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net/quic/quic_data_reader.cc

Index: net/quic/quic_data_reader.cc
diff --git a/net/quic/quic_data_reader.cc b/net/quic/quic_data_reader.cc
new file mode 100644
index 0000000000000000000000000000000000000000..263bafba72ec42e1c6a0f634bdff928230df4f3c
--- /dev/null
+++ b/net/quic/quic_data_reader.cc
@@ -0,0 +1,173 @@
+// Copyright (c) 2012 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 "net/quic/quic_data_reader.h"
+
+using base::StringPiece;
+
+namespace net {
+
+QuicDataReader::QuicDataReader(const char* data, const size_t len)
+    : data_(data),
+      len_(len),
+      pos_(0) {
+}
+
+bool QuicDataReader::ReadUInt16(uint16* result) {
+  // Make sure that we have the whole uint16.
+  // TODO(rch): use sizeof instead of magic numbers.
+  // Refactor to use a common Read(void* buffer, size_t len)
+  // method that will do the memcpy and the advancement of pos_.
+  if (!CanRead(2)) {
+    OnFailure();
+    return false;
+  }
+
+  // Read into result.
+  memcpy(result, data_ + pos_, 2);
+
+  // Iterate.
+  pos_ += 2;
+
+  return true;
+}
+
+bool QuicDataReader::ReadUInt32(uint32* result) {
+  // Make sure that we have the whole uint32.
+  if (!CanRead(4)) {
+    OnFailure();
+    return false;
+  }
+
+  // Read into result.
+  memcpy(result, data_ + pos_, 4);
+
+  // Iterate.
+  pos_ += 4;
+
+  return true;
+}
+
+bool QuicDataReader::ReadUInt48(uint64* result) {
+  uint32 lo;
+  if (!ReadUInt32(&lo)) {
+    return false;
+  }
+
+  uint16 hi;
+  if (!ReadUInt16(&hi)) {
+    return false;
+  }
+
+  *result = hi;
+  *result <<= 32;
+  *result += lo;
+
+  return true;
+}
+
+bool QuicDataReader::ReadUInt64(uint64* result) {
+  // Make sure that we have the whole uint64.
+  if (!CanRead(8)) {
+    OnFailure();
+    return false;
+  }
+
+  // Read into result.
+  memcpy(result, data_ + pos_, 8);
+
+  // Iterate.
+  pos_ += 8;
+
+  return true;
+}
+
+bool QuicDataReader::ReadUInt128(uint128* result) {
+  uint64 high_hash;
+  uint64 low_hash;
+
+  if (!ReadUInt64(&low_hash)) {
+    return false;
+  }
+  if (!ReadUInt64(&high_hash)) {
+    return false;
+  }
+
+  *result = uint128(high_hash, low_hash);
+  return true;
+}
+
+bool QuicDataReader::ReadStringPiece16(StringPiece* result) {
+  // Read resultant length.
+  uint16 result_len;
+  if (!ReadUInt16(&result_len)) {
+    // OnFailure() already called.
+    return false;
+  }
+
+  return ReadStringPiece(result, result_len);
+}
+
+bool QuicDataReader::ReadBytes(void* result, size_t size) {
+  // Make sure that we have enough data to read.
+  if (!CanRead(size)) {
+    OnFailure();
+    return false;
+  }
+
+  // Read into result.
+  memcpy(result, data_ + pos_, size);
+
+  // Iterate.
+  pos_ += size;
+
+  return true;
+}
+
+
+bool QuicDataReader::ReadStringPiece(StringPiece* result, size_t size) {
+  // Make sure that we have enough data to read.
+  if (!CanRead(size)) {
+    OnFailure();
+    return false;
+  }
+
+  // Set result.
+  result->set(data_ + pos_, size);
+
+  // Iterate.
+  pos_ += size;
+
+  return true;
+}
+
+StringPiece QuicDataReader::PeekRemainingPayload() {
+  return StringPiece(data_ + pos_, len_ - pos_);
+}
+
+StringPiece QuicDataReader::ReadRemainingPayload() {
+  StringPiece payload = PeekRemainingPayload();
+  pos_ = len_;
+  return payload;
+}
+
+bool QuicDataReader::IsDoneReading() const {
+  return len_ == pos_;
+}
+
+size_t QuicDataReader::BytesRemaining() const {
+  return len_ - pos_;
+}
+
+bool QuicDataReader::CanRead(size_t bytes) const {
+  return bytes <= (len_ - pos_);
+}
+
+void QuicDataReader::OnFailure() {
+  // Set our iterator to the end of the buffer so that further reads fail
+  // immediately.
+  pos_ = len_;
+}
+
+}  // namespace net