Add a Version class and matching unit tests, roughly based on chrome/installe...

base/version.cc

+// Copyright (c) 2009 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 <vector>
+
+#include "base/string_util.h"
+#include "base/version.h"
+
+// static
+Version* Version::GetVersionFromString(const std::wstring& version_str) {
+  if (!IsStringASCII(version_str))
+    return NULL;
+  return GetVersionFromString(WideToASCII(version_str));
+}
+
+// static
+Version* Version::GetVersionFromString(const std::string& version_str) {
+  Version* vers = new Version();
+  if (vers->InitFromString(version_str))
+    return vers;
+  delete vers;
+  return NULL;
+}
+
+bool Version::Equals(const Version& that) const {
+  return CompareTo(that) == 0;
+}
+
+int Version::CompareTo(const Version& other) const {
+  std::vector<uint16> other_components = other.components();
+  size_t count = std::min(components_.size(), other_components.size());
+  for (size_t i = 0; i < count; ++i) {
+    if (components_[i] > other_components[i])
+      return 1;
+    if (components_[i] < other_components[i])
+      return -1;
+  }
+  if (components_.size() > other_components.size()) {
+    for (size_t i = count; i < components_.size(); ++i)
+      if (components_[i] > 0)
+        return 1;
+  } else if (components_.size() < other_components.size()) {
+    for (size_t i = count; i < other_components.size(); ++i)
+      if (other_components[i] > 0)
+        return -1;
+  }
+  return 0;
+}
+
+const std::string Version::GetString() const {
+  std::string version_str;
+  int count = components_.size();
+  for (int i = 0; i < count - 1; ++i) {
+    version_str.append(IntToString(components_[i]));
+    version_str.append(".");
+  }
+  version_str.append(IntToString(components_[count - 1]));
+  return version_str;
+}
+
+bool Version::InitFromString(const std::string& version_str) {
+  std::vector<std::string> numbers;
+  SplitString(version_str, '.', &numbers);
+  for (std::vector<std::string>::iterator i = numbers.begin(); 
+       i != numbers.end(); ++i) {
+    int num;
+    if (!StringToInt(*i, &num))
+      return false;
+    if (num < 0)
+      return false;
+    const uint16 max = 0xFFFF;
+    if (num > max)
+      return false;
+    // This throws out things like +3, or 032.
+    if (IntToString(num) != *i)
+      return false;
+    uint16 component = static_cast<uint16>(num);
+    components_.push_back(component);
+  }
+  return true;
+}
+