Add Platform Independent Eddystone Encoder

components/physical_web/eddystone/eddystone_encoder.cc

Index: components/physical_web/eddystone/eddystone_encoder.cc
diff --git a/components/physical_web/eddystone/eddystone_encoder.cc b/components/physical_web/eddystone/eddystone_encoder.cc
new file mode 100644
index 0000000000000000000000000000000000000000..40a6a85c4832fb001209ff8523278c6cfd68c03f
--- /dev/null
+++ b/components/physical_web/eddystone/eddystone_encoder.cc
@@ -0,0 +1,98 @@
+// 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/physical_web/eddystone/eddystone_encoder.h"
+
+#include <string>
+#include <vector>
+
+#include "url/gurl.h"
+
+namespace {
+const char* kPrefixes[] = {"http://www.", "https://www.", "http://",
+                           "https://"};
+const size_t kNumPrefixes = sizeof(kPrefixes) / sizeof(char*);
+
+const char* kSuffixes[] = {".com/", ".org/", ".edu/", ".net/", ".info/",
+                           ".biz/", ".gov/", ".com",  ".org",  ".edu",
+                           ".net",  ".info", ".biz",  ".gov"};
+const size_t kNumSuffixes = sizeof(kSuffixes) / sizeof(char*);
+}
+
+namespace physical_web {
+int EncodeUrl(const std::string& url, std::vector<uint8_t>* encoded_url) {

[mattreynolds, 2017/03/09 22:11:30]

Add a check for encoded_url == NULL.

[iankc, 2017/03/09 23:17:50]

Done.

+  /*
+   * Sanatize url.

[mattreynolds, 2017/03/09 22:11:31]

Sanitize URL.

[iankc, 2017/03/09 23:17:50]

Done.

+   */
+  if (url.empty()) {
+    return -1;

[mattreynolds, 2017/03/09 22:11:31]

Define these error codes as constants in eddystone_encoder.h. Or, consider
combining all errors into one failure code (we could just return a boolean true
for success). It's not clear to me why clients will need to distinguish these
errors, so I suspect we won't lose much by combining them.

[iankc, 2017/03/09 23:17:50]

Done.

+  }
+
+  GURL gurl(url);
+  if (!gurl.is_valid()) {
+    return -2;
+  }
+
+  if (gurl.HostIsIPAddress() || !gurl.SchemeIsHTTPOrHTTPS()) {
+    return -3;
+  }
+
+  /*
+   * Necessary Declarations.
+   */
+  const char* raw_url_position = url.c_str();
+
+  static bool prefix_lengths_loaded = false;

[mattreynolds, 2017/03/09 22:11:30]

How about "lengths_initialized"? (we aren't really loading anything)

[iankc, 2017/03/09 23:17:50]

Done.

+  static size_t prefix_lengths[kNumPrefixes];
+  if (!prefix_lengths_loaded) {
+    for (size_t i = 0; i < kNumPrefixes; i++) {
+      prefix_lengths[i] = strlen(kPrefixes[i]);
+    }
+    prefix_lengths_loaded = true;
+  }
+
+  static bool suffix_lengths_loaded = false;

[mattreynolds, 2017/03/09 22:11:30]

You can use the same bool for both array initializations.

[iankc, 2017/03/09 23:17:50]

Done.

+  static size_t suffix_lengths[kNumSuffixes];
+  if (!suffix_lengths_loaded) {
+    for (size_t i = 0; i < kNumSuffixes; i++) {
+      suffix_lengths[i] = strlen(kSuffixes[i]);
+    }
+    suffix_lengths_loaded = true;
+  }
+  /*
+   * Handle prefix.
+   */
+  for (size_t i = 0; i < kNumPrefixes; i++) {
+    size_t prefix_len = prefix_lengths[i];
+    if (strncmp(raw_url_position, kPrefixes[i], prefix_len) == 0) {
+      encoded_url->push_back(i);
+      raw_url_position += prefix_len;
+      break;
+    }
+  }
+
+  /*
+   * Handle suffixes.
+   */
+  while (*raw_url_position) {
+    /* check for suffix match */
+    size_t i;
+    for (i = 0; i < kNumSuffixes; i++) {
+      size_t suffix_len = suffix_lengths[i];
+      if (strncmp(raw_url_position, kSuffixes[i], suffix_len) == 0) {
+        encoded_url->push_back(i);
+        raw_url_position += suffix_len;
+        break; /* from the for loop for checking against suffixes */
+      }
+    }
+    /* This is the default case where we've got an ordinary character which
+     * doesn't match a suffix. */
+    if (i == kNumSuffixes) {
+      encoded_url->push_back(*raw_url_position++);
+    }
+  }
+
+  return encoded_url->size();
+}
+}