[codeview] Move StreamInterface and StreamReader to libcodeview.

We have need to reuse this functionality, including making
additional generic stream types that are smarter about how and
when they copy memory versus referencing the original memory.
So all of these structures belong in the common library
rather than being pdb specific.

llvm-svn: 270751

1 files changed, 72 insertions, 0 deletions

diff --git a/llvm/lib/DebugInfo/CodeView/ByteStream.cpp b/llvm/lib/DebugInfo/CodeView/ByteStream.cpp
new file mode 100644
index 00000000000..879343afbfd
--- /dev/null
+++ b/llvm/lib/DebugInfo/CodeView/ByteStream.cpp
@@ -0,0 +1,72 @@
+//===- ByteStream.cpp - Reads stream data from a byte sequence ------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/DebugInfo/CodeView/ByteStream.h"
+#include "llvm/DebugInfo/CodeView/CodeViewError.h"
+#include "llvm/DebugInfo/CodeView/StreamReader.h"
+#include <cstring>
+
+using namespace llvm;
+using namespace llvm::codeview;
+
+ByteStream::ByteStream() {}
+
+ByteStream::ByteStream(MutableArrayRef<uint8_t> Bytes) { initialize(Bytes); }
+
+ByteStream::ByteStream(uint32_t Length) { initialize(Length); }
+
+ByteStream::~ByteStream() { reset(); }
+
+void ByteStream::reset() {
+  Ownership.reset();
+  Data = MutableArrayRef<uint8_t>();
+}
+
+void ByteStream::initialize(MutableArrayRef<uint8_t> Bytes) {
+  reset();
+  Data = Bytes;
+}
+
+void ByteStream::initialize(uint32_t Length) {
+  reset();
+  if (Length > 0)
+    Data = MutableArrayRef<uint8_t>(new uint8_t[Length], Length);
+  Ownership.reset(Data.data());
+}
+
+Error ByteStream::initialize(StreamReader &Reader, uint32_t Length) {
+  initialize(Length);
+  auto EC = Reader.readBytes(Data);
+  if (EC)
+    reset();
+  return EC;
+}
+
+Error ByteStream::readBytes(uint32_t Offset,
+                            MutableArrayRef<uint8_t> Buffer) const {
+  if (Data.size() < Buffer.size() + Offset)
+    return make_error<CodeViewError>(cv_error_code::insufficient_buffer);
+  ::memcpy(Buffer.data(), Data.data() + Offset, Buffer.size());
+  return Error::success();
+}
+
+Error ByteStream::getArrayRef(uint32_t Offset, ArrayRef<uint8_t> &Buffer,
+                              uint32_t Length) const {
+  if (Data.size() < Length + Offset)
+    return make_error<CodeViewError>(cv_error_code::insufficient_buffer);
+  Buffer = Data.slice(Offset, Length);
+  return Error::success();
+}
+
+uint32_t ByteStream::getLength() const { return Data.size(); }
+
+StringRef ByteStream::str() const {
+  const char *CharData = reinterpret_cast<const char *>(Data.data());
+  return StringRef(CharData, Data.size());
+}