Implemented UriBeacon decoder.

Specifications of UriBeacon:
https://github.com/google/uribeacon/tree/master/specification

Here's the description of the encoding of UriBeacon:
https://github.com/google/uribeacon/blob/master/specification/AdvertisingMode.md

Review URL: https://codereview.chromium.org/950083003

Cr-Commit-Position: refs/heads/master@{#322187}

device/bluetooth/BUILD.gn

@@ -103,6 +103,8 @@ component("bluetooth") {
     "bluetooth_task_manager_win.h",
     "bluetooth_uuid.cc",
     "bluetooth_uuid.h",
+    "uribeacon/uri_encoder.cc",
+    "uribeacon/uri_encoder.h",
   ]
 
   defines = [ "DEVICE_BLUETOOTH_IMPLEMENTATION" ]

device/bluetooth/bluetooth.gyp

@@ -106,6 +106,8 @@
         'bluetooth_task_manager_win.h',
         'bluetooth_uuid.cc',
         'bluetooth_uuid.h',
+        'uribeacon/uri_encoder.cc',
+        'uribeacon/uri_encoder.h',
       ],
       'conditions': [
         ['chromeos==1', {

device/bluetooth/uribeacon/uri_encoder.cc

+// Copyright 2015 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 "uri_encoder.h"
+
+using base::StringPiece;
+
+namespace {
+
+struct expansion {
+  uint8_t code;
+  const char* value;
+};
+
+// The two following data structures are the expansions code tables for URI
+// encoding described in the following specification:
+// https://github.com/google/uribeacon/blob/master/specification/AdvertisingMode.md
+
+// For the prefix of the URI.
+struct expansion prefix_expansions_list[] = {
+    {0, "http://www."},
+    {1, "https://www."},
+    {2, "http://"},
+    {3, "https://"},
+    {4, "urn:uuid:"},
+};
+
+// For the remaining part of the URI.
+struct expansion expansions_list[] = {
+    {0, ".com/"},
+    {1, ".org/"},
+    {2, ".edu/"},
+    {3, ".net/"},
+    {4, ".info/"},
+    {5, ".biz/"},
+    {6, ".gov/"},
+    {7, ".com"},
+    {8, ".org"},
+    {9, ".edu"},
+    {10, ".net"},
+    {11, ".info"},
+    {12, ".biz"},
+    {13, ".gov"},
+};
+
+struct expansion* CommonLookupExpansionByValue(struct expansion* table,
+                                               int table_length,
+                                               const std::string& input,
+                                               int input_index) {
+  int found = -1;
+  int found_length = -1;
+
+  for (int k = 0; k < table_length; k++) {
+    const char* value = table[k].value;
+    int len = static_cast<int>(strlen(table[k].value));
+    if (input_index + len <= static_cast<int>(input.size())) {
+      if (len > found_length && strncmp(&input[input_index], value, len) == 0) {
+        found = k;
+        found_length = len;
+      }
+    }
+  }
+  if (found == -1)
+    return NULL;
+  return &table[found];
+}
+
+struct expansion* LookupExpansionByValue(const std::string& input,
+                                         int input_index) {
+  return CommonLookupExpansionByValue(
+      expansions_list, arraysize(expansions_list), input, input_index);
+}
+
+struct expansion* LookupPrefixExpansionByValue(const std::string& input,
+                                               int input_index) {
+  return CommonLookupExpansionByValue(prefix_expansions_list,
+                                      arraysize(prefix_expansions_list), input,
+                                      input_index);
+}
+
+struct expansion* LookupExpansionByCode(const std::vector<uint8_t>& input,
+                                        int input_index) {
+  if (input[input_index] >= arraysize(expansions_list))
+    return NULL;
+  return &expansions_list[input[input_index]];
+}
+
+struct expansion* LookupPrefixExpansionByCode(const std::vector<uint8_t>& input,
+                                              int input_index) {
+  if (input[input_index] >= arraysize(prefix_expansions_list))
+    return NULL;
+  return &prefix_expansions_list[input[input_index]];
+}
+
+}  // namespace
+
+void device::EncodeUriBeaconUri(const std::string& input,
+                                std::vector<uint8_t>& output) {
+  int i = 0;
+  while (i < static_cast<int>(input.size())) {
+    struct expansion* exp;
+    if (i == 0)
+      exp = LookupPrefixExpansionByValue(input, i);
+    else
+      exp = LookupExpansionByValue(input, i);
+    if (exp == NULL) {
+      output.push_back(static_cast<uint8_t>(input[i]));
+      i++;
+    } else {
+      output.push_back(exp->code);
+      i += static_cast<int>(strlen(exp->value));
+    }
+  }
+}
+
+void device::DecodeUriBeaconUri(const std::vector<uint8_t>& input,
+                                std::string& output) {
+  int length = static_cast<int>(input.size());
+  for (int i = 0; i < length; i++) {
+    struct expansion* exp;
+    if (i == 0)
+      exp = LookupPrefixExpansionByCode(input, i);
+    else
+      exp = LookupExpansionByCode(input, i);
+    if (exp == NULL)
+      output.push_back(static_cast<char>(input[i]));
+    else
+      output.append(exp->value);
+  }
+}

device/bluetooth/uribeacon/uri_encoder.h

+// Copyright 2015 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.
+
+#ifndef DEVICE_BLUETOOTH_URIBEACON_URI_ENCODER_H_
+#define DEVICE_BLUETOOTH_URIBEACON_URI_ENCODER_H_
+
+#include <string>
+#include <vector>
+
+#include "base/strings/string_piece.h"
+
+namespace device {
+
+// The following functions EncodeUriBeaconUri() and DecodeUriBeaconUri() helps
+// encoding/decoding URI with the UriBeacon encoding.
+//
+// Example usage:
+//
+//   std::vector<uint8_t> encoded;
+//   EncodeUriBeaconUri("http://web.mit.edu/", encoded)
+//   // encoded -> {2, 'w', 'e', 'b', '.', 'm', 'i', 't', 2}
+//
+//   const char encodedUri[] = {0, 'u', 'r', 'i', 'b', 'e', 'a', 'c', 'o', 'n',
+//       8};
+//   const std::vector<uint8_t> kEncodedUri(encodedUri, encodedUri +
+//   sizeof(encodedUri));
+//   std::string decoded;
+//   DecodeUriBeaconUri(kEncodedUri, decoded)
+//   // decoded -> "http://uribeacon.org"
+
+// Encodes the input string using URI encoding described in UriBeacon
+// specifications. |input| must be ASCII characters.
+void EncodeUriBeaconUri(const std::string& input, std::vector<uint8_t>& output);
+
+// Decodes the input string using URI encoding described in UriBeacon
+// specifications.
+void DecodeUriBeaconUri(const std::vector<uint8_t>& input, std::string& output);
+
+}  // namespace device
+
+#endif

device/bluetooth/uribeacon/uri_encoder_unittest.cc

+// Copyright 2015 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 "device/bluetooth/uribeacon/uri_encoder.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace device {
+
+TEST(UriEncoderTest, Url1) {
+  const std::string kUri = "http://123.com";
+  const char encoded_uri[] = {2, '1', '2', '3', 7};
+  const std::vector<uint8_t> kEncodedUri(encoded_uri,
+                                         encoded_uri + sizeof(encoded_uri));
+
+  std::vector<uint8_t> encoded;
+  std::string decoded;
+
+  EncodeUriBeaconUri(kUri, encoded);
+  EXPECT_EQ(kEncodedUri, encoded);
+
+  DecodeUriBeaconUri(encoded, decoded);
+  EXPECT_EQ(kUri, decoded);
+}
+
+TEST(UriEncoderTest, Url2) {
+  const std::string kUri = "http://www.abcdefghijklmnop.org";
+  const char encoded_uri[] = {
+      0, 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n',
+      'o', 'p', 8};
+  const std::vector<uint8_t> kEncodedUri(encoded_uri,
+                                         encoded_uri + sizeof(encoded_uri));
+
+  std::vector<uint8_t> encoded;
+  std::string decoded;
+
+  EncodeUriBeaconUri(kUri, encoded);
+  EXPECT_EQ(kEncodedUri, encoded);
+
+  DecodeUriBeaconUri(encoded, decoded);
+  EXPECT_EQ(kUri, decoded);
+}
+
+TEST(UriEncoderTest, Url3) {
+  const std::string kUri = "https://123.com/123";
+  const char encoded_uri[] = {3, '1', '2', '3', 0, '1', '2', '3'};
+  const std::vector<uint8_t> kEncodedUri(encoded_uri,
+                                         encoded_uri + sizeof(encoded_uri));
+
+  std::vector<uint8_t> encoded;
+  std::string decoded;
+
+  EncodeUriBeaconUri(kUri, encoded);
+  EXPECT_EQ(kEncodedUri, encoded);
+
+  DecodeUriBeaconUri(encoded, decoded);
+  EXPECT_EQ(kUri, decoded);
+}
+
+TEST(UriEncoderTest, Url4) {
+  const std::string kUri = "http://www.uribeacon.org";
+  const char encoded_uri[] = {
+      0, 'u', 'r', 'i', 'b', 'e', 'a', 'c', 'o', 'n', 8};
+  const std::vector<uint8_t> kEncodedUri(encoded_uri,
+                                         encoded_uri + sizeof(encoded_uri));
+
+  std::vector<uint8_t> encoded;
+  std::string decoded;
+
+  EncodeUriBeaconUri(kUri, encoded);
+  EXPECT_EQ(kEncodedUri, encoded);
+
+  DecodeUriBeaconUri(encoded, decoded);
+  EXPECT_EQ(kUri, decoded);
+}
+
+TEST(UriEncoderTest, Url5) {
+  const std::string kUri = "http://web.mit.edu/";
+  const char encoded_uri[] = {2, 'w', 'e', 'b', '.', 'm', 'i', 't', 2};
+  const std::vector<uint8_t> kEncodedUri(encoded_uri,
+                                         encoded_uri + sizeof(encoded_uri));
+
+  std::vector<uint8_t> encoded;
+  std::string decoded;
+
+  EncodeUriBeaconUri(kUri, encoded);
+  EXPECT_EQ(kEncodedUri, encoded);
+
+  DecodeUriBeaconUri(encoded, decoded);
+  EXPECT_EQ(kUri, decoded);
+}
+
+}  // namespace device