1 files changed, 159 insertions, 0 deletions
diff --git a/gfx/ots/src/sill.cc b/gfx/ots/src/sill.cc
new file mode 100644
index 000000000..c7b20a980
--- /dev/null
+++ b/gfx/ots/src/sill.cc
@@ -0,0 +1,159 @@
+// Copyright (c) 2009-2017 The OTS Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "sill.h"
+
+#include "feat.h"
+#include <cmath>
+#include <unordered_set>
+
+namespace ots {
+
+bool OpenTypeSILL::Parse(const uint8_t* data, size_t length) {
+  if (GetFont()->dropped_graphite) {
+    return Drop("Skipping Graphite table");
+  }
+  Buffer table(data, length);
+
+  if (!table.ReadU32(&this->version) || this->version >> 16 != 1) {
+    return Drop("Failed to read valid version");
+  }
+  if (!table.ReadU16(&this->numLangs)) {
+    return Drop("Failed to read numLangs");
+  }
+
+  // The following three fields are deprecated and ignored. We fix them up here
+  // just for internal consistency, but the Graphite engine doesn't care.
+  if (!table.ReadU16(&this->searchRange) ||
+      !table.ReadU16(&this->entrySelector) ||
+      !table.ReadU16(&this->rangeShift)) {
+    return Drop("Failed to read searchRange..rangeShift");
+  }
+  if (this->numLangs == 0) {
+    if (this->searchRange != 0 || this->entrySelector != 0 || this->rangeShift != 0) {
+      this->searchRange = this->entrySelector = this->rangeShift = 0;
+    }
+  } else {
+    unsigned floorLog2 = std::floor(std::log2(this->numLangs));
+    if (this->searchRange != (unsigned)std::pow(2, floorLog2) ||
+        this->entrySelector != floorLog2 ||
+        this->rangeShift != this->numLangs - this->searchRange) {
+      this->searchRange = (unsigned)std::pow(2, floorLog2);
+      this->entrySelector = floorLog2;
+      this->rangeShift = this->numLangs - this->searchRange;
+    }
+  }
+
+  std::unordered_set<size_t> unverified;
+  //this->entries.resize(static_cast<unsigned long>(this->numLangs) + 1, this);
+  for (unsigned long i = 0; i <= this->numLangs; ++i) {
+    this->entries.emplace_back(this);
+    LanguageEntry& entry = this->entries[i];
+    if (!entry.ParsePart(table)) {
+      return Drop("Failed to read entries[%u]", i);
+    }
+    for (unsigned j = 0; j < entry.numSettings; ++j) {
+      size_t offset = entry.offset + j * 8;
+      if (offset < entry.offset || offset > length) {
+        return DropGraphite("Invalid LangFeatureSetting offset %zu/%zu",
+                            offset, length);
+      }
+      unverified.insert(offset);
+        // need to verify that this LanguageEntry points to valid
+        // LangFeatureSetting
+    }
+  }
+
+  while (table.remaining()) {
+    unverified.erase(table.offset());
+    LangFeatureSetting setting(this);
+    if (!setting.ParsePart(table)) {
+      return Drop("Failed to read a LangFeatureSetting");
+    }
+    settings.push_back(setting);
+  }
+
+  if (!unverified.empty()) {
+    return Drop("%zu incorrect offsets into settings", unverified.size());
+  }
+  if (table.remaining()) {
+    return Warning("%zu bytes unparsed", table.remaining());
+  }
+  return true;
+}
+
+bool OpenTypeSILL::Serialize(OTSStream* out) {
+  if (!out->WriteU32(this->version) ||
+      !out->WriteU16(this->numLangs) ||
+      !out->WriteU16(this->searchRange) ||
+      !out->WriteU16(this->entrySelector) ||
+      !out->WriteU16(this->rangeShift) ||
+      !SerializeParts(this->entries, out) ||
+      !SerializeParts(this->settings, out)) {
+    return Error("Failed to write table");
+  }
+  return true;
+}
+
+bool OpenTypeSILL::LanguageEntry::ParsePart(Buffer& table) {
+  if (!table.ReadU8(&this->langcode[0]) ||
+      !table.ReadU8(&this->langcode[1]) ||
+      !table.ReadU8(&this->langcode[2]) ||
+      !table.ReadU8(&this->langcode[3])) {
+    return parent->Error("LanguageEntry: Failed to read langcode");
+  }
+  if (!table.ReadU16(&this->numSettings)) {
+    return parent->Error("LanguageEntry: Failed to read numSettings");
+  }
+  if (!table.ReadU16(&this->offset)) {
+    return parent->Error("LanguageEntry: Failed to read offset");
+  }
+  return true;
+}
+
+bool OpenTypeSILL::LanguageEntry::SerializePart(OTSStream* out) const {
+  if (!out->WriteU8(this->langcode[0]) ||
+      !out->WriteU8(this->langcode[1]) ||
+      !out->WriteU8(this->langcode[2]) ||
+      !out->WriteU8(this->langcode[3]) ||
+      !out->WriteU16(this->numSettings) ||
+      !out->WriteU16(this->offset)) {
+    return parent->Error("LanguageEntry: Failed to write");
+  }
+  return true;
+}
+
+bool OpenTypeSILL::LangFeatureSetting::ParsePart(Buffer& table) {
+  OpenTypeFEAT* feat = static_cast<OpenTypeFEAT*>(
+      parent->GetFont()->GetTypedTable(OTS_TAG_FEAT));
+  if (!feat) {
+    return parent->Error("FeatureDefn: Required Feat table is missing");
+  }
+
+  if (!table.ReadU32(&this->featureId) ||
+      !feat->IsValidFeatureId(this->featureId)) {
+    return parent->Error("LangFeatureSetting: Failed to read valid featureId");
+  }
+  if (!table.ReadS16(&this->value)) {
+    return parent->Error("LangFeatureSetting: Failed to read value");
+  }
+  if (!table.ReadU16(&this->reserved)) {
+    return parent->Error("LangFeatureSetting: Failed to read reserved");
+  }
+  if (this->reserved != 0) {
+    parent->Warning("LangFeatureSetting: Nonzero reserved");
+  }
+  return true;
+}
+
+bool OpenTypeSILL::LangFeatureSetting::SerializePart(OTSStream* out) const {
+  if (!out->WriteU32(this->featureId) ||
+      !out->WriteS16(this->value) ||
+      !out->WriteU16(this->reserved)) {
+    return parent->Error("LangFeatureSetting: Failed to read reserved");
+  }
+  return true;
+}
+
+}  // namespace ots