span<const uint8_t> GetHeadTableBytes() const {
+    const TableDirEntry* dirEntry =
+        GetDirEntry(TRUETYPE_TAG('h', 'e', 'a', 'd'));
+    if (!dirEntry) {
+      gfxWarning() << "Head table entry not found.";
+      return {};
+    }
+
+    return {mFontData + dirEntry->offset, dirEntry->length};
+  }
+
+  Span<const uint8_t> GetCmapTableBytes() const {
+    const TableDirEntry* dirEntry =
+        GetDirEntry(TRUETYPE_TAG('c', 'm', 'a', 'p'));
+    if (!dirEntry) {
+      gfxWarning() << "Cmap table entry not found.";
+      return {};
+    }
+
+    return {mFontData + dirEntry->offset, dirEntry->length};
+  }
+
+ private:
+  const TableDirEntry* GetDirEntry(const uint32_t aTag) const {
+    const TableDirEntry* foundDirEntry =
+        std::lower_bound(mFirstDirEntry, mEndOfDirEntries, aTag);
+
+    if (foundDirEntry == mEndOfDirEntries || foundDirEntry->tag != aTag) {
+      gfxWarning() << "Font data does not contain tag.";
+      return nullptr;
+    }
+
+    if (mDataLength < (foundDirEntry->offset + foundDirEntry->length)) {
+      gfxWarning() << "Font data too short to contain table.";
+      return nullptr;
+    }
+
+    return foundDirEntry;
+  }
+
+  const uint8_t* mFontData;
+  const TableDirEntry* mFirstDirEntry;
+  const TableDirEntry* mEndOfDirEntries;
+  uint32_t mDataLength;
+};
+
+/* static */
+UniquePtr<SFNTData> SFNTData::Create(const uint8_t* aFontData,
+                                     uint32_t aDataLength) {
+  MOZ_ASSERT(aFontData);
+
+  // Check to see if this is a font collection.
+  if (aDataLength < sizeof(TTCHeader)) {
+    gfxWarning() << "Font data too short.";
+    return nullptr;
+  }
+
+  const TTCHeader* ttcHeader = reinterpret_cast<const TTCHeader*>(aFontData);
+  if (ttcHeader->ttcTag == TRUETYPE_TAG('t', 't', 'c', 'f')) {
+    uint32_t numFonts = ttcHeader->numFonts;
+    if (aDataLength <
+        sizeof(TTCHeader) + (numFonts * sizeof(BigEndianUint32))) {
+      gfxWarning() << "Font data too short to contain full TTC Header.";
+      return nullptr;
+    }
+
+    UniquePtr<SFNTData> sfntData(new SFNTData);
+    const BigEndianUint32* offset =
+        reinterpret_cast<const BigEndianUint32*>(aFontData + sizeof(TTCHeader));
+    const BigEndianUint32* endOfOffsets = offset + numFonts;
+    while (offset != endOfOffsets) {
+      if (!sfntData->AddFont(aFontData, aDataLength, *offset)) {
+        return nullptr;
+      }
+      ++offset;
+    }
+
+    return sfntData;
+  }
+
+  UniquePtr<SFNTData> sfntData(new SFNTData);
+  if (!sfntData->AddFont(aFontData, aDataLength, 0)) {
+    return nullptr;
+  }
+
+  return sfntData;
+}
+
+/* static */
+uint64_t SFNTData::GetUniqueKey(const uint8_t* aFontData, uint32_t aDataLength,
+                                uint32_t aVarDataSize, const void* aVarData) {
+  uint64_t hash = 0;
+  UniquePtr<SFNTData> sfntData = SFNTData::Create(aFontData, aDataLength);
+  if (sfntData) {
+    hash = sfntData->HashHeadAndCmapTables();
+  } else {
+    gfxWarning() << "Failed to create SFNTData from data, hashing whole font.";
+    hash = HashBytes(aFontData, aDataLength);
+  }
+
+  if (aVarDataSize) {
+    hash = AddToHash(hash, HashBytes(aVarData, aVarDataSize));
+  }
+
+  return hash << 32 | aDataLength;
+}
+
+SFNTData::~SFNTData() {
+  for (size_t i = 0; i < mFonts.length(); ++i) {
+    delete mFonts[i];
+  }
+}
+
+bool SFNTData::AddFont(const uint8_t* aFontData, uint32_t aDataLength,
+                       uint32_t aOffset) {
+  uint32_t remainingLength = aDataLength - aOffset;
+  if (remainingLength < sizeof(OffsetTable)) {
+    gfxWarning() << "Font data too short to contain OffsetTable " << aOffset;
+    return false;
+  }
+
+  const OffsetTable* offsetTable =
+      reinterpret_cast<const OffsetTable*>(aFontData + aOffset);
+  if (remainingLength <
+      sizeof(OffsetTable) + (offsetTable->numTables * sizeof(TableDirEntry))) {
+    gfxWarning() << "Font data too short to contain tables.";
+    return false;
+  }
+
+  return mFonts.append(new Font(offsetTable, aFontData, aDataLength));
+}
+
+uint32_t SFNTData::HashHeadAndCmapTables() {
+  uint32_t tablesHash = std::accumulate(
+      mFonts.begin(), mFonts.end(), 0U, [](uint32_t hash, Font* font) {
+        Span<const uint8_t> headBytes = font->GetHeadTableBytes();
+        hash = AddToHash(hash, HashBytes(headBytes.data(), headBytes.size()));
+        Span<const uint8_t> cmapBytes = font->GetCmapTableBytes();
+        return AddToHash(hash, HashBytes(cmapBytes.data(), cmapBytes.size()));
+      });
+
+  return tablesHash;
+}
+
+}  // namespace gfx
+}  // namespace mozilla