1 files changed, 69 insertions, 0 deletions
diff --git a/rel32_utils.cc b/rel32_utils.cc
new file mode 100644
index 0000000..fa59386
--- /dev/null
+++ b/rel32_utils.cc
@@ -0,0 +1,69 @@
+// Copyright 2017 The Chromium 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 "components/zucchini/rel32_utils.h"
+
+#include <algorithm>
+
+#include "base/logging.h"
+#include "components/zucchini/io_utils.h"
+
+namespace zucchini {
+
+/******** Rel32ReaderX86 ********/
+
+Rel32ReaderX86::Rel32ReaderX86(ConstBufferView image,
+                               offset_t lo,
+                               offset_t hi,
+                               const std::vector<offset_t>* locations,
+                               const AddressTranslator& translator)
+    : image_(image),
+      target_rva_to_offset_(translator),
+      location_offset_to_rva_(translator),
+      hi_(hi),
+      last_(locations->end()) {
+  DCHECK_LE(lo, image.size());
+  DCHECK_LE(hi, image.size());
+  current_ = std::lower_bound(locations->begin(), locations->end(), lo);
+}
+
+Rel32ReaderX86::~Rel32ReaderX86() = default;
+
+base::Optional<Reference> Rel32ReaderX86::GetNext() {
+  while (current_ < last_ && *current_ < hi_) {
+    offset_t loc_offset = *(current_++);
+    DCHECK_LE(loc_offset + 4, image_.size());  // Sanity check.
+    rva_t loc_rva = location_offset_to_rva_.Convert(loc_offset);
+    rva_t target_rva = loc_rva + 4 + image_.read<int32_t>(loc_offset);
+    offset_t target_offset = target_rva_to_offset_.Convert(target_rva);
+    // In rare cases, the most significant bit of |target| is set. This
+    // interferes with label marking. We expect these to already be filtered out
+    // from |locations|.
+    DCHECK(!IsMarked(target_offset));
+    return Reference{loc_offset, target_offset};
+  }
+  return base::nullopt;
+}
+
+/******** Rel32ReceptorX86 ********/
+
+Rel32WriterX86::Rel32WriterX86(MutableBufferView image,
+                               const AddressTranslator& translator)
+    : image_(image),
+      target_offset_to_rva_(translator),
+      location_offset_to_rva_(translator) {}
+
+Rel32WriterX86::~Rel32WriterX86() = default;
+
+void Rel32WriterX86::PutNext(Reference ref) {
+  rva_t target_rva = target_offset_to_rva_.Convert(ref.target);
+  rva_t loc_rva = location_offset_to_rva_.Convert(ref.location);
+
+  // Subtraction underflow is okay
+  uint32_t code =
+      static_cast<uint32_t>(target_rva) - (static_cast<uint32_t>(loc_rva) + 4);
+  image_.write<uint32_t>(ref.location, code);
+}
+
+}  // namespace zucchini